Yes, coops, I mean on the flat - this whole discussion is about tests on the flat. You say 'your bikes must be lower geared or lower powered' - yes they must be - and the effect of that is a lower top speed - exactly what the proposed test is about! So if I have these test results I will have a clue about that - otherwise I won't.

 

Now I can't see how flecs 'figures' can be relevant on the flat - the higher power figure must be for going uphill ? Obviously a bike that goes at 15mph will use loads more power than the same bike at 8mph.

 

Ian I see your point but your bike 1 must be a quite different from bike 2 - probably without gears, with a heavy battery etc ? Naturally you would compare the figures of similar bikes - that both have big wheels and gears and are both designed for efficient pedalling. I wonder if the torq was de-restricted when it won these competitions or not. It will be interesting to see what actually this Torq does on the flat - if it has a high peak power then as it is accelerating this power will be employed at whatever lower revs it happens and it should have a great effect on the 0-100 test don't you think?

 

I am proposing tests on the flat because they are easily repeatble otherwise everybody would have to live next to the same hill. And using the bike on the flat can have simlar demands to hill climbing - when you have high head wind, so the more powerful bike will give you higher speed.

Bike 1 is an Ezee Sprint, 26" wheels, identical battery to the Torq.

Bike 2 as you've guessed is an Ezee Torq

 

The Torq delivers it's peak power at the unusually high speed of about 12 mph, and has virtually no torque under 9 mph hence its poor unassisted performance from a standing start and the need for substantial rider input on steepish hills. Unrestricted speed in still air is 22mph on an absolutely level surface, less on the slightest gradient. Restricted unassisted speed is 16 mph which it will easily maintain over gently undulating terrain due to the fact that the overgeared motor is still in it's peak torque band at this speed.

Edited June 21, 200718 yr by Ian

 

Now I can't see how flecs 'figures' can be relevant on the flat - the higher power figure must be for going uphill ? Obviously a bike that goes at 15mph will use loads more power than the same bike at 8mph.

 

 

Of course, the 8 mph maximum power and torque point is an optimum for hill climbing, but it will also use that 470 watts on full acceleration in your test as it passes through that point. The same for all e-bikes, they'll all hit their maximum as they pass their respective points under full acceleration.

 

The figures were just to illustrate that the maximum power wasn't at 15.5 mph or whatever top speed is on a bike.

 

Certainly less power will be used cruising at 8 mph than at 15 mph, but the differences are very small on the flat in fact, and academic anyway, since no-one is normally going to cruise at 8 mph.

 

Believe me, I am not trying to be awkward, but you still haven't resolved the issue of what is flat. No-one can judge a 2% variation from flat and even 3% is very difficult to discern, but they make a very large difference in bike performance as I've shown, much larger than the difference between mainstream bikes,

 

In fact hardly anywhere is truly plane flat, and that's just one of the reasons why I can't see how the tests can help, since returns would be so suspect, as others have observed too.

 

I treat your suggestion seriously and accordingly I tried four times to time the acceleration on one of my bikes today. Frankly it wasn't possible to accurately time and ensure an exact speed termination point. As an e-bike nears it's maximum the acceleration rate slows, and at takes at laast 1 to 2 seconds to be sure that it's ended. That makes the time cut off point very indeterminate. Add to that the extreme difficulty of operating a stopwatch while riding or watching a digital readout of seconds and I can't see how the results could be in any way reliable. One rider will anticipate the maximum point from prior knowledge of their bike, while another will be a stickler for the test and go by the actual readout on the speedo, a difference of one or two seconds.

 

And of course that brings us to speedos. In my experience well under half of riders ever calibrate theirs, just using them as received with a standard and inaccurate wheel size setting.

 

Sorry Chazpope, but I just can't see it working reliably enough.

.

.

Yes' date=' coops, I mean on the flat - this whole discussion is about tests on the flat.[/quote']

 

There seems to have been some misunderstanding then chazpope, this thread became "Determining electric bike range and hill climbing ability" when it split off from the original Powacycle Salisbury v Powacycle Cambridge? thread after the discussion drifted from the original topic . A little confusing, I know; it seems we've been talking at slightly cross-purposes for much of this thread .

 

As flecc said though, even on the flat the acceleration of a bike is a result of torque so would be some indicator of hill-climb strength anyway.

 

It has already been said many times in this thread that tests will not produce useful results, and the reasons given.

 

For example, in the simple tests you describe, your attempts to achieve consistency do not work:

About 'judging the flat road' - I did propose a solution - do it in both directions and this would cancel the effect of any inperceptible incline and to a certain extent wind' date=' don't you think?[/quote']

flecc had previously said why the non-flat road makes the measurements worthless. Doing the test in both directions does not cancel error from a non-level surface, it increases it: you would be measuring acceleration and hill climb one way, and speed and downhill freewheel ability the other, in both tests. "Charge the battery to full" does not eliminate large likely variation in charge level and capacity depending on battery age & other factors. Errors in measurement of distance and timing are also inevitable.

 

The intended measurements themselves provide little useful information for most people, since they give no quantitative measure of hill-climbing ability, or efficiency of acceleration/speed and hence range; the first test sets out to give an assessment of acceleration, the second top speed.

 

To attempt to control the variables & errors for more useful tests like actual hill-climbing etc. will be even harder, and is largely why this approach has been the subject of much discussion here: I hope this thread settles the matter and prevents much wasted time and effort for no benefit: tests are not a productive way forward.

 

In my earlier post I suggested only 2 tests. I am not at all sure to what extent if you can derive the range from these' date=' I am simply trying to have a discussion about it, far from trying to promote it with pseudo science as some test-sceptics would suggest. [/quote']

 

I can't see any way straightforward way to derive the range from those tests, and certainly not accurately. Even if you were to try to idealise a "range" test and drive constant speed on the flat non-stop, no pedals, it suffers the same problem of too many variables to give accurate results, but it also fails to measure meaningful range (these are the sorts of unrealistic range figures we tend to get from bike makers anyway) since it does nothing to indicate how it is affected by the level and efficiency of the motor's higher power output for gradients and acceleration.

 

The facts have been given and you simply can't discuss facts; I don't recall anyone mentioning pseudo-science, and myself, flecc and Ian have all tried to make clear to you that tests can only produce misleading results at best: its not a matter of us questioning the test approach to getting data, and the results on one bike in one set of conditions are quite possibly useful to the owner - all of us who ride ebikes and gauge their performance do that in our own way - the problem arises when you try to compare apples and oranges i.e. results obtained under different conditions which cannot be fairly compared side-by-side due to inequalities.

 

I hope you can see that even tests which are designed to be so simple that they don't measure anything of much use to the majority of ebikers will not produce accurate results, let alone useful results, and that you save yourself the time & effort of doing a task which can only be misleading to others.

 

At this stage I think it would help the discussion if we had some figures from interested participants.

 

What would achieve the goal of determining electric bike range and hill climbing ability has been said repeatedly in this thread; figures will only serve to mislead and confuse more than many are already.

 

Stuart.

Edited June 22, 200718 yr by coops

In fairness to Chazpope, Stuart, I said pseudo science in response to him saying that top speed was at 200 watts, and was the maximum power of the bike. Clearly both are very far from the truth, though judging from his further postings, I think that wasn't quite what he meant. It seems it might have just been badly expressed and that he meant the maximum power to maintain a bike at a given speed would be at it's highest speed, true of course.

 

I've hit on another problem though Chazpope, which I think would finally kill the acceleration test as a gauge of hill climbing.

 

Here are two bikes from one manufacturer which would invert the results.

 

The eZee Quando would easily win the acceleration test to 15.5 mph when matched against the eZee Chopper, the latter only going to it's maximum which is short of 15 mph, and taking longer to do that.

 

According to your test that makes the Quando the better climber, but it's not. The Chopper outclasses the Quando on steep hills, anything over 12%.

 

How can this happen? Quite simply, the Chopper motor is geared down to lose some speed in favour of hill climbing, making it better in that department. But because of that, so much of it's acceleration band is in the higher motor rev range where the net power available is very rapidly reducing, the more suitably geared Quando motor is the better, the top of it's power curve falling neatly in the middle of the zone of interest and therefore most effectively able to accelerate. To make matters worse, the Quando which your test would indicate was the better climber, only has a single 70" rider gear so cannot cope with the steepest hills, the Chopper has a full 7 speed hub, adding still more to it's hill climb capability. Only a reviewer or experienced commentator can tell someone that sort of thing.

 

Looking back on all the comments, everyone agrees with the theory, but no-one agrees that the tests could reliably tell us anything, carrying them out being riddled with such a gamut of problems and variables.

.

coops yes this discussion is off topic now and really it needs to go under a different name so that other people who would be interested can take part - I started this as a comparison between 2 bikes on the flat, proceeded to propose tests and then someone decided this is a discussion about 'determining range' and changed it. To me this was never about range - it is about choosing a bike based on its pereformance on the flat - which I believe can be measured to an accurate enough degree by an interested cyclist. The heading does not reflect the discussion at all and it should be changed - don't know how.

 

I believe there is a considerable body of ebike buyers who like me will be using the bike for commuting, shopping and other general city use (i.e. not hill climbing) All I care about performance-wise is how fast the bike accelerates and how fast it goes - so these tests would be enough for me to decide where to go. In fact I don't care about range at all - every night I recharge my bike anyway - simply because when the battery is full it goes faster, but that is me.

 

Hill climbing ability is of course important - so there is the valid question - would tests on the flat be indicative of the bikes hill climbing ability ? I believe they would be - because they reflect the bike 'power'. How well that will work is what we are discussing here - and hopefully we will get to the bottom of it, but not without experimentation I think.

 

flecc I feel you are doing 'not the propper version' of test - where you measure the time it takes to get to 100m (not the time it takes to get to top speed) - the second version - where there are 2 tests only is the 'official one' Clicking a stop watch considering you don't even have to pedal at a fixed mark should not be that difficult, also getting some one else to do it can work.

 

re what you say of these 2 bikes - perhaps it would be so - but think of cars - does the 0-60 test reflect the car's handling and genaral ability to go round curves and uphill ? No, but still these tests are very popular. Hill climbing ability on a e-bike will always be a slightly fuzzy subject (because is is always to do with pedalling will always be affected by gears, the exact value of the incline etc.) and I am not saying that the overall enjoyability of a bike as a hill climber can be judged from these tests. However I don't think the tests would be 'misleading' as generallty they will reflect the bikes power which also drives the bike uphill. There may always be exceptions - if some special bike is designed to go up a 10% hill all the time its test would be off but I think not wildly off if you see what I mean.

 

I don't understand what evrybodys issue with non-flat is - if you do the test in both directions as instructed (and obviously take an average of the 2 measurements) the effect of incline would be cancelled wouldn't it?

 

Ian the ez sprint is rated as 350W nominal on non UK sites - this explains its great performance - and this will show in the test. If the Torq really gets to 100m slower than the Sprint then maybe it is less suitable for city use and at traffic lights when you expect not to be pedalling it hard - this will also come out in the tests.

I did look at the test in both senses Chazpope, a specified distance and the run to maximum just to see the difference, and it wasn't on an entirely flat surface either, but I wasn't trying to be specific since I was riding a non standard bike and the measurement wouldn't have value.

 

I just wanted to see what it was like trying to get a figure for your tests.

 

The problem on having ground not level isn't solved by two way runs if the person conducting the test doesn't know it's not level.

 

The fact is that no-one, you included, can judge if a road has a 2% incline, and very few can even detect 3% reliably. Therefore many people will do the test one way unaware of an incline, invalidating their result.

 

Honestly though, do you really believe that a number of people are going to measure out an exact 100 metre stretch, ensure they have a fully charged battery, own a stopwatch, and carry out such tests, reporting accurately. I honestly doubt there's the slightest chance of that happening. And that's without considering all the variables that others have mentioned, battery age and type alone making a very large difference to performance in a given bike.

 

I deliberately didn't say the above paragraph before because I wanted to see if anyone wanted to give results and didn't want to prejudge whether anyone would respond. But as you see and as I suspected, there hasn't been one posting indicating willingness to do the test.

 

The theory is good, but the realisation is too user dependent on co-operation and accuracy. I think you might be surprised how close the mainstream bikes would be in such a test, most of the differences being from tester error.

.

Edited June 22, 200718 yr by flecc

chazpope,

 

coops yes this discussion is off topic now and really it needs to go under a different name so that other people who would be interested can take part - I started this as a comparison between 2 bikes on the flat' date=' proceeded to propose tests and then someone decided this is a discussion about 'determining range' and changed it. [/quote']

 

Your discussion is off-topic in this thread and should be continued in the correct place & under its correct name: to do so, go to your original Powacycle Salisbury v Powacycle Cambridge thread and post there. The subject of this thread is "Determining electric bike range and hill climbing ability" and always has been clearly labelled as that since it started, when it was moved here so that your original topic & proposal could be fully discussed in the Powacycle Salisbury v Powacycle Cambridge thread, after the subject of discussion diverged from what you intended (it often happens) and that thread is the appropriate place for your discussion .

Hill climbing ability is of course important - so there is the valid question - would tests on the flat be indicative of the bikes hill climbing ability ? I believe they would be - because they reflect the bike 'power'. How well that will work is what we are discussing here - and hopefully we will get to the bottom of it' date=' but not without experimentation I think.[/quote']

 

No, as I said in my last post, your acceleration test would give some indication of torque, but gives no quantitative measure of ability on gradients, which is what most people will want to know i.e. can I get up my local hills?

 

I don't understand what evrybodys issue with non-flat is - if you do the test in both directions as instructed (and obviously take an average of the 2 measurements) the effect of incline would be cancelled wouldn't it?

 

No, as I explained in my last post, and flecc explained in the link contained therein. Please read them, and our other posts in this thread, to answer your questions about why tests are unreliable.

 

Ian the ez sprint is rated as 350W nominal on non UK sites - this explains its great performance - and this will show in the test.

 

No it doesn't. The U.K. version is not 350W and as has been said many times in this thread, the "nominal" power rating of a motor, on its own, gives no indication of performance, whatsoever. The U.S. 350W version of the ezee sprint has a different motor from the UK version in line with their generally different ebike laws (e.g. 20mph limit, not 15mph) and is illegal for road use in the U.K.

 

If the Torq really gets to 100m slower than the Sprint then maybe it is less suitable for city use and at traffic lights when you expect not to be pedalling it hard - this will also come out in the tests.

No it won't: because your test parameters are subjective so will your conclusions be. First, you don't have to pedal hard to get results on a Torq; second, a derestricted Torq with only gentle pedalling, or perhaps none, would probably wipe the floor with almost any other production ebike, even over 100m! What is suitable for one person does not suit another. The only clear way to evaluate bikes is to give performance & usage limits, then let people choose according to what fits their needs, usage & riding style.

 

Your approach is very misleading and posting incorrect speculation as facts is misleading for others. Please don't do it!

 

To avoid further confusion about what is the topic of this thread, please continue your discussion of your original topic i.e. your test proposals on the flat, if you want to, in your original thread.

 

Thank you .

 

Stuart.

Edited June 22, 200718 yr by coops

re the incline business - wrong perceptions are already taken care of in the test - it directs you to do it always both ways; i feel the wind may be more of a problem. stop watch - every old digital watch is one, and if you don't have one lying around - it is a quid on the market

 

I don't know what if any the response would be, certainly the wrong heading does not help that. I for one would not be interested in the topic as it is now, I guess I will re-post it. Otoh if one dealer or manuf does the tests - others will follow and one day, who knows - non b/s figures may be published. Thers is no data yet to judge if these tests would be worth it or not - we can only make a guess about it for now, wheather permitting I will have a go on the weekend, but I have to dig out my computer first.

Thanks Chazpope.

 

With respect though, you are operating from an extremely poor knowledge of electric assist bikes and just making wrong assumptions all the time. You've posted mistake after mistake in speaking of them, the latest being yet again on the understanding of motor ratings.

 

The Sprint 350 watts you spoke of is the US nominal rating on that overseas motor, the same thing as the UK 200 watt and European 250 watt nominal ratings. and has nothing whatsoever to do with either the motor output or it's performance.

 

In fact that US market Sprint 350 watt motor has a maximum power of 700 watts. As it's geared to achieve roughly 20 mph for that market, that 700 watt maximum occurs at about 12 mph. The UK and Europe 200/250 watt Sprint motors have maximum power of 500 watts, occurring at about 8.6 mph.

 

These mistakes make it difficult for the very knowledgeable members of the forum to give credence to what you're saying, and I think it best if you follow the general postings for a while and also read back on past entries to improve your knowledge of the bikes and motors.

 

These nominal ratings are a notional legal requirement for the power put down onto the road as an average over time. As such they are virtually impossible to assess or measure, and amount to a guide to manufacturers. For example, a five minute climb at 400 watts power at the wheel interface with the road, followed by a five minute glide down the other side on no power will meet a legal requirement of 200 watts, this being the average over the ten minutes of the trip. You can see that this doesn't in any way relate to a bike's actual outputs.

.

Edited June 22, 200718 yr by flecc

I don't think I am misleading in any way re the 350W power - I am merely stating a fact. What I mean by 'explains its great performance' is that the UK version may have a 250 nominal power but we don't know that do we. So it could well be the same motor power-wise with some or none fake modifications so that is can be called a 250W. This of course is pure speculation but is in line with the general opinion here that the quoted nominal is nonsense. Same as how the nominal power of Salisbury went from 180 to 200 and according to them it has been the same thing all the way - so there is a lot of sense in what I said I think.

 

coops this is what you said re flatness

 

flecc had previously said why the non-flat road makes the measurements worthless. Doing the test in both directions does not cancel error from a non-level surface, it increases it: you would be measuring acceleration and hill climb one way, and speed and downhill freewheel ability the other,

 

My take on this is that whatever power is required to go uphill is added to the bike power in going downhil. The average power consumption is the same as on the ideal flat, therefore any imperceptible gradient error will not have an effect on the result.

 

Please explain in more detail why you think this is not so ?

Oh dear, there you go again, making wild assumptions!

 

The Salisbury motor did not jump from 180 to 200 rating. It's manufacturer had a brushed nominal 180 watt motor that was intended originally and that was mistakenly published as being the current version on the Powacycle site.

 

In fact the Salisbury in the market had a more up to date brushless nominal 200 watt motor. They were two totally different motors as I previously advised, the 200 watt rated one being more powerful and justifying it's higher notional rating. When the website error was brought to their attention, Powacycle corrected it, as I also previously informed you.

 

I explained this in your first thread, but you said you didn't understand, even after I clearly explained further. There's a lot you don't understand, including when to stop bluffing. You clearly don't understand this subject or have knowledge of the bikes. I tried to help in my last post by advising you on gaining the necessary knowledge to speak on this, but again you responded with bluff and guesses as I've shown above.

 

Likewise, the US Sprint motor is not the same power as the UK version and since you lack any of the necessary knowledge of these, you should not make assumptions that it might be. That's what we mean by misleading.

 

I really do not wish to have a row, none of us do, but if you wish to promote your rational test idea, it's best to avoid pretending to knowledge you haven't got. In that way you'll have the attention of members on the idea, and not as at present, focused on your obvious bluffing, mistakes and persistence with them.

 

You got off on the wrong foot with me as a result of your curt and dismissive responses on your Salisbury motor type thread, but it's really time for you to learn from events after your negative experiences in this second thread.

 

I make mistakes too, and when I do and a member corrects me, I apologise and thank them for the correction, since I'm grateful for the opportunity afforded for me to learn more. There's nothing to be gained for me to just pretend that I'm right.

.

Edited June 22, 200718 yr by flecc

Determining Range and Hill Climbing Ability

 

Chazpope

Junior Member Join Date: May 2007

 

(1)________________________________________

I believe there is a considerable body of ebike buyers who like me will be using the bike for commuting, shopping and other general city use (i.e. not hill climbing) All I care about performance-wise is how fast the bike accelerates and how fast it goes - so these tests would be enough for me to decide where to go. In fact I don't care about range at all - every night I recharge my bike anyway - simply because when the battery is full it goes faster, but that is me.

(2)

Hill climbing ability is of course important - so there is the valid question - would tests on the flat be indicative of the bikes hill climbing ability ? I believe they would be - because they reflect the bike 'power'. How well that will work is what we are discussing here - and hopefully we will get to the bottom of it, but not without experimentation I think.

(3)

re what you say of these 2 bikes - perhaps it would be so - but think of cars - does the 0-60 test reflect the car's handling and genaral ability to go round curves and uphill ? No, but still these tests are very popular. Hill climbing ability on a e-bike will always be a slightly fuzzy subject (because is is always to do with pedalling will always be affected by gears, the exact value of the incline etc.) and I am not saying that the overall enjoyability of a bike as a hill climber can be judged from these tests. However I don't think the tests would be 'misleading' as generallty they will reflect the bikes power which also drives the bike uphill. There may always be exceptions - if some special bike is designed to go up a 10% hill all the time its test would be off but I think not wildly off if you see what I mean.

(4)

I don't understand what evrybodys issue with non-flat is - if you do the test in both directions as instructed (and obviously take an average of the 2 measurements) the effect of incline would be cancelled wouldn't it?

(5)

Ian the ez sprint is rated as 350W nominal on non UK sites - this explains its great performance - and this will show in the test. If the Torq really gets to 100m slower than the Sprint then maybe it is less suitable for city use and at traffic lights when you expect not to be pedalling it hard - this will also come out in the tests.

 

Itspeteinit's contribution:

 

re (1): You have defined what you want from an e-bike. I get the impression (impression only because I have only ridden 3 models) that they are not really 'designed' at all (I feel idignation rising in the distance): they evolve from the components that are 'available'. Sure there is a drawing made so that these available parts will 'fit together' - but as for conforming to a predetermined objective I think not. Did eZee think "We have a great motor here ( the Torq motor), let's put it into a 20 inch wheeled folder, it will go up hills like stink" It does! But who said " We won't put any gears on it, it will mean having a wide frame at the rear because we cant put a heavy motor like that in the front of a folder".

Then another idea: "Why don't we put it in a MTB type bike, that will appeal to a largish market. Then, unrestricted (for the American Market), it will go like stink on the flat because it has 700C wheels. It will need a lot of rider work on the hills (let them ride Choppers) Of course, with the motor in the front wheel it will be a bit of a rough ride". "Why don't we put suspension forks on the front?" "Nah!".

So here's your e-bike Chazpope - its the Torq. I have not come across an e-bike at that price with those accomplishments (but a few out there are being hyped up to that standard - we'll see!. No need for road tests, the answers are on the Forum, in quadruplicate.

 

re(2): No tests on the flat will not reveal hill climbing ability. Back to the Torq - It's a dream on the flat (I'm talking speed here), but on hills, well, who or what are you? If you need loads of help because your personal wattage is low (Age, Health, Fitness) the help is not there unless you can do at least 10mph on 10% gradients. But I don't have to pedal on the flat or I can please my self.If I don't help it I can achieve 22 mph (subject to certain variables). If I give it the benefit of my 50 odd watts I can do, well about 22 mph.

 

re (3):

I was once a 'pure' cyclist, with luggage. I never found hills at all charming. Even given the promise that 'what goes up, must come down'. The losses riding up a hill (time/speed) are never compensated by that thrilling decent. My consistent prayer was "not another down then up: losing all that height: why don't they keep it flat?". Flat on a bike is easy. Hills anathema, especially on an e-bike with all that added weight. Unless it's the other kettle of fish that has a low geared motor. There's no legal embargo on motor gearing, only on motor power (on-road).

 

re(3):

This "all the time" introduces an element of speciality which is not relevant to e-cycling where ever it is carried out. In practical terms some hill climbing ability must be present (whether by accident or design). Nowhere is plateflat. With its limited legal power the ability to climb hills (motor gearing) will affect the other criteria of performance (maximum revs). It's what nearly everybody who writes on this Forum complains about. The nanny-state's interference in freedoms which precludes an e-bike 'doing it all'. But why should we worry? There's a plethora of e-bikes that will do 15 mph (the legal limit in the UK) on the flat and climb a wall (or nearly).

Flecc's 'Q' bike does all that and more. If we want to break the land speed record we are on the wrong machine. This whole discussion is academic and esoteric.

 

re (4):

The answer is in the above. Everybody's issue with non-flat is the gigantic difference between flat and hills. The downside does not make it alright for the legs and it does not make an average for science that is equal to the flat. Perhaps the Tour de France is a good indication: the difference between the climbers and the sprinters - on the hills and on the flat. Two entirely different sorts of 'engines'. The ability of one sort of cyclist in both disciplines is quite different.

 

re (5):

I've always thought of my Torq having good acceleration away from rest. Like the Sprint. On a head-to-head I don't know: have not thought about it.

But on a hill in Devon (8 to 10% x 1 1/2 miles long) where I had to stop often, to catch my breath and rest my legs, I had no troube in restarting. I was already in the lowest gear (39 inches - my modification). Open the throttle and put pressure on the pedals and I was 'flying' at 10 mph for a while until gravity brought me back home to reality. The Sprint would have fared better because it would not have given up at 8mph without me pedalling.

 

Now if only Isaac Newton had owned a bike! .

Peter

peter

 

thanks for all the interesting comments.

 

you advise to read the forum for an idea of the bikes performance - this is all well but surely it would be easier to look at figures, and I appreciate that you also need to be aware what they mean. For example your experience with the Torq for whatever reason seems to be in some ways opposite to Ian's above ? You would think it is accelerating quite well from start while Ian kind of doesn't. If only we had a figure (test:) for this acceleration things would be put in better perspective.

 

I do not get yout point re 4 above - the question here is: 'when measurung speed and acceleration without pedalling on a visually imperceptible gradient (appearing as flat surface) - would it be safe to assume that doing it both ways and quoting an average would cancel the effect of this hidden gradient' (excuse the twisted description but that's what it is) I think my logic is ok and I explained why. Getting different figures would be an indication that there is in fact a gradient and maybe you can choose another testing spot, sorry if I got in geek mode here a bit

 

 

flecc

 

Yes you said that there was a mistake re Salisbury - but not in this great interesting detail. But I had 2 good reasons not to be so sure, and about that you still seem to have an axe to grind. One: my dealer told me that the Salisbury has gone up to 200 from 180. Two: long after it was posted as 200W on the website - Carl of powacycle told me it was 180W. When I pointed out that it is 200 on the site he corrected himself to the effect that 'the manufacturer told us that it was 180 and then they told us that in fact it is 200'. I totally believed Carl, but not the marketing dept of the chinese co who wrote this figure - hence my comment.

 

So you seem to have some special insight into exactly how and why this happened, please provide your sources as I have, and likely you would be right. But that does not mean you can pontificate the way you do - I did say it was pure speculation and this is a forum where speculations should be allowed. It kind of looks that when you exhausted out the argument on the flatness cancelling issue you started poining out my inferior knowledge - I never said I have extensive electric bike knowledge nor am I a posting grandmaster like yourself. In fact I have been reading your inputs and I mostly take them on board, but here is one I din't:

 

Certainly less power will be used cruising at 8 mph than at 15 mph, but the differences are very small on the flat in fact, and academic anyway, since no-one is normally going to cruise at 8 mph

 

I mean the power difference between 8 and 15mph on the flat is huge, not very small.

 

I mean the power difference between 8 and 15mph on the flat is huge, not very small.

 

I knew you meant that, but I disagree, it is not huge.

 

On the Salisbury motor question, I'm quoting from my knowledge of what is produced at the Chinese end and how and when it has been marketed, not from Powacycle themselves.

 

I didn't exhaust any arguments, and have no objection to just speculation. But you seem to be determined to be confrontational and make wild statements and false technical comment, guessing your way through. It's not fair to speculate about reputable companies like eZee the way you've done in your inferences about motor ratings. It's not right to say "we have no way of knowing" in that matter when we do in fact know, that lack of knowledge being yours. It's not right to say we've said that notional is the same as nonsense, especially after it's been explained to you in detail what notional means and the fact that it's a legal definition, showing how it's not relevant to the technical matters we're concerned with.

 

Your responses to my attempts to help in your first thread were frankly arrogant and bordering on rudeness, and you don't seem to have improved much in this one. Since you obviously think you don't need advice or help and are certain of your infallibility in all these matters, I'll leave you to those delusions. I've better things to do than put up with your ill mannered conduct.

 

All the best with your performance measuring project.

.

chazpope, I have replied to your question in the relevant thread and all further discussion on that topic should be done there.

 

Stuart.

Edited June 23, 200718 yr by coops

I knew you meant that, but I disagree, it is not huge.

 

FYI the actual difference is something like 200% - this is a huge difference. Call it another one of my delusions if you like but the power required to push the bike through the air is proportional to the cube of its speed - twice the speed requires 8 times more power - hence the big difference.

FYI eh, that arrogance shows again! That's the theory Chazpope, and I know it as well as you and knew it before you were born.

 

But I also have those little things called experience and practical knowledge, and therefore know of the common circumstance which frequently largely undoes that relationship.

 

You've also been shown how those additional factors change theory by Ian, when he illustrated how the Sprint and Torq upset your test theory, and by me, when I showed you how two other bikes, the Quando and Chopper actually inverted the theory.

 

But the difference in this posting is that I'm not going to tell you what it is that upsets your theory for two reasons. First because as I've indicated before I'm fed up with your denial responses based on bluff, and second, because if you are as knowledgeable as you purport to be, you don't need me to tell you.

.

Edited June 26, 200718 yr by flecc

FYI the actual difference is something like 200% - this is a huge difference. Call it another one of my delusions if you like but the power required to push the bike through the air is proportional to the cube of its speed - twice the speed requires 8 times more power - hence the big difference.

 

For information purposes, 8 times more power is a 700% increase, not 200%. Your facts are correct, but your conclusions are relative and only applicable to cycling on the flat, which isn't what the rest of us are discussing here and its getting very confusing, so to avoid that please try to keep your posts in the same context as everyone else.

 

From 8mph to 15mph the power increase required is relatively big, maybe even 8 times as you say, but the power output for both, on the flat, is small compared to whats required to climb even a modest hill at a modest speed, say a 7% gradient at 9mph, which requires over 2.5 times the power of 15mph on the flat (thats over 7.5 times more than 8mph on the flat) for even a modest rider & bike weight of 100kg combined.

 

These facts are easily verifiable from experience: try cycling at 8mph and then 15mph, on a flattish surface, then try doing 8mph up a 7% gradient (if you can find one!), and make your own mind up which is the biggest difference.

 

Stuart.

Edited June 26, 200718 yr by coops

coops,

 

both figures 8 and 200 are correct and relevant. You will note above that I referred only to the air resistance component of the power as being 8 times bigger; you also have the rolling resistance power into play which is linearly proportional to speed so the combined effect is about 3 times more or 200%difference.

 

I am specifically referring to flecs quoted wildly inaccurate statement about cruising power difference on the flat and I am not making a big deal about it other than to point out that imho it is totally wrong. What you say re power uphill is true but does not prove or disprove this particular point.

Ok chazpope, fair enough: I agree on your figures, clear now; I misunderstood your statement re 8 times and 200%.

 

I think you still don't see though: flecc's statement was accurate, especially in the context of the topic being spoken of i.e. hillclimbing - thats how I understood it. Your last statement is equally valid in the context of cycling on the flat. The problem as I see it is confusion over the topic of discussion, and the context of statements.

 

What I said about power needed for hills was to illustrate that.

 

Stuart.

Edited June 26, 200718 yr by coops

coops,

 

both figures 8 and 200 are correct and relevant. You will note above that I referred only to the air resistance component of the power as being 8 times bigger; you also have the rolling resistance power into play which is linearly proportional to speed so the combined effect is about 3 times more or 200%difference.

 

I am specifically referring to flecs quoted wildly inaccurate statement about cruising power difference on the flat and I am not making a big deal about it other than to point out that imho it is totally wrong. What you say re power uphill is true but does not prove or disprove this particular point.

Enough rope yet Flecc?

I'm still smiling Paul.

 

Chazpope isn't the first to confuse the status of theory which is very condition dependent with the status of immutable physical laws and accord the wrong importance.

 

Like most who make that same mistake, he appears to have a closed mind.

 

Stuart's observation meaning that 200% of next to nothing is still next to nothing is also relevant of course, and next to nothing isn't huge in any usage.

 

However, my point is solely on the relative values on the flat in the same conditions as Chazpope's statement.

.

Edited June 26, 200718 yr by flecc