Powacycle Salisbury v Powacycle Cambridge ?

chazpope

Pedelecer
May 25, 2007
52
0
I have ridden both the Salisbury and the Cambridge for long periods of time and the Salisbury feels much less powerful than the Cambridge at low levs, acceleraion and generally starting and getting quick out of junctions. Although both bikes are rated at a nominal 200W the Salisbury needs to be rolling at full speed before the power takes full effect, so overall it feels a bit geriatrtic compared to the Cambridge.

As a plus point -the Salisbury has a better quality feel than the Cambridge, does not rattle as much, the tyres are smooter, the suspension works better and it is lighter by 1kg.

However it does not have an integral light (strange on a bike where you carry a big heavy battery) and the battery indicator is awkwardly positioned under the seat - not much use when you are riding - also it tends to stay on 'Empty' during use regardless of the state of charge. In contrast the Cambridge has a nice 6W 24V light that does an excellent job lighting your path with a voltage indicator that is quite informative as you tend to remember its state under different conditions and judge the state of your battery.

I guess until the industry matures choosing a bike will involve a lot of guesswork. There needs to be a unified preformance test quoted for electric bikes, something like:

0-15.5 mph in so much seconds with fixed weight
top speed on the flat without pedalling
range in miles without pedalling


These are important characteristics that no manufacturer quotes at the moment - so you do not know what you are really getting. Specs like 'range - 15-20miles with gentle pedalling' mean next to nothing when chosing a bike.
 

flecc

Member
Oct 25, 2006
52,763
30,349
Carl of Powacycle explained previously that the motor's internal gearing of the Cambridge is different.

It's a balance of options, more top speed or better acceleration and climbing.

The eZee Torq is the most extreme case of this in practise, a high top speed gained at considerable cost to acceleration and hill climbing.
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chazpope

Pedelecer
May 25, 2007
52
0
just to clarify - going on just the throttle the Cambridge also has a higher top speed that the Salisbury - it is totally better dynamic performance in every way

as to the range - you cannot guess what it would be untill you test it - and so far there is no definiton of 'range' - what is gentle pedalling for one would give someone else a heart attack - so all this talk from the bike co's is b/s I am afraid
 

coops

Esteemed Pedelecer
Jan 18, 2007
1,225
1
Manchester U.K.
EDIT 2: off-topic post moved to new thread, see below - thanks Russ :)

EDIT: Any comments are welcome, but may be better to post in a more relevant thread to keep information sources logically organised & accessible to all :D.

Stuart.
 
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rsscott

Administrator
Staff member
Aug 17, 2006
1,398
193
.......EDIT: Any comments are welcome, but may be better to post in a more relevant thread to keep information sources logically organised & accessible to all :D.

Stuart.
I've started a seperate thread here

This thread is now for the original topic of PowaCycle Salisbury v PowaCycle Cambridge please folks!
 

rsscott

Administrator
Staff member
Aug 17, 2006
1,398
193
Have you been hacked Russ?

That link takes me to a mural.
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Oops, guess which website I was browsing ;). I'm decorating the kids bedroom next week so I was looking for mural ideas. The ones on that site look fantastic - until I saw the price....£4000 :eek:
 

flecc

Member
Oct 25, 2006
52,763
30,349
I guessed that was it Russ. Thank goodness it was a "decent" site. :D

Brings to mind one of my most embarrassing moments, when I accidentally misdirected an email to the person I was criticising in it. :eek:

Links are dangerous things.
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coops

Esteemed Pedelecer
Jan 18, 2007
1,225
1
Manchester U.K.
Hi chazpope

In reply to your last post on this subject, quoted here in full:

chazpope said:
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 ?
You said
chazpope said:
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.
and
chazpope said:
I don't think I am misleading in any way re the 350W power - I am merely stating a fact.
Actually you're stating two, unrelated facts and saying one explains the other! The U.S. Sprint is 350W and the UK Sprint does have great performance, but as I have previously said to you

coops said:
the "nominal" power rating of a motor, on its own, gives no indication of performance, whatsoever
so there is no connection between the two; to say the latter is explained by the former is incorrect and misleading!

On the non-flat road question: both tests will essentially measure hillclimbing ability one way (uphill) and top freewheel-limited speed the other (downhill). The energy efficiency of a hub motor is rather less going uphill than on the flat, and also not all the energy output of climbing will be returned as motion downhill: these two losses mean the total and average energy consumption overall is not the same as on the ideal flat, it is higher.
Going uphill the bike is working against gravity and downhill its accelerated by the same force, but the reduction in speed going uphill will likely be more than the gain in speed going downhill. Doing measurements both ways on even slightly different gradients will increase errors because downhill speed variance will likely be much less than climbspeed variance, so you will get quite widely varying averages.

Ironically, what the tests would illustrate is how much a bike's speed is affected by slight variations in gradient, though this is not necessarily an indication of hillclimbing ability since some motors can maintain speed well on such a slight uphill surface, but fail to climb steeper slopes.

Stuart.
 
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