Cytronex lacking "go"

[HarryB]

I had to have a new motor fitted to my cytronex. I spoke too soon about the reliability but it was all sorted out quickly by Mark at cytronex. However it may be coincidence or not but the bike lacks some of its previous power or "go". I think the decription is that "it couldn't pull the skin off a rice pudding". Of course this is always subjective but it won't really reach 15 mph with a fully charged battery and never gives that electric bike push when you hit the button.

Previously you really had to wait to get to get to 7 mph before you pressed the button otherwise you would get squeals of protest. With this motor the delivery seems soft and no squeal. Also the performance noticeably drops as the battery loses its charge. Anybody any suggestions - could it be the motor or battery? I have checked the voltage - fully charged (hot) 44V, quickly settling to 40.9V once cooled down. It doesn't cut out any sooner that it used. Top speed of the motor when fully charged, no load is 16.7mph but goes down to 14.9mph, no load at the end of the 10 mile journey.

I know some tongxin were wrongly labelled so perhaps I got one of the wrong speed - 160 rpm? Any other ideas?

 

[flecc]

The only guess I can make is that on the newer motors the drive roller assembly is adjusted to be under greater pressure to reduce the drive slippage that could occur and perhaps a windings change to slightly reduce the power.

I always felt that well over 400 watts peak was a high power to transmit through such a small smooth roller track.

This is just a "stab in the dark" guess though, so maybe check with Mark to see if he feels that's normal.
.

 

[frank9755]

Sorry to hear it's not quite working properly, Hal.

For comparison, my no-load speeds for my 175 Tongxin are 17.4 when fully charged and about 15.5 after a 20 mile ride. That's with a Ping LiFePO4.

Hard to know what your problem is.
- It could be wrongly labeled. If it is a 160 I would expect you would be getting significantly higher range from the battery and, of course, you should be able to climb up steep hills - steeper in fact than you are likely to find without travelling a fair distance!
- However it could be a faulty motor, which would be unlucky. With my Tongxins I generally experience an initial short rush of higher speed operation which soon settles down to give pretty consistent performance until the battery is exhausted - I've not seen that gradual fall-off.

What happened to your old one, out of interest?

 

[HarryB]

What happened to your old one, out of interest?

I think a spring came adrift in the freewheel and it made a strange noise. Mark suggested a new motor as they weren't sure they got all the debris out - wish I had opted for the original to be repaired and risked it.

Your figures suggest it is a 175 rpm motor as the ping battery probably produces a higher voltage than the NiMH and that accounts for the slightly higher no load speeds.

 

[HarryB]

The only guess I can make is that on the newer motors the drive roller assembly is adjusted to be under greater pressure to reduce the drive slippage that could occur and perhaps a windings change to slightly reduce the power.

.

I don't think so as the single speed bikes I tried pulled like steam trains compared to mine and they must have new motors. I makes me realise that you do need a reasonably powerful motor to make an electric bike worthwhile - I am regretting selling my Agattu now.

 

[Barnowl]

Mmmh definately something wrong there. Have you contacted Mark at Cytronex yet? My 7.3fx pulls fine although I never did get any squealing if I put the boost on to soon (which I've done a few times in error at next to no speed at all).
I can't say the pull on mine is noticably worse than the single speeds I rode at Presteigne or any of the e-bikes I've tried.

 

[flecc]

I don't think so as the single speed bikes I tried pulled like steam trains compared to mine and they must have new motors. I makes me realise that you do need a reasonably powerful motor to make an electric bike worthwhile - I am regretting selling my Agattu now.

If it's that different Hal, it must be a faulty motor, so best get back to Mark and get something done about it.
.

 

[frank9755]

My figures above were from memory, so I charged the battery overnight to check. I was actually underestimating quite a bit. The freshly charged battery gives no load of 20.2mph; before recharging the same battery gave 17.2.

I think the numbers I quoted before were actually what I got recently while riding the bike - top speed on the flat without pedalling.

Different controller and battery, but your one is clearly not right!

 

[HarryB]

Mmmh definately something wrong there. Have you contacted Mark at Cytronex yet? My 7.3fx pulls fine although I never did get any squealing if I put the boost on to soon (which I've done a few times in error at next to no speed at all).
I can't say the pull on mine is noticably worse than the single speeds I rode at Presteigne or any of the e-bikes I've tried.

Do you know what the no load speeds are for your motor with a fully charged motor? I think it should be between 19 and 20 mph. From memory I think that is what my original motor was.

 

[Barnowl]

Do you know what the no load speeds are for your motor with a fully charged motor? I think it should be between 19 and 20 mph. From memory I think that is what my original motor was.

Hal, torrential rain means I'm in the car today but I'll check the "no load" when I get home. I'm assuming by "no load" you mean what speed shows on the speedo with a fully charged battery and the front wheel off the ground and running on boost?

 

[HarryB]

Hal, torrential rain means I'm in the car today but I'll check the "no load" when I get home. I'm assuming by "no load" you mean what speed shows on the speedo with a fully charged battery and the front wheel off the ground and running on boost?

Yes it does - otherwise your weight and any incline/decline make the figures meaningless. The low speed settings would be good too. Thanks.

 

[Mark/Cytronex]

Just seen this thread Hal.

If there is something wrong we will of course put it right for you promptly, you just need to contact us. I would like to give your bike a good ride myself to see what the problem is.

Our new single speed bikes use a different means of control, they are designed for London where accelerating fast from low speeds is important due to the frequent stop, starts. They sense the speed and apply appropriate assistance, so you would notice a lot of thrust with these bikes (Barnowl tried the Cannondale Capo at Presteigne which we had only just produced in time and was not correctly set up).

That said the performance of your bike should certainly not be disappointing and if it does not pull then there must be something wrong. So let's get is sorted for you.

Regards,

Mark

 

[HarryB]

Sorry Mark, I wasn't in any way being critical of you, your company or the bike. I was more worried that the lack of go is subjective and so I was getting some facts and figures from the forum before trekking all the way to Winchester. It does seem to run a fair bit slower than it should so I will give you a call at some point.

 

[Barnowl]

Top speed, no load 17.9mph
Low speed, no load 14.9mph

Battery fully charged this morning but not used today. Batterys probably done about 1200 miles (about 60 charges) in total.

Mark
I tried 3 of those bikes but the memories are fading.

 

[simonbarnett]

Sorry Mark, I wasn't in any way being critical of you, your company or the bike. I was more worried that the lack of go is subjective and so I was getting some facts and figures from the forum before trekking all the way to Winchester. It does seem to run a fair bit slower than it should so I will give you a call at some point.

Though the resolution of this is between you and Mark , please keep the forum informed. Cytronex and it's benefits/drawbacks are of interest to others. My first ever post was looking for an ebike that didn't look like one and I still think it's a unique selling point. So all reports are interesting.

 

[Barnowl]

Top speed, no load 17.9mph
Low speed, no load 14.9mph

Battery fully charged this morning but not used today. Batterys probably done about 1200 miles (about 60 charges) in total.

Update
After 10 miles:

Top speed, no load 17mph
Low speed, no load 14mph

 

[matt-derby]

Which Cytronex?

Hi Barnowl,

Which Cytronex bike do you have? or more importantly which hub?

Matt

 

[Barnowl]

Cytronex Trek 7.3FX 175 RPM Tongxin Nano Hub (Last Years bike).

PS. Just in case there's any confusion HarryB has the problem. I'm OK.

 

[Barnowl]

HarryB, I retested after charging the battery this morning. The still warm battery gets the following unloaded speeds.

Top speed, no load 18.3mph
Low speed, no load 15.2mph

 

[Mark/Cytronex]

Harry's Motor

The no load speed on Hal's motor with a full charged battery is consistent with a 160rpm motor, as is the feel he described. However he hasn't been in contact so I can't confirm it.

We keep 160rpm because some customers request them (where they have steeps hills or don't want the speed). They don't provide the thrust associated with Cytronex bikes, so we only supply them if specifically requested by the customer.

We did have one wrongly labelled motor before (it was faster), we only found out because I went out with the customer on another bike and found that I could not keep up! I guess this is what has happened here, especially as it was clearly not right from the moment Hal had the new motor. Whatever the case, we will of course sort it out for him as soon as he gets in touch.

While we are on the subject of acceleration and thrust, AtoB have just conducted a review of our Cannondale Capo single speed bike. Whilst David doesn't reveal much before publication, I did get an email to say that he had found the same speed as the Trek last year (which had 24 gears) but 30% greater range. As a reminder the Trek achieved the fastest time for any legal bike tested on AtoB's 10 mile test circuit, and the fast wheel achieved the fastest time for a non-road legal bike.

Of course the way to judge performance is to try each different bike you are interested in before you buy.

In the rare event that a customer does have a problem with one of our bikes, we aim to sort it out straight away. In this case I think it is just a case of a mis-labelled motor.

Regards,

Mark