SRM Cranks

[Bellscycling]

Hi There,

 

Are there any hubbers using SRM cranks? I would like to recieve some feedback on the reliability and frequency of maintanence on these crancks.

 

Looking forward to hearing from you guys!

[bruce]

Probably your best option is to contact http://www.activeworx.co.za/ they are the local agents for SRM.  They usually have some second hand units available, which they will warranty.

Reliability is a function of maintenance and operating procedure.  The units need to be serviced every couple of years (battery replacement and calibration), for which they get sent back to Germany.  They are sensitive to temperature change, so you need to make sure you set the zero torque point on every ride, and during a ride if there are big temperature changes.

 

[Marius]

***, I thought I should switch to a SRM to get away from the PowerTaps sensitivity to Temperature, so much for that idea..

[Bellscycling]

Thanks Bruce, I'll give them a call.

[bruce]

***' date=' I thought I should switch to a SRM to get away from the PowerTaps sensitivity to Temperature, so much for that idea..

[/quote']

My experience has been that SRM is more sensitive to temperature than powertap.  In a powertap the strain gauges are arranged in a torque tube, and are less sensitive to temperature shift than srm.

[Marius]

Really, omw.. Mine is really buggered I think. When it's cold or just raining really lightly it goes wacky. I'd get like 300W on the one pedal stroke and then 360W with the other on a hill, I mean really!!!!? It's bonkers!

[bruce]

Really' date=' omw.. Mine is really buggered I think. When it's cold or just raining really lightly it goes wacky. I'd get like 300W on the one pedal stroke and then 360W with the other on a hill, I mean really!!!!? It's bonkers! [/quote']

Does the behaviour change after zeroing the torque?

When I refer to temperature sensitivity, i'm referring to how much the zero torque offset changes due to temperature change.

If your unit is behaving wierd in rain/cold, even after zeroing the torque, then there is something else wrong.

[Marius]

Really, weird, I must've zero'd it 3 times yesterday before the ride, then again twice when it started giving me weird readings. It's really strage, when I use it in my area, doing my normal training rides it's fine, but as soon as I venture off my normal training routes it goes wacky.

I did contact BikeMax about it and he reffered me to Martin at Bicycle Power Trading, needless to say I have not heard anythign from him yet.

[bruce]

Really' date=' weird, I must've zero'd it 3 times yesterday before the ride, then again twice when it started giving me weird readings. It's really strage, when I use it in my area, doing my normal training rides it's fine, but as soon as I venture off my normal training routes it goes wacky.

I did contact BikeMax about it and he reffered me to Martin at Bicycle Power Trading, needless to say I have not heard anythign from him yet.

[/quote']

Hmmn, you haven't got any polar wireless sensors on the bike have you?  Assuming you are using a wired powertap?

[Marius]

Let me think, I have my Polar Speed Sensor on the front wheel. I took of the Polar Cadence sensor a while ago already cuz it stopped working after a crash. Yes, got the Old Wired SL.

[bruce]

Let me think' date=' I have my Polar Speed Sensor on the front wheel. I took of the Polar Cadence sensor a while ago already cuz it stopped working after a crash. Yes, got the Old Wired SL. [/quote']

Try a ride without the polar sensor on the bike.

[Marius]

Thx Bruce, will try it, just need a rainy day:-P

[bruce]

Thx Bruce' date=' will try it, just need a rainy day:-P

[/quote']

Location: Western Cape