questions about power meters?

[ratz]

Yes, mainly for walking.
Real situation is that I don't know what pedals my knees like and what does not. My physical terapeutist recommended me to go back to SPD because it can hold my heal out more than Frogs. I am riding it on turbo now do I cannot say if it is better.

Ah well then a trial of some inexpensive Keo pedals may be in-order. They can get had for pretty low cost and would tell you if PowerTap P1 left only would work for you. Left only is great because you can hen upgrade to Left/Right later to spread costs out.

Look KEO Classic 2's are about $40us; the have two version 1 with 6 degrees of float and 0Degrees. Mounting on the shoe allows for angling.

 

[Bill K]

So after some more research I realised that power2max NG would be probably compatible with Vendettas BB and it is possible to buy it with cheap cranks FSA Gossamer Megaexo what seams that may be shortened. So I see way to have shortened craks with spider based PM

I am using the Power2Max "classic" with 170mm FSA Gossamer crank arms. It looks from the pictures like the new Power2Max NG will fit the same.
I did need to add a 2.5mm spacer to the drive-side bottom bracket to push the spider out so it clears the V20 bottom bracket clamp. Without the spacer it would scrape, just a little bit.

Also, I wanted to have the crank arms shortened by BikeSmith, but he cannot shorten these due to the design of the crank arm.
He can shorten 175mm crank arms to 153, but he cannot shorten 170mm crank arms.

 

[super slim]

https://www.dcrainmaker.com/2016/12/5-random-things-i-did-this-weekend-36.html
DC Rainmakers latest tests on Dec 5th, using a Dura-ace hollow crank went well, except on some REALLY rough cobblestones!

Wattteam are meant to be working on MTB cranks next, so hopefully the U shaped solid cranks will be in them!

I am using the Power2Max "classic" with 170mm FSA Gossamer crank arms. It looks from the pictures like the new Power2Max NG will fit the same.
I did need to add a 2.5mm spacer to the drive-side bottom bracket to push the spider out so it clears the V20 bottom bracket clamp. Without the spacer it would scrape, just a little bit.

Also, I wanted to have the crank arms shortened by BikeSmith, but he cannot shorten these due to the design of the crank arm.
He can shorten 175mm crank arms to 153, but he cannot shorten 170mm crank arms.

Bill, how much did you pay for them?

 

[snilard]

I am using the Power2Max "classic" with 170mm FSA Gossamer crank arms. It looks from the pictures like the new Power2Max NG will fit the same.
I did need to add a 2.5mm spacer to the drive-side bottom bracket to push the spider out so it clears the V20 bottom bracket clamp. Without the spacer it would scrape, just a little bit.

Thank you for sharing this knowledge. Is axle long enought to work with spacer? Is spacer placed between frame and BB or between BB and spider?

Ah well then a trial of some inexpensive Keo pedals may be in-order. They can get had for pretty low cost and would tell you if PowerTap P1 left only would work for you. Left only is great because you can hen upgrade to Left/Right later to spread costs out.

Look KEO Classic 2's are about $40us; the have two version 1 with 6 degrees of float and 0Degrees. Mounting on the shoe allows for angling.

I have different opinion on what I consider pretty low cost... I would also need new shoes to test road style pedals. I need walkability. No way, but thanks for support.

This discussion about new PM is academical for me because I have working PM and don't have budget to switch to another. I like to know my possibilities even if it is out of budget. So I hope that it doesn't bother you.

 

[Bill K]

Bill, how much did you pay for them?

I bought the Power2Max 2 years ago (Nov. 2014) and paid $749
Prices have come down since then.

 

[Bill K]

Is axle long enought to work with spacer? Is spacer placed between frame and BB or between BB and spider?

With the spacer, the axle is slightly too short but it still works well. The left crank arm cannot slide completely onto the shaft so it is probably not as strong but I think it is plenty strong for me.
The spacer also affects the chain line so you would need to adjust the front derailleur.
I used a spacer between the frame and BB (Shimano part #Y1F813000) although adding a spacer to the spider would also work.
A smaller spacer (1.5mm or so) might also work. I just used the only spacer I had.

 

[DavidCH]

Watteam powerbeat looks very interesting to me. It looks ideal as it's not based on the pedals, if the bike goes down with a pedal scrape the power meter is out of the way.

Sure I know it probably won't give 100%readings but it sure would be better than the powercal chest strap that I have and if I want to put it on some 150mm Sram Rival cranks that are currently being cut down it's got to be a win win. Has anyone tried these?

 

[snilard]

Sure I know it probably won't give 100%readings but it sure would be better than the powercal chest strap that I have and if I want to put it on some 150mm Sram Rival cranks that are currently being cut down it's got to be a win win. Has anyone tried these?

Sram Rival crankset may be shoretened to 150 mm and it is hollow?

 

[DavidCH]

Sram Rival crankset may be shoretened to 150 mm and it is hollow?

I'll keep you posted. I did get a warning but the engineering company I used said it looks good. I used 172mm sram rival cranks. If it was for a DF then I certainly wouldn't use it. But for a recumbent on the flats - mainly ... I won't be going more than 300 watts.

Engineering is a science of compromise.

When I get them I will centre a straight marker line along the crank and after every ride if it's not straight then I will stop using them.

 

[snilard]

I'll keep you posted. I did get a warning but the engineering company I used said it looks good. I used 172mm sram rival cranks. If it was for a DF then I certainly wouldn't use it. But for a recumbent on the flats - mainly ... I won't be going more than 300 watts.

Engineering is a science of compromise.

When I get them I will centre a straight marker line along the crank and after every ride if it's not straight then I will stop using them.

I have seen shortened hollow cranks from Rotor on recuben of one pretty strong guy. There were glued threaded inserts in new holes. So I think that with this glued inserts it should work.

EDIT: SRAM cranksets aren't on list of supported ones!!!

 

[DavidCH]

The oracle has spoken...

 

[ratz]

The oracle has spoken...

New Rival is Forged Aluminum
Old Rival OCT is hollow

OCT = OPEN CORE TECHNOLOGY = Hollow.

So I doubt very much they have shortened the old Rival OCT cranks, I've seen a pair that someone tried; ti was ugly. There have been 3 generations of the Rival; the OCT being the middle one. They might have shorted the old Rivals but that was over 4 years ago. OCT was the main product for at least 3 years.

 

[DavidCH]

I got a message from the watteam, my idea was to buy the power meter for the Shimano Ultrgra 6800 165mm cranks and put it on the Sram Rival. As the crank is probably stiffer, but they said if they had to give a refund with that sort of abuse then they wouldn't give a refund. So I might just buy them for the Ultegra cranks

 

[bazzawill]

Watteam powerbeat looks very interesting to me. It looks ideal as it's not based on the pedals, if the bike goes down with a pedal scrape the power meter is out of the way.

Sure I know it probably won't give 100%readings but it sure would be better than the powercal chest strap that I have and if I want to put it on some 150mm Sram Rival cranks that are currently being cut down it's got to be a win win. Has anyone tried these?

The Powerbeat does look tempting DC Rainmaker found the preview version he had was fairly accurate and it looks like they addressed his few concerns in subsequent iterations.
Now I am torn between the tail box upgrade and a power metre I could potentially afford except not really but I can dream.