S30 vs Powertap C1 (chain-ring power meter)

[murmur]

Well I was installing my xmas-present-to-me, a Powertap C1, on my S30 this afternoon and ran into an issue that will probably mean returning it. The C1, not the S30. Looks like the bottom-bracket clamp on the right side has a severe interference with the sensing ring on the C1. There's no getting around the bump-out for the clamp, so it would be a spacer on the right side if anything. As this picture shows, though, there's a lot of space left at the point of interference. And the engagement of the left pedal arm on the spline shaft would be compromised by that same amount, even if a spacer would work on the right.


I found a thread wherein Ratz predicted this problem on the V1. Looks like it's real.

Dave

 

[murmur]

Me again! Now I'm wondering if the S30 could be retrofitted with the S40's chainstay and by that swap get compatibility with the Powertap C1. According to what I see in the original S40 thread, and this still from the front of one of Cruzbike's S40 videos, it looks like the C1 could work with an S40.

 

[Bill K]

Pretty good chance the new chainstay will work.
I just retrofitted my V20 (2 years old) with the new chainstay, and a new Power2Max PM on a Rotor 3d+ crank.
The crank and bottom bracket definitely would not work on the old chainstay, work great on the new one.
Check with Robert at Rose City Recumbent Cycles.

Well I was installing my xmas-present-to-me

Ditto!

 

[ratz]

Yes the new chain stay is designed to solve that problem. Many spider meters rubbed the old chain-stay; some you could file and make work; now there really is no need just get the new stay if they have them in stock.

 

[murmur]

Oh, that is good news. I'll see if they have spares. Thanks guys!

Dave Dixon

 

[murmur]

Things are not looking good for reverse-retrofitting(?) an S40 chainstay onto an S30. At least not onto an S30 with front suspension, which is what mine is. Robert hasn't gotten back to me yet with a final answer, but I can see why he said "depends on whether your bike has front suspension.". The chainstay has to flex if the fork moves through the steer-tube, as in the front-suspended S30. So at the very least it will require disabling the air-bladder suspension, if not fitting the S40 fork.

 

[ratz]

Things are not looking good for reverse-retrofitting(?) an S40 chainstay onto an S30. At least not onto an S30 with front suspension, which is what mine is. Robert hasn't gotten back to me yet with a final answer, but I can see why he said "depends on whether your bike has front suspension.". The chainstay has to flex if the fork moves through the steer-tube, as in the front-suspended S30. So at the very least it will require disabling the air-bladder suspension, if not fitting the S40 fork.

have 1 on my s2.1 works good with shock disabled

 

[murmur]

Oh, ok. Well I'm not sure how much I'll miss the front suspension. Seems the consensus around here is that it was a (failed?) experiment, and mine won't hold pressure for more than a few days at a time, but suspension (in general) was one of the big reasons I wanted this bike, originally.

Dave

 

[super slim]

Replace your fork valve and use a metal sealing cap.
http://cruzbike.com/forum/threads/air-shock-management.2519/

http://cruzbike.com/forum/threads/front-shock-how-do-i-know-if-it-works.7161/

here is how I fixed the leaking Front suspension.
https://cruzbike.com/forum/threads/vendetta-evolution-ideas.8568/page-2#post-111268

My Silvio V1.0 front air cylinder shocker leaked, and I just replaced the top 2 O rings in the sealing plug at the top of the suspension, make certain that you lubricate the plug and O rings well with O ring grease and rotate the plug a lot as you are pushing it make into place, so the O rings do not roll and loose their seal.

I would try to fix the front suspension leak, and file the BB clamp a lot, as I did to my Silvio V2.2 to fit a triple crank with + 2 mm chainline compared to my Silvio V1.0 45 deg seat and BB clamp on the BB shell, NOT the BB bearing caps, as history has repeated itself, but added disk brakes and a very beautiful hydroformed frame!
There is a LOT of excess metal on the BB clamp so don't be worried about metal removal.

This is a cheaper option to the S40 chainstay, and if it does not work, you have only lost a bit of your time.

If going with the S40 chainstay, and you are 90 kg and fit a 700c*30 tyre, then the recommended tyre pressure is 76 psi, for max comfort AND min rolling resistance!

 

[murmur]

hmm, I'll think about that, Super. I've accidentally, and brightly, marked where on the BB clamp the material-removal would begin (the small ring marked it for me when I was attempting to install the crankset). It remains to be seen where it would end, though. The crank needs to move inward about 8mm, so maybe 9mm of filing! I'll take a picture and do some measuring tomorrow.

 

[super slim]

This is the filing I did to the S30 BB bracket and the inside edge of the 25 T Qring

 

[murmur]

The white mark in this picture is from the C1's small chainring impinging on the BB clamp portion of the S30 chainstay when I attempted to install the C1. The mark is 9.4mm to the outboard of the chainstay bracket's junction with the composite flex-arm. So that's an absolute maximum on mods to the bracket to move the small ring inboard. I guesstimated 8mm would be needed to get the spider to seat on the BB bearing face when I had the C1 on my crankset. 8mm of material removal on the bracket is going to take a major portion of the weld that's showing in grey; I would guess close to half of the thickness of that weld would be gone.

 

[murmur]

Robert's (@Cruzbike) opinion is that too much flex will remain in the S30 front triangle (with the shock movement disabled) to be compatible with an S40 chainstay. I don't quite understand why he thinks that, unless he doesn't see a way to completely immobilize the fork action.

Waiting on additional discussion with Cruzbike on this. I can understand their caution in recommending field mods to their bikes given that there are arguably liability concerns. From what you guys have told me, I'd be willing to buy an S40 chainstay for "unspecified purpose" and mod the bike, but the cat may be out of the bag, now.

Dave

 

[tiltmaniac]

We have a late gen (non suspended) S30 that could use a new style chainstay.

 

[super slim]

We have a late gen (non suspended) S30 that could use a new style chainstay.

Would it be possible for ALL Cruzbikers that want a S40/V20 chainstay, to contact Robert at support@cruzbike.com, so that a total number of extra S40/V20 chainstays could possibly be ordered in the next batch of V20/S40 bikes.

This would allow Cruzbike and the bike fabricator to work out a price!

I think that a "Fit to your bike, at your own risk, as NOT an original designed component for your model bicycle, form", that was created by a lawyer, would have to be signed, to avoid legal obligations to Cruzbike, in the Lawsuit Country of the world!

 

[super slim]

The white mark in this picture is from the C1's small chainring impinging on the BB clamp portion of the S30 chainstay when I attempted to install the C1. The mark is 9.4mm to the outboard of the chainstay bracket's junction with the composite flex-arm. So that's an absolute maximum on mods to the bracket to move the small ring inboard. I guesstimated 8mm would be needed to get the spider to seat on the BB bearing face when I had the C1 on my crankset. 8mm of material removal on the bracket is going to take a major portion of the weld that's showing in grey; I would guess close to half of the thickness of that weld would be gone.

The inside edge of the granny 25T chain ring from the BB CL, is 39 mm on the S30 and 37 mm on the V1.0, if this helps!

 

[murmur]

So it seems like we're at an impasse. Robert apparently won't sell me an S40 chainstay without the S40 fork to go with it, but he doesn't have S40 forks in stock. So this C1 power meter will go back to Powertap before the 30-day return period expires.

 

[AlexisBV]

Issues like these are why I got Powertap P1 pedals instead of a 2inpower... the only thing I regret about the pedals is that I can't use my SPD shoes with them.