Solmors

I just got my hands on a used SRAM Quarq CinQo "175mm (SRAM s975 arms) 130bcd 53/39 10spd rings BB30/PF30 type spindle" (bikeradar com/reviews/training/power-meters/sram-s975-quarq-crankset-review) for next to nothing. I am hoping to put it on the bike I already have, a Motobecane Mirage Pro (bikesdirect com/products/motobecane/road_bikes/mirage_pro-xv.htm). It looks like there might be two problems.

1. The bottom bracket on my bike is a Shimano BB-ES25 wheras the Quarq has a BB30. I'm assuming this might be an issue.
2. My Shimano Claris front derailleur and shifter is set up for 3 speeds on the front crankset. I'm hoping there might be a way that I can fudge it to get it to work.

I recently got back into cycling, mostly on a smart trainer using zwift. I am loving having the power displayed and trying to keep my power in a certain range, so it would be great to have that ability on the road as well. If not, well I can resell the power meter on ebay for a fairly good profit margin.

Thanks!

DrIsotope

The BB-ES25 is an Octalink for an English-threaded 68mm bottom bracket. For a 30mm spindle, you would need a BSA30 BB, in which a BB30 will not fit. The spindle is not long enough.

BB30 is not compatible with a BSA bottom bracket shell. Most of the cranks with longer 30mm spindles will work, i.e. BBBRight, BB386, etc.

Solmors

I thought that might be the case. Thank you for the info!

trailflow1

Sram made the S Series cranks with longer spindles.

Your SRAM S975 spindle might be the longer version. Even though it is still labeled BB30. Measure the spindle without the preload adjuster thing or spacers. If it is 105mm then you can use a BSA30 BB. If it's 85mm then your out of luck. The spindle is too short for the external cups of the BSA30 bb.

DrIsotope

Some further digging shows that the GXP version has the longer spindle, but the BB30 is the typical shorty for use in press-fit bottom brackets without external cups.

trailflow1

I've got one of these ''BB30'' S Series crank with the longer spindle. They definitely exist. Sram may have two different versions on the market. But they never announced any changes when they released them.

Here are two examples of S975 cranks with the longer spindle. You can tell because of the sram preloader or spacer attached. This preloader and spacer is not needed on older short bb30 cranks.

https://forum.slowtwitch.com/forum/S...75mm_P4265501/

https://www.ebay.com/itm/SRAM-Quarq-...IAAOSwKfVXHmI1

Solmors

Looks like it is 100mm from the base of the the threads to then end of the spindle, and 95mm if the little plastic spacer thing is on it. Maybe I am measuring it wrong, so I added a picture with and without the plastic part. Also included an image of everything I got from the seller.

Edit: I cant post pictures or URLs. So here is this imgur com/a/qMFTyMe

trailflow1

That's the long spindle version. There is still a 5mm black spacer next to the preloader. Both of those are fully removeable. They will slide off the spindle with some persuasion. You'll need to take both off when using a BSA30 bb.

DrIsotope

First a pic assist:



I just measured both of my BSA30 bikes (one with a Rotor BB, the other with Wheels Mfg.) and they are both 92mm measuring from the outsides of the cups (68mm shell + 12mm cup +12mm cup.) If you can pull the NDS spacer and have ~92mm from crank to the flutes, you should be good to go, provided the NDS crank arm clears the chainstay.

Solmors

Thanks guys!

I was able to pull off the other black spacer and it does measure 105mm now. Measured the shell of my bottom bracket on the frame, looks like it's 68mm like you said, and from pedal to pedal looks roughly 92mm. (i.imgur com/qD8KWZn.jpg)

So what I need to do now is get a BSA30 bottom bracket? And cups to make it fit? Do you have any recommendations, or maybe a link to one that would work?

DrIsotope

Having used both Wheels Mfg and Rotor BSA30 bottom brackets, I'd recommend the Rotor-- it comes with the required tool, so all you need is a 3/8" ratchet. You can buy crank spacers by the pack, but the spindle with the threaded bit and the nut should be perfect. I didn't need any extra spacers with either of my Rotor 3D cranksets, which should have the same spindle length as your SRAM/Quarq.

trailflow1

BSA30 bb's come with cups. I think you mean spacers ? You might need a few 0.5mm plastic shims to fill any remaining small gap.