86,5mm shell + MTB crankset

[sqber]

I just bought my first CX bike and it has PF86 bottom bracket (hence the frame shell should be 86,5mm). I have Quarq power meter cranksets on my MTB and I would like to take the cranks and use them on my CX bike during the winter time. MTB has 92 mm frame shell, which is 6mm wider than the CX bike, therefore I assume the crank's spindle is also longer on the MTB. Can I use spacers or adaptors to put my PF92 specific MTB crank (1x) to a PF85 specific frame? I just assume that putting 3mm spacers on each side of the bottom bracket will do the trick or will it? Thanks!

[ultimobici]

I just bought my first CX bike and it has PF86 bottom bracket (hence the frame shell should be 86,5mm). I have Quarq power meter cranksets on my MTB and I would like to take the cranks and use them on my CX bike during the winter time. MTB has 92 mm frame shell, which is 6mm wider than the CX bike, therefore I assume the crank's spindle is also longer on the MTB. Can I use spacers or adaptors to put my PF92 specific MTB crank (1x) to a PF85 specific frame? I just assume that putting 3mm spacers on each side of the bottom bracket will do the trick or will it? Thanks!

If your crankset has a 24mm axle you should be able to use a collet style bb unit like Hope’s with a few spacers.


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[grover]

I'm assuming your Quarq spindle is GXP not 30mm?

The GXP captures the non-drive side bearing between a lip on the spindle and the crankarm. So you can't put spacers on the spindle on the non-drive side between the bottom bracket cup and the crankarm. The position of the crank in relation to the frame, chainline, is essentially set by the position of the non-drive bearing.

So if you install a MTB GXP crankset (designed for 92mm shell) into a road GXP bottom bracket (86.5mm shell) you push the chainline far too wide and the crankarms sit assymetrically in the frame.

The easiest solution is to buy a set of GXP road arms with the same interface as your quarq spider and just swap the spider onto the different crankarms each season.

Another option would be to use spacers between the frame and the bottom bracket cups on the non-drive side. That would move the non-drive bearing wider and centre the cranks/get correct chainline.

[sqber]

Another option would be to use spacers between the frame and the bottom bracket cups on the non-drive side. That would move the non-drive bearing wider and centre the cranks/get correct chainline.

Thank you a lot! Yes, the Quarq spindle is GXP.
So, I have to find a 41mm internal diameter spacer(s) to add between the BB cup and frame. Hopefully some of my LBSs have some laying around
And a further note: I'm planning to adjust the chainline anyway (bought some longer crank bolts and spacers to shift the chainring towards the frame).

[ultimobici]

Another option would be to use spacers between the frame and the bottom bracket cups on the non-drive side. That would move the non-drive bearing wider and centre the cranks/get correct chainline.

Thank you a lot! Yes, the Quarq spindle is GXP.
So, I have to find a 41mm internal diameter spacer(s) to add between the BB cup and frame. Hopefully some of my LBSs have some laying around
And a further note: I'm planning to adjust the chainline anyway (bought some longer crank bolts and spacers to shift the chainring towards the frame).

That’s why the collet style bb units are best for this. They clamp themselves into the frame and reduce the chance of creaks.


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[ooo]

I think only Wheels Mfg thread-together BB offered for GXP without adapter,
other thread-together BB offered with 24mm bearing + shim for 24-22, but...

https://wheelsmfg.com/bb86-92-outboard- ... black.html
https://www.bike24.com/p2222077.html
Wheels Mfg BB86 thread-together BB for use with 24/22mm spindle cranks will not work with Quarq SRAM/GXP cranksets (Elsa, Riken, SRAM Red 22, SRAM S975, SRAM S2275, CinQo Saturn, Saturn2). If your Quarq spider has an ID less than 49.5mm, it will not fit over our BB86-OUT cup.

https://bbbcycling.com/en_en/bbo-29-bottomfit-bb86-92
https://www.bike24.com/p2260143.html
BBB BottomFit BBO-29 (thread-together) - small out cups D=44 mm 16 notches,
requires shim to convert shimano 24-24 to sram 24-22

https://www.tokenproducts.com/bottom-br ... -bracket-1
https://www.tokenproducts.com/images/BB ... ankset.pdf
https://www.ridewill.it/p/en/token-2284 ... le/264453/
Token BB841T-41 (thread-together) - unknown cups diameter (ask by email/FB),
requires shim to convert shimano 24-24 to sram 24-22

https://www.hopetech.com/product/press-fit/
https://www.hopetech.com/wp-content/upl ... mplete.pdf
Hope BBPF41SSN - this one have smallest outside diameter, because it uses special (internal) tool HTTPFA for threading
requires shim to convert shimano 24-24 to sram 24-22

[DDX]

I'm using this bb :
https://www.on-one.co.uk/i/q/BBTOKBB92/ ... om-bracket

Comes with 1x 2.5mm spacer.
I'm using 2 spacers with my quarq xx1 and bb86 frame.

[sqber]

Thanks for all the help and comments! I have now done some 50 kms on the new bike with the Quarq crankset. My solution was a budget bodge:
- got myself two 2.5 mm spacers, which go between the BB and the frame. No cost, just a little hunt in several LBS-s as these seem to be quite a rare thing (although Shimano gives one for free with every PF bottom bracket, but apparantely most mechanics just through these to bin right away).
- punched the SRAM PF86 bottom bracket out of the the frame, installed the spacers and pressed the same BB back in. Used some antislip compound between the frame and BB. Cost saving about 100 Euros compared to a Hope or similar bottom bracket with threaded sleeve (+ adapters + special tool in the case of Hope).
- installed Garbaruk 44t oval chainring on the Quarq boost spider with twelve 1 mm spacers (3 for eached bolt). Got myself some longer than usual chainring bolts in order to fit the spacers. I couldn't use the chainring that came with the bike as the bolt circle pattern was asymmetric and wouldn't fit to Quarq. Total cost about 60€ (new chainring and bolts)
- installed the crankset to the frame.
- RIDE!

So far no creaks or sounds, just pure fun. The chainring is still very far away from the frame, but as I rarely use the lightest 3 gears anyway, it is not an isse. If I had even longer chainring bolts, I would add one 1mm specer.
Happy days!