PF30 shell diameter discrepencies

Discuss light weight issues concerning road bikes & parts.
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Flapmeat
Posts: 44
Joined: Sun Mar 22, 2015 1:52 pm

by Flapmeat

Hi all, having an issue with my PF30 (BBRight) shell diameter.

Actual size of the shell I have is 46.22mm, or 1.820". Unfortunately I ordered a wheels MFG threaded PF30 before I measured the shell, and theheir cups are 45.89mm...obviously undersized. The crankset as of right now with the wheels MFG BB does move noticably under even light power.

Does anyone know of a BB solution for BBRight with oversized cups to fit my shell? Warranty is out of the question as it is almost 6 years old (this is the first year of ownership for me) and a new frame is also out of the question.

AJS914
Posts: 1757
Joined: Tue Jan 28, 2014 6:52 pm

by AJS914

Did you install it with retaining compound. The usual is Loctite 609 but you could try 680 which fills gaps up to .5mm.

by Weenie


sungod
Posts: 1415
Joined: Fri Dec 24, 2010 9:37 pm
Location: it's raining, it must be uk

by sungod

according to...
http://www.bbright.net/bbrightdrawings.pdf

...bbright pressfit should be 45.88 min / 45.96mm max, assuming your measurements are correct, the frame is way oversized (and the wmfg bb seems undersized against that spec.)

as above, retaining compound is an option, use 7649 primer for best results as bb/cup surfaces will probably be inactive

another would be to use a bb that threads together, you don't mention what actual crank type you have, for shimano there's this...
http://wheelsmfg.com/bottom-brackets/bb ... black.html

with a frame that is out of spec., it might be a better solution than using pressfit, but you need to check internal clearance will allow this type pf bb to be fitted

Flapmeat
Posts: 44
Joined: Sun Mar 22, 2015 1:52 pm

by Flapmeat

sungod wrote:according to...
http://www.bbright.net/bbrightdrawings.pdf

...bbright pressfit should be 45.88 min / 45.96mm max, assuming your measurements are correct, the frame is way oversized (and the wmfg bb seems undersized against that spec.)

as above, retaining compound is an option, use 7649 primer for best results as bb/cup surfaces will probably be inactive

another would be to use a bb that threads together, you don't mention what actual crank type you have, for shimano there's this...
http://wheelsmfg.com/bottom-brackets/bb ... black.html

with a frame that is out of spec., it might be a better solution than using pressfit, but you need to check internal clearance will allow this type pf bb to be fitted


I should have noted that the WMFG BB I have is the threaded PF30 for use with a BB30 long spindle Quarq

I ordered 609, should be here Thursday. Will let dry all day Friday and hope for the best. Thank you both for the recommendations!

sungod
Posts: 1415
Joined: Fri Dec 24, 2010 9:37 pm
Location: it's raining, it must be uk

by sungod

if it's the thread-together type, before trying loctite i suggest try using ptfe tape to wrap the contact area of the bb each side

wrap the tape tight, experiment to see how many turns are needed, on the side that will rotate as the bb is tightened make sure you apply tape in the direction that will not 'unwrap'

if the tape is shearing off on inserting the bb, you can first put the bb in the deep freeze, it'll contract enough to give plenty of clearance - wrap the tape tight, put the bb in a ziploc bag and freeze for 10-15 minutes, take to the bike in the bag, only remove at the last moment and press in, this avoids having frost/ice form on the contact surfaces

if you do try loctite, i don't think it'd be advisable to use activator given the time it takes to screw the bb in - with activator the cure is fast, it's intended for press-fit, the loctite may harden and break up before the bb is fully tight

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