Hello:
Migrating from BB30 to PF30 and am having difficulty with the installation. Frame is a Cannondale Super Six Evo (PF30). Bearings are Wheels Manufacturing PF30 (regular, not angular contact). I'm using a Cannondale SI SL Crankset with a 104mm spindle. The crankset will not spin freely and barely makes one revolution (yeah I'm spinning that thing as if my life depends on it). Just to be sure that I am not over loading the bearings, I even tried it without the wave washer.
It appears that the diameter of the spindle is to big and binding the bearings. I do have to get a rubber mallet to hammer the spindle through each of the bearings. Tried with an FSA crankset (spindle is integrated) and it installs with far less force than the Cannondale spindle. The FSA crankset spins very nicely. Anyone run into this problem before? Any suggestions? Would sanding down and polishing the spindle be a good idea?
Thanks,
C.
PF30 Bottom Bracket Problem
Moderator: robbosmans
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highdraw
Well, a couple of things have to be separated to determine your best course.
So, here is the first thing to try...since you already tried without the wavewasher which btw, was a good first step to understand the underlying dynamic.
Three dynamics at play:
1. tolerance stack up of your spindle relative to Wheel Mfg bore I.D. (s)
2. lack of co-axiality of bearing bore centerlines...a common issue with PF30.
3. Improper lateral spacing...even without the wavewasher.
To determine root cause:
First step is to remove your SI SL crank. Then, reinsert spindle thru bearing bores without the left crank arm on and spin it.
How does it spin? If it spins easily, then your PF30 BB installation is ok and so is your SI SL spindle OD tolerance...your issue is lateral spacing.
So first try this and report back and if your SI SL crank still binds without the left crank arm attached...then I will advise your next steps.
Sound good?
So, here is the first thing to try...since you already tried without the wavewasher which btw, was a good first step to understand the underlying dynamic.
Three dynamics at play:
1. tolerance stack up of your spindle relative to Wheel Mfg bore I.D. (s)
2. lack of co-axiality of bearing bore centerlines...a common issue with PF30.
3. Improper lateral spacing...even without the wavewasher.
To determine root cause:
First step is to remove your SI SL crank. Then, reinsert spindle thru bearing bores without the left crank arm on and spin it.
How does it spin? If it spins easily, then your PF30 BB installation is ok and so is your SI SL spindle OD tolerance...your issue is lateral spacing.
So first try this and report back and if your SI SL crank still binds without the left crank arm attached...then I will advise your next steps.
Sound good?
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With just the spindle installed, it still very tight. I put in a cheap FSA Gossamer crankse (two piece) and it spins freely. I just have to nudge it with my mallet and it goes in easy. With the 104mm spindle, I have to strike it hard and multiple times. Wish Cannondale had left BB30 alone. Apart from shit bearings, it ran quietly for me.
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highdraw
CHL wrote:With just the spindle installed, it still very tight. I put in a cheap FSA Gossamer crankse (two piece) and it spins freely. I just have to nudge it with my mallet and it goes in easy. With the 104mm spindle, I have to strike it hard and multiple times. Wish Cannondale had left BB30 alone. Apart from shit bearings, it ran quietly for me.
Next step:
This evaluates Spindle diameter versus lack of bore alignment side to side:
With just the drive side of crank and spindle and no left crank arm, insert spindle into just one bearing on one side. Does it take a hammer blow to get the spindle threw the inner bearing race of just one bearing?
When you try this for the other bearing is there a difference in terms of tightness for each side?
Or...
Does the resistance/tightness come when you try to push the spindle threw both bearings?
Let me know and will advise next step
It takes multiple strikes to get the spindle through the first bearing. With one bearing engage, it feels tight. With two bearings engaged into the spindle, it feels even tighter. It takes multiple strikes to engage the second bearings as well. It certainly feels like it's a harder engagement than what I experienced on previous BB30 frames (SS6, SS6HM, CAAD9, Slice). When I used ceramic bearings on previous BB30 frames, the crankset would spin endlessly. It doesn't even make it through one revolution right now.
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highdraw
You have a couple of options. I was somewhat hoping it was bore misalignment but you have a poor tolerance stack up of spindle diameter relative to bearing inner race bore I.D. which sounds to be uniform for each bearing.
Hard to know the true culprit or rather offender without a micrometer for spindle O.D. and/or bore gauge to measure bearing I.D. Your spindle maybe slightly oversize or your bearings a bit undersize.
With this sort of thing, always err on the side of prudence or caution to identify the root cause. Cranks cost more than BB's and bearings.
So...you could call your local bike shop and ask them if they have some BB30 bearings on hand that you could see if they slide right onto your crank spindle and evaluate if your crank spindle is oversize.
If you establish that your particular bearings are NOT undersized but rather your spindle is a bit oversized...then your next step is to sand your spindle down slightly. This can be accomplished with 600# wet paper followed by #1200 for surface polish. A little sanding makes a big difference, so don't take off too much. You do this incrementally to each end of the spindle where the spindle interfaces to each bearing. You do NOT want to do this however until you establish your spindle is oversized and not your bearings undersized. If you don't want to pay for another BB to test this, then drive your crank down to your bike shop and ask to perform a test fit with a BB30 BB or BB30 bearings on hand to determine the root cause.
Hope that helps.
Edit: And don't know this without parts in hand but you can evaluate...if you have installed this crank and it was drop in with other BB's then a pretty safe bet the bearings are undersized. Will give you a tip moving forward. Never force aka pound a crank spindle thru a bearing bore. Reason is you can very easily ruin the bearings. Btw, in this case may not be a lost cause because the bearings were poorly sized to begin with if you have built this crank with other BB's in the past no problem. When you pound a crank in, it brinells the bearing balls due to point loading of the inner and outer races. In fact, this is most likely your root cause of poor bearing rotation after pounding your spindle in. Never do that. Measure the parts to figure out why they won't go together and take back the part that is out of spec would be my suggestion.
Brinelling:
https://en.wikipedia.org/wiki/Brinelling
Hard to know the true culprit or rather offender without a micrometer for spindle O.D. and/or bore gauge to measure bearing I.D. Your spindle maybe slightly oversize or your bearings a bit undersize.
With this sort of thing, always err on the side of prudence or caution to identify the root cause. Cranks cost more than BB's and bearings.
So...you could call your local bike shop and ask them if they have some BB30 bearings on hand that you could see if they slide right onto your crank spindle and evaluate if your crank spindle is oversize.
If you establish that your particular bearings are NOT undersized but rather your spindle is a bit oversized...then your next step is to sand your spindle down slightly. This can be accomplished with 600# wet paper followed by #1200 for surface polish. A little sanding makes a big difference, so don't take off too much. You do this incrementally to each end of the spindle where the spindle interfaces to each bearing. You do NOT want to do this however until you establish your spindle is oversized and not your bearings undersized. If you don't want to pay for another BB to test this, then drive your crank down to your bike shop and ask to perform a test fit with a BB30 BB or BB30 bearings on hand to determine the root cause.
Hope that helps.
Edit: And don't know this without parts in hand but you can evaluate...if you have installed this crank and it was drop in with other BB's then a pretty safe bet the bearings are undersized. Will give you a tip moving forward. Never force aka pound a crank spindle thru a bearing bore. Reason is you can very easily ruin the bearings. Btw, in this case may not be a lost cause because the bearings were poorly sized to begin with if you have built this crank with other BB's in the past no problem. When you pound a crank in, it brinells the bearing balls due to point loading of the inner and outer races. In fact, this is most likely your root cause of poor bearing rotation after pounding your spindle in. Never do that. Measure the parts to figure out why they won't go together and take back the part that is out of spec would be my suggestion.
Brinelling:
https://en.wikipedia.org/wiki/Brinelling
