FSA Gossamer bottom bracket maintenance

[Number_35]

My youngest son brought his Kona "Jake the Snake" cross bike over this morning, for me to try to find a strange clunk. A friend of his had thought that the bottom end needed to be serviced. The noise was only there when pedaling. I didn't think it was the bottom bracket as the axle turned freely (by hand with the chain off) with no noise and no grittiness.

First finding - Two broken spokes on the rear wheel. Replaced them, installed new rim tape, and trued the wheel (including tightening most of the other spokes). The noise remained, but I was glad I'd caught this.

Second finding - One pedal was rough, the other marginal. Swapped in both pedals off another bike. The noise remained, but again this needed doing.

Finally, I tackled the bottom bracket. Was a bit stumped at first, but found these two YouTube videos:

https://www.youtube.com/watch?v=nMlYo84wBFk

https://www.youtube.com/watch?v=rsjN6B3eZb8

Both videos are good as far as they go, but neither show what to do once the crank is removed. As it turned out, "Jake" has internal sealed bearings. I don't know how to get those units out, but fortunately it wasn't required. I pried the dust covers off with a dentists' pick, and lubed the bearings with fresh grease. Put the covers back on, and was pleased to find the noise gone. A bit weird, as the bearings weren't quite dry - they still appeared to be lubed by the melted remnants of the original grease.

Oh well, all's well that ends well ... I hope! We'll see how it is after he puts a few miles on.

 

[AZjeff]

So Jake has press-fit bearings, not one of the industrie's best ideas. I have a bike with them and don't take my bikes to a shop for anything but probably will if/when they need replaced. The first video shows external bearings, not the same thing and easily serviceable. In the 2nd video I think the guy is just greasing the ID of the internal bearings where the crank axle rides on it. Not sure what good that does, doesn't hurt but sure doesn't need that much grease. He doesn't seem very knowledgeable.

 

[Number_35]

AZJeff, agreed, the Jake unfortunately doesn't have the external bearings as shown in the first video. And I agree, greasing the interface between the bearing shells and the crank axle as in the 2nd video misses the point - that's not how it works.

Press-fit bearings - GRRRR, I feared as much. Thanks for the confirmation. I'll try to keep on top of these and keep them lubed, and hopefully they'll last a long time. And yes, it looks like shop time if I do have to replace them at some point.

 

[khittner]

A "clunk" when pedaling sounds like a loose crank arm, rather than bottom bracket bearings. Alloy crank arms used to require a re-torque or two after some miles following a bottom bracket service, but my bicycle-wrenching days were, uh, several semesters back . . .

 

[Number_35]

Originally Posted by khittner
A "clunk" when pedaling sounds like a loose crank arm, rather than bottom bracket bearings. Alloy crank arms used to require a re-torque or two after some miles following a bottom bracket service, but my bicycle-wrenching days were, uh, several semesters back . . .

That was my first thought as well ... but loose crank arms are likely very rare with this FSA system. The drive side crank arm and hollow axle are one piece, and the other crank arm fits onto the splined end of the axle. That's a poor description ... this internet photo will help. (10^3 words vs. one picture and all that ...)

Having said that, my vocabulary failed me when I described the sound as a 'clunk'. It was that to an extent, but there was more to it. Perhaps a bit of grinding/scraping/rattling as well. Regardless, it is quiet now, but I will look for a tool when the inevitable happens ... perhaps something like this:

https://www.youtube.com/watch?v=yOJAKBQOU9U

 

[NYEngineer]

If you end up changing the crankset out on that bike, Shimano is the way to go. They make a CX crankset that I use on my Dahon folder that is absolutely bomb proof. Their external bottom bracket isn't bad either.
For the utmost in smoothness and reliability, Chris King makes a killer bottom bracket. I have them on two bikes. They also have a greasing tool that forces new grease in and old grease out using a grease gun.

 

[Number_35]

NYE, that sounds very appealing. Is it possible, though, to fit external bearings to a bike factory-equipped with pressed-in bearings?

The Chris King bracket, with the greasing tool, sounds excellent. As you'll know, the Jake is a good bike, and I don't mind putting some work into it. We'll stay with the existing system for now, though, and see how it holds up. (Or perhaps I should press out the bearings now to make sure they aren't seized in when the time comes ...)

The stock photo I attached above is not quite accurate - I should have caught this before posting it. It shows the axle separate from the drive side. On the Jake, they're one piece.

 

[NYEngineer]

Forgot about the press fit. Check out Praxxis Works. They make a bottom bracket adapter that goes in where press fit does but works like external. I used one on my wife's Salsa Spearfish. Works great.

 

[AZjeff]

Originally Posted by Number_35

As you'll know, the Jake is a good bike, and I don't mind putting some work into it. We'll stay with the existing system for now, though, and see how it holds up. (Or perhaps I should press out the bearings now to make sure they aren't seized in when the time comes ...)

.


If you keep grease in it and water out it should last a long long time.

 

[nthach]

Lots of bike mechanics HATE BB30/PF30 bottom brackets. Cannondale made BB30/PF30 an "open" standard but the majority of bikes with BB30/PF30 are carbon fiber frames with looser tolerances than steel or aluminum frames. A SRAM tech rep said if I ever buy a new bike, avoid their BB30 cranks since the crank spindle is made from aluminum. It's not so much the bearings - but the frame tolerances. My current road bike is standard threaded. The custom bike builders led by Chris King and Paragon Machine Works(I know my ex's husband works for them) have been pushing the T47 standard - it gives the benefits of oversized bearings with the same ease of service and reliability as a threaded bottom bracket. Specialized and Jamis have been using FSA's BB386 standard on some of their bikes - built on the BB30 standard but with a wider shell and some backwards compatibility with standard external bearing cranks.

The solution that I've heard works is a Praxis Works conversion bottom bracket and replacing the BB30 crank with a Shimano Hollowglide II or SRAM GXP one. This is the bottom bracket, it's a two-piece setup with an extended sleeve and collet assembly that "locks" the bearings in axis. https://praxiscycles.com/bottom-brackets/conversion-bb/

 

[Number_35]

Originally Posted by AZjeff
Originally Posted by Number_35

As you'll know, the Jake is a good bike, and I don't mind putting some work into it. We'll stay with the existing system for now, though, and see how it holds up. (Or perhaps I should press out the bearings now to make sure they aren't seized in when the time comes ...).

If you keep grease in it and water out it should last a long long time.
So I had hoped ... but real life intervened.
Originally Posted by nthach
Lots of bike mechanics HATE BB30/PF30 bottom brackets. Cannondale made BB30/PF30 an "open" standard but the majority of bikes with BB30/PF30 are carbon fiber frames with looser tolerances than steel or aluminum frames. A SRAM tech rep said if I ever buy a new bike, avoid their BB30 cranks since the crank spindle is made from aluminum. It's not so much the bearings - but the frame tolerances. My current road bike is standard threaded. The custom bike builders led by Chris King and Paragon Machine Works(I know my ex's husband works for them) have been pushing the T47 standard - it gives the benefits of oversized bearings with the same ease of service and reliability as a threaded bottom bracket. Specialized and Jamis have been using FSA's BB386 standard on some of their bikes - built on the BB30 standard but with a wider shell and some backwards compatibility with standard external bearing cranks.

The solution that I've heard works is a Praxis Works conversion bottom bracket and replacing the BB30 crank with a Shimano Hollowglide II or SRAM GXP one. This is the bottom bracket, it's a two-piece setup with an extended sleeve and collet assembly that "locks" the bearings in axis. https://praxiscycles.com/bottom-brackets/conversion-bb/
You can add me to the list of those who wrench on bikes and don't like the BB30 system!
Originally Posted by NYEngineer
Forgot about the press fit. Check out Praxxis Works. They make a bottom bracket adapter that goes in where press fit does but works like external. I used one on my wife's Salsa Spearfish. Works great.
So, Jr phoned the other day asking about a bike problem. He came over and I was a bit dismayed to find that the pressed-in drive-side BB30-style bearing had completely disintegrated. There was almost nothing left on that side. Fortunately I had just done the post-winter maintenance on his single-speed, and had removed the studded tires and installed the 3-season knobbies, so he was OK for transportation.

I guess the silver lining is that it will be easy to knock out the intact bearing on the non-drive side.

I could replace both bearings with same, but really like the idea of this Praxis system.

In the experience of you veteran bike mechanics, what will the stop be for the existing bearings? I'm hoping for a snap ring I can remove. The damaged side looks to have a collar there, but that may be a remnant of the bearing that's masking a snap ring. If it is a permanent sort of collar, I don't think the Praxis system will work (unless I can drive out the collar). If there is a permanent collar I can't remove, I'll to press in new BB30 bearings.

Photos of the carnage to follow!

 

[Number_35]

More details - the old ravaged BB assembly is a PF-30, not a BB-30 type. I was able to drive it out with my specialty tools - a hammer and a piece of scrap wood.

The BB I.D. is 46 mm. The bearings (well, at least one survivor) has an I.D. of about 29.9 mm, and the O.D. of the hollow crank measures at 29.8 mm. There will be some +/- with my old calipers, but that'll be close.

Anyway, I'm now looking for suggestions on the best retrofit. Many thanks in advance!

 

[Number_35]

Got it - not too bad a job at all, once I had it apart.

The photos show the bike's empty bottom bracket, the PF-30 assembly, good side (original bearing still OK), bad side (original bearing missing), and the only bits left of the original bearing. No special tools required - the bearings sit in a non-metallic holder, and as there was nothing left of the bad one, I was able to press a replacement BB-30 bearing in by hand.