[LexSuperfly]

Hey guys

I noticed I could wiggle my crank when I had it on the stand. The bearings can't have but a few thousand miles on them after a year. It's a Trek Superfly frame with an old Shimano LX crank.

Is this amount of play normal?

https://flic.kr/p/2mBRiNR
Thx for your help!

 

[shwndh]

Hey guys

I noticed I could wiggle my crank when I had it on the stand. The bearings can't have but a few thousand miles on them after a year. It's a Trek Superfly frame with an old Shimano LX crank.

Is this amount of play normal?

New video by Alexi Boado

photos.app.goo.gl

Thx for your help!

Absolutely not. What kind of wiggling? Is the bottom bracket loose, one crank arm, both moving laterally, etc? Are we talking about the bottom bracket bearings? A picture would help. Sound like BB is loose from what you describe.

Oh man. Totally missed the video. Yea, I would check the preload. if the other side is moving as well, it's the bearings .

 

[J.B. Weld]

No amount of play is normal, you need to overhaul that and see what's wrong. Maybe it just needs the preload tightened but from the looks of it I doubt it, more likely bad bearings or bearings loose in the frame.

 

[LexSuperfly]

I assumed as much. Thanks gents. Appreciate your help.

Not sure how to preload a BB bearing. The crank just slides in through both bearings and the opposing crank grips. I have the crank as far through as possible.

But this is strange because the bearing is relatively new and installed by TREK. Now I need to find a replacement bearing set.

 

[the-one1]

It wouldn't be a preload issue since the wiggle is fore and aft and not left to right.
Its either worn bearings or worst, the BB shell is loose from he carbon frame.
Remove the crank and check the BB.

 

[LexSuperfly]

I did remove the crank. Something was loose and I was getting a creaking noise when applying torque so I took everything apart and found the cassette wasn't on tight enough. At least that's what I think the noise was due to. Didnt ride it thoroughly. Will do so today.

I sure hope its not the BB shell...Ill ask the guys at Trek. Frame only has a few thousand miles on it.

 

[J.B. Weld]

I assumed as much. Thanks gents. Appreciate your help.

Not sure how to preload a BB bearing. The crank just slides in through both bearings and the opposing crank grips. I have the crank as far through as possible.

Tighten "B" with the crankarm bolts loose.

 

[LexSuperfly]

Thats just a plastic dirt cover.

 

[J.B. Weld]

Thats just a plastic dirt cover.

No, it's a preload adjuster.

 

[LexSuperfly]

wow I had no idea. ok I will try it. Thanks JB.

 

[Shark]

Yeah it's a preload adjustment. If you have been treating it as a dust cover, things were loose enough you may have damaged the bb bearings or something else.

Sent from my SM-G991U using Tapatalk

 

[LexSuperfly]

Well I didn't install it, Trek did.

 

[127.0.0.1]

.........

 

[LexSuperfly]

Great...

 

[Nat]

The bearings can't have but a few thousand miles on them after a year.

That's pretty good!

 

[LexSuperfly]

Why do you say "that's pretty good"?

 

[mrpizza]

A few thousand miles of riding in a year is a great achievement!

 

[LexSuperfly]

ohhhh...I though you were referring to the crank/BB situation.

After the gyms closed last spring for COVID, the bike became escape #1 for most of us I assume. Then my 17 year old Trek aluminum frame cracked and Trek sold me a carbon frame for less than 50%...they moved everything over that was compatible and looks like something went wrong in the process.

 

[Harold]

A few thousand miles on a pressfit bb? Not unusual for one to be toasted after that. I had some that only made it about 500-600mi before getting rough.

 

[LexSuperfly]

oh that's good to know! Did they wiggle like that when they had failed?

Which brand would last longer?

Hopefully I can just push out the old bearings and pop in new ones.