Clicks in the bottom bracket?

[JHZR2]

On both of my what I’d call thin wall aluminum bikes - my Scott Scale MTB and my Trek Verve 3, I get some clicking when I pedal. I thought on my mtb that maybe I cracked the frame. I’m pretty tall and on the upper end of what the typical bike design weight is (per my understanding). I’ve never seen any signs looking it over carefully.

As I’ve put the miles on my verve, I’ve started to get a click or cracking type sound when pedaling on it. I’m sure with the tagalong I typically have on it that we’re putting a lot of power down (we do try to ride fast), and a lot of weight.

I think I’ve traced that one to the bottom bracket and pedal assembly. I can consistently get a click/crack sound with the left pedal at the 10 o’clock position.

Is this common? Typical? I never encountered this with my Easton tubed prior mtb, or my Raleigh before that.

It’s the same sound on two different bikes from different manufacturers. It seems like maybe it’s just nature of the beast with these types of bikes that seem to have thinner wall tubing designed to be lighter.

Any suggestions? Could it also be that I’m just too heavy for the OE BB? I’m not that heavy but I am 6’4 and 250#, fairly muscular/athletic.

Thanks!

 

[wwillson]

I find that trying to figure out where a noise or click is coming from while riding can be almost impossible. While it could be the bottom bracket bearing, I doubt it is on a fairly new bike. If you put the bike on a stand and turn the crank, is it rough or does it have a catch? If you have to tools to remove and replace the bottom bracket, take the bearings out and see if they are rough.

[edit] That type of bottom bracket is really easy to remove with the correct tool. The "Do Not Disassemble" just means don't take the bearing out of the assembly. It's nice that they even show which way is tighten/loosen. It's about a 15 minute job. I'll give you a pointer, don't over tighten the bottom bracket when you put it back in, it just needs to be snug and that's it. Some people think they need to do the torque olympics on them and all it does is makes it really difficult to get off the next time and ruins the threads in the bottom bracket shell (the part welded to the frame).

I once had a click that no matter what I did, I couldn't get rid of it by working on the front end of the bike. That's where it sounded like it was coming from while I was riding. It took me months of riding and listening to this annoying click sound, to realize it was coming from the rear disk brake. A simple adjustment of the caliper and it went away. Made me feel silly chasing a sound and I wasn't even looking in the correct area

 

[fsdork]

Do you wear the same cycling shoes on both bikes? If so, it could be something in the shoe/cleat interface.

 

[JHZR2]

Do you wear the same cycling shoes on both bikes? If so, it could be something in the shoe/cleat interface.

No. Speed play frogs on my mtb, flat pedals on the trek.

 

[JHZR2]

It took quite a bit of force to do this by hand upside down, but I was able to make the clicks by getting the pedals vertical (as opposed to what seems to cause
It when riding), and flexing the assembly.

Of course someplace else in the frame may be flexing too.

 

[wwillson]

A video is worth a million words.

I would at least take the crank arms off and see if you can feel if the bearings are rough. Undo the clamp on the left crank arm and the right crank arm should pull out along with the spindle.

 

[MRC01]

Likely causes I've seen over the years

• pedal-shoe interface
  • already discussed
• pedal bearings
  • they spin at the same rate as the bottom bracket
• crank arm - bottom bracket interface
  • remove crank arms, grease the mating surfaces, reinstall
• bottom bracket bearing
  • remove the spindle, check for spindle wear at the bearing surfaces, bearing smoothness & free play, service/grease as needed and reinstall
  • Note: check bearings individually, and then check the spindle installed but without crankarms. Sometimes the bottom bracket sides aren't perfectly aligned in the frame, so the spindle might not spin smoothly & freely when installed, even if the bearings are fine. When this happens you'll usually see excessive wear on the spindle where it meets the bearings.
• cranks
  • Shimano crank arms (Ultegra & Dura Ace) are glued together and sometimes the glue fails
  • Look at the seams along the inside of the crank arms
• seat-seatpost interface
  • stress in the bottom bracket can transfer through the seat tube
  • remove the seatpost, grease and reinstall

 

[Number_35]

The external bearing assemblies are threaded oppositely (L side = RH thread, R (drive) side = LH thread) such that they shouldn't loosen with use ... but sometimes they do.

A loose one can result in a creaking or clicking noise when pedalling. You'll need a special tool to tighten them without scratching them.

After tightening I add matchmarks with a paint pen to see if the bearing assembly moves in future.

A clicking noise can be caused by the L crank not being tight enough on the axle. They used to say it was important to retighten the L crank arm after the first few miles of riding (not unlike checking lug nuts 50 miles after a tire change.)

 

[NYEngineer]

Yep. ^^ Exactly like 35 said. If mine start making noise, I disassemble, check everything for cleanliness and tightness and reassemble with fresh grease. Grease the BB threads where they go into the frame. Usually quiet after that.