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Trying to diagnose a creak on my road bike, and figure out what I can do about it.
August 1, 2012 2:09 AM   Subscribe

Trying to diagnose a creak on my road bike, and figure out what I can do about it.

A few weeks ago I started noticing a creak coming from my road bike (this one). Symptoms:

- the creak gets sounds like its coming from the cranks
- it's there when I pedal and gets louder the harder I push the cranks
- it's there in all gears and when pedalling with either foot on its own
- it's not there when I spin the cranks on the workstand, coast or pedal backwards

If this were an older bike then I would be 99% sure that the bottom bracket bearing need replacing / regreasing, but I have only done about 1500 miles on this bike from new - this doesn't seem like enough to require a BB service. On the other hand, I have been riding it daily in some pretty rough weather (the UK has had record-breaking amounts of rain this summer) so maybe some water could have sneaked in somewhere.

Is there anything else I could tighten/loosen/regrease before I pin the blame on the BB? And if the BB is the culprit, how likely am I to be able to fix it myself? It's a carbon frame, so I suspect that there may be torque tolerances involved which I am ill-equiped to deal with.

Also: I noticed when I put the bike up on the workstand to take a look that there are no dust cap s or anything on the crank axle. The right-hand side is a gaping hole, and on the left-hand side you can see the bolt (pics). Should there be something covering these?
posted by primer_dimer to Sports, Hobbies, & Recreation (26 answers total) 1 user marked this as a favorite
 
It's your saddle.
posted by alex_skazat at 3:02 AM on August 1, 2012 [3 favorites]


Also: I noticed when I put the bike up on the workstand to take a look that there are no dust cap s or anything on the crank axle. The right-hand side is a gaping hole, and on the left-hand side you can see the bolt (pics). Should there be something covering these?.

No. You have outboard bearings - they're outside of your actual frame - so there's nothing actually where you'd traditionally see your bottom bracket.

Some outboard bearings do less than perfect in bad weather - especially rain. I've replaced a X7 bottom bracket (SRAM, MTB) after oh, 2 weeks of bad weather.
posted by alex_skazat at 3:05 AM on August 1, 2012


I've heard similar noises when the pedals themselves needed tightening in the crank arms. In my case they weren't visibly loose, but a little extra torque took care of it.
posted by jon1270 at 3:15 AM on August 1, 2012


Oh, and the pedal threads should've been greased before installation, so you might want to check that.
posted by jon1270 at 3:18 AM on August 1, 2012


I've heard similar noises when the pedals themselves needed tightening in the crank arms. In my case they weren't visibly loose, but a little extra torque took care of it.

Good idea! I've already regreased my pedal spindle bearings in case that was making the noise, but I'll check the tightness of the pedals themselves.
posted by primer_dimer at 3:19 AM on August 1, 2012


Hope that fixes it. It's been about 3 years since I dealt with this, but I think greasing the threads themselves was an important part of the fix. Good luck.
posted by jon1270 at 3:57 AM on August 1, 2012


I had the exact same problem and I took my bike to the shop because it was still covered under warranty. I don't know what they fixed but it was something in the rear hub or cassette and it wasn't something simple.
posted by 14580 at 4:36 AM on August 1, 2012


I think pedals is the traditional answer here but wanted to mention that I have been absolutely convinced the creaking was coming from the cranks when it was, in fact, coming from my saddle. Check to see if it creaks when you stand.
posted by makeitso at 5:08 AM on August 1, 2012 [1 favorite]


Nth'ing the saddle - I've had just this issue. While out riding, get up off the saddle and pedal standing, and see if the sound continues. If it does, it may well be your bottom bracket needs to be repaired. If the sound mysteriously goes away, something broke or stretched or came loose in your saddle. Begin by tightening the post, and go from there.

Also, check that the handlebars and stem aren't even a little loose - that can also cause mystery creaks that sound like bad business in the BB.
posted by Slap*Happy at 5:11 AM on August 1, 2012


Are you using clipless pedals? Make sure the cleats in your shoes are tightened properly, too. I hate hunting down noises like this just to find I had a shoelace end tapping against the frame or something silly like that.
posted by backseatpilot at 5:11 AM on August 1, 2012


Nthing saddle; definitely check before doing anything BB-related. I just fixed a similar problem - I would have described the symptoms identically and was sure it was a problem with the crankarms. But before I took those off, I took the seatpost out, took the saddle off the seatpost, took all bolts out and regreased. When I reinstalled, the creak was gone! Bliss.
posted by chinston at 5:15 AM on August 1, 2012


Oh, also I had the creaking even when standing while pedaling. In fact, it was even more noticeable then. You'd think that would eliminate the saddle as a possible source, but I think this was just causing the frame to flex subtly, which was then resulting in a creak at the seatpost bolt.
posted by chinston at 5:19 AM on August 1, 2012


Thanks everyone for the suggestions; I will try them one-by-one so that I can come back and mark the best answer :-)
posted by primer_dimer at 5:21 AM on August 1, 2012


In my experience, where you think the sound is coming from has little to no bearing on where it really occurs. I've been wrong every time. The best bet is to have a riding buddy come along side and move forward and backward to help pin down the location to the front, center or rear. If it can be reproduced on a stationary trainer (this itself unlikely) then you can really nail it down.

Oh, and half the time the sound is in the saddle/seat post.
posted by dgran at 5:34 AM on August 1, 2012 [1 favorite]


Seeing as there seem to be quite a few votes for the seatpost, I will ask a follow-up question: should I grease the seatpost and if so with what? The frame is carbon but the seatpost is alloy.
posted by primer_dimer at 5:40 AM on August 1, 2012


Based on a very similar issue I've seen with more than a few bikes, my vote is actually with the cranks. If it creaks while you're pedaling off the saddle, that would rule out the saddle. The fix was shown to me by a good friend who is one of the best bike mechanics I've known and is very simple: wrap a few loops of teflon tape around the threads of the cranks. Teflon tape is used for plumbing and other pipe threads; you get it at any hardware store.
posted by bumpkin at 6:08 AM on August 1, 2012


You have grit in your external crank bearings or one of the ball-bearings is out alignment/fractured. Usually only notice this under load (hard pedalling) in its early stages, it eventually gets worse and more noisy.

Here's a fairly thorough bunch of checks you can make to diagnose and fix the problem and also cover some of the other suggestions up-thread.
posted by a non e mouse at 6:26 AM on August 1, 2012


Make sure the bolts that hold the chainrings to the crank are tight, also check that they sre not cracked. This caused mysterious creaking until I figured it out
posted by Confess, Fletch at 6:33 AM on August 1, 2012 [1 favorite]


Older and wiser mechanics than I have strongly discouraged lubricating the seat post in any way. Pop the seat off completely and try that for a standing test ride before you decide it's the seat post.
posted by chairface at 7:19 AM on August 1, 2012


My understanding is that a carbon frame should not have any lube for the seatpost. If this is plain wrong, I defer to people who know better.
posted by computech_apolloniajames at 7:23 AM on August 1, 2012


Pop the seat off completely and try that for a standing test ride before you decide it's the seat post.

Great idea, that would never have occurred to me!
posted by primer_dimer at 7:26 AM on August 1, 2012


Only grease metal to metal interfaces.

You can also try making it creak by grabbing the crank in flexing it inwards in various parts of its revolution. I find this easier on the ground than in the stand. If you can make it creak by hand in any orientation, check how well the crank is attached to the bottom bracket. If it's in only in orientation, suspect the bottom bracket.

I've seen a creak in a clipless pedal as well. A little lube fixed that one up.
posted by advicepig at 8:59 AM on August 1, 2012


Carbon assembly paste ("liquid torque") can be used between carbon/carbon, carbon/alloy or alloy/alloy interfaces, and has solved more than one unidentified creak for me.
posted by anagrama at 9:45 AM on August 1, 2012


Seconding Confess, Fletch, for the chainring bolts were the cause of my mysterious creaking too. I found this out after (/lightly/) lubing my seat post. I don't really recommend that...
posted by radioaction at 12:05 PM on August 1, 2012


I would think that if you wanted to put some lubrication on the seatpost without using grease, then some graphite powder would probably do the trick and would be extremely unlikely to damage anything because it's pretty gosh-darn inert and is just carbon anyway. It's also cheap and super versatile and if you don't already have some then you should.
posted by Scientist at 1:55 PM on August 1, 2012


After stripping/re-greasing/re-tightening the cleats, pedals, saddle, seatpost clamp, chainring bolts, bottom bracket, and wheel skewers, it turned out to be the crank bolts that needed a damn good torquing. Best Answer goes to bumpkin, but thanks for all the suggestions - I will bookmark this page for the next time I am trying to fix a creaky bike :-)
posted by primer_dimer at 3:05 AM on August 7, 2012


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