Cracking noise from fork / wheel?

For what it's worth, I have a Litespeed Tuscany with a Time carbon fork, and this bike generates no unusual noises at all. If anything, it's more quiet than the high end steel frame/fork combinations I used to use.

A few possibilities:

--Some of your spokes are loose. Consider getting your front wheel retensioned.

--You have a crack in your front rim, or one of the rim's spoke eyelets is cracked. Check this closely.

--There is a significant problem with your CF fork. If it were me, I'd pull it out, check that the dropouts fixtures haven't delaminated, check for delamination at the crown, steering tube, any cracks in the legs etc.

--Check for anything loose on the front end that would make a noise under the sharp force of hitting a small hole. Could be something small and trivial.

Quoted post said:

Originally posted by cornish_frog
I've recently built up a new bike which includes a full carbon fork (Litespeed) and DuraAce wheels. Everything's fine except that when I go over particularly nasty potholes (the small deep ones that you can't see easily!) I get a big 'CRACK' from somewhere at the front. First time I thought a spoke had gone, but no. It's happened 3 or 4 times in 100 miles. Is it the fork fibres splitting inside somewhere? It looks fine! The headset is not loose at all.
My previous bike had carbon forks with an Al steerer, and 105 wheels, and that didn't have the problem. The only other difference is the Ti frame, and it does seem that Ti amplifies any rattles etc. more than Al.
Any ideas?

It's probably your front hub ends slipping on the fork dropouts. My all carbon fork and Ksyrium SSC SLs do this when they are not properly greased. The fork flexes under load and generates a force that trys to slip the fork dropout against the hub end. I confirmed this by leaning the bike over about 30 degrees and then pushing on the side of the fork to flex it. It reproduced the exact sound I was hearing. I did a search on the forums and found that someone else had solved the same issue by simply putting grease on the hub ends and re-installing the wheel.

Good Luck,
David

It might also be a slight creak from your handlebar/stem.

Oh isn't diagnosing mystery creaks fun! 😠 It took ages for me to find the source of a "creaky bottom bracket" which was actually the spoke nipples..

Thanks for the suggesions, folks.
I'll check everything over again and try the greased hub ends.
Cheers!

is it one great big creak/pop? could be your bar turning slightly in your stem.

It could also be your sti levers. They can snap open and closed just enough to make an unbelievable cracking sound.

Thanks, RV! You've guessed it, I didn't tighten the bars enough in the stem - can even see the skid marks on the bar as its turned slightly (and for some reason the bars are a bit more angled down now than they should be!):o

Quoted post said:

Originally posted by davidbod
It's probably your front hub ends slipping on the fork dropouts. My all carbon fork and Ksyrium SSC SLs do this when they are not properly greased. The fork flexes under load and generates a force that trys to slip the fork dropout against the hub end. I confirmed this by leaning the bike over about 30 degrees and then pushing on the side of the fork to flex it. It reproduced the exact sound I was hearing. I did a search on the forums and found that someone else had solved the same issue by simply putting grease on the hub ends and re-installing the wheel.

Good Luck,
David

Haven't heard of this problem, but personally, I wouldn't want to put grease on the hub ends. From what you describe, sounds like your fix stopped the noise because the hub is now slipping in the dropout when the fork flexes....not a good thing for steering response or safety, IMO. Wouldn't it be better just to tighten the skewer to increase the clamping force?

Curious what carbon fork you have...is it very flexy when you ride?

Quoted post said:

Originally posted by dhk
Haven't heard of this problem, but personally, I wouldn't want to put grease on the hub ends. From what you describe, sounds like your fix stopped the noise because the hub is now slipping in the dropout when the fork flexes....not a good thing for steering response or safety, IMO. Wouldn't it be better just to tighten the skewer to increase the clamping force?

Curious what carbon fork you have...is it very flexy when you ride?

Well you can minimize it by tightening the ever living [censored] out of the front wheel, but the small amount of movement that is occuring is nothing to worry about. I actually think it is a design flaw in the Mavic Ksyriums. The hub ends are flush smooth without any pattern on them at all. Your dropouts are made of quite soft aluminum and the typical hub end which has a none smooth grid pattern on it will actually cut into the dropout to help hold it in place. The flush ends on my front wheel aren't ideal. Funny thing is tha back wheel does have hub ends with the grid pattern.

What I should ptobably do is try and get the same ends that go on the back wheel and replace the fronts with them.

Glad you found your creak,
David