Are carbon full suspension bikes inherently more creaky/clunky than their aluminum counterparts?

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Are carbon full suspension bikes inherently more creaky/clunky than their aluminum counterparts?
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Posted: Sep 14, 2018 at 9:03 Quote
I went all out and purchased my first carbon framed bike this year - a brand new Trek fuel ex 9.9! Despite being a light, nimble and great riding bike, creaks/clunks were evident on the first ride. My last bike was an aluminum full suspension. With regular maintenance it didn't make any unusual noises. Every couple of seasons it needed new pivot bearings, but that's to be expected.

The chainstay on the 9.9 was replaced under warranty due to sloppy tolerances where the bearings fit into it. That fixed the noises, but immediately I noticed a new clunk.

Trek has been pretty good so far about trying to help, but I'm still pretty bummed about this.

Do you all just say f-it and ride with headphones or what?

Posted: Sep 14, 2018 at 9:27 Quote
So on your dropper post...Does it have a knurled top nut or a smooth top nut?

Posted: Sep 14, 2018 at 9:32 Quote
Trek9er wrote:
So on your dropper post...Does it have a knurled top nut or a smooth top nut?

Knurled, i think. It is exactly like the post in these pictures:

http://www.bermstyle.com/bontrager-drop-line-dropper-seatpost/

Posted: Sep 14, 2018 at 9:44 Quote
More then likely 90% of your clunking is coming from that. I just had mine warrantied for the smooth top nut one on the 19's and I installed the dropper post cable correctly since it wasnt from the factory and 99% of noises were gone. All I hear now are normal rattles and the cables up by the bars hitting each other. Before my slash I had the fuel ex 8 and that was so annoying. Finally after 8 months of complaining on 2 different bikes I got a new one.

Posted: Sep 14, 2018 at 9:54 Quote
Hmm, it does it when I'm seated and when I'm not. I'll keep it in mind though when I head into the shop tmmo. When the new chainstay was installed, the previous creaking/clicking/clunking went completely away - only to be replaced by a new one. My thought is that if it was the seatpost, the noise wouldn't have changed.

Either way, this has been a very disappointing foray into superbike territory. Easily the most issues I've ever had with a bike in 20+ years (and over 10 new bikes). I've only listed one warranty issue with the bike here. There have been more haha. I'm 140lbs wet and ride cross-country trails - in fairweather - in the prairies... a bike manufacturer's dream consumer, really Wink

Posted: Sep 14, 2018 at 10:04 Quote
Trek9er wrote:
More then likely 90% of your clunking is coming from that. I just had mine warrantied for the smooth top nut one on the 19's and I installed the dropper post cable correctly since it wasnt from the factory and 99% of noises were gone. All I hear now are normal rattles and the cables up by the bars hitting each other. Before my slash I had the fuel ex 8 and that was so annoying. Finally after 8 months of complaining on 2 different bikes I got a new one.

I'm sort of wondering about just asking for a new frame assembly because it's been about 6 months of constant issues for me too. Glad to hear they actually replaced your bike.

Posted: Sep 14, 2018 at 10:29 Quote
seans wrote:
Trek9er wrote:
More then likely 90% of your clunking is coming from that. I just had mine warrantied for the smooth top nut one on the 19's and I installed the dropper post cable correctly since it wasnt from the factory and 99% of noises were gone. All I hear now are normal rattles and the cables up by the bars hitting each other. Before my slash I had the fuel ex 8 and that was so annoying. Finally after 8 months of complaining on 2 different bikes I got a new one.

I'm sort of wondering about just asking for a new frame assembly because it's been about 6 months of constant issues for me too. Glad to hear they actually replaced your bike.


Sorry I only got a new dropper post. The updated one. On my fuel it took about 100 ish miles for the post to start rattling and it wasnt as bad as my current slash. Straight off the showroom floor mine clunked and rattled like crazy and I just kept getting the "they all do that" BS. So I walked over to another bike and tried shaking the seatpost and Im like..no they don't. Mine had movement up and down as well as side to side.

Doubt you will get a new frame. My slash had the pivot bearings pressed in wrong and bearings were seized etc and they only replaced a bearing. Your'e bike was probably made the same day mine was where everybody was hungover from a night of partying.

Posted: Sep 14, 2018 at 10:30 Quote
Trek9er wrote:
seans wrote:
Trek9er wrote:
More then likely 90% of your clunking is coming from that. I just had mine warrantied for the smooth top nut one on the 19's and I installed the dropper post cable correctly since it wasnt from the factory and 99% of noises were gone. All I hear now are normal rattles and the cables up by the bars hitting each other. Before my slash I had the fuel ex 8 and that was so annoying. Finally after 8 months of complaining on 2 different bikes I got a new one.

I'm sort of wondering about just asking for a new frame assembly because it's been about 6 months of constant issues for me too. Glad to hear they actually replaced your bike.


Sorry I only got a new dropper post. The updated one. On my fuel it took about 100 ish miles for the post to start rattling and it wasnt as bad as my current slash. Straight off the showroom floor mine clunked and rattled like crazy and I just kept getting the "they all do that" BS. So I walked over to another bike and tried shaking the seatpost and Im like..no they don't. Mine had movement up and down as well as side to side.

Doubt you will get a new frame. My slash had the pivot bearings pressed in wrong and bearings were seized etc and they only replaced a bearing. Your'e bike was probably made the same day mine was where everybody was hungover from a night of partying.


PM me and I will send you the response I got from trek about the seatpost.


But it is a clunk/rattle or creaking/pop?

Cables inside the frame can make a kinda rattle noise. My dropper cable wasnt attached to the holder on the down tube and clunked/rattled when I dropped the bike taking it out of my truck or on chattery downhill

Posted: Sep 14, 2018 at 10:43 Quote
It's a definite clunk now that comes from vertical forces, where before it was from side loading, especially noticeable when sprinting/climbing. Interestingly, the amount of pedal platform has a significant effect on this new noise. I now run the shock in open all the time to reduce noise. All the cables are secured within the frame at the port in the downtube (I was wondering what you meant by installed incorrectly).

Thanks again!

Posted: Sep 14, 2018 at 10:44 Quote
Just fyi - I've went through with a torque wrench and checked all the pivots bolts, rear derailleur, brake caliper etc. and any other likely culprits.

Posted: Sep 14, 2018 at 11:08 Quote
seans wrote:
It's a definite clunk now that comes from vertical forces, where before it was from side loading, especially noticeable when sprinting/climbing. Interestingly, the amount of pedal platform has a significant effect on this new noise. I now run the shock in open all the time to reduce noise. All the cables are secured within the frame at the port in the downtube (I was wondering what you meant by installed incorrectly).

Thanks again!

Weird...

Leaning against wall on the bike. Apply all brakes and try to pedal forward? Does it clunk?

Just bouncing on bike while stationary, in full pedal mode(locked out). Does it clunk?

Posted: Sep 14, 2018 at 11:13 Quote
No clunk when trying to pedal forward with brakes on. Clunks big time when bouncing up and down in full pedal platform mode.

Posted: Sep 14, 2018 at 11:16 Quote
seans wrote:
No clunk when trying to pedal forward with brakes on. Clunks big time when bouncing up and down in full pedal platform mode.

More then likely something in the linkage area then or the shock itself. Good luck on figuring it out.

Posted: Sep 14, 2018 at 11:17 Quote
Thanks for your help man.

Posted: Oct 23, 2019 at 15:16 Quote
Hi, Whatever became of your problem? I have had a clunk all summer, when the shock compresses. Figured it was that since there isn't any play in the linkage. Just paid S4 for a total rebuild of the rear shock, and it still happens. Its super annoying. Not only can I hear it, but I can feel it. I just emailed trek, about it too, and awaiting a response. Should I replace frame bearings too? Even though there's no play?

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