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In riding my son’s cyclocross/tri bike back into the garage after he was out training on it earlier I noticed a noise that I’m struggling to identify.
It’s certainly happening in the top three (largest) sprockets on the cassette, possibly the fourth but that’s harder to identify.
It’s sounds like when the b tension adjuster isn’t wound in enough and the upper jockey wheel is making contact with the cassette under load but it’s not that.
I’ve checked:
➡️ I’ve tried all the B tension and no B tension.
➡️ BB Bearings
➡️ Jockey wheels
➡️ The gears are properly indexed
➡️ The rear wheel bearings - lovely and smooth
➡️ That the rear wheel is tight in the frame
➡️ Rear mech hanger is straight and tight.
The drive chain was fully overhauled, by me, back in the summer before the season started. The bike has now had a couple of races and everything appeared fine.
You can swing a leg over and in a single turn of the pedals here the noise. I cannot replicate it in the stand so guessing it’s torque related???
Up until now the build has been simple but bullet proof. SRAM Rival shifters, rear mech (non clutch) and an Askium wheelset.
Its really got me puzzled.
What am I “obviously” missing?
I did think it could be the rear wheel bearings or freehub bearings but off of the bike everything feels good. Although he is a junior he does push a big gear so it could be a bearing but the noise is not evident when in a higher gear, even really moshing on the pedals.
I’m happy to book it in to an LBS but wanted to get the basics covered first … help.
Could be a worn chainring, which is worse when the chain is at an angle. I've had this with new chain and cassette on a used narrow wide ring.
New hanger
The chainring, Garbaruk, is newish and not showing any signs of wear.
@llama - are you thinking perhaps it’s bent?
Cable catching a spoke or cassette tooth?
@DickBarton - I did give the cabling a good going over and couldn’t see that anything was making contact with things that shouldn’t make contact. I would guess that it would do the same in the stand 🤔
You can feel it in the pedals making me think it’s mechanical. It’s not the pedals either as you can really honk on them in a higher gear and the feedback isn’t obvious.
Spoke tension?
The end of the cable is a good shout, where it exits the pinch bolt
Just been back out to the garage …
Spoke tension is good both DS and NDS.
Cable end is well out of the way.
I think Llama may have it - hanger looks straight but I’ve no way to really check.
If the hanger were to be bent could it just affect a few gears?*
* can you tell I’m a SS Luddite … 😁
If the hanger were to be bent could it just affect a few gears?*
Exact symptoms of a bent hanger. Without a tool it’s virtually impossible to tell if it’s perfectly straight, which it needs to be.
As well as a hanger, get a alignment checking tool too. Chances of them getting a bit bent on a CX race are significant. The ZTTO ones are decent enough and not expensive .Straighten the existing hanger, keep the other as a spare.
Thanks Folks.
I cannot get to the LBS today so will order a spare hanger and look at that ZTTO alignment tool.
if it only happens when you;re ON the bike then maybe the're a hairline crack? certainy sounds like rider weight is affectig the alignment
Seeing as you're only getting the issue under load on the drivetrain have you looked a bit further afield? (Assuming you eliminate hanger alignment):
-Cassette nice and tight on the FH body?
-Chainring(s) tight
-Crank/BB correctly Torqued?
-Cables/Hoses knockinig at funny angles?
-Seatpost creaking in the frame? (I had this the other day)
-Saddle/saddle clamp creaking?
-Loose spokes? (might only make a noise under torque when in lower ratios?)
-
Basically check everything, just because the noise seems to be coming from the mech doesn't mean that's where the problem is...
is it threaded through the cage right.
not that i've ever made that mistake...
Thanks again folks.
Hoping it’s not a crack. My son gets the same noise as me and he is considerably lighter than me!
Cassette nice and tight on the FH body? ✅ I did check this but will check again.
-Chainring(s) tight ✅ It’s a SRAM three bolt splined ring and is torqued correctly
-Crank/BB correctly Torqued? ✅ Yes to the full silly spec that SRAM requires i.e bastard tight
-Cables/Hoses knockinig at funny angles? ✅ It’s not that - more graunching than tapping.
-Seatpost creaking in the frame? (I had this the other day)✅ Does it in and out of the saddle
-Saddle/saddle clamp creaking? ✅
-Loose spokes? (might only make a noise under torque when in lower ratios?) ✅ All checked.
We went out earlier, definitely the largest four sprockets on the cassette.
It is also threaded through the cage correctly … I always check that as … erm … I have form! 🫣😂
I should add … if you sit and spin it’s not so noticeable but honk on the pedals and there it is.
pedal rebuild...
pedal rebuild...
Will check it out. Pedals are newish and it doesn’t happen honking on them in taller gears but I’ll give it a look.
I know you have all been waiting patiently for an update on this ...
I ordered a new mech hanger and that arrived yesterday.
Initially I thought I had been sent the wrong one as rather than a cast silver looking jobbie there was a nice black CNC hanger.
Anyway new mech hanger fitted and all bar the tiniest bit of graunching is now apparent and that's possibly down to be having tinkered so much with B tension etc initially.
So I'm very much now a happier camper.
Thanks all for the input and suggestions, after decades of riding bikes this is my first wonky hanger ... and it wasn't even on MY bike ... 😆