Getting ‘grinding’/gritty noise/feeling on my transmission under pressure (it runs fine on the stand).

Its a new SolarisMAX frame with (lightly) used XT rear mech (it was fine on the old frame), new XT 11-46 cassette and a new KMC (should be) 11 speed chain.

Folk i was riding with say that the rear mech was ‘jumping’.

It’s quietest on the 46 so I’m reckoning the B tension screw is correctly set up.

Can’t see a stiff link.

Tried running the barrel adjuster across full range (i.e. from changing up to changing down a gear) so I’m ruling that out.

Not done anything different on this build from any other (that I’m aware of) and when I rebuilt the SodaMAX (for bike packing duties 🤪) it works fine…

So, what is wrong/what have i **** up?

Is it a goosed rear mech?
Actually a 10 speed chain?
Bent mech hanger (frame is new and hanger was shipped loose rather than in place)?

Before I strip and rebuild the trans…

TIA

Should also state that I’ve run the barrel adjuster the full range (from shifting up to shifting down a gear) so ruling that out…

Is the chainring new? If not, it may be ‘grabbing and releasing’ the new chain – you can sometimes spot it at about the 7-8 o’clock position when turning the cranks.

Is the chainring new? If not, it may be ‘grabbing and releasing’ the new chain

My immediate thoughts too.

Is the chainring new?

Nope. But would that give you the grinding noises? And would it make the rear mech ‘jump’? Wouldn’t that be ‘eased out’ by the cassette?

I’ll give it a look though (and I do have a spare chainring as it happens…🙃)

Tried running with the clutch off? IME that can have an effect on smoothness if the clutch is a bit tight/sticky.

But would that give you the grinding noises? And would it make the rear mech ‘jump’?

Yes, and yes. Take a look at this Park Tools video:

Yes, and yes.

Duh, yeah. I was thinking it was ‘clicking’ from the top….🤦🏼‍♂️

That pretty much looks like it’d be the most likely cause (thanks for the video). I’ll get the bike up on the stand (and dig out the spare chainring). 😁

Re. Clutch: yeah, I tried it both off and on (to no difference).

Remember that MM200 loop we did with David and the way my rear mech was jumping as climbed up past Druid Temple Farm? That was caused by a worn small chainring and I had to ride the other 190 km in the big ring.

@scotroutes yes, I do remember…

It’s ironic that because the rear mech was jumping i figured cause must be happening at the back. Glad I asked the question now as I’d have rear mech and chain changed before I even thought of the chainring…

Makes sense that the harder I’m pressing (on the crank) the worse it’ll get.

Thanks folks. I’ll change my ring and see how it goes.

You’ve definitely not routed the chain through the mech wrong? Assuming you’ve just built it up.
That little running tab that it’s fairly easy to go the wrong side of.

Is the freehub fitted correctly, with the spacer between the freehub bearing and wheel bearing?

You’ve definitely not routed the chain through the mech wrong?

Ha, as if… I’ve done that before (its pretty obvious when you have, just running through on the stand…).

I’ve also missed the tab on the hanger before (but that doesn’t like to change properly, hardly surprisingly as that’s what the b tension screw pushes against…).

Swapped chainrings.

There is definitely evidence of wear on the teeth of the old one.

Gave it a quick try (not easy as its pitch black here in the middle of nowhere) but no noise and couldn’t replicate the issue (which pretty sure I could before) so looks like its sorted.

Thanks all (esp. @frogstomp for correct identification).

I would definitely have been looking at the wrong end and wasted time and effort. 🙃

Thought this was Joe Rogan posting for a second 😂

Have you looked at the jockey wheels?

Mine was hard gunk on a jockey wheel. Took an age to identify the cause. Skipping at the what looked like one point in the chain. Even a new chain didn’t cure it. Replacement mech did. And then I cleaned it.

Thought this was Joe Rogan posting for a second 😂

Have to say I was very surprised to see the post was about transmission….

Have to say I was very surprised to see the post was about transmission….

I’m afraid that says more about you than me…

It was in the bike section after all 🤷🏻‍♀️

Tomorrow I might even see the sun when I’m at home so will get to the nearest rise and see if it really is fixed.

I have faith though. 🤪

Pleased to report that the 5 minute ride down the road to the first ‘hill’ and back today indicates that my transmission issues have indeed been fixed by changing the chainring. No grinding/no noise.

Thanks again for everyone’s help.

Also happy to report I do not have any transgender issues either. I also thank those who I confused for their concern…

Also happy to report I do not have any transgender issues either. I also thank those who I confused for their concern…

I most intrigued by the fact you didn’t seem to know what your transgender issue was, being STW I assumed this would be a thread full of intense discussion as to which specific sub category the issue fell into…..