what would the symptoms be of a fcuked gearbox?

strange rumbling sound?
if coasting in neutral it feels like a rear brake binding at the same point?
if on a paddock stand, notchy to and difficult to turn the rear wheel?

I have just replaced the rear wheel and sprocket bearings but i am now a bit worried it could be something more costly.

I will have a good look at it tonight so some pointer on what i could check out would be appreciated.

Wheel bearings?

replaced them already unless they were dud of course but unlikely as they were OEM.

knackered links in the chain? crap around the front sprocket, clutch not engaging/disengaging properly?

unhook the chain and spin the wheel on it's own - eliminate that

get cosy with the chain and have a bloody good look at it - stiff links etc

gearboxes are weak on 29s though eh?



EDIT - if your last action before all this was wheel related then check it is not too tight, the bearings in right etc.

Why would the gearbox die after you changed bearings?

CMSMJ1 wrote:unhook the chain and spin the wheel on it's own - eliminate that

get cosy with the chain and have a bloody good look at it - stiff links etc

gearboxes are weak on 29s though eh?

EDIT - if your last action before all this was wheel related then check it is not too tight, the bearings in right etc.

Why would the gearbox die after you changed bearings?

Thanks for the input - really appreciated as i was at my witts end with it last night but feel a tiny bit better now. PS Its an NC23. when i turn it now (with chain on) i can feel a point that is stiff if that makes sense, and it does feel all notchy turning the wheel. I was more worried about the sound it was making, it was quite bad, I thought something was dragging under the bike at first, then i stopped to check it still had oil in the engine as the sound got worse!

I am not thinking the gearbox has died just because I changed the bearings, I was wondering whether my initial thought that the rumble/metallicy screeching was actually all down to the rear wheel bearing was wrong. It could be a bearing not in right I suppose. Something i last touched is more likely to be the issue....

I will try and 'free wheel' the rear and check the chain - should it spin easy anyway with new bearings? it seemed a bit stiff when i put it on after changing them. i used a torque wrench to tighten the nut up so i doubt its too tight.

could be the brake dragging that is making it stiff , so listen for sound from that.

i will check but the rear disc was cold.....after riding a few miles home with the noise.

I once had a rumbling and draging feeling through the footpegs, thought it was chain related, ended up being a rear caliper front bolt needed greasing. So give it a look, even if the disc seems cold.

Just didnt have the time to check it properly last night, i have taken the chain off the sprocket, put the wheel back on and torqued it back up - it spins freely now, no funny noises.

That leaves the chain to have a good look at, check the rear brake isnt binding anywhere after its been pressed a few times.