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I've just got myself a new SLX Shadaow Rear Mech. This is the first Shadow mech that I've had, but it seems to be very noisy with rattling compared to the old style mechs.
I've had a good look at it and the noise seems to be due to the b-screw (assuming nomenclature is the same on new mechs) banging against it's stop. Also, the movement here causes excessive chain rattle. Older style mech had a lot stronger spring here which seemed to work better at stoping the noise.
I've tried to stop movement here with zip ties and wirte but to no avail. Also, you need movement to allow removal of the rear wheel.
Any one else have the same problem?
Anyone got any great ideas to solve?
Have you got the mounting plate positioned correctly on the mech hanger? There is a small pip that needs to sit where the b tension screw used to sit on older style mechs and its quite easy to incorrectly locate the mounting plate.
I've got it mounted right. Took me a while to try the different options, but I'm pretty sure it's good.
It probably sounds like I'm taking the proverbial, but are you certain you've got the chain threaded around the right way. When mine wasn't it sounded like the mech was rattling.
There's a plate between the two side plates of the cage, and the chain needs to be above it.
Sorry if this isn't helpful
Is the b tension screw taking up the slack etc.? Something sounds waaay too loose as i stands currently.
dan1980 I know hte bit you mean and thats only an issue on the GS (med cage) mech, the SGS (long cage) are different and cant normally be routed wrongly.
Nope I'm not being a moron! I'm an aerospace engineer for a living so pretty handy at these things normally.
The purpose of the b-screw is to get the top roller in the right position, i.e. just below the cogs.
The problem is that there needs to be some movement to allow you to remove the rear wheel. But the movement is causing rattling and the b-screw to hit against the stop.
I'm on a bit of a bike 'silenting' trip at the moment. Perhaps I'm being too picky, but I'm sure it should be quieter than it is.
The b tension screw shouldnt move off its stop as it always got spring tensin holding it in place. Hmmm...
Exactly, I think perhaps the spring tension is not enough.
And the b-screw does move off to allow removal of the rear wheel.
Any chance of some pics, as im struggling to make sense of it, unless the spring tension is too low. Personally my XT one is stronger than its non shadow equivalent.
Righto, I'll try and get some pics out tonight.
Thanks for the help BigYinn!
I helped? Sorry 'bout that! 😳
Nope I'm not being a moron! I'm an aerospace engineer....
I've seen plenty of moronic aerospace engineers! 😆
Nothing to suggest until I see pics though as it's an odd one and you definitely shouldnt be needing to add cable ties.
Righto,
I've tried rotating the mounting plate a bit. There's two 'pips' on this mech, so I've tried the other one. This puts the mounting plate in a horizontal rather than vertical position and increases the spring tension considerably. This solves my problem but The top roller is now a long way from the cogs.
I'll try it like this and see how I get on with the shifting. Like this the b-screw is rendered useless. Adjusting it only moves the top roller further away from the cogs. It won't go any closer.
Perhaps it's the angle of my dangle (mech hanger) that's the problem...
Ah ha!