i was having problems with my gear selecting at the rear so took my bike to my lbs and asked them to index the gears and i left the shop 20quid lighter and with what i thought was my gears working sweet and crisp.had a wee jaunt today and they werent as crisp as id have thought they would or should be,the female who done it yesterday told me to bring it down today and she’d have another look.so get phone call later today to say she thinks my rear mech has had it and its been damaged with to many falls.not that ive had to many so i told her that and she says its how i transport my bike with the rear wheel of and lying on its side,would this make the mech stop working and cause it to stop selecting the gears as it didnt look very bent.now have to purchase a new one but not sure i can afford 60quid for new shimano slx.would i get away with deore one???many thanks for any advice…

Quite possible she’s right if you transport the bike laying on the mech. Other possibilities include bent hanger, worn mech pivots, dirty/worn cables, toothless jockey wheels, worn/dirty drivetrain and a myriad of other things.

does it skip across/between gears or slip over the top?

Does is skip more in low, mid or high gears?

Does it shift faster up than down/vice versa?

Does the leve/trigger feel sticky or stiff?

cheers coatesy.she said there wasnt to much wear on the gears so it was def the mech,just cant afford 60quid for new slx so would deore do as replacement??its deore shifters and was deore brakes before i changed them for slx

classifieds?
£20 for shadow deore
£25 for slx
roughly

na triggers are fine its more when im changing up from small gear on rear to next one up it doest shift 1st time and so on so i need to shift up and down abit before it goes to the next gear.it does seem to come down easier than going up.doesnt go over the gears at either end just sticky shifting up,

cheers walla24 ive seen new deore for about 25 so id rather buy new then i have come back if its faulty….so deore is ok to put on then??whats the diff between the deore and slx

shouldn’t they have noticed this before/while trying to set it up, and saved you £20 ?

i need to shift up and down abit before it goes to the next gear

That just sounds like the cable needs to be a bit tighter

well she said it was bent and she straightened it and done the gears but when i got home and had a wee blast on it today the gear selection wasnt as crisp as i had hoped for.so took it back today and she fetled about with it saying she had to re-align the mech again and said it had been banged again when all id done was transport it home.**** knows im no bike mechanic so got to take her word for it….
might see if i can tweek the barrel adjuster and see if it makes the gear selection ant better but it has been slowly getting worse as time goes on….

bent mech or just the hanger on the frame ? That would make more sense to me and be cheaper

try adding some tension to the cable–>
look at the barrel adjuster and undo it (lefty-loosey), keep your finger on the cable so you can feel if its tightens or slackens.

deore is fine with deore shifters.

Difference between deore shadow and slx is nothing really, a couple holes drilled saves about 10g! but otheriwse identical.

The shadow deore is just the newer version of deore, looks different and is slightly better tucked away to avoid collision with things.

She may be right though, if you lean your bike up on its rear mech with no wheel in you may bend the hanger which in turn means that mech allignment will be off- usually characterised by it shifting fine in the middle but having issues at either end of the cassette (in some cases shifting off the cassette entirely, so make sure it cant do this)

Also it may be worth checking the higher (“H”) limit screw, to ensure that when the cable is not attached the cogs on the mech line up with the smallest ring on the cassette. If this is correct to begin with it makes setting up gears a whole lot easier.

From experience it is rarely a fault with the mech itself, usually the hanger or incorrect setup mech/cable.

Its usually pretty clear if the mech is shot, ie big scuffs, dents, bends etc

will have a wee look at the cable tension tomorrow.if not then i’ll maybe opt for the deore mech.will i need a new hanger if my one has taken a battering??

If its straight- No
If its been straightened properly- No

If its been straightened and you can see stress lines (like metal wrinkles) then Yes.
If its bent, like really bent then Yes probably as it will snap/stress when bent back.

What bike is it?

its a genisis core 20(green one).i noticed when i git home that the mech was a bit loose and tried to tighten the hanger botl to the frame and it was slack and it tightened then went abit slack then tightened again but didnt want to start tightening it to much incase the bolt snapped or ripped the threads.will have a proper look tomorrow.

she did point out that the mech had a couple of scuffs aound the main body of it,but didnt look like it was ripped to shreds or anything.

Cool, yeah may need a new hanger.
Post up when youv had a look

cheers buddy.i will get back to you in the morning.

well been out on a wee jaunt today and the gears are still abit sticky.had a look at the rear mech and cant see any bend or strain on the hanger and the gears go up and down only its abit slow….who knows what the problem is.might be the mech its self as its not the hanger i dont think….

corroded/sticky cable?
worn chain/cassette?

Starting with cheapest,new cable inner,good flush of the outer with GT85 or WHY and set ’em back up again.
Ian

my bets on cables

I’d always change the cable before anything else, unless I could see something really obvious.

cheers guys i’ll try the cables as the person in the shop said they didnt see any wear on the cassette or chain…..is it easy to replace the cables??

Very specially in the slx shifters all guides can be found online.