Can't find any 7 speed rear derailluers?

[Matthew_T]

After a few members of the cycling club i go to mentioning that my derailluer was bent towards the wheel, i have been looking for a new one. the one at the moment actually hits the spokes when I go into my lowest gear (which makes a noise when I go up big hills). I have had a look at some 9/10 speeds on CRC and they seem a reasonable price.
But i cannot find any that are 7 speed! I have looked on both CRC and Wiggle and Halfords (but they wouldnt have anything anyway). I dont want to bother with upgrading my cassette because that will be a lot of hassle and cost more, so i just need a derailluer.

 

[Theseus]

I may be wrong here, but it isn't the mech that sets the number of gears it can cope with, but the gear shifters. So long as the mech can cover the distance. Thus you may have problems shifting a 10 speed with a 7 speed mech, but not the other way round.

 

[4F]

hmm i may have a new unwanted sachs huret one kicking around, i will have a look in the morning if you interested.

 

[mcshroom]

If you can't find a road mech that fits, and you have shimano shifters then a 7sp mountain bike rear mech would work (along with allowing bigger rear gears if you want them) Something like this.

I think you can use 9 speed rear mechs with 7 speed drivechains as well, but not the other way round, as the jockey wheels on the mech are thinner on 9sp models to take a thinner chain.

Are you sure that it's the mech that's bent, and not the hanger it's fixed to?

 

[cycleruk]

If you are on ebay then there are companies that sell these. i just brought a deraileur that is 7 and 8 speed compatible, there also do it as direct mount or hanger mount depending on what frame you. Question, what bike do you have as they will be slightly different depending on if its a mtb or roadie. Heres the link http://stores.ebay.c...d=p4634.c0.m322 hope this helps

 

[the snail]

Are you sure that it's the mech that's bent, and not the hanger it's fixed to?

It would be worth checking this first - take it to a bike shop and get it checked out. I think the hanger is usually designed to bend before the mech. It shouldn't be too expensive to fix - either replace the hanger or they will have a tool to straighten it with. Watch out if the mech is fouling the wheel, you could be heading for a big/expensive accident!

 

[funnymummy]

Ok i'm going to admit to complete dumbness on this one...
I never knew derailleurs came in different sizes/gears! I honestly thought it was just a standard thing & that the gears were controlled by the shifter!
This may now solve a problem been having with my sons bike

 

[mickle]

7 and 8 speed mechs are indistiguishable. 9 uses a narrower chain and therefore narrower jockey wheels. Fit 7/8 speed jockeys to a nine speed mech to make an 7/8 speed mech.

The important thing is 'capacity'. Which is two numbers and refers to (a) the size of the largest rear sprocket (which determines the angle of travel of the parallelogram and therefore how closely it sits to the sprockets) and (b) the tooth difference of the whole system - ie (52 minus 39) plus (32 minus 11) equals total tooth difference, which determines the length of the cage plate and the mech's ability to take up slack in the chain during gear changes.

 

[funnymummy]

Thnak you Mickle

 

[albion]

Plenty of ebay.The main thing you need to consider is cage length and capacity.Usually long cage for triple/mega range and short cage for some double chainwheels.If near/under £10 it won't be a 9 speed one.

 

[Globalti]

It's very unlikely that the mech is bent; most bikes have a replaceable gear hanger, which is built in as a deliberate weak spot like the fuse in an electrical circuit, the idea being that the hanger will bend and even snap before the much more expensive derailleur breaks. Get the hanger checked out by a bike shop with a setting gauge before wasting your money on a new derailleur. The hanger will probably only cost you £2 - £3 to replace.

If the hanger is not replaceable the shop will simply bend the frame back using the gauge to get it aligned right.

 

[mickle]

It's very unlikely that the mech is bent; most bikes have a replaceable gear hanger, which is built in as a deliberate weak spot like the fuse in an electrical circuit, the idea being that the hanger will bend and even snap before the much more expensive derailleur breaks. Get the hanger checked out by a bike shop with a setting gauge before wasting your money on a new derailleur. The hanger will probably only cost you £2 - £3 to replace.

If the hanger is not replaceable the shop will simply bend the frame back using the gauge to get it aligned right.

£8 - £12 more like, but yes.

 

[mickle]

Thnak you Mickle

Thnak me?

 

[Matthew_T]

Thanks guys for the replies, I will take a pic of it in a minute so you can tell how bent it is and if i need a new derailluer or a hanger.

 

[Theseus]

Thnak me?

Thnak: The sound of a hand hitting back of a head.