fitting derailleur/front mech to Giant frame (please help!!)

dogllabtoof

I have stripped down my old road bike and am in the process of putting all of the equipment on to a Giant frame. However when i have looked at the front mech and rear derailleur, they are not going to fit :shock:

Im assuming i need a different kind of hanger for the rear derailleur, but how do i know which one i need? where can i get one? can anyone tell me?

As for the front mech, the frame has some kind of bracket fitted, which im guessing the mech attaches to. But i cant see how it will fit to this bracket. Do i need to buy something to fit it to this bracket? I tried removing the bracket and fitting the mech as it was on my old frame (around the seat tube), but the bracket wont fit round the tube

Any help and advice on where to get whatever i need would be greatly appreciated. Hope its not expensive, as i have spent my budget.

redddraggon

There's two different types of front derailler. Band on and braze on.

Your frame seems to require a braze on, but the mech is a band on. If you can't take the band off you'll need to get a new braze on mech. Braze on mechs are better as you can get an adapter to make them into a band on - but a band on can't be made into a braze on.

Rear derailler - I've no idea.......all mechs should have the same thread to connect to the hanger shouldn't they?

redddraggon

And to add.....band on mechs need different diameter bands for different size frames. You need to get the correct band size for the seat tube.

dogllabtoof

Thanks RED.

The frame does not have a hanger, so ill need to buy one. Wasjust wondering if all giant frames used the same hangers, so i dont buy the wrong one.

Gutted about the front mech ill have to see how much a new one is, and try and sell mine.

Thanks again.

david 142

"The frame doesn't have a hanger"
Can you be more explicit? Do you mean that it was designed with a replaceable hanger which is currently missing? If so, you should certainly try to source a replacement as without it your wheel might not be properly secure. Are there indications that something might have beem cut off? Is it possible that the frame might have been designed for hub gears etc? If so you might need axle fitting mech

dogllabtoof

I think it may require a hanger that slots in to the slot where the wheel is fastened (dont know the official name), as on the side where the gears will be there ar 2 small holes (none on the other side).

I will post a picture for clarity, but dont know how to do it :oops: can anyone give me instructions on this?

david 142

Wish I could help with the pic, but I dont know how to do it on this site.
The bit that the wheels slot into is usually called a drop out. With a steel frame the gear hanger is part of the dop out. Drop outs for aluminium frames are designed to be replaceable because if bent in a spill they can be expected to break completely when you try to straighten them. The replaceable bit is often located by two small screws, and finally clamped by the wheelnut or skewer. However, the overlapping parts of drop out and hanger will be machined down to half thickness, so it should be fairly obvious if a replaceable hanger is missing. If this is what you need, then the bad news is that there are no brand standards - they differ from model to model and its probably going to be necessary to take the frame details to a Giant dealer.
There used to be a system where a mounting plate slotted for the axle fitted against the drop out. They had a small clamping bolt which engaged in the rear of the axle slot to stop everything falling off when the wheel nut was undone, and they were locked into place by the wheel nut itself. The link I posted earlier leads to a page showing a couple of mechs designed to work this way.

dogllabtoof

Thanks for the advice.

I have managed to find this hanger (#20), and i looks like it would fit. The dropout has 2 holes where i imagine it would fasten to the frame.

http://www.derailleurhanger.com/giant.htm

My question now is how would this fasten to the frame? the website says the hanger comes with 2 screws, do they mean bolts? the holes in the dropouts are not threaded.

SDP

i have never seen a giant frame with unthreaded holes :-o

what model frame is it >?? what has happened to teh original hanger ?

usually M5 taperhead bolts...

call MDT for help http://www.mdt-products.com/

david 142

I have seen other frames where the threads are in the hanger, but if this is the case then I would expect to see countersunk holes when looking at the inside of the drop out.
For my money importing bits from the States on the strength of a picture ought to be a last resort - probably not economic to return if incorrect. A swift Google turned up a giant dealer near you:
Bike Traks
39a, High Street
TS9 6NH Middlesbrough
phone: 01642 724444 | fax: 01642 724444
info@biketraks.co.uk
www.biketraks.co.uk
I'd have thought it worth your while to phone them