Rear mech clips spokes in first gear?

dennisn

Fudgey wrote:

Oh really. The last one i totally rebuilt with new nipples and spokes last year has been perfectly fine thanks.
I have also modifed/rebuilt several car engines before, that last one was a turbocharged 2.0l Zetec from an old Mondeo.
That went on to make 400bhp in my old track car..
Oh, i am not a mechanic either, nor been on any engine building courses. I have read the odd Haines Manual however...

If you say so.

fudgey

dennisn wrote:

If you say so.

I do. This is a rubbish video of it on the rolling road, fresh engine so being ran in before mapping etc.
I didnt paint it or fit the roll cage, but rebuilt it from the ground up.

http://youtu.be/Po0kV41YcYo

thegreatdivide

k-dog wrote:

Semantik wrote:

Also it would be very unusual (tho' not impossible) for a new mech hanger(not previously fitted to a frame) to be bent or out of alignment.

I don't think that's right - it's not the straightness of the hanger which is the issue but the combination of hanger and frame - and the 2 will never be perfect.

The hanger needs to be installed and then assessed properly so that it's square to the wheel.

Exactly. My brand new Foil frame required a hanger adjustment during assembly.

drlodge

I've had a similar problem on my Wyndmilla, I checked the hanger prior to building the bike up and it is straight. When engaged in 1st (low) gear the rear derailleur was a few mm from the spokes, however when I sat and rode the thing up a hill in first gears, I could hear the RD pinging some spokes very lightly.

The RD is campag Chorus EPS and I set it up perfectly. To solve this I screwed in the low gear adjustment screw ever so slightly - too much and the RD wouldn't move out of low gear due to pressure on the stepper motor. I think its all down to the geometry of the wheels and hubs but I was very surprised to have this issue.

fudgey

Yes, i think its more to do with the wheels as i tried another and there was over double the space.
Still looking into buying a mech alignment tool as i am sure it will come in handy between myself and friends etc.
And when i get one, ill report back!

dennisn

Fudgey wrote:

Yes, i think its more to do with the wheels as i tried another and there was over double the space.
Still looking into buying a mech alignment tool as i am sure it will come in handy between myself and friends etc.
And when i get one, ill report back!

Maybe you should look into a dishing tool instead.

svetty

Note to self when contemplating this thread: Step away from the keyboard....... :idea:

Semantik

k-dog wrote:

Semantik wrote:

Also it would be very unusual (tho' not impossible) for a new mech hanger(not previously fitted to a frame) to be bent or out of alignment.

I don't think that's right - it's not the straightness of the hanger which is the issue but the combination of hanger and frame - and the 2 will never be perfect.

The hanger needs to be installed and then assessed properly so that it's square to the wheel.

I don't doubt there is some value in this and in an ideal world this is a useful thing to check but I seriously doubt that many bikes which are mass produced have their derailleur hangers checked for alignment at the factory build stage suggesting that most hangers do NOT require any further alignment when fitted from new.
I realise that hangers can easily go out of alignment AFTER they've been fitted to a frame and I do use a hanger alignment tool regularly myself.