1996 Explosif in need of re-alignment

[Matthew F]

Hi all,

I've recently been enjoying getting back out on my '96 Explosif, but had forgotten just how badly out of alignment the rear end is. The picture below hopefully gives an idea of the scale of the problem. Believe it or not, the brakes are properly centred with respect to the rim! In its current state I can't use the largest sprocket on the rear as the derailleur cage rubs on the spokes if I do.

The wheels were built in a friend's workshop, I've been back there to double check and he demonstrated to me that the wheel is dished correctly and that it's the frame that's out of whack.

I'd be grateful for any advice anyone can offer. If cold setting is the answer, would anyone have a recommendation of someone in the London area who would undertake such a job?

Cheers!

Matthew

 

[Janners BJJ Clunker Rider]

Following as I am confused. Not saying you are wrong in any way, but I don't get it. If the rear mech sits correctly under the largest sprocket, in what way would the frame cause it to touch the spokes?
My first action would be to pop on another back wheel and see what happens.
I'll add I am no expert, so my point of confusion is easily reached, very easily reached!
I shall wait and learn.
Hope it gets sorted.

Regards
Janners

 

[Matthew F]

That's a good question, it was some time ago I spent a while trying to sort the rear shifting and couldn't get the chain to run on the largest sprocket no matter what I did, without the derailleur cage rubbing on the spokes. My inclination was that the cage was rotated on the vertical axis, so not flat against the wheel, if that makes sense. (So it could equally be an issue with the derailleur or hanger, potentially.)

Good suggestion on trying a different wheel, I'll nab one off my wife's bike and will give it a shot! I've run her wheels on the Explosif before but it was so long ago I can't remember how they were.

 

[FluffyChicken]

That look like a Hope hub ?

With a wheel, if it loos wrong, turn it around and try it. If it's dishing*, it'll be wrong in the opposite direction now.
If it is the same, it is probably the frame.


*or the axle...

Things to check.
Check it is seating properly, some axles at the end, hope included can be a bit larger then the dropout and may need bashing in the full distance. easiest with the Q/R out.
Check the drop out holes/slot looks good.

You can measure the frame to find out, I think Sheldon Brown has a quick DIY method (string and stuff).

 

[Matthew F]

It is indeed a Hope Ti-Glide. Thanks for the tip on turning the wheel round, will try that in a minute. Will check Sheldon's site, and the dropouts too.

Now to make things thoroughly confusing, I've just had a look at my wife's bike (a '99 Fire Mountain with hand-built wheels from Merlin) and it seems to have the same issue! The only things in common between these two bikes is they're both steel Konas and they were both built up by me.. have I done something really stupid?

 

[mdvineng]

Tyre treads look central to the seatpost in both pics

 

[Matthew F]

Wheel turned around on the Explosif and still offset to the right.

(It's not in exactly the same place as before - one brake pad contacts the rim slightly before the other now so there may be a small dish error, but it's minimal compared to the overall offset to the right.)

The axle looks well seated in the drouputs, so I'll try Sheldon's measuring technique.

Thanks for all the suggestions so far!

 

[FluffyChicken]

If you can correct it by sliding the non gear side down a bit and tighten, then you could file the drop out a bit to set it up, cheats method..

 

[Matthew F]

I've measured as per Sheldon's article and see about 2mm more gap between string and seatpost on the drive side than I do on the non-drive side. I guess it's cold set time or a cheeky dropout modification then!

I'm a little bit scared of the former, knowing how thin that Columbus Max tubing is in places.. hence I'd be interested to know if anyone knows a good workshop in the London area that might deal with this for me.

 

[2manyoranges]

Where are you in London. I had a steel frame retracked by Herne Hill Cycles and they did a good job. Very messed up rear triangle: niece rode in Cambodia and Laos, then flew back to Heathrow. No bike. Next day - 'where's my bike, BA?' - "In vancouver'. 'Right...when will it be coming back then...' 'Tomorrow'. Two days later 'where's my bike BA?' - 'In Chile, Santiago'. (You couldn't make it up), A week later, back in London with a completely mangled rear triangle. Brixton Bikes said 'you need a new frame' to my neice. I said 'it's salvageable...but don't watch them retrack it'. 'Why?' '....because 9 foot scaffolding poles are involved...and lots of welly....'

Two days later: perfect rear triangle, no paint flaking, all joints good, and that frame did thousands more miles in Asia, South America and the most hostile environment going, South London.

I've certainly filed dropouts in the past. But I would suggest that in this case - since you used 'Sheldon's String' I would go with re-tracking. Once filed, you can't put the metal back in the dropouts. Makes the frame lighter, though.