Albion 

Hi fellow C&V forum members, I would value any advice you might care to offer with a challenge encountered assembling my build. In brief, I found a 1978 Centurion Super le Mans in great condition and hardly any wear, but the frame is too large. The next day I found a 1974 Centurion le Mans frame (all this dated by the ever-helpful T-Mar). A simple matter to swap the frame over, right? Not for me! Because the front forkend/fork dropout distance on the old frame is about 95mm and not the more usual 100mm, in particular the hub width of the lovely alloy Suntour wheel I propose to use from the newer, and larger frame. Yes, I can get the old fork to accept it but it's really a struggle and I don't want to court a catastrophic failure. Of course, the fork from the newer frame won't work because the steerer tube is longer, and although I could cut it down, there isn't enough thread.

Any thoughts like trying to set the forks, somehow reduce the axle length, etc. would be most gratefully received. And for amusement, here is the story of how I got the Centurion in the first place: https://www.bikeforums.net/classic-v...r-le-mans.html


1974 Centurion le Mans "Designed by Mitchel"

juvela

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most regulars are going to have the same thought

i.e. "wait for a better frame"

if you are a first timer you are going to discover many little snags such as this on the project you have set yourself

when you factor in the time, effort, work, & possible additional expense to accomplish what you have set yourself you should think about the question of "what will i have when i am done?"

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Spaghetti Legs 

I have a Park dropout alignment tool, but if you don’t have one you can look up how to make your own. Use that tool to push the forks out to some point past 100 mm, like 120 mm. Use that technique to symmetrically expand it out to near 100 mm.

The brute method is lay fork on floor on its side, step on one leg and pull up on the other. Flip over and do the other side for symmetry. That does lack some precision however.

krakhaus 

You could take the fork to your local shop and have them cold set the fork to 100mm, while you're there, have them thread the steerer down to where you need it.

Senior Ryder 00 

+1 on this suggestion.

Also​​​​​, there’s a bike co-op/bike kitchen in Tempe that should be able to help you.
Cheers, Van

Albion 

Thanks for the suggestion - I will try increasing the dropout width using something home-made. Re the interesting suggestion to look for a better frame - any thoughts as to what I might use, in keeping with a fairly good set of components? I'm keen to hang on to the components if possible.

Prowler 

A caution: With the help of articles by Andrew R Stewart , I was able to correct the fork alignment on my Fuji TS III and check and tweek the alignment on 4 other bikes over this past winter. I borrowed a frame straightener and made other tools and jigs. I will suggest that aligning or respacing forks is an exacting activity and, possibly, little understood by LBS mechanics today - in this age of aluminum and carbon bikes. You cannot "eyeball" it. If done poorly you will (not might) have handling issues.

So, my caution is that you may find mechanics who say they can respace your fork. And you may or may not find mechanics who actually can do it well and have the tools and measurement means to ensure its done well. But to do it well could take some considerable time which, at shop rate, may cost way too much for you. Caveat emptor.

Sonofamechanic 

Albion, with the caveat of sounding too “bush mechanic” on this...if you laid the fork on a table, set a ruler along the dropouts and then “sighted” thru the steerer tube to find center, would that allow you to determine if perhaps one of the legs had been pushed in 5mm? Either way, using the ruler and sighting you could cold bend the leg(s) back out to 100mm quite easily while staying centered on the steerer tube.

Albion 

Hi Sonofamechanic, many thanks for this. I checked the forks as suggested and they seem to be in alignment. The remains of a wheel the frame came with also is 95mm, and I noticed that the great Sheldon brown states that some older front hubs are 96mm, here: https://www.sheldonbrown.com/frame-spacing.html

So I think I shall give it a try. If that doesn't work, I'll take the fork from the larger frame and see if my LBC can extend the threaded portion (the Park die and holder is more than $200!)

randyjawa 

Perhaps, if there are spacers in the hub/axle assembly, removing one from each side might solve the problem. If that can be done, be sure that the axle ends do not extend too far past the drops.

Sonofamechanic 

Thanks for that info. That smaller fork has the matching paint and fantastic patina....hope you can find a way to keep it with the frame!

aland2

Be gentle as it's easy to damage the brazing with all that leverage