Dawes Imperial Renovation (Help)

[Alphaville]

HI All

I have a 35 year old Dawes Imperial (531c reynolds tubing throughout). It has been left in the open in a barn and most of the steel related fixtures have rusted.

I am looking at replacing the groupset with a Campagnolo set off ebay. the things that concern me having seen the changes in gear, cassette, bottom bracket, etc technology are as follows;

1. Bottom bracket; will the Campag bottom bracket fit the threads on the Dawes
2. Allthough I had some Campag large flange, mavic rim, double butted stainnless spokes made fitted with a 6 speed close ratio cassette, it looks like now most are fitted with "screw in" cassettes??. seeing some of the pictures of these it is clear a new cassette wont fit are the older style threaded blocks still around.
3. For the rear derailleur if I use friction gear change levers can I still use modern click change derailleur. And does it matter what number of gears it is designed for if I am using friction levers to drive, provided that top and bottom travel are set down.
4. Any suggestions for other full renovation welcome. (Painting, etc)

Many thanks for your time and trouble

[anonymous-user]

I recently did a Claud Butler (reynolds 531) and I am not really that clued up on tech. I will say however that the frame was old and had much more modern gubbins on (shimano biopace and 105) and the shifters were friction ones not clicky ones.

In terms of reconditioning - get some wet and dry paper and autosol for rubbing metal bits and bats down. Repainting is best left to the pros I think.

PS enjoy it. I loved doing it so much I bought another one just to make it all shiny and sell it to someone who'll enjoy it.

[Catchme]

Sounds like fun.

1. Bottom bracket on the Dawes will probably be English Thread, so you'll need to switch the Campy BB.

2. Plenty of screw-in blocks around on ebay - Regina, Sugino, etc. I think the closest ratios I've seen are 13-19 on a 5-speed block. Old-school blocks run to about 7 speeds max.

3. The click change gear shifts are indexed to move the cables a certain amount when you shift - this matches the spread between cogs to give you a one click-one gear shift system, in theory!! I've not tried putting an indexed shifter onto an old threaded-block system before. Give it a go but I imagine the spaces between the cogs on the block won't quite match the indexing on the shifter. If you want to retain thefriction shifting, no problem, as you have complete control over how much cable you move with the levers. You'll need to adjust the high/Low screws on the derailleur to stop it jumping off the rear cogs though. Regarding the number of gears you deploy on the back wheel - you'll need to measure the distance between the rear dropouts to see what your options are. Old 5/6 speeds have about 125mm distance between the dropouts - so if you want to expand your system to take up to 8,9 or 10 speeds, you'll need to bend the rear end. You'll also need to think about a 2/3 ring system on your chainset, if you want to expand the rear-end, as the chainline between the front and rear cogs will get a bit extreme if you want more rear gears. If you get the frame professionally done, they can bend the rear stays for you (just work out what you want to do before asking them to bend the frame) and, if needs be, braze on a front derailleur mount (though you could use band-on). I use Ellis Briggs and they are pretty good at that sort of thing.

Good luck.

[Alphaville]

Thank you very much for your time and a comprehensive reply.

just to confirm; the index distance is set by the index style shifters rather than the deraileur itself? and therefore as i think you have said the friction shifter should drive the deraileur wherever I move the shifter.

[Catchme]

Correct. The derailleur is basically a parallelogram under tension with a spring. The cable either increases spring tension, or releases it providing derailleur movement. You control the cable movement, you control the spring tension. Indexed systems change tension by a set amount every time you click the shifter, so you need to make sure this movement is in synch with the spacing between your cogs.

[Alphaville]

Thanks again.

also todays problem:

I have picked up a second hand front deraileur (campag chorus) and while it did state 32mm I made the assumption (incorrectly) that it would fit the 531 tubing. I hear you laugh.

Anyway my thoughts are rather than getting rid that I would put an adapter (some sort of collar to space out this difference). Any ideas?

I though an alluminium coke can cut into a strip and then wound round to sufficient thickness and clamped in place by the deraileur?

[Catchme]

If I was going to use a collar, I would use a rubber collar - something like you see supplied with light fittings for bikes. Give it a go - but, given the pressures appled to the shifter, I would look to getting a collar that fitted directly onto the seat tube.

Welcome to the world of building bikes....! You'll make many calls on bits to fit to the bike, then find out that they don't quite work!! Think about it as inventory for the next build....