rear wheel spacing 6 speed m

[garygkn]

I have a nice road bike from the mid 80s it is a colnago super.
The block is a 6 the group set is Campagnolo.
The rear drop out spacing is 130mm is this correct for this age lf bike.

[Brucey]

no I don't think so; it has been cold set I expect, unless it is a later frame built for 8s then downgraded. I had an (identical?) frame from ~1984 and it was set to 126mm as you might expect.

cheers

[garygkn]

I assumed it was 126mm but the spacing of the frame came in at 130mm. The wheel slips in easy enough no pressing the forks together. I'll measure the width of the hub tomorrow. The bike rides smoothly and it has done extremely low mileage. It came with a set of training wheels, unused Shimano 600. I am pretty sure these are 126mm again with a tight small 6 block. Strangely I prefer the feel of the 6 speed over 9 and 10. Not sure what it is but the only draw back is I don't have a very low gear with 52 42 small block. However I carry just the essential tool kit and I seem to ride in higher gears without issue unless it's a real steep grad.

[garygkn]

Brucey - I think you are right it may have been an 8 down graded to 6 maybe in order to sell at a lower cost than the 8? The hub is 130mm the drop outs are 130mm. May be it was a way of using up some of the 6 speed group sets. I was looking at the block it is 12-19 paired up with a 46 34 24 on the front there would be much lower gears available for the hills. If I add the differences 7 and 22 that's 29 would that be OK with a campag short rear mech?

[JohnW]

I like 14 - 28 six speed blocks - they give me just the spacing that suits me. I had an issue with a six-speed block on a Campag screw-on hub, spaced and dished for a 130mm rear end.........the issue was restricting the travel of a modern (9-speed) long-cage rear changer - the grub screws weren't long enough and if I'd used that changer the chain would have overrun at both ends of the block. A short-cage Nuovo Record rear changer was OK, but wouldn't take up the chain-length for a wide-range triple. For that kind of set up, you'll need to think about getting everything working and compatible.

My solution was an 8-speed cassette on a new (free)hub and the other wheel onto a different bike.

126 was certainly the norm for the 1980s - I don't think that 130 had ben introduced as early as that - had it?

[garygkn]

I did some research and I think my frame is 1991. To be certain I'm going to email Colnago with the serial number from the drop out. The chain set is not the original 80s version it is the later one from after 1987. Later I'll pop a picture up.

John I have thought of doing a similar thing to as what you did.
Moving the wheels over to a different bike and using an 8 speed wheel although I'd go for a cassette hub.

[Brucey]

. If I add the differences 7 and 22 that's 29 would that be OK with a campag short rear mech?

maybe... best to try it and see.

BTW 130mm would have been standard on a road bike circa 1990.

cheers

[garygkn]

Maybe I have a 1990?

Colnago were quick:
'Unfortunately we don't have this serial number in our system.
Probably it is too old, and we don't keep all numbers.'

I am impressed with the ride. Very smooth and feels solid. Zips a long silently.
For the moment I'll leave as is as i'm getting used to the 52 again - I think the issue is more when I am fatigued.
I noticed on my old Sigma tourer which for some reason had a double 50/39 a 50/40/40 went straight on the same bb and I did was swap out the front mech.

[Brucey]

possibly the rear end has been reset or the frame has been built up with slightly older parts or something.

BTW IIRC (do check) but that rear mech has a rather large capacity (for a short arm campag one). I think that the largest sprocket it will accommodate (with the parallelogram set to the correct angle) is 32T or something mad like that. So if you need lower gears that might be a way to do it.

cheers

[garygkn]

I think it must be a 1990 frame.
The 1986 frame is similar.




Why re set the rear to 130mm and replace a 126mm 6 speed wheel with a 130mm 6 speed wheel?
If that was done what was gained?
It could have been an export model built up specifically with a 130mm 6 speed?

Perhaps that rear mech would work with a 52 42 30?
It looks like a medium for Campag?

[Brucey]

Why re set the rear to 130mm and replace a 126mm 6 speed wheel with a 130mm 6 speed wheel?
If that was done what was gained?

well the rear wheel would have been stronger that way, but I think it is more likely that your bike was 'converted' to 130mm, used like that for a time, then built up differently and then sold on. It is commonplace for last year's road bike to be sold on with a set of 'training wheels' for example, and back in the day I would have had a set of bits like that (with the wrong wheel spacing and a slightly older indexing setup) that I might have put onto a frameset before selling it on.

Nothing wrong with that of course, and I am only speculating, but you can see how it might happen.

BTW you can look up the specs of the rear mech so I'd do that if I were you. I think it will take a large sprocket but the overall capacity isn't enough for a wide ratio triple chainset.

cheers

[garygkn]

I can see that 46/34/24 with 12-19 would work.
But would 52/42/30 with 12-19 work?

I've no idea what that rear mech is?
Could it be Athena or Chorus?
http://www.hilarystone.com/gearscampagnolorear.html
CGR15A CAMPAGNOLO CHORUS REAR DERAILLEUR 1987–90 Mint! £85


This looks promising:
http://www.disraeligears.co.uk/Site/Home.html

I'll look through this and see what I can find?

[Brucey]

http://velobase.com/ViewComponent.aspx?ID=9f7fb5dd-6e42-4f07-8f3b-f2c7b6b1dbd0

IIRC the Athena version differs in detail from the chorus version.

Max sprocket 32T
Total capacity 33T

which means that (in theory) 22T at the front (either chainset you propose) leaves 11T for the rear, i.e. 13-21 T max.

In reality you could set it up to run (say) a 30T sprocket and accept that you won't be able to use anything smaller than a 19T sprocket when you are on the inner chainring, else the chain will run slack. This is likely to be OK for some folk because the small-small gears are liable to be duplicates of others on the middle ring anyway.

cheers

[garygkn]

Top man Brucey you have component detective skills to be admired.

Much appreciated,
Gary

[Brucey]

I've also got one of those mechs in my parts stash, too...

cheers