Replacing 7spd for 5/6spd on record hub.. Problems?

[tedbrownbread]

Hi, just wondered if anyone could help me here? This is my first retro build.. I'm cautiously restoring an old Sheffield Wilson bike I picked up. I drove myself round the bend trying to get the right hubs and rims but i think i've done it, all made up with stainless spokes too. The hubs are low flange campy records and behind the freewheel i can see British Standard threading markings.
My problems is my shiny shimano 600 arabesque derailleur only covers 5/6 speed ( according to shimano. Could it take 7?) My front crank set is a twin sugino one. Looks great.. and the existing chain does fit that..
First question is will the sugino crank set and chain be compatible with any 5/6 speed block?
Second question is will a 5/6 speed block on this hub be ok with spacers or will i need to get the wheel re dished or... do i have the wrong hub for a 5/6 speed!!!!!?
Thanks for reading, hope this makes sense, Alex

 

[monty dog]

The easy answer is to try it - a 7 speed freewheel can be quite tight on a 126mm OLN rear and depends on the adjustment range of the rear mech - I've successfully run a 7 speed rear with a frame and mech designed for 6. In terms of the chainsets, they're virtually universal - only 9, 10 and 11 speeds need narrow chainrings. You shouldn't need to redish the wheel due to changing the freewheel - just wind in the rear mech stop screws - you only need to redish if you respace the hub body on the axle.

 

[Old Ned]

The bodies on Campag (not 'Campy' please, it sounds SO limp wristed!) hubs are the same for 5/6 as for 7 speed, they only made one size. It's the spindle and spacers that are different. To do it properly you may need to source the shorter spindle and associated spacer 'washers' to correctly run a 5 speed. Have a look in the 'Archive' section on 'Campy Only' website ( http://www.campyonly.com/history/catalogs.html ) as in the various catalogues you will find info and exploded drawings etc. of the hubs.

For a 5 speed block the distance from the inside of the dropout/edge of spindle locknut to the end/shoulder of the block thread on the hub should be 30mm and the dropout width is 120mm. For a 6 speed it should be 35mm and 125mm. Redishing may be necessary if you reduce the drive side dimensions as the wheel will most likely not centre.

I'm going through all this myself at the moment with a couple of 70's frames built at 120mm and needing to adjust some hubs to suit. I've discovered that some of my Campag hubs have all sorts of weird spacers and washers fitted by other peoples' attempts at 'upgrading' to 6 and 7 speed in the past and trying to get wheels to centre.

EDIT - is it a Sheffield or a Birmingham Wilson you've got?

 

[dutchie]

The bodies on Campag (not 'Campy' please, it sounds SO limp wristed!) ....

Please, no 'Campy' as well. The proper name is Campagnolo.

 

[hamster]

Shimano are very conservative about what their mechs can do. So I'd give it a try. The main problem is when you have very large cogs. IF you have a reasonably conservative cog size, you stand a good chance of getting away with it...

 

[tedbrownbread]

Great news
Thanks for all this.. I thought myself campy sounded soft and rubbish, campag it is when abreviating from now on..
I will go for 6 speed as the (sheffield) Wilson frame is being cold set at my local shop at the moment to fit 126mm. It was 120mm. Basically I have had it stripped and some mig welding done on it (a long fine crack) and begrudgingly made the desition to cold set before paint.
I couldn't afford the time or money to find a nice 120mm hub that would almost certainly have involved getting the Mavicg 40's I had my heart set on built onto it. The hub i have is sweet! Got my dream rims and all affordable (just) plus the future is open to 126mm set ups now.
I may try build the bike up with the 7speed on but first.. Since posting this i learned the shimano 600 arabesque rear derailleur I have has a center to center range of 70mm so will get my gauge out on the block when its back from the shop.
The frame if you're interested is a 50th anniversary model hand built by the old guy in 98 I guess, it was red metalic and is technicly too small but I like that 56" and I'm 6'. It came to me in a mess with nothing but a saddle stem, rear mech and a sugino crank set worth keeping on it. Rust, a crack but no dents.
Final finish will be a translucent deep candy red (toffee apple)with a silver sparkle under it. I may leave of the main decals to show off the paint but will get the wilson name on the front and can even get the old 50th anniversary sticker from wilson too.
I am planning to use the bike for short hilly 10mile sprints on evenings (when little one is asleep) and the odd long haul in the summer. Also want gear ratios for down hill sprints with clocking high speeds in mind. Can't wait to get this on the road and some pics posted!
Thanks again, will post the outcome.. Alex

 

[tedbrownbread]

Having re read my first post I see I wrote 'cautiously restoring' I then let on I'm cold setting for a 126mm spacing in my later post.
I feel this doesn't exactly add up. It was not easy to decide!
Do any of you have an opinion on this desition?
I would have prefered to keep 5 speed and 120mm but.. Time and money!!
Oh no.. I think the little guys on my shoulders look a bit like this and :evil:

 

[dbmtb]

Re Campagnolo naming etiquette.

UK - Campag
USA - Campy
Northern mainland Europe - Campa

Anyone want to fill in any gaps?

 

[Citoyen du monde]

The bodies on Campag (not 'Campy' please, it sounds SO limp wristed!) ....

Please, no 'Campy' as well. The proper name is Campagnolo.

I fullheartedly agree with not using either Campy (the American preference) or Campag (the British preference) or Campa (the French preference). It is in fact a family name, so I find it is in poor taste to shorten it unless one of the family members is a close friend.

As regards the problem at hand, there are a number of issues that have not been addressed. different brand freewheels had different widths, so the axle spacing needs to correspond to the specific freewheel that you have. Some 7-speed freewheels will take up the same width as a "standard" 6 speed freewheels, others will be considerably wider. You will know immediately whether it will work when you thread it onto the hub and fit the wheel in the frame. If you make any modifications to the hub spacing, you WILL need to re-dish the wheel. There is no way around this if you want the bike to handle the way it does with properly dished wheels. Your chain has likely been cut to a length that is specific to one combination of rear derailleur, chainset and freewheel combination. If you change one single of these elements, you run the risk of having either too long or too short a chain. Furthermore, chains wear in together with a freewheel and to a lesser degree chainset and if you change one, you often find you need to change teh other to prevent there being skipping of the chain. As for the derailleur having the lateral motion to handle the wider freewheel, I would say that most derailleurs produced to handle 5-6 cog set-ups will also handle 7 cog set-ups. They may however need to have more lever movement than is comfortable, especially if you use levers like Simplex retrofriction ones that have greater than average lever travel for each shift.

 

[Old Ned]

The dimensions I gave (30mm/120 for 5 and 35mm/125 for 6) were taken from an article by Mike Mullett in an early 70's 'Cycling' when Regina blocks were the norm for most riders. Mike most probably used the dimensions required for these as his 'standards' as in the accompanying article he describes the various Regina body/sprocket types and possible combinations to suit varying requirements.

Are you saying that if using another brand of block these dimensions may not necessarily be correct?