1977 Carlton Corsa 5 speed to 7 speed?
1977 Carlton Corsa 5 speed to 7 speed?
Hi there Iam restoring my 77 Carlton Corsa, i have stripped all the parts and the frame is at the resprayers just now, i would like to know is it possible to change fromm the exsiting 5 speed free wheel to a 7 speed freewheel paired with the original huret rear derailleur?
Re: 1977 Carlton Corsa 5 speed to 7 speed?
Perfectly do-able. You will need to add a larger spacer or a few 3/8" washers to the drive side of the axle to leave room for the additional gears and re-dish the wheel to centre the rim in the frame. The frame technically needs cold set but it should easily spring enough in this case as the difference is only a few mm.
The mech should cope fine, you will just need to tweak the limit screws.
The mech should cope fine, you will just need to tweak the limit screws.
Re: 1977 Carlton Corsa 5 speed to 7 speed?
Personally I would fit a 6 speed freewheel, which is still readily available, and will not need any change to your wheel or frame. You might find a new chain is in order though if your existing chain is worn and slips.
I have got a Carlton Corsair (not sure if it is in any way related to a Corsa) which I bought new in 1983 and decided to refurbish a couple of years ago. I was told 27" wheels were generally of poor quality and I would see a big benefit in changing to 700c. This was fine until I realised the 700c's would need longer reach brakes, frame rear stays splaying out, new tyres, new freewheel..... and possibly a new chain. Luckily my friendly local bike shop sourced me some Chinese-made 27" wheels. Probably not as good as 700c but a good deal better than my previous wheels with the advantage of no other changes to the bike being required. Jolly pleased with the respray which was carried out by a company who specialise in powder coating those beach-buggy tube-like off-road vehicles.
I have got a Carlton Corsair (not sure if it is in any way related to a Corsa) which I bought new in 1983 and decided to refurbish a couple of years ago. I was told 27" wheels were generally of poor quality and I would see a big benefit in changing to 700c. This was fine until I realised the 700c's would need longer reach brakes, frame rear stays splaying out, new tyres, new freewheel..... and possibly a new chain. Luckily my friendly local bike shop sourced me some Chinese-made 27" wheels. Probably not as good as 700c but a good deal better than my previous wheels with the advantage of no other changes to the bike being required. Jolly pleased with the respray which was carried out by a company who specialise in powder coating those beach-buggy tube-like off-road vehicles.
Re: 1977 Carlton Corsa 5 speed to 7 speed?
a 'compact 6' is the same size as a five speed (more or less) but I have not seen one of those for years. All the commonly available 6 speed freewheels are the conventional spacing, giving a freewheel that is the same width as a 7speed one (which will be 'compact' spacing) to a good approximation.
There is no problem with the shifter, the chain (unless it is worn) but you may not have enough axle length for a standard 6 or a compact 7.
If a compact 6 is the best way, you may be able to make one by deleting cog #7 from a 7speed freewheel and grinding off any now redundant sticky-out bits. Just check the ratios will be OK and that cog#7 doesn't hold all the others on the body....
hth
cheers
There is no problem with the shifter, the chain (unless it is worn) but you may not have enough axle length for a standard 6 or a compact 7.
If a compact 6 is the best way, you may be able to make one by deleting cog #7 from a 7speed freewheel and grinding off any now redundant sticky-out bits. Just check the ratios will be OK and that cog#7 doesn't hold all the others on the body....
hth
cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~