makeitwork

I recently bought an early 90s Jamis Exile with original cogs that are still in pretty good shape, but I'm thinking of upgrading.

Two questions:

1. The cluster has six cogs. Are these even made anymore? Would I also have to swap out the chainrings?

2. Would an upgrade be worth the time and expense? I pretty much just ride vintage, so I don't know much about modern gearing.

I'd like a quieter ride with smoother shifting, but not if it'll be an expensive, frustrating upgrade.

Thanks!

ogbigbird

i myself mainly ride only vintage and the such, but as far as swapping out the front chainrings if you upgrade your rear cluster... no. check the LBS or look on line to see if u can get a 6speed rear cluster. a freewheel should be no problem, but as far as a cassette goes, i couldn't say. if you are happy with the gears you have now and all the components look to be in good shape, i wouldn't bother unless money wasn't an option. for anymore speeds than 6 for the rear, you'll have to change the shifters if indexed and make sure they would fit the cluster if its a cassette and clear in the frame and axle length.

makeitwork

Thanks! That's just the info I was looking for. The shifters are indexed, so that would complicate things even more. If I stumble on a 6-speed freewheel at a good price, I'll go ahead and do it, since the swap would be straightforward. But that doesn't sound very likely.

I'll move this upgrade down the priority list, to the "Complicated/Small Improvement" section

dscheidt

No, you still need to find a freewheel that's compatible with your indexing. There's no standard spacing for six speeds. If your shifters have a friction mode, you can use anything. You can also likely use a seven speed freewheel. (It'll fit the wheel, maybe not the frame or axle.)

JiveTurkey

As ogbigbird mentioned, determine if you have a freewheel or cassette system: https://sheldonbrown.com/gloss_e-f.html#freewheel

Freewheels are an older technology, but are much more common--and still made--for 6-speed.

What kind of shifters are they? Chances are they are Shimano(-compatible), so a new 6-speed freewheel would be an easy swap.

makeitwork

I'll probably start taking things apart in the next day or two. It looks like a freewheel -- when I pull the wheel to replace the tube/tire I'll take a closer look. The bike's probably from the early 90s, so it could go either way.

The shifters look pretty ordinary -- indexed -- so they're probably Shimano-compatible, but I've been thinking of upgrading those, too, for something a little more responsive.

rickowensis

Rear dropout spacing needs to be checked before proceeding. Older 5-6 speed (rear cogs) road bikes used 120mm spacing. 6-7 and occasionally 8 speeds used 126mm, 8 speeds+ use 130mm spacing.
( Note the overlap in dropout spacing and cogset speeds, pointing out the need to measure. )

I have increased speeds in the rear cogset a few times on vintage bikes and dropout spacing MUST be checked to ensure an easy swap. After rear wheel removal, measure the distance between the inner faces of the dropouts. 120 - 121mm, 126mm - 127mm or 130 - 131mm.

If you have 126mm and 6 speeds, you should be able to go to 7 and possibly 8 speeds without too much problem. You'll probably need a spacer to prevent the cogset from rubbing the inner right face of the dropout. Keep in mind that adding one or two speeds will CHANGE your chainline but most bikes seem somewhat tolerant of small shifts in the chainline - adding a gear - while still allowing acceptable shifting.
You will still have to match your shifters to cogset speeds if indexed.

HillRider

That's not quite accurate. The only 6-speed freewheels that fit in 120 mm spacing were the relatively uncommon Sun Tour Ultra-6.

Regularly spaced 6-speed freewheels, 6-speed cassettes and all 7-speed freewheels and cassettes used 126 mm spacing.

I've never heard of any OEM 8-speed cassette (or the fortunately rare 8-speed freewheel) that didn't require 130 mm spacing. The only way an 8-speed hub could be made to fit in 126 mm spacing was if someone respaced the hub and was willing to accept way too much dish.