Change Gearing on 1980s Carlton Carrera with Shimano 105

[Musties]

I have a mide 1980s Carlton Carrera that I am not getting back into shape for riding here in Oman. Problem is gearing is too high for some of the hills. The chainset is Shimano Golden Arrow, sometimes referred to as Golden Arrow 105.

The front chain ring is 52/42 and my first thought would be to change the inner ring to a 39 or similar. How easy is it to buy a modern day component that will be a replacement? Do I need something from same era or willl today's Shimano chain rings fit.

On the back is a 6 speed cassette with some high gearing. Again, how easy is it to change this out for a more modern day 6 speed cassesst with more appropriate gearing?

I am pretty handy with the spanners but am just not so up to speed with what options I have.

Thanks in advance for any advice.

 

[Spokesmann]

Try a 28 block on the back, save messing around with the front end.

 

[Musties]

Where to find rear cassette

Great - thanks for the tip. Any idea what I should be looking for? I have done a bit more research and it looks like I have a 24/13 Shimano Uniglide. Removing it looks very straightforward but a search on the internet for Uniglide cassettes has no been too fruitful. Can these still be obtained?

 

[otherself]

I have run 6/7 speed (3/32") chains on 9 speed chainrings (compact Tiagra chainset) with no real issue. No slipping anyway. Possibly will wear the chain quicker but I can't comment on longevity.

 

[glpinxit]

http://sheldonbrown.com/k7.html
Uniglide is no longer available. I recently changed a freehub body over so I could use ultraglide and am on 13-25 and 52/37. You need to know the bolt circle diameter (BCD) of your (front) chainset to know what is available. BCD 144mm (older stuff mostly) has an effective lower limit of 42 teeth. Somewhere on the web you will find a conversion table to give BCD from the distance between the bolt centres or if you know what your cranks are you can look it up on Velobase and then check eBay. You may need to bear in mind the capacity of your rear mech to handle wide gear range (based on tooth count difference between the sum of the two largest front + rear cogs and the two smallest).

 

[Musties]

Re: New Front Chainring Found

Sorted! Managed to pick up a new 39 tooth front chain ring that looks like it willl fit from a local bike shop (the only one here in Oman) in Muscat. Will see what difference that makes to getting up some of the big hills here.