Dawes Fox - finding some lower gears

[Jeremy67]

Hi folks, I've posted an intro here http://www.retrobike.co.uk/forum/viewto ... 3#p2933053

I have an early eighties Dawes Fox with 2 x 5 Shimano gears (SR range I think). Chain rings are 52/40 and the freewheel 28-14. Top gear is perfect but I live in the South Downs and would love to have some lower gearing than I currently have.

I was planning to change the small chain ring but with this BCD they are rare and 40T seems to be the smallest. Likewise I've not seen freewheels with anything larger than 28T.

So then I thought I'd need to change the whole crankset (I have a taper square setup) and of course it didn't take long for the demon in lycra on my shoulder to sow the seed of moving to 15 speeds. A half hour search has led to this: https://www.ebay.co.uk/itm/Shimano-FC-2 ... 2792805448 however I'm aware that's for an 8/9 back end and there may be issues:

• The front mech may not have enough movement. How is the amount of movement specified so I know what to look for? I realise I may have to change shifters too.
  
  Chain width. Will the old chain work on the new chain wheels or can I run a chain suitable for the new chain wheels (7.1mm) on my old freewheel?

I'd hugely appreciate answers to my specific questions, discussion of the general issues or alternative suggestions (one of which, I'm aware, is get fitter!).

Many thanks

Jeremy

 

[Jonny69]

Going back to your original plan, I *think* your current chainset is 130bcd. You can get a 38 tooth Stronglight Dural chainring, assuming it’s the same fit as a Shimano. It’s a 9/10 speed one but works fine with 5/6/7/8 speeds.

Out back, I’m assuming it’s a screw-on freewheel. The issue is not going to be the freewheel, because they come much bigger, but the derailleur maximum rear tooth clearance. 32 ought to be ok. Assuming also that it’s not indexed, you could put a 6-speed freewheel on and gain another gear at the same time. 38 front / 32 rear will probably solve your gearing needs. Nothing else on the bike needs to change then. Worst case is that the derailleur capacity won’t be able to accommodate the full range, so with a sensible chain length it might not like pulling round the 52 ring and the 32 at the back. But you can work around that!