Chainrings compatible with original 105

square_wheels

I ride a Raliegh Team Corsa that has orignal Shimano 105 groupset (from about 22 years ago). I'm looking to change the chainrings but obviously won't find any exact replacements. They are 130mm BCD will anything like Sora/Tiagra 7/8 speed still fit OK?

I'm also interested in changing the rear free wheel (again original 105 6pd) what if anything will be a direct replacement?

whyamihere

Chainrings will be fine.

The freewheel is trickier. Almost all bikes now have the freewheel mechanism inside the hub, and the sprockets just slide on to the hub. The only screw-on freewheels you can really get hold of now are the kind that come on very cheap bike shaped objects. Halfords would probably have one if you just need *something*...

A more expensive and difficult option is to change the rear wheel and fit a new cassette. Any Shimano hub will take an 8 speed cassette, and if you set the rear mech so that it is limited so that it can't move to the highest or lowest sprockets, you can use your 6 speed shifters (or upgrade the shifters and use whatever cassette you want). This would also require the frame to be spread though. On a 22 year old bike, I'm guessing that the rear hub is 126mm between the frame ends, and that it's made of steel. Current hubs are 130mm wide, so the frame would need to be spread by 2mm each side. A steel frame will take this easily.

Monty Dog

Basic 130mm chainrings from the likes of Stronglight will fit the fill - about a tenner each from the likes of Ribble Cycles. Plenty of 6-speed freewheels still available, from original models from the era through to modern, wider ratio ones. Original ones tend to be close-ratio e.g. 12-17 which you might struggle with depending on fitness / terrain.

stabilised

Decent quality 6-speed screw on freewheels are getting tricker to find, but not impossible. Try somewhere like SJS, as they are good for out-of-date bits like that. Most common seem to be 14-24 and 14-28 ranges (the last are all you'll find in Halfords, intended for the cheapest mountain bike-style BSOs they sell and of appropriate quality). That's too wide a spread for a road bike, unless you live somewhere really hilly. I use a 20 year old bike for winter/commuting duites, with 105 drivetrain and it's been really durable and still all works more or less reliably. I'm going to have to ditch the bottom bracket (only had 18 years use out of it!) as that is completely shot. I was recently given a beautiful pair of Pete Matthews built wheels (Panini Roubaix tubular rims on Campag Record hubs, mid-80s, I guess) which came with a 13-18 six speed freewheel. It took me back to when I occasionally, unsuccessfully and briefly attempted to race bikes and rode a block like that. Needless to say, it went straight in the bottom of the toolbox as a momento and a 14-24 went on so that I can actually use the wheels now and again without having to get off and push a lot. I can't believe I once thought a 42-18 bottom gear was a good idea.