Upgrades for old BSA road bike

dodgyknees

Hi, I have an old 1985 BSA Shadow 10spd drop handlebar road bike.

Used it a lot back in the '80's & early 90's, mainly for commuting, but it's been languishing at the back of the garage for years as I'm an avid mountain biker these days.

Given its age the 'old' BSA is in pretty good nic, although the bottom bracket is shot and has more swing in it than Frank Sinatra.

I'd like to do some basic upgrades to get it going again and was therefore wondering if I could fit a modern BB and chainset to it, something like a Shimano Tiagra 4600 BB and chainset.

Does anyone know if these modern components would fit on a 1985 BSA?

arlowood

A lot will depend on the size of the bottom bracket shell on your BSA frame whether you can replace your old BB/chainset with a modern version.

Nowadays most BB shells are 68mm in diameter and come in either English or Italian thread formats. There is a good chance that your mid-80's BSA will be a 68mm spec in English threading (I had a 1986 Mercian with Campag Mirage and that took a standard 68mm sized cartridge type bottom bracket)

Your best bet is to remove the existing crankset - it's probably a square taper BB so you will need an appropriate crank puller to get the crankset off. Next remove the BB if you can source the right tool to do it. Remember that the RH (Drive side) retaining cup will almost certainly have a LH thread so you need to apply clockwise force to loosen it. The LH retaining cup has a standard thread - so anticlockwise to remove it.

Once you have removed the BB you can check the shell diameter - easier still get hold of an old Shimano Hollotech BB (you can pick one up 2nd hand for a few pounds) and offer it up to see if it fits (don't forget the different thread profiles on the drive and non-drive side).

Also if you find that the Tiagra BB will fit , you will need to source a suitable Shimano chainset as your old BSA one will now be redundent.

rolf_f

Talk to Spa cycles. You should be able to get a standard internal cupped Shimano BB for it from them - it will cost little and be better than modern external BBs. They can also supply Stronglight chainsets that will be a straight swap for yours (assuming you want different gearing - if not then there is only really any point in changing the rings unless the crankset is oddly sized). You can have just about any gearing you like within reason with the Stronglight cranks and they'll look much better on the bike than a new one.

craker

Got a photo? It might just be that the bottom bracket wants tightening up (loosen the lockring on the non-drive side, turn the bearing cup until it gets tight, tighten up the lockring). While you're at it, regrease the bearings with some lithium grease. Or as Rolf says, just buy a square taper cartridge bb (can be had for a fiver for an unbranded one).

dodgyknees

Thanks for the info guys.

Guess I need to remove the old cranks and BB and see what can be done. It's not a quality bike but I'd still like to get it back in shape.