Cottered cranks and bottom brackets

Ok, perhaps against my better judgment I bought an old steel crankset for my Raleigh town bike build. It's shiny steel and has the heron emblem as one of the arms and looks nice - and it was pretty cheap on ebay so I took it!

Anyway, I need to fit it to a frame that was designed for a cotterless crank and has a 68mm BB shell. I guess that the BB shell design has remained more or less constant for donkeys years, so would the cups etc for a cottered crank be the same as for a cotterless model, with just the spindle differing?

If I have a cotterless crank that fits then can I simply swap in the right length spindle instead? Are cotterless and cottered spindles the same diameter? Please excuse my ignorance in this matter!

Cheers, Gareth.

I reckon its probable, but not definite that a replacement axle will work with the existing cups and bearings. If the bearings are caged, I'd remove the cages, add a couple of balls each side and have loose bearings (and get a plastic liner to keep out water). however, lengths will be a suck and see affair. Even different makes of cottered chainset will require different lengths.
Years ago, I got the shop to fit a sealed SKS BB unit made for cottered chainsets and this was fab. Maybe your local shop has one lurking somewhere in a spares box?

Personally, I'd be inclined to take back the steel c/set and get a cotterless, which is far easier to install and has good availibility of BB's, is lighter and wont rust. The only crank I've ever broken was a steel cottered one, which tore across the pedal threads, albeit slowly so there was no accident.

Following your message, I looked around and found this

http://www.sjscycles.co.uk/product-Unbr ... m-6861.htm

which is undoubtedly the easiest fix. My next question is, would the 136mm spindle be too long for a single ring crank running to a Sturmey hub gear in a 120mm-spaced rear end?

Cheers, Gareth.

till you try it, you'll never know. I now see the sense in a cottered crankset - it will go with the hub gear and keep it in-period. for £15, I'd probably take a punt, and if it dont fit, the rarity of the unit should make it easy to sell.
It might be worth seeing if you can get a washer that fits behind the fixed cup in case its not long enough. This same washer used to also be sold to fit on hubs prior to screwing on a block to alter the chainline.
best of luck

:?

Raleighs had their own shell width, as well as their own thread.

Give it a go, but I'd try to use just an axle with your existing BB cups and cones.

Let us know how you get on.

Depending on how old your Raleigh is, this will probably be a lot of help http://sheldonbrown.com/raleigh26.html as it explains pretty much everything

i replaced the cottered spindle on a shopper bike with raleigh 26tpi BB shell at 78mm with a cotterless one

yes it worked but i did use caged bearings instead of loose with original cups

the only prob was cos the shell was so wide the lockring didnt have enough thread to go on....but this wont be a prob for you

so if going for a normal spindle you would prob need some sort of 3 series..maybe 5 but i doubt it...

sure there are lots of options which could be successful..