I have a 2005 Lemond Chambery and want to put an octalink chainset on it but it’s always had an external BB on it. What length octalink BB do I need? Never used one on a road bike.

You need to get whatever length is specified by the chainset that you’re using.

I’ve no idea why anyone would want to convert to Octalink, though. It’s obsolete and IME not very durable.

I think the octalink BB on my road bike is 73/118mm if that helps. It does have 135mm rear axle spacing in case that makes a difference. FYI it’s outlasted every external bb I’ve ever used – easily done over 10,000km and still going so I wouldn’t worry about durability.

I’m just trying to convert the slightly beat up bike to dedicated turbo use cheaply. 118mm sounds good thanks.

FYI it’s outlasted every external bb I’ve ever used – easily done over 10,000km and still going so I wouldn’t worry about durability.

Fair enough. I used to get through Octalinks in a few months, and have yet to kill an external BB. Though to be fair the former were off-road and the latter are on, so it’s an unfair comparison.