Wednesday, 12 September 2012

Stripping My Old Frame: Removing a Stuck Octalink Bottom Bracket

My old Tifosi bike was fitted with 105 equipment. I've recently replaced the bike with a completely new home build after many thousands of trouble-free riding miles (see previous blog posts about that project). But I still have a fondness for the Tifosi frame so last weekend I set about stripping it down so that I could consider its future properly.

After almost 8 years of use and many thousands of miles without a complete strip-down and rebuild it was certainly possible that some of the components may be a bit hard to shift.

Carbon forks and 105 callipers: written off

I'm a bit gutted that my carbon fork and 105 brake callipers have simply been trashed by so many years, quite literally, in the front line against the British weather. Removing the securing nut from the back of the fork was stiffer than I'd expected. The exposed bolt has fused with the nut so when I removed the nut half the bolt came away with it. Unfortunately, it gets worse. It turns out that the alloy crown on the fork has corroded badly too and bonded to the brake calliper itself. I could get the drill out and start trying to remove the bolt from the crown but there's no point because the nut needs a surface at the back of the crown to tighten against and this has completely disappeared in a puff of white aluminium oxide. From now on I'm going to remove the front brake (from my other bikes) and re-grease at least once a year.

Crank Removal

The Shimano Octalink system replaces the traditional square-tapered spindle with a hollow spindle with eight splines that fit snuggly in the crank arms.

Despite so many years uninterrupted use removing the cranks was fairly straightforward once I had the right tool. My crank puller was designed for square tapered cranks. The puller really works by holding the crank still and pushing the spindle (and the rest of the bike) away from you. To do this it needs a firm surface on the spindle to push against. For square tapered cranks there is plenty to push against but the Octalink presents a very small lip (this is the older first generation Octalink system). To engage with this you need a specially designed crank puller or an adapter tool from Shimano. I've seen tips on the internet about using various coins to do this but I have quite a collection of British, European and US change and I wasn't happy with the fit on any of these coins. My local bike shop had the required adapter which made the job easy.

Bottom Bracket Removal

The real challenge came when I tried to remove the bottom bracket. Removing the non-drive side is easy because it is just a small plastic sleeve. The drive side actually contains the spindle, bearings and the housing and was firmly stuck in the frame.

Years ago a bike mechanic I used to use would weld the spindle to the bottom bracket shell and then reattach the crank and use that as a lever in this situation but that trick only works on the (even) older loose bearing types. However, for any type of job that required use of an extractor tool he would always place the tool in a vise and use the bike (or wheel) as the lever.

Even with the vise trick, getting the extractor tool to keep its grip while I applied the leverage was still a problem. Various people suggested using a skewer or other long bolt to clamp the extractor to the bottom bracket. I could not get this to sit securely with my tool which has a wide open end but I did hit on a slightly simpler solution. I used one of those cheap spanners you get in portable tool sets and the orignal crank bolt to clamp the extractor.

Finally I was able to securely apply the leverage I needed to remove the bottom bracket!


  1. Brilliant; saved me a journey to the bike shop!

  2. ditto. Well done.