Bottom Bracket install - plastic cup

Ian Penna · 04-29-2012, 07:17 AM

I am replacing my old BB with a Shimano UN26 and can't work out how to tighten the plastic cup on the left side. My tool (UN54) works fine on the chain side but not on the left. I was told at the shop that I just needed to tap the tool to make it fit the plastic cup but after destroying one plastic cup, I am at a loss. Do I need to purchase a specific tool for a plastic cup? I read that the UN26 now comes with an alloy cup that replaced the plastic version.

swbikemechanic · 04-30-2012, 04:26 AM

(04-29-2012, 07:17 AM)Ian Penna Wrote: I am replacing my old BB with a Shimano UN26 and can't work out how to tighten the plastic cup on the left side. My tool (UN54) works fine on the chain side but not on the left. I was told at the shop that I just needed to tap the tool to make it fit the plastic cup but after destroying one plastic cup, I am at a loss. Do I need to purchase a specific tool for a plastic cup? I read that the UN26 now comes with an alloy cup that replaced the plastic version.

Very strange the tool should be the same on both sides, have you tried putting a rear QR through the axle to hold the tool in place?

Ian Penna · 05-11-2012, 09:24 AM

(04-30-2012, 04:26 AM)swbikemedic Wrote:
(04-29-2012, 07:17 AM)Ian Penna Wrote: I am replacing my old BB with a Shimano UN26 and can't work out how to tighten the plastic cup on the left side. My tool (UN54) works fine on the chain side but not on the left. I was told at the shop that I just needed to tap the tool to make it fit the plastic cup but after destroying one plastic cup, I am at a loss. Do I need to purchase a specific tool for a plastic cup? I read that the UN26 now comes with an alloy cup that replaced the plastic version.

Very strange the tool should be the same on both sides, have you tried putting a rear QR through the axle to hold the tool in place?

Thanks for suggestion, axle is not hollow. Went back to local shop & bought UN26 tool & no probs. The UN52 tool I had was good for metal side but not quite right for plastic. All sorted now.