Hey guys, I need to take off, clean and re-install my gf's Truvative ISIS drive Bottom Bracket.

I picked up the BBT-18 tool and was dumbfounded when I realized it's 8-pointed. Unable to find a 8-point 36mm socket and knowing a 6-point socket won't work, I ended up trying a 12 point 36mm socket at a local store and it works fine.

Now my question to those that have used the Park Tools BBT-18 tool, is the 12 point safe to use with the 8-point tool?

I'll need to torque the lockrings after I clean and re-grease the BB and I'd prefer to use a socket rather than an adjustable wrench.



Here's a photo of the BBT-18



Any feedback would be great.

is the 12 point safe to use with the 8-point tool?

Its not a safety issue either it will work or wont(if you got it off why not the reverse?) Torque spec is around the 30-40nm so if you end up using an adjustable lean on it a bit I have never bothered with a torque wrench when installing various BBs but do use it religiously on most of the 5/6mm cap screws on my carbon bike

The 12-point socket will be fine. The required installation torque is fairly high but no where near enough to distort the socket or Park tool. The open end wrench shown in the second photo is actually a Park HCW-15 double end headset wrench and has 32 mm and 36 mm openings. Headset locknuts are typically octagonal.

I agree that the octagonal rear end is bizarre and pointless. The bigger issue I had with that tool, though, is the incredibly sloppy fit with the Truvativ bottom bracket I was using. The ID of the tool is so oversized that some of teeth barely engage with the notches. Rather than ruin my bottom bracket, I bought one of these tools which has a far tighter fit and uses a sensible square drive: Truvativ Isis Drive BB Tool > Accessories > Tools > Bottom Bracket Tools | Jenson USA

Thank you all for the reply's.

I spoke with Park Tools and they don't recommend using the 12mm socket. They recommend using an adjustable wrench...Park Tools branded of course

Most Bottom Bracket lockrings tighten to 20-30 ft.lbs so it's not something extreme. I did also order something similar from ChainCycle, X-tools BB 8-prong tool.

X-Tools BB Tool 8 Prong | Chain Reaction Cycles

It has a 1/2" drive capability which is great if I want to torque for piece of mind.

I would search for a special socket called a spline socket. They fit any fastener. One socket can fit similarly sized metric, SAE, and Whitworth bolt heads. You can get spline sockets at any well-stocked auto parts store.