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Hi all
I don't know if a bike forum is the right place to post this question, but I'm putting together a tool kit to enable me to remove and reinstall the threaded GXP bottom bracket on one of my bikes, and it's proving trickier than I expected...
I want to use the Park Tool BBT-69.2 with a 3/8" drive tool to loosen the BB cups. The internet seems to think that a sliding t-handle is better than a ratchet (might break) or a breaker bar (less stiff due to pivoting head). There are loads out there but Stahlwille (allegedly "the German Snap-On") seems to do a good one.
Now, Stahlwille describe this tool as both 3/8" drive and 10mm drive. But 10mm is actually slightly bigger than 3/8". Does anyone know whether this is normal practice in tools-world? Or should I avoid the Stahlwille, on the basis that it might not have the tight fit I'm looking for?
Regards
Gareth
The advantage of a T-bar over a ratchet isn’t strength, it’s the ability to apply force evenly and therefore minimise the risk of damage to components and threads. Especially if something is expected to need a lot of force but you know there are fragile threads, then a T-bar is the correct tool. It must be said that a long lever allows more force to be applied however. A T-bar is more versatile than a breaker bar as it sacrifices the jointed head for a sliding Chuck that can be at either end or any point in between.
No real thought on 10mm vs 3/8” as drive because ive never needed to do this. Personally I’d stick with one standard or the other though. Poor fit is not unlikely to improve your chance of a troublefree job.
Personally, I would have expected 1/2” drive to be more suitable for a bottom bracket that might need persuasion, though. Certainly if buying tools for the job I’d go straight there rather than lighter weight 3/8 stuff.
I never heard of a 10mm drive, nor has Wikipedia:
https://en.wikipedia.org/wiki/Socket_wrench#Ratcheting
Just use a shimano HT2 spanner? IIRC SRAM only use the old (larger) size.
A socket tool is nice, but overkill.
I really wouldn't worry about it too much, if you need that much force to remove it you'll be clamping the tool in a vice and rotating the frame anyway.
Bike on ground, tool on bottom bracket, jack carefully placed under tool, preferably tool held in place through the bb in some way, stand on or hammer the tool handle is my method.
Stahlwille describe this tool as both 3/8″ drive and 10mm drive
Just a guess, but it's probably just a nominal size, not meant to be an accurate measure of the real size.
Tbf, I’ve never heard of 10mm as a drive standard either but I didn’t look it up! 😁
SRAM are old standard HT2 fit, and generally it is ok to just use the cheapest pressed steel BB spanner you can find, but occasionally you come across one that’s s t u c k, and then a socket and lever are helpful if not absolutely essential. Personally if I found one that jammed I’d probably be up for a T bar in preference to a long lever, just in case...
Thanks everyone for the really helpful replies. Good to know I'm in the right ball park at least. Vincienup, I'm looking at 3/8" rather than 1/2" drive because the BB tool is 3/8" drive. I plan to use the tool to torque the BB back up to spec, so it makes sense (to me!) to use it for removal as well.
I bought a Park Tools BB tool earlier this year for a bike build. I’d managed with a pressed steel spanner for years but thought I’d buy the proper tool for the job, because...... well it’s a new tool and it’s...... a new tool.
It’s 3/8” square drive with a 1” hexagonal spigot that you can either put a spanner or socket on if it’s tight, or as said above clamp the tool in a vice and turn the frame if it’s very ****ing tight.
Remember Park Tools are American and therefore use imperial sizing, except where they use metric like the rest of the world. 3/8” square drive are 3/8”, 10mm is just a “nominal” size that someone at Park though to slap on the specs to sell in Europe, not realising that we all use 3/8” square drive because it’s been around for ever, ie: before the British adopted the metric system. (Well, a bastardised metric system that was just imperial measurements converted)
Sorry to rant on. In short? Yes it will be fine with a breaker bar or ratchet or whatever.
Just get a breaker bar. If you can't remove it with a breaker bar then you're in big trouble anyway 😉