Technique question - BB tool wrench attachments

Jamey

While I was sorting my bottom bracket over the weekend I purchased two bottom bracket tools. The first was an all-in-one device with its own handle (for undoing the BBs) and the second was a socket-head attachment for a torque wrench so that I can tighten them up correctly. Both of these are for a Shimano square taper design, by the way.

The all-in-one tool worked fine because it has a central pin/bolt type thing that goes into the axle and stops the tool from slipping out under pressure, but the wrench attachment doesn't have this central part and as a result I found it nearly impossible to hold the wrench into the BB at the high torques required without it slipping, so I resorted to using the all-in-one tool for tightening, which effectively means I've wasted my money on the wrench attachment.

Am I doing something wrong? Is there a technique I'm not aware of or is this a known problem with the attachment style of BB tool?

Jamey

Actually, I'm going to ask this in the "Road Gear & Know-how" forum instead as it's quite a general thing.

Can everyone please reply here instead:
http://www.bikeradar.com/forum/viewtopi ... 8#15001878

Mods - feel free to delete this thread if you want. Apologies.

ride_whenever

Post does not exist...

If you're torqueing to a value on the bb then ideally you want two people to do it, or use a tube to extend the torque wrench so you can do it easily to 40nm (IIRC) with one hand whilst holding the socket on. You can do this on your own reasonably easily if you sit down, put the frame on your lap brace the top tube against your (rock hard) abs then you have one hand for tightening and one for holding.

Also BB torques are not hugely important as they just need to be bl**dy tight as you're just screwing metal against metal and there is a flush fit to stop it going too far, also remember to grease the threads with anti-seize obviously.

Jamey

I had a quick look at the torque figures on Park Tools and they say between 50 Nm and 80 Nm for cartridge type BBs (which mine is).

Which, as you say, is bloody tight.

I used lithium grease on the threads, will that do? Or do I need to go out, buy some anti-seize, take my BB out, clean the grease off, put the anti-seize on and re-tighten it to super-mega tightness?

biondino

Yes.

ride_whenever

Grease is normally okay, but antiseize is preferred, especially with steel cartridges in an aluminium shell.

If you look at the recommended torques, 50Nm-80Nm, that's a fairly wide range, it's not like a carbon stem/bar with the range 4-6Nm where the difference is between using your first finger to turn the key and using your little finger! 50Nm-80Nm is a vast tract of torque values, so let rip. Depending on how much of your bike you've assembled there are various ways to do it, but try to load the frame fairly evenly when tightening.

Jamey

The whole bike is already assembled (I use it for commuting every day) so this is the only job I'd be doing.

My new workstand has turned up so I can use that. I'll clamp it on the seat tube and try to steady the frame using whatever other tube is available to rest my shoulder against.

ride_whenever

Unless you have a kestral workstand then i'd not use it for bb tightening, you need a really solid brace, to remove the bb from my commuter it took three guys at the LBS, they laid it on one side, one guy stood on the tool to stop it slipping, one guy braced the frame and another used a 4' bar to get the damn thing out!

Generally i lean it against the wall (if it's assembled that is) and push down trying not to laterally stress the frame, but I think you'll be better off top tube in armpit and squeezing it up towards you.

redvee

I've got 2 shimano BB tools but now I'm on a HTII BB only one is of any use due to the larger spindle diameter. I now use a 12" metric jussie and 8" of 10mm bar with 3 nuts to hold the tool in place.

Jamey

ride_whenever wrote:

Generally i lean it against the wall (if it's assembled that is) and push down trying not to laterally stress the frame, but I think you'll be better off top tube in armpit and squeezing it up towards you.

Ok. Any reason why pulling up is better than pushing down?

Jamey

Also the non drive side part of my BB (the part that just holds the main cartridge) is plastic so I'm guessing I can't be quite as brutal on that side and I'll need to be a bit more careful, is that correct?

How many NMs would you tighten the plastic cup to, roughly?

ride_whenever

Re pushing vs. pulling, if you push down then you're stressing your wheels, and whilst it's a commuter, they'er unlikely to be as tough as MTB wheels which will happily take the punishment. Pulling will just hurt you, which is better i suppose.

Tighten the plastic cup untill it is flush into the frame, then a short nip. It just supports the N-driveside of the cartridge, so doesn't need to be hugely tight.

david 142

If you push down, especiallywith your weight on the handle, and something slips, then your knuckles are likely to be the first casualty, and your face could be heading towards something hard as well!

If you pull while bracing the frame against yourself there wont be quite so much uncontrolled movement if something goes wrong.

BTW, A rear wheel skewer can often be used to hold a bb tool in place. Just remember to adjust it frequently!

Pat920

I've always used a skewer to hold the bb tool - I don't think you can tighten it otherwise. And I stand the bike on the floor and use an adjustable wrench (rather than socket tool). That way I can stand on the wrench (I tend to abuse my bikes). And all I have to remember on my bike to undo the BB is that the wrench should be pointing forwards when I stand on it (unlike the pedals).