How to correctly measure a BB?

[skunkmuncha]

hi all newbie here, my question i would like to put to you all is how do i correctly measure up for a new bottom bracket. mine has just gone on my bike but i want to learn how to fix it myself, ive measured my frame where the BB sits and got 70mm which i believe is an italian thread.

Ive phoned local cycle shop told them it was 70mm but they went on to say to me, is it a 113 or summit like that, i have no idea what they mean?

how do i measure it correctly?

thanks

 

[robgul]

Measurement for cartridge style BBs is the axle length (range is usually between about 110 and 120mm) - you can measure with a ruler and a good eye - but you really need a Vernier caliper to get an accurate answer. The diameter is usually one of two standards - and the vast percentage are not "Italian" thread.

Sheldon Brown has some stuff that will help with answers.

Rob

 

[skunkmuncha]

thanks rob for the reply, just to confirm the axle is the bar that goes thru the bb itself, so to find this out i will need to remove the crankset. im gonna be buying a tool kit which will allow me to do all this. if i post a link to an item that i will be purchasing can you please tell me if it has everything in there i need to do the job http://www.ebay.co.uk/itm/Bike-Hand..._Cycling_Tools_RepairKits&hash=item3f0fece2ee.

would it be possible to have a link to sheldon brown article.

thanks

 

[RecordAceFromNew]

Sheldon link here. I think this is also worth exploring for completeness.

Italian bb is a little uncommon except for Italian frames.

 

[mickle]

68mm or 72mm. Not 70mm.

What makes you think it has an Italian fred? They are very rare indeed these days. Assuming a 68mm square taper the only other bit of info you need is the actual length of the actual axle. In mm. Assuming it had the correct length in in the first place.

 

[ohnovino]

Easiest way to find out: remove the old one and read the numbers on the side.

 

[mickle]

Easiest way to find out: remove the old one and read the numbers on the side.

Doh. Easiest way to find out: Measure it.

 

[smokeysmoo]

FYI there is no vernier gauge in that tool kit. It's a specialist piece of kit that personally i wouldn't worry about. When you strip the bb out lay it down and measure the overall length from end to end. If still in doubt pop into your LBS whi will measure it accurately for you

 

[mickle]

Don't people have doddle-sticks and scratch-poles these days?

 

[skunkmuncha]

hi thanks all for the advice. could i have your thoughts for one quick moment as i mentioned above ill be getting myself a cycle tool kit but can i ask which one shud i buy, they are only a couple of quid difference so might as well pick the best one.

1st one
http://www.ebay.co.uk/itm/Bike-Hand...s&hash=item3f0fece2ee&clk_rvr_id=310652975444

2nd one
http://www.ebay.co.uk/itm/New-Bike-..._Cycling_Tools_RepairKits&hash=item25694f73be

 

[accountantpete]

hi thanks all for the advice. could i have your thoughts for one quick moment as i mentioned above ill be getting myself a cycle tool kit but can i ask which one shud i buy, they are only a couple of quid difference so might as well pick the best one.

1st one
http://www.ebay.co.uk/itm/Bike-Hand...s&hash=item3f0fece2ee&clk_rvr_id=310652975444

2nd one
http://www.ebay.co.uk/itm/New-Bike-..._Cycling_Tools_RepairKits&hash=item25694f73be

I prefer to buy my tools individually and from decent tool makers like Park. Too often you get really cheap stuff (like chain tools which bend and break under the considerable force required) in these collections.

 

[RecordAceFromNew]

hi thanks all for the advice. could i have your thoughts for one quick moment as i mentioned above ill be getting myself a cycle tool kit but can i ask which one shud i buy, they are only a couple of quid difference so might as well pick the best one.

1st one
http://www.ebay.co.uk/itm/Bike-Hand...s&hash=item3f0fece2ee&clk_rvr_id=310652975444

2nd one
http://www.ebay.co.uk/itm/New-Bike-..._Cycling_Tools_RepairKits&hash=item25694f73be

The wheelies outlet one is better for traditional bbs, because it has both a C spanner and pin spanner which the other doesn't seem to have. The Tredz bike one has a Hollowtech bb spanner which is missing in the other. Pick the one that is more useful for your bike(s).

I have a set that looks like the wheelies outlet one, the tools are made in Taiwan (Lifu), a bit rough, but ok and not made of particularly soft cheese. Accountantpete is right of course but to replicate these tool kits piece by piece with Park's will cost 5X more. These are fine for occasional amateur applications imho, but that 6 slot spoke key in Wheelies' if like mine IS made of cheese and should go straight into the bin before it mangles any spoke nipple.