Confused On Which Bottom Bracket i Need To Buy?
 

Hi there I have a Black Wolf Lithium Mountain Bike now the bottom bracket was very loose and wobbly I took it to my nearest garage and he tightened the locking using a hammer of all things :twitchy:

He Highly suggested me installing a new bracket as he said it was broken

I managed to remove my Square cup and gone bottom bracket completely with the help of eBay but there are no measurements on the Bottom Bracket Itself now I read you need do measure the width of were the bottom bracket used to be so I think its 68MM

http://i.imgur.com/BIOVa4O.jpg?1
http://i.imgur.com/AcPM94C.jpg?1
http://i.imgur.com/Baucnq3.jpg?1

Now I see you need another measurement for example there are


68 - 113mm
68 x 118mm
68 x 122mm

How do I measure the longer side and were do I measure it from I tried google but its confusing me please be detailed as you can as i'm still very new to bicycles also do I need specific one to fit my crank arms and does British French Italian matter I don't know what I have proberly being British being in the Uk but things also get imported too :cry:

Thanks

Joe

OK, if you want to confirm the BB width, run the tape measure through the inside so you can sure, though I agree that it's almost surely a 68mm X 1.370" BSC threaded shell (BSC=ISO). Spindles are measured overall to the ends of the square taper, excluding the threaded stud (if any). To measure offset, measure from the ends to the tops of the bearing area shoulder, as shown below
.http://bikeforums.net/attachment.php...hmentid=438608
click image to enlarge

Look for a Code on the spindle such as 3-P, 3-S etc.

Sheldon Brown's Bottom Bracket Size Database

Scroll down a bit.

IF the old parts are good, just stick in eleven NEW 1/4" bearing balls/side. with fresh grease, You don't need the retainers. The grease will hold the balls in place.

Hi there I have just measured the inside were you mentioned and its defiantly 68mm now I have just measured my bottom bracket in total length and I get 126 mm without the threads so that's 68-126 mm that seems a little big I mean ever since I had this bike its seemed like an unusual size when I replace the unit is there some sort of washers/spacers available just encase its a little long as this bike was second hand so I can't be sure what has been replaced here is were I measured from :)

http://i.imgur.com/2QNUK0p.jpg?1

If this is indeed correct which I have checked 4 times then the measurements are 68-126 mm can you recommend me good affordable bottom bracket please from eBay UK or Halfords and I will buy it tomorrow :-)

Cheers

Joe

Hi there the only Code I found on the spindle was KB0410E if that means anything I'm quite sure its Shimano I checked the site and I can't find anything related to it :)

Joe

The 126mm spindle reflects it's age. Spindles were all longer years ago, and over the years have gotten shorter as the cranks were offset or bent outward.

I have a bunch of 126mm spindles, but I'm in NYC and mailing costs to the UK would be prohibitive. Search places like ebay-UK, and the dominant mail order firms, for a 126mm bottom bracket. Since the BSC is very common, once you find the right length, it's simply a matter of confirming that it's for BSC/ISO. You may not find this type of BB, and instead can but a cartridge type, but that's OK too.

Thanks for the repliy mate i have a question is it possible to use a shorter BB example 122mm or is that a very bad idea that would cause problems as it seems 126mm cartridge type BB are a little scarce online :-(

Cheers

There's usually some wiggle room on spindle length. The issue is crank arm and inner chainring clearance to the chainstays. Usually the closest place is the inner chaining, or middle on a triple and the chainstay.

Unfortunately, you destroyed the evidence so to speak when you took things apart, but maybe you have good visual memory and can remember how close the fits were. Figure a 4mm shorter spindle with the same asymmetry means things are coming in 2mm per side. If you have vague memory that that should be OK, buy the 122,, spindle and cros your fingers.

You also need to consider if your derailleur will be able to drop to the inside gear with a shorter spindle.

If you plan to do much of this type of work I would suggest that you obtain a good steel rule and an inexpensive pair of calipers; a tape measure is a little crude for this kind of work. They are inexpensive and will last forever.

If you are stuck with a tape, don't use the tape's hook for a starting point; instead start on, say, the 10mm mark and then measure from there. The hook is movably attached to accommodate both inside and outside measurements so is non-ideal for either.

you could try here, they list a 122.5 & 127mm.
Shimano UN55 Square Taper Bottom Bracket | Chain Reaction Cycles

edit; you need the tool to install this bb.

+1
Hooks can get bent etc.
Also, since we are dealing with MM, don't use the INCH side!

I can't really tell from your picture, but look at the ends of the spindle.
Do they have the same offset?
Often the DS is a bit longer.
IF it's a couple mm longer, swap the spindle end for end and reinstall.
Do you still have clearance to the chain stay?
Does the FDER travel in enough?

Your pictures don't really show if the current spindle & cups are bad. Are they?

you could get a Shimano or copy, UN xx ( 2 models 2 prices) cartridge BB ($20+ new installation tool $) match the right end length.. so the crank fits as before .

Hi everyone i went to Halfords today to get the new Bottom bracket the size i measured was 68 x 126 but that was wrong as he measured it at 122.5MM he got me the correct bracket which was a VP-BC73 68 X 122.5 Square which cost me £9.99 and a B/H/brakt Shimano tool i installed no problems although i didn't have enough grease as i would have wanted most of which was smeared from the old bracket the installation went fine no wobbles used my wrench to get everything nice and tight and everything is perfect now thanks everyone for there replies i will keep these measurements for future use when this one hits the dust thanks guys :)

Joe

a good site for the OP (sheldon's has been listed previously)

Park Tool Co. » ParkTool Blog

WTG, not so useless Joe...

Do you have any pitting in the bottom bracket spindle or races?

A good bike shop should have caged bearings. Otherwise get a bunch of loose bearings of the same size as came out, and pack them in with grease, as many as will fit. Reassemble. Total cost, a couple of bucks.

We also have a local bike co-op that has piles of old bottom bracket parts. A good bike shop might have a bin of discards that they would let you dig through.

Try this search in E-Bay:
(126,127,126mm,127mm,127.5,127.5mm) bottom bracket

You may also need some spindle bolts if not included.