bb + crank combination
 

so us road bikes have same bb size right? this is for my 1989 centurion ironman

has anyone tried any of these cheap bb brands?

http://www.amazon.com/FSA-7420STL-Ca.../dp/B0037N523W

http://www.amazon.com/Sunlite-Square.../dp/B003COD29C





crankset ill probably end up with

http://www.icatchdeals.com/tec9-fixe...5mm-170mm.html

http://www.cyclingcloseouts.com/Prod...set_White.aspx

Centurion Ironman is not a US bike, it is Japanese (maybe it was Taiwan by then). Most bikes in the US are not US made (just about none anymore, but that is another story), and depending on the manufacturer and country of origin, they will have different sizing. For example, I have an Italian bike that has one size, a Japanese bike that has a second size, and a French bike with a third size. All of the bikes were sold new by dealers/bike shops in the USA. Of these three bikes, only the Japanese bike uses the so called British standard, which is by far, the most common standard.

Myself, I would buy the crankset and bottom bracket from the same supplier, to avoid the finger pointing if something doesn't fit right, or you need to return/exchange a part.

Your two crankset choices state that they use different length bottom brackets in their specifications.

ahh how do i know which standard is mine? how can i check what size bb i need (see below)


17 sprocket
http://cgi.ebay.com/ws/eBayISAPI.dll...=263602_263622

165 crank uses 107-110 square taper (recomends shimano bb, eigthinch does not make bb)
http://www.cyclingcloseouts.com/Prod...set_White.aspx


shimano UN54 68 and 73 x 110
http://www.bikebling.com/Shimano-UN5...m?1=1&CartID=1


shimano UN26 73 and 68 x 110
http://www.universalcycles.com/shopp...s.php?id=20912

how do i know if my bb has 68 or 73!?
and suggestions between the 2?

Again, your time will be better spent doing some research on the Park tools or Sheldon Brown sites than trying to get answers to all of the complications entailed in replacing a BB and full crankset. If you don't have the original parts it is extremely difficult for a lay person to figure out what is needed, and not possible for even a mechanic (I was one for over 20 years) to do over the Internet. You have to end up with a combination such that the cranks are reasonably symmetrical on the frame and the chainline (chainwheel to cog alignment) correct. That requires a lot of measurements, including of your rear wheel and triangle.

If you insist on doing this at home then have enough respect to do some studying on your own. I'm more than willing to help anyone fill in the gaps but your piecemeal approach is impractical. If you had followed my previous suggestion at all you would already know that an older road bike has to have a 68mm bottom bracket, for instance.

mhm okay thanks ill look around more sry

edit: read parktools, good info for installations/taking apart
read as much as i could handle of sheldonbrown

so i need to buy a bb that will allow me to have a perfect chainline in accordance w/ my rear wheels hub and sprocket?

okay didnt have the best measuring tools but
my measurements shud be pretty accurate

tooken from a.winthrop(thanks :p)
english size threading
111m x 68 bb (is it limited to 111 only?)
square taper

frame spacing: roughly 130mm

rear fixed hub spacing w/o sprocket : 120mm


i read alot about chainlines and stuff but am still confused about how to measure chainline

take rear frame spacing and divide by 2. 130/2 = 65
"Measure the distance from the inside of the rear fork end (or the outside of the axle locknut) to the middle of the sprocket. (Example: 18 mm)
Subtract the dropout-to-sprocket spacing (Example: 18 mm) from the half-over-lock-nut dimension (Example: 60 mm) to determine the actual rear chainline (Example: 42 mm)"

i dont have any sprockets so how would i do this? sry if its dumb question
im honestly trying my best right now im just not the fastest learner

idk where to go from here

Everything you wanted to know about bottom brackets, but were afraid to ask:

http://www.sheldonbrown.com/bbsize.html

wow great page of information.. cant believe i didnt come across this myself

question: my bb size is 111mmx68 and im trying to make a fixie

that means i need a single chainline crankset that has 111 length
on this whole list is shimano cranksets, there are no single chainlined cranksets w/ 111

what can i do about this? different brand crankset or are there certain bounderies that can be broken

If you'd read all of the info at Sheldon's site on bb size and how they mate to specific cranks you'd do much better. What crank do you have now or what specific crank are you going to settle on? The bb as far the bike is concerned is about the shell width and threading, and it's pretty much assured you've got a 68mm shell and English threading. The bb only has to match the bike frame for specific shell width (and sometimes is simply a matter of spacers with some systems) and threading. The rest matches the crank. So, decide on a crank...maybe the old one is fine with a new ring? Doubles can often work well with a single ring on the inner position...

nice thanks man, and i have no crank right now i was planning on buying one according to the bb i purchased.

so if i got this crankset, then i could get any bb with measurement between 107-110
http://www.cyclingcloseouts.com/Prod...set_White.aspx

http://www.bikebling.com/Shimano-UN5...m?1=1&CartID=1

Highly doubtful your bike has 130mm rear spacing. You should consider getting a micrometer. Even the cheap plastic one Harbor Freight will work for this measurement. Your bike came with 126mm spacing.

i need to pick one of those up lol i was using a ruler :X but my ruler measured out to like 131
yea i agree with 126 though

You don't use a micrometer for measuring rear spacing - or for measuring anything else more than maybe an inch in thickness. Even vernier calipers will not go up to that width on newer bikes. All you need is a ruler with metric graduations. And yes it could be as you measured - someone could have cold set it to other than the original spec.

Chainline - All you are doing is figuring how far out from the center of the frame the rear cog and front chainwheel are, and trying to make those two measurments the same. You change those figures with different equipment or by moving/adding/subtracting spacers, but the rear triangle has to be the right width for the hub you use and it has to be centered on the frame. That is at least half a dozen variables, and if you are that confused it is doubtful you will end up doing it correctly.

My final word on this: You STILL do not have all the info you need to get proper chainline and cranks, you do not understand BB/crank specs and their interrelationship (let alone the proper terminology), and it is NOT a good idea to get a bb first and then find cranks to "fit." The only way you can predict chainline on the front is by buying a full unit that has that info available or by actually mounting and measuring something you plan to use, and the only way you can tell if the front chainline will work with the rear is to have a cog mounted on the rear wheel, on a properly spaced and centered rear triangle and then measuring and calculating properly.

These forums are wonderful but you have to remember you usually know precious little about who is giving you advice, and you need to do as much research as you can so that you can present solvable problems and properly convey what you need. Your problem is especially hard to address remotely. What is your objection or difficulty in getting advice/help from a bike shop? You could also see if there's a bike club whose members could help you.