What size bottom bracket fits this bike? - Roadmaster Granite Peak 26" Mens Mountain Bike

hi if i remember correctly to size up for a bottom bracket, flip your bike upside down resting on handle bars and seat carefully not to damage anything, and where the bottom bracket go's through the frame of the bike you take a tape measure and measure the width of only the frame housing where the bottom bracket go's into this is a lot easier to do when the crank arms are removed. also on some bottom brackets when removed from the bike has all the data stamped on it depending on the type of bottom bracket. if not measure the width of the frame where the bottom bracket sits in too and that will be the size of the bottom bracket you need, then determine which type it is once you have remove the cranks arm which are attached to the bottom bracket could be splined drive or square tapered type bottom bracket basically the shape of the metal part that the crank arms push and bolt on to then match up on a cycle part website.

Multiply the size in inches by 25.4 converts it to metric.

Best is to show the bike to a bike shop and they should advise the size of bottom bracket and types available, for free. From my experience shops want to see the physical bike even if they have the bike spec on book.

I'd advise you to consult a bike shop as there may some interactions between a given BB and a given crank that may result in chainline problems. If you work with them and they can't get the recommended parts to work they will have to make it right.

Why is your crank "very worm [sic] after little use"? Do you mean the chainrings (which are replaceable)?

There may be other things at work here that a shop might spot and resolve.

As this example shows, they don't publish all of those variables...

http://www.bikepedia.com/quickbike/BikeSpecs.aspx?Year=2004&Brand=Schwinn&Model=Mesa+GSD&Type=bike

Ask Schwinn.

http://www.schwinnbikes.com/contacts

1-800-626-2811

The year it was made might affect the answers. Ever seen this before - "*All prices and specifications are subject to change without notice."

impossible to tell you without knowing the bike brand and model and year, although you have provided that 1999.

If you take into a bike shop, which is the usual place to purchase the parts you need, they will be able to tell you what size Bottom Bracket will fit your bike, also what options you will have for replacement cranks and bottom bracket. This could be a very complicated issue when replacing with parts that are 11-12 years newer, the shop will be best equipped to give you all your options.

Yes, of course you can replace the bottom bracket.

First though you will want to make sure that the clicking noise is in-fact coming from the bottom bracket. Even though it sounds like it is coming from that area there are other things that can cause a clicking noise, such as the examples below.

Front derailleur cable end hitting the crank-arm is a common clicking noise.
Pedals can also cause a clicking noise that sounds like its the bottom bracket.
chain rubbing the front derailleur
chain has a kink in it.

The size of your bottom bracket is related to a few factors:
1 - thread pitch (your bike is english)
2 - Bottom bracket width (your bike is 68)
3 - Crank style and brand. This I do not know for your particular bike as you did not provide the year of the bicycle or brand of crank, and they change.

Taking off cranks and removing and installing a bottom bracket requires many bike specialty tools and is probably not the best project if you have never done this before or own the tools. It will be far less expensive to have your local bike shop replace the Bottom Bracket then to do it yourself. Plus they can tell you what size it needs and if the click is even coming from that part or not.

Go to a bike shop and let them measure your cranks. Do you have a one piece or three piece crank? Do you have metric wrenches? Bottom bracket tool? You have to know the answers to these things to get the right size bearings, if it is a one piece you more than likely have a #66 but without seeing it, who knows.

I think I know what you are asking, but you haven't given me much to go on. Here are the names of the parts going from pedal to pedal -- pedal, crank arm, bottom bracket arbor, crank arm, pedal. Are you asking about attaching the crank arm to the bottom bracket arbor? And if so, are you missing the tapered pin that older bikes used to make this attachment? If so, the crank arm has 3 holes in it - one for the pedal, one for the bottom bracket arbor, one for the tapered pin. And your bottom bracket arbor will not have a square end, but will have a round end with a flat spot about 3/8 inches square. If you are missing this pin, then take the bike to a bike shop. It's a very inexpensive part, but might be hard to find the right size- or might require a little modification to fit. good luck Al K

I have the same bike, I believe the correct Bottom Bracket size is 68mm x 122.5, if you use a Shimano BB-UN300 which is also compatible with the BB-UN55/54 sizes. There are many Chinese knock offs for a few dollars less, but not worth the risk of premature failure.

On a side note, if you measure the length of the stock spindle it’s about 124mm which Shimano does not make.