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Square Spindle SIZE VARIATION?
Hey Friends - didn't see much about this in the the other threads ...

I have a dept. store schwinn, and bought a new crankset to put on it.

The BB on the bike is a square spindle type, and the crankset is also. But when I tried to install it, it wouldn't go on all the way, not matter what.

I measured the openings of both the old crank and new one, and sure enough, the opening on the new crankset is slightly smaller than the old one. Thus the crankset doesn't go on all the way.

I was thinking to just replace the BB, but want to make sure it will be compat with the crankset.

How do I do that? What measurement do I look for to ensure compatibility?

Any idea here?

For reference, here's the crank: http://www.amazon.com/Cannondale-CODA-Mountain-Crankset-170mm/dp/B003HI37B6/ref=pd_sbs_sg_3

And here's the bike (God lovit): http://www.walmart.com/ip/Schwinn-26-Mens-Mountain-Bike/11065254
Ok you will want to measure the old spindle from end to end, and the new one. The new one to be replaced is 130mm which we already know. The old one is the one to get the measurement. If you are measuring with a ruler or tape measure then just convert that to mm.
Good maintenance to your Bike, can make it like the wheels are, true and smooth!
This is a common problem when replacing chainsets at the cheaper end of the market, if the new one isn't exactly the same as the old one, it is not unusual to have to try several or change the axle to get a reasonable chain line, you can even have the crank arms fouling on the chainstays.
This is best done by a LBS, who can swap parts as they go along.
Bill - can you please clarify? How do we already know that the new one with be 130mm?
OK - I measured the spindle (the one that is on the bike currently, which the new crank will not fit onto) and it is 125mm. I see there are many sizes out there, but I'm wondering how to know which one will work on my particular bike. As much as I can figure, the new one would need to be shorter, yeah? But how do I know what exact size to get? This is likely what you (trevgbb) meant by saying it is, "best done by a LBS, who can swap parts as they go along," to find the right fit, right?
So here's what I'm going to do: I'm going to put the old crankset (Suntour) back on the bike for a minute, to measure the chainline. Then I'm going to put the new crankset (Coda) on, and estimate how much shorter of a spindle I need. That should work, don't ya'll think?
... but in the process of doing so, I had the brilliant idea to read the specs that came with the crankset and learned it "can be used with any 110mm bottom bracket with tapered square spindle ends ..."

it's reasons like this that i will have a flat forehead when i get old.
Been there, done that, got that T-shirt (+ the flat forehead)...
If you can take a pic of both the old and the new BB that can tell us a lot more than you are telling. Pics always help a lot I think.
My dad always told me a Sledge a matic can fix any thing.
"can be used with any 110mm bottom bracket with tapered square spindle ends ..."
this just means that it will fit the square spindle ends, not that you will get the right chain line!!
you still wont know this until you have completed the assembly.
You have by now, found there are many different axle lengths, different BB widths, and different chainset designs, which all result in different chainlines, and it can be very difficult to get this right unless you replace like with like, or you can carry out trial assemblies and have access to multiple choices of parts, as will happen in a LBS.
In extreme cases, you can have the chainset so far out that you cannot get the FD to work, or so close that the crank arms catch on the chainstays.
It aint as easy as you think!!!
There are two types of taper generally in use:-

See Sheldon Brown for info':-

Yours may be different though if it's a special make?

Take your cranks to your LBS and see if they can match them up.
Ride hard or ride home alone!
Here are 3 pics which clearly show ( I hope) why you cannot buy a chainset off the shelf and fit it.
a cheap no name set as commonly fitted to cheap chain store bikes, the depth from the back of the small ring to the start of the taper is 18mm.
a bottom end shimano set, the depth is 8mm.
a slightly more expensive set,the depth is 1mm.

It can be seen that none of these sets will replace the other and give the same chain line, without altering the axle length.
I go back to my previous post, this job is best left to a LBS unless you can replace like with like.
My apologies as I must've been reading something else so please forgive me.
Good maintenance to your Bike, can make it like the wheels are, true and smooth!
I got the 110 mm BB as suggested in the manual - and it was a success!

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