MTB Help!

[bkboom123]

While building up my buddies bike tonight everything was going smooth, almost too smooth....Then bam! The FD doesnt fit, its too big. I know, how stupid of me to not see this coming. I built countless road bikes with no issue and am moving on to MTB's this winter. This is my third of five builds between myself, my dad, and my friend's bikes this winter.
My friend picked up a NOS 2008 Motobecane Fantom Elite Frame, hardtail, on ebay. Of course there was no info on required sizing of the FD, or anything for that matter. I just assumed all these multi-use style FD's would work. NOT!

So now I am stuck with an essentially new Shimano XT FD and am looking for the size FD I need for this build, ASAP.
I don't even know what size I need here, as I am new to mountain biking...
Help por favor :crap:

[bmeryman]

Often Shimano FD's will come with little spacers that you can throw in there to make them fit any standard size tubing. If you do not have these check your local bike shop. They did the trick on my mountain bike just fine. I'd send you my extras, but I'm not at home at the moment. They look like this:

http://ecx.images-amazon.com/images/I/31WROvnun1L._SL500_AA300_.jpg

Good luck and have fun!

EDIT: There are spacers of different thickness; make sure to get the right one.

[jonnyBgood]

All the new Shimano front mountain bike derailleurs come with two different size shims so they can fit all three size seat tube diameters.

28.6 31.8 34.9mm

[bkboom123]

Who would thunk it....Shims.

Thanks guys!

[dogdriver]

Now that your problem is solved, here's a meditation in the same vein. Please pardon the French (I probably missed an edit or two), its a paste from an industry blog...


Lastly, here is a ramble not composed by yours truly…

This industry is fu$$ed!
Does anyone else feel like we’re heading backwards in this fu$$ing industry?
Let’s take a look at front derailleurs. You used to have to know the seat tube diameter and then, bottom swing or top swing, top pull or bottom pull. Leaving us all with a million derailleurs just so we could have that one the customer would need when they needed it. Then Shimano came up with this great idea. We’ll make one size clamp, send shims to fit all the other sizes and make it be both bottom and top pull. This left you with really only two choices, top swing or bottom swing. This lasted for a few years and unicorns and rainbows abounded.
During this time the giant red S decided that it was a good idea to have the front derailleur mount directly to the chainstay. So you have a funny little adaptor and then disassemble an E type derailleur and put the thing together. As far as I can tell, this was the start down the slippery slope on which we are now standing. If you aren’t sure what I am muttering about, check out the QBP catalog. Go to XX front derailleurs. Now you get it. To help you out, QBP has even added a link to a front derailleur “standards” page. It’s not a standard when there are ten of them…
If you can get that figured out, you are moving in the right direction. Next you need to decide what kind of headset you need. Mind you that there are internal, external and integrated, campy, zero stack and to add to the standard you can now get everything in an assortment of tapered combinations… This one is about a year or two in the making, but same idea.
Now for rear hubs. 130, 135, 142 or 150? Good question. Would you like a skraxle, bolt-on, qr or thru? 6 bolt rotor or center lock? How would you like it if we just gave you an enema and took your money instead?
It seems that once we finally get all the dumb standards sorted out and convince the manufacture that they are unnecessary or retarded they decide to try 50 new things. Which of course will only work if you have the right parts that are usually available about six months after the standard is introduced. So you bought an SWorks frame, congratulations. I’m sorry you can’t ride your bike for another 90 days because we can’t get you _________ (fill in the blank).
Anyways, just what I’ve been dealing with for the past few days…
Let me know what you think of all the “standards.”
Oh and I almost forgot, is it ICSG 05 or just plain old ICSG?