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Sdlong92 06-23-09 03:49 PM

First Bike Building Attempt, Derailleur Choice Questions
 
Hello,

I just picked up a frame and fork the other day for a decent price and want to attempt to build up my own bike.

http://lh5.ggpht.com/_vqzZHQl3xrI/Sk...2/CIMG2390.JPG

I haven't made it very far but am stuck at a point I have no idea what to do I realized. The seat tube has a collar already on it for a front derailleur. DO front derailleurs come with their own collars to use or am I supposed to use this one?

http://lh6.ggpht.com/_vqzZHQl3xrI/Sk...2/CIMG2391.JPG

A big question I have is what kind of choices in derailleurs do I have? Does it matter what I choose really? I plan on using bar end shifters. Does that fact alter anything as far as derailleur choices are concerned? I also have a few vintage parts bikes as well, is there any reason I can't use the derailleurs from those bikes?Another question that is totally separate, what is the difference in derailleurs off a mountain bike vs road bike?

I've checked online a few places but I can't seem to find a site that specifically has a bike building walk-through. They all either skip what seems like a lot of steps or are very vague. Does anyone have a site that I can peruse that addresses frame up bike assembling?

Edit: Planning on using 7spd cassette

Thanks for any help in advance,
-Donny

bluenote157 06-23-09 03:58 PM

Nice looking frame.
That front derailleur collar is so that you can use braze-on front derailleurs. Otherwise, you'd have to get a front derailleur that is the same diameter clamp (which isnt really a problem these days..i dont think..)
What do you mean by vintage parts? Are they shimano?
If you are going friction with your barend, then it doesn't matter what derailleur you use. If you are going to go with say.. an 8 speed shimano bar end, then your safest bet would be to stick to pretty much any modern shimano rear derailleur with the excpetion of pre-1997 dura ace.
www.parktool.com has a repair section... also you can go to shimano's site and look at their tech documents.

bikinfool 06-23-09 05:16 PM

Biggest difference with mtn bike rear derailleurs is the generally longer cage used to add capacity for lower gears. Take off that simulated braze on derailleur clamp, unless you have a vintage braze-on fd to use in your parts box, and just get an appropriate clamp on style. Is that a 126mm spacing rear end on that bike (wondering why a 7 speed hub I assume or is it because of your shifters)?

If you want to try a print book you might get Zinn and the Art of Road Bike Maintenance, has a good guide for tools needed and all aspects of building up a bike including your own wheels. Sheldonbrown.com, parktool.com and the forums are great online sources.

Panthers007 06-23-09 05:28 PM

Shimano Ultegra RD-6500 GS - excellent quality. Retails around $80 - $100. Here it is at $40.

http://www.cambriabike.com/shopexd.a...EAR+DERAILLEUR

hernick 06-23-09 11:05 PM

So you need two derailleurs.

I'm assuming that triple crankset is a road crankset, with a 52 or 53 large chainring and a 30 or so small - which means you need a road-specific triple front derailleur. You can go either with a braze-on FD or a clamp-type with the proper size clamp for your seat tube diameter (which you can measure easily by wrapping a bit of paper around it and measuring that paper afterwards). Unless you're counting grams or got a great deal on some superior model (105 or Ultegra triple), I suggest a Tiagra FD-4503 or FD-4403. A Sora FD-3303 or FD-3304 would also be fine. Hey, just about any Shimano triple road FD made in the last 10 years is good stuff.

As for the rear derailleur, the deciding factor is cage length. Since you have a triple crankset, you can't go with a short cage (SS) model, you need either a medium cage (GS) or a long cage (SGS). A GS lets you use a cassette with a big cog up to 28T (officially 27 but 28 always work and 30 usually works) - but total capacity is around 33-35T so if you use a 11-28 cassette you might be a bit short and some cross-chained combinations with the small chainring might have some chain slack. A SGS RD (long-cage MTB derailleur) lets you use any cassette you want, with a big cog up to 34T, and has 10T extra capacity, letting you use any cassette you want. The GS would be perfect if you want to use a narrower cassette like a 12-21, a 13-23, a 13-26. The SGS would be perfect if you want to use a wider cassette like a 11-30, or a 11-34.

My suggestion of a rear derailleur would be either the plain ol' Deore SGS, ugly but quite good and around $20 at cambriabike, or a Tiagra RD-4500 GS. Of course, that $40 Ultegra GS at cambriabike is a mighty fine deal!

hernick 06-23-09 11:12 PM

Oh, about that stuff about the difference between road and mountain derailleurs... Well, for front derailleurs, the cable pull ratio is different, and the chainring clearance is different as well - so you really need a road-specific, triple-specific front derailleur.

As for the rear derailleur, there's less of a difference. Cable pull ratio is identical, which means that indexed shifters will index with both MTB and road rear derailleurs. If you're planning to operate your bar-end shifters in friction mode, anything will work. One difference is in cage length availability - road RDs are made in SS (short cage) and GS (medium), MTB RDs are made in GS (medium) and SGS (long). Cage length determines maximum slack take-up capacity, which determines how wide of a gearing difference you can use without chain slack. Also, road RDs are limited to a 28T big cog, MTB RDs to a 34T big cog.

My guess is you probably won't find a suitable FD in your old parts bins, but who knows... As for the RD, that's much more likely. Try any old medium or long cage RD from your parts bin and it may well work!

chrispe 06-24-09 12:17 AM

Do you plan on using friction bar end shifters or indexed? Also measure the rear spacing. I'm betting its 130mm which means you will need to used and 8,9, or 10 speed rear hub and then use a spacer if you want to use a 7 speed cassette. You'll be fine if its 126mm though.

Sdlong92 06-24-09 05:07 PM

Firstly, thanks to everyone who took time to post and PM me with well wishes and advice! It's much appreciated and now I don't have so much of a head ache when I look at the frame.

Anyhow, so scouring Craigslist I found a triple chainring front derailleur as well as a rear derailleur. They are Shimano Sora, not the best I know... BUT they were $15 for the set! So I had to buy them :cry:. The model according to Shimano works with triples.

http://lh6.ggpht.com/_vqzZHQl3xrI/Sk...512/SoraFD.JPG

http://lh6.ggpht.com/_vqzZHQl3xrI/Sk...512/SoraRD.JPG

http://lh6.ggpht.com/_vqzZHQl3xrI/Sk...lleursSide.JPG

Trying to do this thing on the cheap you see. It's gone pretty well seeing as how I started the whole process with $30 seed money a couple weeks ago and have been flipping beaters for it!

Panthers007 06-24-09 07:40 PM

I'm using a Shimano XTR - which isn't supposed to work with my set-up whatsoever. But it works like they were all born together.

Moral of the Story Dept: Don't believe everything you read from Shimano - or anyplace - unless you try it first.

bikinfool 06-24-09 07:45 PM


Originally Posted by Panthers007 (Post 9161484)
I'm using a Shimano XTR - which isn't supposed to work with my set-up whatsoever. But it works like they were all born together.

Moral of the Story Dept: Don't believe everything you read from Shimano - or anyplace - unless you try it first.

What about using XTR wasn't supposed to work?

Sdlong92 06-25-09 11:43 PM

Campy Veloce Brakes
 
So I just bought a set of Campy Veloce brakes on closeout for $19.99. I was wondering if anyone has had any personal experience with them? I've read online that they are supposed to be fairly decent. Has anyone used them on their bikes for an extended time by chance?

Panthers007 06-26-09 12:48 AM


Originally Posted by bikinfool (Post 9161521)
What about using XTR wasn't supposed to work?

Shimano gives the largest chainring the XTR will handle as being between 44 - 48T max. I'm running it on an Ultegra triple 52 - 39 - 30 crankset. Smooth as silk. I believe this is another example of Shimano rating their derailleurs by the maximum size of that which is present in the gruppo the derailleur is from or part of. And I've noted this policy by Shimano scares people away from trying it anyways - when they'd find it does indeed work.

Same policy for their Ultegra RD's - which say 27T Max. I've seen them working fine up to 32T.


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