Hey guys,
I had a couple of quick questions regarding a bike that I'm gearing up to build right now. My plan is to build a road/cross/touring bike on the nashbar cross frame. I want to run a triple crank on the front because the area that I live is ultra hilly and I figure that if I do some light touring the triple will come in handy when loaded. I'm going to go with barcon shifters since I want to run disc brakes and to my knowledge there are no STI type shifter/lever combos that will work with discs. I'll probably build my wheelset with mtn bike hubs and I know that 9spd cassettes will work with shimano freehubs.
My main question is, why do many cross bikes come equipped with mtn bike rear deraileurs(sic?)? I'm probalby going to take advantage of nashbars spring sale and pick up a cheap rear deraileur. I just don't know whether to go with the 105 (this is what I was planning on) or a mtn. rear deraileur. Is it just a toughness issue? This isn't really going to be a race cross bike, more of a do everything mutant so the durability doesn't concern me that much. Any insite would be appreciated on this issue, and on my build plans in general. I'd rather know if I'm doing something horribly wrong before I order parts and since I've pretty much focused on fixed gear/ singlespeed builds in the past I'm a little new to the geared game. Thanks.
The BikeForums Team
-adv-
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avid makes disc brakes that work with sti's http://www.speedgoat.com/product.asp?part=112197&cat=30&brand=16
but if you want ultra durability, barcons are still a good option---maybe even kelly take offs (google search)
you can use any rear derailleur you want. a lot of people go with a mtn der----cause maybe they want a bigger sprocket than 27t in the rear. 105 is fine, and will work great, i have dura ace on my cross bike, and ive used ultegra and XT. wihtout issues.
is the frame spaced 135 or 130? this will determine what rear hub you use. if it is 130, good luck finding a disc hub. their not readily available to my knowledge. just go V brakes, lighter/cheaper etc.
take care
jeremy
jhota
i think jeremyb hit it on the head with the sprocket idea. though road mechs are available with long cages, long cage mountain derailers are much more common. i actually wanted a short-cage XTR derailer for the durability (off-road) but couldn't find one - went with a long-cage instead, but road mech probably would hold up almost as well... so my next cassette will probably have a 32t max cog instead of the 25t i've got now - might as well use the range since i have it...
Pigtire
That's it right there. Using a cassette w/ a teeth count greater than 28 would benefit using a long cage rear derailleur. Actually my reason for going mtb parts is because I too have very hilly rides and using anything below 28 rear is a major pain in the a@#$:D
irb_2
if you are going to use a triple up front then you will have to use a long cage RD. road or mountain will work fine.
Jarery
I live on the side of a mtn, use a 105 long cage rear in order to utilize an 11-32 casstte for the hills with a double 39/48 up front.
I left my rear brake as canti since its basically an emergency backup, and use Avid BB7 Road Disc with 105 sti shifters up front.
Works well as a commuter on hills in rain, would suck as a racer and be illegal due to the discs anyways.
phillybill
You got the 105 long cage to work with an 11-32? I had not tried that, I thought they topped out at about 27/28 teeth?
DogBoy
Interesting...my 105 LC RD wouldn't handle the 11-32 so I got an XT. If you want discs but cant find a 130 spaced rear hub, you could always do disc front canti rear. I'm pretty sure thats what Jarery runs. Spacing for the front hub is the same for road/mtn I think so finding a rare hub wouldn't be a problem.
Jarery
yep, disc front, canti rear. Front fork is nashbar carbon cross with disc mounts.
Odd, about the rear derailer. Im looking at it right now sitting in my office, its definatly 105 long cage, and cassette is ...well its too freaking dirty to count teeth while im at work. But im pretty positive it was 11-32 when I bought it. No problems shifting, just need to be aware of cross chaining more than the stock casstte since it will really grind when crossed either way.
tajsss
I've heard it varies by frame. Some frame's derailler hangers a little different and allow the 105 to work up to a 32 but reports I've heard have been mixed. I've got my 105 short cage running on a 28 right now and it looks like it could go lower. Haven't tried it yet though.
Sinfield
Thanks for all the advice guys. I went with a 105 RD because nashbar was having a sale although it mentioned that it was triple compatible so perhaps it is a medium or long cage one? I also picked up a set of Kend Kwick reflective 700x35 cyclocross tires because they were dirty dirty cheap. How bad do these things suck? Even if they do, I'm only out 20 bucks for a set of rubber I can at least roll around on.
I'm kinda rethinking the disc idea after a few of your posts, especially since I took a harder look at my budget and realized that I can get V-brakes or canti's for much cheaper than discs. I seem to remember seeing them somewhere but you can get aero brake levers for v-brakes correct? All the mtn. bikes I've ridden with canti brakes seemed to pale in comparison to v-brakes which is why I ask the question, and why I'm sort of leaning towards the V's (also not concerned about the mud clearence, I likely won't be doing any cross racing). I may still build my wheelset with disc compatible hubs (I figure why not keep the option open for down the road).
Finally, I'm currently bidding on a set of dura ace barcons on ebay. I really like the idea of being able to run them in index mode if I get in trouble somewhere along my australian tour.
qqy
I own one of those CX framed and it's a 135mm rear spacing, so you're going to need MTB hubs. The frame is very stiff and I don't think you'd be able to fit a road (130mm) hub in there. Discs are a great idea, but Avid BB7s are $200 more than Nashbar's cantis, so it's up to you if that's worth it. I have the CF fork too and it's great with discs - very rigid.
If you run the 105 rear derailleur, you're limited to about a max 28t rear cog. With an MTB cassette the max cog is 34t. I run a XTR SS into a compact crank, controlled by 105 STIs. I don't know if the GS 105s can take a bigger cog than 28, but Shimano doesn't recommend it.
Sinfield
How do you like the frame? I figure for around 200 bucks it's pretty hard to go wrong with it. I'll be building the wheels up w/ disc compatible mtn. hubs just so that I have the option down the road, but I think I'll go w/ a cheap set of canti's to get me going on it. I think I'm also going to go w/ their steel cross/ touring fork since it has rack mounts, is cheaper, and will most likely be a little more durable when I'm in the middle of my tour.
jhota
How do you like the frame?
i love mine. it's not what i'd call "comfy" - but my other four bikes are steel. it's very stiff and accelerates nicely - i've been riding it with my mountain bike buddies and pissing them off. it's faster over the terrain we ride, even though it beats me up more than their suspended hardtail rigs...