Ok, I'm confused about drivetrain choices
 

Hi All,

I'm planning my LHT build (yep, another one! :) ) and am officially confused about drivetrain options. I've noticed talk about "rapid-rise" and some builds using a mix of road and MTB parts.

I'm building up a commuter/grocery getter/touring rig with an emphasis on the first two. I'm leaning towards an all-MTB drivetrain (XT level) with a triple up front and a 11-32 (or similar) cassette in the rear. I'm not loyal to shimano or SRAM, whatever works! I do, however, have a set of 9-spd Dura-ace barcons that I want to use. So can I use the newer rapid-rise shifters? Will any 9-speed front deraileur work with barcons? I know some deraileurs have different ratios but that's as much as I know. :(

I'm shopping Ebay (and Nashbar, and Performance, and JensonUSA, and....) and could use some advice on what models to watch for. Or maybe point me in the right direction (links).

Thanks,
Dave

The decision to use mtn or road components is decided by the gearing you want to have. For an 11-32 you will need to use a mtn RD, because road will not shift onto the larger gears. The barcons will work with rapid rise, but they will function in reverse of what youv'e learned. For the front; use a road FD if you want chainrings around 30-42-52 while something like 26-36-48 would use a mtn FD.

Get the XT-M750 (M760's are rapid rise) rear derailleur to go with your DA barcons. That's exactly the set up I use on my LHT. These are the last of the non-rapid rise derailleurs still available new. You can find them as low as $40 new.

http://www.jensonusa.com/store/produ...erailleur.aspx
http://www.performancebike.com/shop/...tegory_ID=5111

Rapid rise derailleurs will work with any shifter, only they'll shift in the opposite way you'd expect.

Any 9 speed front derailleur will work with the barcons. While the cable pull ratios between road and mtb front derailleurs are different, that only matters with indexing and barcons don't index in the front.

The only other issue in mtb front derailleur compatability is that most of them require at least a 12 tooth difference between the middle chainring and the big ring for best performance. This means that you can get some annoying rub on a 26-36-46 crankset. You can make it work, but it isn't as smooth as it is within its design parameters.

Despite the massive amount of wind recently expended on the subject, rear derailleur cable pull ratios aren't going to be a concern either. All Shimano and Shimano compatible indexing rear derailleurs, with the exception of old D/A, are the same.

The other issues in rear derailleur compatability are cage length and capacity. With a modern mtb rear derailleur, these issues are also moot.

My setup.. 2004 poprad commuter tourer fun do it all bike..
105 STI shifters.
28 38 48 touring crankset (nashbar)
105 front der
xt rear der
road or mtn casette (12-25 stocker normal use wheelset, 11-32 tour wheelset)

great setup for me so far, sounds right up your alley. I love the STI's, love having the 28 chainring.. The close ratio 12-25 casette is great on road.. needed the 11-32 on tour! (might go to a 26 tooth third ring up front for the next one!
~Steve

Thanks!
 

Thanks for the replies. Now I'm not so worried about spec'ing out a drivetrain. I'm leaning towards a setup with a 48 tooth big ring up front. I think that will be a good mix of road and mtn qualities.

Also looking for a little advice on brakes/levers. I'm going with drop bars and since I'm using barcons I don't need STI. Any recommended brake levers? Do I need to worry about compatibility with cantis/linear-pull brakes? Is this what the 'travel-agent' is for? I also have a couple 700c disk forks so I might try running a BB7 disk up front.

Thanks,
Dave

Canti and linear pull brakes need different levers. The only road levers made specifically to work with linear pull brakes are Dia-compe 287-Vs, which aren't cheap. Any standard road lever will work with cantis. The travel agent gets around these limitations by allowing you to use standard road levers with linear pull brakes.

Here is my brake recommendation, simply based on the fact that I use them on my LHT and they have performed well for me:

Brakes: Tektro Oryx cantilevers
Levers: Tektro R200A

The drivetrain on my LHT looks like this:

Shifters: Dura Ace 9sp barcons
Cranks: Sugino XD300 175mm
FD: 105 triple
RD: Deore M510 (note, not "Rapid Rise")
Cassette: SRAM PG-950 11-32

YMMV, but this has been working well for me.

Thanks guys! I've made some decisions on parts for the bike. I'll put most of the details in another thread but I did order a Sugino XD600 crank to go on my cherry pearl LHT frame. :D I won a 9-speed LX front derailleur off Ebay that I hope will work with the Sugino crank. If not, I'll probably go with a 105. I haven't bought a cassette or rear derailleur yet. But I do think I will go with a 11-32 cassette.

I also decided to go with standard road levers (cane-creek) and canti brakes (shorty 6's).

-Dave

I think the Sugino comes standard with 26-36-46 chainrings, so you may have the inner cage of the LX front derailleur rub against the middle ring when shifting to the big ring. You can raise the derailleur a bit higher than the manufacturers recommendation (which comprimises performance), grind the inner cage a bit which isn't something I'd do with a nice new part, or just get a 48T big ring.

Cantis take some patience to learn how to adjust, but once you figure it out, it isn't a big deal and they'll stop extremely well. Expect the Avids to squeal a lot until you figure out how to get the toe-in right.

Sugino
 

Interesting. My Sugino XD came standard with a 48 for the big ring.

Richard

From what I've seen, the Sugino XD crank comes in a number of different configurations: 24-36-46, 26-36-46, 26-36-48, and 24-36-48. What I would prefer is 24-34-46, but the replacement chainrings are not ramped and pinned like the originals. Not sure how much difference this would make in shifting performance.

http://www.rivendellbicycles.com/web...ngs/12067.html
http://www.lickbike.com/productpage....=%270043-70%27
http://www.bicycleclassics.com/cranks.html
http://store.somafab.com/suxd600cr.html
http://www.yellowjersey.org/cranx2.html

I picked these up as well.

I use a rapid-rise XT der. with my bar-end shifters on my Cross-check. It works fine, and I actually like the fact that they move in the same way on both sides--higher gear up, lower gear down.

I probably wouldn't mind rapid-rise derailleurs....if all my bikes were equipped as such......I don't want to confuse my shift lever direction...:)

I guess I don't mind the rapid-rise derailleurs cause this is the only road bike I have! :p I will have to wait and see if the LX front derailleur will work with my crank. My crank is the 26-36-46 version.

I have read about the avid's squealing but I also read that once set-up they shut-up. I ordered kool-stop replacement pads for them too.

-Dave

Touring drivetrain is easy.

22-32-44 front
11-34 rear

That gives you from 108 all the way down to 17 gear inches (assuming a 700C wheel).
In other words you can spin out on descents at about 35mph, and climb walls at about 3mph.