Haven't seen your name in a while nun, did you ever see my pm?
Cheers

I'm also interested. I know there is this 40x26 and have contemplated whether you could get by with 24t granny with careful shifting.

I notice that the X9 MTB crank that Nun mentions limits the jumps to 14 teeth with 42-28t, 39-26t, 38-24t, and 36-22t offerings. I at some point briefly used a road triple with a 50-39-24 and found the shifting kind of clunky, but usable. It was clunky enough that I decided to swap cranks before doing a loaded tour in the mountains, so I only use it a short while.

I wonder if a double designed for 40-24 rings with the right ramps and pins might do better. FD choice and setup would probably vary how acceptable it would be as well.

Yes, it shifts just fine. It is not quite as smooth as my original double on the cx bike, but really close and has never given me a moments trouble. Highly recommended as an easy road double replacement.

I've been running 42-26 rings on the inner and middle rings of a Sugino triple using an IRC compact double derailleur (16t capacity) for a while and it works ok. I don't see why it wouldn't also work using 40-24 rings

I road toured with a double and almost never used the small ring so my next bike was setup as a single with a wide range MTB cassette.

I'm working on a new dirt touring bike and it will also be a single with a newer even wider range MTB cassette. I find getting ride of the front derailleur is well worth the slight loss in gear range. I just move the gear range I need around by using the correct front ring for the trip. I am fine with coasting downhills and I can comfortably pedal at low, medium and high RPM so I get a lot of range out of 9-10 gears.

My gear is on the mid to lightweight end of the touring spectrum which helps a lot with not needing a huge gear range.

Although I use a triple, I think my experience with my inner and middle rings is pertinent to this discussion. My triple uses a 52/42/24.

The upshift from the 24 to the 42 is a bit slow, but I can usually make that shift in about 30 feet of distance without any difficulty. The downshift to the 24 is virtually perfect. I use a chain catcher to make sure that I do not drop the chain but I quite frankly have no idea if it is needed or not.

Derailleur is a vintage Suntour. I use a friction front shifter, I am quite certain that an indexed front shifter would work poorly, as I usually have to overshift a bit when shifting up from the 24 to 42, then trim it after the shift is complete.

If I ran the 42 and 24 as a double, it would probably shift smoother because I could mount the front derailleur slightly lower down the seat tube closer to the 42 and 24 chainrings. First photo is 52/42/24, on one trip I put a 46 on instead of the 52 as shown in the second photo. Both bikes use the same vintage Suntour derailleur.

http://bikeforums.net/attachment.php...hmentid=472502 http://bikeforums.net/attachment.php...hmentid=472503

Nice thread-- I just was wondering about this a month back when building up a vintage touring bike for a friend and had a heck of a time changing it all out for a triple for him.

As for me, I'm two-years new to touring and built up my own (fairly robust/heavy) vintage touring bike to be able to handle anything that might come at me. I have a half-step + granny set up in front (a 48-42-26) and just a 5 speed freewheel in back from 14-34.

In the past two years of sporadic tours, I've never had to go to the granny, including a couple cascade mountain passes and a trip up Mt. Constitution in the San Juan islands. I'm certainly fit, but not a high mileage trainer by any means, so I would think, choosing carefully, a double could be made to work just fine for pretty much anyone. Some of the MTB gearing referenced above is a good starter I think.

A buddy and I just rode the ice field parkway (Jasper AB to Banff AB), both on compact doubles on cross bikes. I weighed my gear before leaving and it was 50 lbs not including my camera bag which was probably close to another 5. The passes were a grind but we lived to tell the tale. We saw one other guy with a double and all the other cyclists we encountered were running triples.