I used to live in Des Moines. Back then there was Brown’s Woods and behind the Science Center to ride. BW got closed. What is there to ride currently?

In hindsight the ideal bike for Des Moines would be some type of ‘crosser with 38c-45c tires, since there are long stretches of pavement that turn into dirt road. The suspension fork is unnecessary since there is only one rock in town (unless it got moved) and the 29er wheels reduce impacts adequately for what is there. I’d say whatever you choose, keep it light and fast.

The issue causing the problem is the extreme difference in chainring sizes on a road triple. This is even a problem with road shifters designed to work with road triples to a slight degree. It’s the decision that Shimano made to have only three and a half index points that really threw a wrench in the works. Compare to a Campy set up, and the difference is quite clear. Anyway, there isn’t any need to fret.

Tom could get himself a road compatible RapidFire shifter pod for the left side. They are new for ‘07 and quite elegant looking, having alot of aluminum construction, much like a SRAM X-9 shifter pod. Your Paul idea would also work, and for that matter, Campy makes some killer flat bar stuff too.

If it’s cheap that you want, any old skool thumb shifter will do the job on the left side mated to your right side shifter of choice. Suntour XC-Expert thumbies show up on e-bay yet NOS and quite cheap. I believe some mail order based bike shops also sell Suntour left side thumbies yet, as well.

Another flat bar option for left side shifting would be a grip shift, with it’s micro indexed set up. That could be matched with a similar right side shifter for a balanced look.

And as far as the crankset, I would seriously consider a compact double road set up. Tom: You won’t be needing that granny, as you have surmised, so why have it at all? Your compact roadie crank can cover nearly the same ratios as a triple with less shifting woes and less weight. Give it some thought!

Also has a speed and cadence calculator.

A 34×16 is a harder gear on a 29er than a 26″ bike. A full width 29″ knobby also raises the gearing significantly compared to a narrow 700C road tire.

I think with some careful figuring you can use the same gearing on and off road, especially if you use a triple.

There is no reason to use the Thumbies unless he wants bar-top thumb shifters. Any Shimano 9-speed shifter works with any Shimano derailleur and 9-spd cassette. You can use a “triple” front shifter with any front derailleur with 2 or 3 rings. too.

Rapidfire, Dual Control, road STI, it all works with the same derailleurs.

Ted is correct that since I live in Des Moines, most of my riding is flat. I currently have a 26″ MTB and a road bike. My road riding no longer includes racing and road rides are usually less than 75 miles. Plus, as I get older, riding in the drops is not happening as much. I’d like a frame with the comfort of my MTB, but with the rolling ability of my road bike.

As for the dirt riding, on the MTB, I rarely find myself in my granny gear (locally). I would hope to find a gear range that would work for both off-road and for the majority of my road rides. If I had a 29er with road tires and a 48-50 in the front I should be good for most pave conditions. Swap out to the dirt treads with a 34 and it should be close as well. A triple would be even better.

Do I need to consider the change in gearing with respect to the change in tire size? Example, does a 34×16 feel the same in a 26 vs. a 29?

Thanks for all in the input.
Tom

On your other points: You have valid concerns for a very technical, mountainous area. However; Tim is in Des Moines, Iowa, so his idea bears merit for the intended riding style and terrain. As in anything concerning bicycles, what works for one may not necessarily even be a consideration for another.