some wheel size related questions
 

My friends and I are in the process of making touring plans for next summer. I'm currently assembling a bike, and I'm trying to decide what type of wheels to use between 700c and 26". I know this has been brought up many times, but I figure someone may have specific insights especially helpful to my situation.

My original plan was to use 36h 700c Velocity Deep V rims with cross tires. I'm used to 700c, and I appreciate the way it rolls over uneven terrain. Using aero rims like these, durability ought to be very high.

This plan was foiled (at least for now) after attempts to order revealed that Velocity USA is currently out of stock on 36h 700c Deep V rims. They said that they expect to receive a new shipment midway through January.

With my progress delayed, I've been reconsidering exactly what I want. 26" MTB Deep V rims are readily available, and for much cheaper. 26" rims would also definitely be stronger than 700c in the long term. I could forget my order for the 700c rims and get 26" right now instead. I would have to alter my gearing, but that's trivial, and brakes aren't a concern either.

I would expect that the main concerns for touring will be wheel durability and tire availability. I know 26" is more durable, but I don't think it would be significantly better than the 700c since they're both aero triangle section rims.

Our first tour attempt outside the US is probably going to be Mexico. Some offroad use is expected. Anyone with experience know about the relative availability of 26" and 700c tires/tubes over there?

How much would speed be affected by switching to 26" ? Gearing would be modified to be identical with either wheel. Will a 590x32 tire go basically the same as a 622x32 tire? I've also read in the commuting forum about people freaking out about flats with skinny tires on MTB rims; is there a greater danger of a pinch flat on a 26" rim than on a 700c rim with the same tire width?

Last thing -- I could use a frame with either road or MTB geometry with either type of wheels. I'm thinking that if I use a road frame with either wheel type, it'll be faster due to the geometry? I'm not totally clear on what exactly makes a road frame faster than a MTB frame, but from what I do know it seems like those factors would be irrelevant to touring. Relatively high BB would be useful to me (this would make 700c+MTB frame attractive) but it's not terribly important.

thanks for any help!!

Gary Fisher has 29" Geometry frame bikes with 700C wheels that could also use many types of tires from 42C to 2.35's.
http://www.fisherbikes.com/bikes/ser...ries=dualsport
http://www.fisherbikes.com/bikes/ser...ies=trail-29er

IMHO, if you've got deep-V rims (they don't **HAVE** to be Velocity!) there's no significant difference between 700c and 26 inch. Your money, your choice. Buy what matches your frame.

I've found NO difference in durability, pinch-flat-proneness, or rolling resistance given equivalent width/pressure tires.

Good luck & enjoy your build!

For a go anywhere touring bike it's got to be 26". Stronger rims are available in 26" and there's a much wider choice of tyres the world over. If you've got 700c forget about getting tyres in most countries in Asia and Africa.

You only get punctures caused by rims if the tyres you use are too narrow for the rim.

Road geometry is "faster" because of the normally more aerodynamic body position. Also, the tubing tends to be lighter weight. Since both of these things are comprimised somewhat on a touring bike, the difference is smaller between touring and MTB frames.

A touring bike is really a middle ground between a road racing bike and a MTB. If your touring leans more towards supported credit card touring, a racing style bike might make more sense. If your touring is more offroad and remote, something like a Pugsly might be a better choice.

I'm not a big fan of deep V rims for touring. They are designed for TT and tri use, not touring. Sufficiently strong wheels for most purposes can be built with box profiles. Box profile rims weigh less, catch less crosswinds, are more likely to have eyelets which make truing easier and are more likely to fit wider tires than deep V rims. It's worth noting that Velocity recommends their dyads for touring and tandem use, not their deep V.

thanks for all the suggestions so far.

I have both an MTB frame and a road frame lying around, so getting wheels to match the frame isn't an issue.

Originally, I was planning to use the Dyad rims. I emailed Velocity and was told that the Deep V is actually stronger, but heavier. I thought that the additional weight would be negligible compared to the benefit of added strength, so I decided to go with Deep V. If the weight really does matter that much, I will reconsider.

Availability of tubes/tires in other countries is pretty important and one of the main points in favor of 26" assuming it's true that 26" is the most common size worldwide. If 700c isn't available in most of Asia, that would be rather annoying.

Like everything else, it's a set of tradeoffs. The biggest advantage of the dyad over the deep v is that you can safely mount wider tires. It also happens to be lighter and less susceptible to crosswinds, but those are smaller advantages. The deep v is stronger, but is it enough stronger to make up for the drawbacks? Not for me. This really applies to the 700c option though since the dyad is not available in 26".

For 26", the deep Vs are wide enough for relatively fat tires. Still, I'd probably go with an eyeletted box profile because it makes the build and maintenance easier. Plus, just going down to 26" increases durability. OTOH, I don't do a lot of off-road touring either.

I can't comment on availability of tires/tubes abroad.

alright. I'll go ask the bike shop about the availability of the Dyad today. Depending on cost I may end up going with the 26" deep v anyway simply because there are a pile of them currently on ebay for ridiculously cheap.

btw, I think that the Velocity Aeroheat AC is the same extrusion as the Dyad except in 26". May also be worth considering.

http://velocityusa.com/images/dia/dia-aeroheat-atx.gif http://velocityusa.com/images/dia/dia-dyadx.gif

I'd consider using whatever size your friends are using - it makes pooling spares a lot easier if everyone can use the same spare tubes, tires, etc.

You say you have both frames now, but not from the sound of it a touring frame in 700C. While MTB frames make good tourers, not all MTB frames do. If both frames where ideal geometry for touring, I would go for MTB if any offroad or roughroad, and I would go touring for smooth sailing. From that I would then decide on the tires, because the issues are basically the same rugged tires and out of the way places, favour 26" and greater ease of sourcing. More upmarket roads and terrain are probably going to favour getting 700c, though touring grade 700c is difficult to get everywhere.

There are a lot of good rims out there that are perfect for touring. I used alex rims, and they didn't budge, under my considerable weight. I think abuse is far more important than touring. For me I try to keep it smooth on a long tour. I think one covers more ground that way. I think well build rims and huge loads are fine as long as you keep it smooth. If you can't keep it smooth, I would be looking for fat tires like 1.9 slicks, or suspension.