Oh geez, now I'm thinking about tires constantly because of this thread. I think that the profile of the tire matters regarding the road resistance. The correctly designed tire will give the same road resistance regardless of the size (on the road anyway) because only the the center of the tire will be riding on the road. Take a look at these Schwalabe Big Apples. The profile looks really good and I also think they would be "The Bomb" on my LHT. They are 26 x 2.0 in size.

http://www.universalcycles.com/shopp...ls.php?id=4787

Or this one looks really good at 26 x 1.9

http://www.conti-online.com/generato...opcont_en.html

Rolling resistance comes from casing deformation, not the friction of the contact patch against the road. Yes, if you could pump up those 26x2.0 Big Apples to the same 130psi as a 700x23, the rolling resistance would be similar. The problem is that you need to beef up the fabric to maintain strength as you increase the size of the tire, so you'll never have a large tire that has the exact same rolling resistance as a smaller one. It's too bad.

That said, they've made a lot of progress in supple, "high-performance" large tires... since my earlier post in this thread, I've spent quite a few miles on some 26x1.75" Panaracer Paselas. While they're not as quick-feeling as 700x25s at their recommended pressure, they seem to be fairly efficient -- they don't tire me out quickly. ;) And the other benefits apply -- they're comfortable, I can go over rough ground with impunity, etc etc.

I traded the crummy tires I mentioned earlier in this thread for some Continental Winters, and that made an amazing amount of difference. Same size tire, 26x2, and it really isn't a huge difference between them and my road bike like the other tires made.

I have commuted on tires ranging from 23-28 mm. Fatter tires are great if you are riding on trails or crappy pavement, but offer few advantages if your roads are in good condition. If speed is important to you, the issue isn't rolling resistance but weight. Wider tires should have no more and perhaps less rolling resistance if they also have a smooth tread. However, many wider tires have knobbier treads that will create more rolling resistance and lower traction on corners. If your route has a lot of hills, the added weight of wider tires could be a real downside. My commute route is very hilly with decent roads, and my preferred tire size is 25 mm. I've got 28s on one of my commuters and will probably replace those with 25s when they wear out.

Fatter tires should be more comfortable riding, assuming that you are running them at lower pressure. However, if the pavement is good on your route, that may not be an issue at all.

The biggest advantage to wider tires, IMHO, is that they wear better and tend to flat less often. I get much fewer flats on my 25-28 tires than 23s and they also last a lot more miles before needing replacement. I can easily get 3,000 miles of wear from 25-28 tires, but I'm lucky to get 2,000 miles from 23s.

I've ridden with 23s, 25s and 32s.

The 32s are definitely the most comfortable since I do encounter a lot of stuff on the roads. That said, I've only ever flatted twice on my 23s (which I'm running now) in 1700mi, and both times it was avoidable. I flatted a LOT on 25s but I realized later it was due to too low pressure and horrible stock rim "tape". I plan to stay on my 23s as I ride a lot of hills for my commute (around 1500ft each day), and my bike + me weigh only 165lbs so I don't need really high pressures to avoid pinch flats. I've also gotten a lot better at riding around obstacles, and handling them when I do ride into them. My good weather commuter bike is also my only true road bike so I don't want to have to change tires either for group rides, etc.

My hybrid has 32s though (came with 25s), because it's heavier and I also use it for hauling/utility. The more weight you have, the wider you want your tire to be, unless you want really high pressures and discomfort.

I don't believe width in the range up to 35mm makes much difference to speed though.

From a NYC commuter...

I prefer wider tires for commuting. My everyday bike has 26x1.5 inch slicks (its an older gary fisher mtn bike).

I used to ride a bike with 700x23 or 700x25 tires but the aero and other speed benefits were out weighted by comfort and uneven pavement. When you're commuting, you can only go as fast as the lights and traffic will let you which is usually 15-20mph....at this range, your tires are not going to be the end all with respect to speedyness.

Maybe if I commuted in a suburban area without a large volume of people, cars, potholes and gratings on the road a skinnier tire would make sense. I'll save my skinny tires for weekend rides

These are self-imposed limitations:

http://www.twinsix.com/gear/mens-tech/the-cat-6-2011-j

Here is an interesting little article regarding tire width. It is mostly refering to off road or dirt road travel in regard to tire width but I am interested in an all around tire so I have been wondering exactly how my 26 x 1.5 would hold up on dirt roads. I have a pretty good idea how it would perform but I like to hear others say it will be just fine.

http://blog.adventurecycling.org/201...vel-roads.html

I've used 26x1.5" tires (Sunlite City Slick) to good effect on gravel and dirt rides, and they're reasonably efficient on roads. It helps to drop the pressure a little for the rocky stuff, then pump the tires back up when you hit the pavement. :thumb:

A few words about the Jan Heine study referred to, which concluded that wider tires have lower rolling resistance than narrower tires. The caveat to this statement is "all things else being equal," which they seldom are. Heine's study reached that conclusion for tires that weighed about the same -- that is a 32 mm tire that weighed no more than a 23 or 25, which we all know is hard to find. Heine's conclusions are also a bit self-serving as his company (Compass Bicycles) sells one of the few wide, light-weight tires -- the Grand Boise tires that cost about $60 each. Most of us are not going to spend $60 each on commuting tires.

Heine's journal, Bicycle Quarterly Press, periodically reviews tires and has tried to spread the word about the advantages of wider tires. In general, I agree with their views, but again it seems like they are somewhat biased. They never seem to review high quality, light-weight clinchers that are readily available -- such as the Vittoria Randonneur Hyper, Continental GP 4 Seasons, Clement Strada -- for much lower prices than Gran Boise.

I've always felt that the only real drawback to wider tires was the weight of the tires themselves............ assuming equal tire pressure.

I'm currently running the stock 700 X 40 Schwalbe Marathon Mondials that came on my Salsa Vaya. Having a steel bike with a steel fork and wide tires does make for a very comfy spring commute. And I can run over pretty much anything. At 85PSI, the Schwalbes feel very sprightly for a 40mm tire.

Time will tell if I decide to go back to my 35mm Specialized Armadillo Infinity tires for commuting. They're kind of a harsh ride, but very tough, and may be lighter than the Schwalbes.

I lose more time at stoplights than I could possibly make up at 1.8% difference in rolling resistance. :D

it's not just the weight that has to be equal, but also the air pressure inside the tire, and i've never seen any wider tires that can take 130psi like most road bike 23s can take.

now, is 130psi the most practical pressure for city bike commuting, perhaps not depending on a given situation, but i do know that on days when i ride my road bike into work, there's an indescribable joy that only comes from flying across smooth asphalt with a rock hard tire.

but when it's wet out (or wetness threatens) i'm back on my hybrid with 35s @ 85 psi. staying alive is another type of indescribable joy ;)

here's my 2 cents for 28s