700x32 versus 700x45 - opinions requested from folks who've gone up in tire size

Right now I run 700x32 tires on my touring frame commuter bike. I want to put some bigger tires on for helping to soak up the bumps from all the crappy roads around here but also to give me the ability to take the bike onto some rough trails as well. Just wondering if anyone else has made a substantial jump upwards in their tire size. If so, was there some all of the sudden noticeable increase in rolling resistance, or is there some magic quotient where increase in tire size = x decrease in average speed? Thoughts? The reason I'm considering 700x45 is that my bike essentially has to be a sort of Swiss-Army-Bike, in that it needs to fulfill several roles such as: daily commuter with lightly loaded panniers, grocery-getter with heavily loaded panniers, rough trail cruiser.

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Permalink Reply by peter moormann on February 14, 2013 at 11:32pm

45's are a bit of work to push on the pavement.

But damn, they sure are cushhy through potholes.

I'd get a set if you plan on riding in mush all the time.

Why not...... switching tires instead of buying another bike is smart savings.

Im 210 lbs's; rollin 700 x 28-35mm on the pavement and crushed limestone for 3 decades.

In my opinion anything bigger than 40 and you lose a lot too much control and feel for road/dirt.

A think Clement makes some really great tires for all around shitty conditions.

I'm currently running USH35 in the back and MSO 40 up front.

Work great in .... frozen mud, icy limestone,slush and ashphalt .

Ritchey Excavaders are good too.

Look in to cyclocross tires, they generally have minimal rolling resistance with good traction for loose turns and getting up slimey hills.

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Permalink Reply by James BlackHeron on February 15, 2013 at 9:03am

Many people go 650b when tire sizes get that large as the diameter of 700's starts getting a bit tall on the bike. But you aren't short so it shouldn't be an issue. It just doesn't have much of a following. Fat-tired 650b is the new fad though, IMHO.

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Permalink Reply by Tricolor on February 15, 2013 at 9:20am

Is there a reason for such a big jump? That's passing over at least three other tire sizes.

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Permalink Reply by Steve Courtright on February 15, 2013 at 9:52am

Have you tried inflating your tires to less than the maximum PSI? I never inflate to the maximum anymore and the change in comfort is very noticeable. And all you need is 5-10 pounds less. And I have not seen any change in flats either. It might be worth a try before you go to a huge, heavy tire.

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Permalink Reply by Kelvin Mulcky on February 15, 2013 at 9:59am

I'd be interested to know what you're using now.

Width is just one factor affecting the ride quality. Casing construction, thread pattern, tpi, flat protection, etc will affect the responsiveness of the tire. Another factor is air temp, when it's this cold out even the most supple tires are going to ride a lot stiffer.

One tire that is getting a lot of good press lately is the Rock n' Road 43mm tire (designed and distributed by Bruce Gordon in Petaluma, CA) You might look at other file tread CX tires with a high TPI to get a more supple ride. Other than that, the classic fat tire road tires are the Pasella, Rolly Polly, Roughy Toughy and Jack Brown.

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Permalink Reply by James BlackHeron on February 15, 2013 at 11:16am

Also, how wide are your rims you are using now? You are probably going to want at least 20mm rims (inside dimension) to run 45's without having to worry about issues with pinch flats, poor tire life (sidewall wear) and just crappy handling when turning (mushy feel) on a commuter bike. I know MTB guys run some wild wide tires on skinny rims but those ride like ass on the road IMHO.

Even a wider rim like the CR18 is too small for a 45mm tire IMHO although I know some folks run them. Something like a Rhyno-lite rim has something like a 24mm internal width would be about right for big fat tires and they don't cost that much (in the $25 price range.) I'd want to build up a new wheelset with wider rims for such a wide tire myself. If I were going to go to that expense, including the tires, I'd made damn certain that the tires are going to fit on the bike and not have any clearance issues.

Don't forget about fenders. Commuting without fenders is something I wouldn't even dream of. Getting fenders that are going to work both with clearance on such huge tires and to actually keep the water off of you might be hard. I'm not sure how many >50mm wide ISO-622 fenders are out there on the market.

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Permalink Reply by kiltedcelt on February 15, 2013 at 7:30pm

I'm thinking that instead of shooting all the way up to 700x45 I'm going to look more at probably no bigger than 700x40. My current fenders (SKS Alley Cats), are supposed to be good up to 700x38 so I imagine I can probably squeeze a 40 under them. My other issue as James brought up, is that the frame may not accept a 45 and have any room left for fenders. I also don't want to get crazy switching out rims either and what's on the bike are some cheap Xero Lite CXr rims that came off my old parts-donor bike that supplied the components for the touring bike build.