scrub

I just used the old calipers to take a quick look at the actual width of tires mounted on rims; on the Open Pro I measured a Michelin Jet at 32mm and a Maxxis Raze at 31mm, on the CXP22 my WTB crosswolfs were 31mm.

I'm looking for a bit of a fatter tire for some rooty/rocky trails and looking for a "true" 35. Anyone have any actual tire widths measured and memorized?

M_S

Not measured or memorized, but Hutchisons (Bulldogs and Pirannahs) are significantly wider than Michelins and WTBs

Andy_K 

Have you considered the Continental Cyclocross? I haven't tried it, but the nominal size is 700x42. Given my past experience with Conti, I'd expect it to be closer to 38 on most rims, but you never know. If you've got lots of clearance, it might be worth a try.

scrub

I have tons of clearance up front and I'd thought of that Conti or the 700x40 Ritchey cross.

amillhench

Schwalbes are almost always true to size.

moralleper

I really like my Hutchisons (Bulldogs and Pirannahs) The tires have a taller stance as well. I have the Perannahs mounted on my open pros now.

caloso

I have Specialized El Capitans (labeled as 34mm) on my OP wheels. I'll try to measure them tonight and let you know what I get. If they're like their road tires, they'll be wider than labeled....

bluenote157

Sorry to hijack this thread. What are the widths on open pros? What is the max tire width you can go on this?

Andy_K 

The outside width of an Open Pro is about 20 mm. Mavic lists the ERTO size as 622x15, which sounds about right for the inside width. They also say the max tire width is 28, but you can definitely ignore that. I've run 35's on a rim that is 2 mm narrower than the Open Pro. You can definitely use 35's on Open Pros, probably 38's.

bluenote157

Thanks Andy_K that is exactly the answer I was looking for! Onward to a plusher ride.. 35s it is.

RubeRad

(bump)

Exactly the info I was looking for too! Now I am not afraid to go with open pros for a new wheelset, with the intention of running 35 on a Surly Crosscheck for commuting.

fietsbob

Anything that passes the UCI tire width Max is fine. there are Go/No-go gages for ruling on that .

Andy_K 

Especially for commuting.

Bekologist

Schwalbe has a good selection of much wider than UCI width cross tires. and that conti one is also pretty fat.

I run 35c tires on Open Pros on and off road without any concerns and have pushed them pretty hard too.

RubeRad

I just put some Continental CountryRide on my Open Sports (not Pros, but I think they're only about 1mm wider), and although they claim to be sized 622-37, when inflated I'm measuring a max width of 33mm. They look badass on my crosscheck, not at all balloony.

kenrudman

I have run Kenda Kwik 35s on my OpenPros with no problems. Don't have a caliper to measure, but they are much wider than the 32m Happy Mediums I usually run for our dry racing conditions in LA. The Kwiks were a little slow on grass, but are great for commuting.

avhed

Continental GP4000S II 25 mm or 28mm? Which do you think will have lower rolling resistance on the Open Pros?
Will such a narrow rim be a compromise in the support department for a 28mm tire?
A previous version of the 20mm tire has lower rolling resistance than the 23mm, but generally the wider tires have a lower rolling resistance.

Andy_K 

28's work just fine with Open Pros.

avhed

Continental says the 28mm is for poor road conditions. Anyone have thoughts on that?

Andy_K 

There's nothing particularly special about it. Wider tires provide more cushion on bumpy roads. If you ride on chip seal you can definitely feel this.

A wider tire also gives you better puncture protection and better grip (if not overinflated). In theory they have lower rolling resistance too, although exactly what that means is a matter of some disagreement.

There's really not a lot of downside to choosing 28's over 23's or 25's if your frame has the clearance for them.

avhed

More than in theory, In tests too.
What disagreement?

fietsbob

Think the Tubular tires the ride on the Cobbles on the Farm Roads Paris to Roubaix are 25s ..

Andy_K 

Ask in the commuter forum and you'll get a few counter arguments. I'm not sure I can recite them as I'm a believer in the superiority of wider tires.

Basically, it starts with the observation that wider tires have less rolling resistance than narrow tires at the same pressure but wider tires should be run at the same pressure as narrower tires. Then it moves on to discussion of the flexibility of various tire compounds, correlated with the fact the really wide tires are usually made from stiffer materials than race tires. Usually it resolves into some sort of claim that there aren't really suitable tires on the market to allow for meaningful comparisons.

Kopsis

I haven't seen any scientific data that shows wide tires have lower rolling resistance. If that was really the case, you'd see people running 28s on track bikes. What the research has shown is that when inflated to give 15% deflection, wide tires maintain better traction on typical road surfaces and as a result you have less power loss to sliding friction. The better power transfer is more than enough to overcome the slightly higher rolling resistance, so wider tires end up being faster. But it's worth noting that once you have enough traction, having more is of no benefit so going even wider than that will start to cost some efficiency.

Of course all this is down in the noise compared to aerodynamic drag at typical road speeds. I'm only 145lbs yet I ride 25s on my CF bike and 28s on my Al frame. I'm probably sacrificing a couple of watts, but if I'm not racing that's a small price to pay for the added comfort.

Andy_K 

See, there it is.

It's really a purely academic debate. For any non-racing application (and even for some racing) a 700x28 has no practical disadvantages over a 700x25 of the same model tire while offering some small but noticeable advantages.