Square vs. round tyres?
I read that squarer tyre profiles are grippier than more rounder profiles. How much truth is there is this?
I normally run 2.1 tyres on a Mavix XM117 rim – how wide a rim would I have to run to: 1) get a noticably squarer profile on my 2.1 tyres? 2) sensibly run a 2.3 tyre?
Great question. Here are some broad generalizations:
– Squarer tires (on which the side knobs are very exposed) do get excellent traction, especially in loose conditions where the knobs can penetrate. The WTB Weirwolf comes to mind.
– Compared with rounder tires, squarer tires are more likely to squirm on hardpack. They also tend to hold well then … let go. For this reason, square tires seem best for expert riders. Mark Weir used to say this about the Weirwolf. If you knew how to ride it, it was amazing. Otherwise, it was a bit sketchy. But unbeatable in loose dirt.
– Round tires tend to deliver more consistent cornering forces and traction. They work well in a wider range of conditions. They might not give you the same ultimate cornering traction, but, like I said, they’re easier to ride.
– The profile of your tire is partly a product of the size of the tire and the width of the rim, but the design of the tire has a much greater effect. The old Intense DH tire — very square.
– I prefer rounder tires. My dream tire has tightly spaced center tread that transitions into side knobs that are well supported and well exposed, but that preserve an overall round profile. Examples: WTB Mutano Raptor, Maxxis Minion, Specialized Eskar and Resolution.
– I have no idea which rims you should run with your tires, especially not knowing which tire you run. Try a 2.3 on your current rim, and see how you like that.
This is crying out for a diagram, but I’m pinned with other stuff today. Hopefully soon.
I appreciate the way Lee describes square-vs-round and then picks some tires that combine square cornering knobs with roundish profiles. Very helpful, very informative.
From a less-experienced/less-skilled rider’s perspective I have found that round profile tires require you to corner with a technique that assumes some drifting will occur — or maybe corner more carefully. I don’t like the progressive drift nature of round tires.
I like the hold-hold-hold-hold-BREAK TRACTION feature of square edged cornering knobs. It requires you to first figure out where they lose their grip before you get too aggressive in your cornering, but since I like to carve turns and not drift them, I appreciate the holding abilities of square-edged tires.
Great topic to post, Lee!
Oops, forgot another point.
Sometimes it can be fun to run a square tire up front for really precise steering and a rounder tire in the back to let you drift a bit at the rear wheel. I find cornering unbelievably scary with a round front tire.
Sort of related to this. If I want to run a large tire in the back and The frame doesn’t have too much clearance, am I better off with a wider or a narrower rim?
I suppose a narrower rim would leave more clearance.
Lee, do yuo think there is a loss of performance in running too fat a tire on too narrow a rim? Like running my 2.5 Minions on XC rims designed for much narrower tires? Too much flex?
Hmm. I kind of like doing that.
– You get a rounder tire profile.
– You can moderate the flex with air pressure.
I prefer the stiffness of wide rims over narrow ones. All of my bikes have DH-width rims, with a variety of tire sizes, from 1.9 to 2.5.
Dude: The Chunder XC 1.9s on my P.3 are superfast and supersick!