Why Our Bike Tires Wear Lopsided

It has nothing to do with the load o’ tools in the left underseat bag on my Tour Easy. It has everything to do with the fact that we ride on the shoulder of crowned roads.

Faired Tour Easy on crowned road

Faired Tour Easy on crowned road

Here’s a cross-section of one defunct Schwalbe Marathon rear tire with the tread obviously thicker on the left side, which would be the right side of the mounted tire:

Schwalbe Marathon tire cross-section

Schwalbe Marathon tire cross-section

Maybe I should change the tires more often?

  1. #1 by Erik Scott on 2011-07-07 - 10:33

    You may actually be a candidate for tire rotation, as in “dismount the tire, spin it around, and remount it backwards”. At least the front wheel may be reversible without dismounting. I’ve never thought about it, though – do quick release skewers have a preferred direction?

    • #2 by smellsofbikes on 2011-07-07 - 14:15

      Front skewer doesn’t matter, rear skewer only fits on in one direction because it interferes with the derailleur. However, a lot of times flipping the front wheel means the brakes drag a little, because wheels often aren’t perfectly symmetric (and is entirely unmanageable on bikes with disc brakes.) But you can just pull the tire off and put it on the other way around: bike tires may claim they’re directional but they’re not really, for most purposes. On road bikes, tread is decorative only and the underlying casing is symmetric, so there’s no reason to worry about riding a tire backwards.

    • #3 by Ed on 2011-07-07 - 15:53

      The Marathons have a directional arrow, so they’re nominally one-way-only tires. In point of fact, I don’t see how the tread pattern orientation could possibly make any difference, given the existence of tires like the Tom Slick, and I flipped the tire around a few months ago while I had it off to fix Yet Another Flat. Hasn’t made any detectable difference in the handling.

      QR skewers almost certainly don’t care, but the sheer embarrassment of riding with the Phil legend on the front hub facing the wrong way rules out that option… [grin]

  2. #4 by peter on 2011-07-07 - 10:35

    Interesting. Hadn’t expected riding on shoulders to have so much effect on thread wear.

    Out of interest, is that the Marathon Plus, or a plain Marathon? I’m running plain Marathons myself (and since begin of this year the Marathon Racer, but the front tyre developed a broken carcas a week ago after only 4 months and 1978 km, so it has been returned under warranty. Hope it was an exception, as I otherwise like the Marathon Racer.

    The Marathon Plus I thought had a thick blue ‘pad’ of rubber inside (where your tyre shows the yellow stuff), so now I’m doubting exactly what tyre you use: the Plus, or the ‘new’ Marathon (model 2011), which has ‘Greenguard’, as opposed to the old Kevlar-guard of the pre-2011 Marathon model. I’m not a fan of the changes to the good old Marathon with Greenguard, as that’s basically a Mar. Plus in disguise now.

    Do you feel safe riding such sloping shoulders? It means that, even when riding straight ahead, there’s always a sideways force present. When it’s wet, snowy or icy, or there’s some rubble on the street, that can make for interesting, err, ‘escapades’, I expect. Or maybe it’s because I’m spoiled over here with pancake-flat bicycle paths, that I’m overly apprehensive?

    • #5 by Ed on 2011-07-07 - 16:02

      It’s an old Marathon, at least IIRC, and I thought the liner was blue, too. Maybe they changed the formulation a while back and I’m just behind the power curve; I tend to buy tires in lots of three every year or so.

      riding such sloping shoulders?

      That’s an extreme case, being the outside edge of a slightly banked curve. We generally don’t notice the crown and it really doesn’t affect the handling. Then again, we don’t ride near the traction limit very often. Getting rid of the trash would be a nice touch; we’re not holding our collective breath.

  3. #6 by david on 2011-07-07 - 13:46

    I Have Been Told that one should put the QR skewer levers on the port side — but only to counterbalance all the crap already hanging off the starboard side, so it oughtn’t actually matter. :)

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