How I Came to Love Big Bike Tyres

In June the excellent Bicycle Quarterly had a very good article about tests they performed on bike tyres to establish how tyre size impacted rolling resistance. The results were surprising.

I had always assumed that a narrow tyre like the 700 x 23 on the typical road bike would have less rolling resistance than a fatter tyre like a 700 x 35 on a hybrid or touring bike. But the Bicycle Quarterly tests found that the opposite is true, the fat 35 tyre has less rolling resistance than the thin 23.

The Schwalbe Marathon 700c x 35c

I always liked a fat 35 tyre, on the kind of rough rural roads I ride on it is much more comfortable. In the harvest season rural Irish roads are often very mucky from dirt carried out of fields by tractors, a 35 is much safer. On the rough gravel and dirt paths I often ride on a 23 tyre is useless.

I doubted the results of the Bicycle Quarterly tests, they were counter intuitive. But last week I was riding my Raleigh Royal with its Schwalbe Marathon 35s on a wet road, when I noticed that the tyres were bone dry apart from a very narrow wet strip in the centre of the tyre. I suddenly realised why the Bicycle Quarterly tests were right. Even thought the 35 is much wider than a 23, when inflated to full pressure its shape does not distort under the weight of the rider. There is actually very little rubber in contact with the road on a fully inflated 35.

No doubt there are advantages to a 23, it is lighter and slightly more aerodynamic than a 35. This will make a difference at racing speeds, but for most cyclists a fat, comfortable, puncture resistant, threaded 35 tyre is a much better bet than a slick 23.

The Bicycle Quarterly article

The Schwalbe Marathon Tyre - 700c x 35c from Halfords