What tire size?

I posted previously about the need to correctly inflate your tires to maintain a 15% tire drop both front and back. This requires taking into account the weight of both the rider and bike, the weight distribution on the tires, and the size of the tire.

But what is the best tire size?

I have 3 sets of 700C wheels, each with different tires. The Shimano training wheels have 25 mm and 28 mm tires, and the Dura-Ace racing wheels are equipped with 23 mm tires. I believed that narrower tires roll with less resistance, and are faster. So, I trained on the wider, more comfortable tires, saving the 23 mm tires for race events.

Well, apparently, I was mistaken. 25 mm tires, if inflated the same, have a smaller contact patch on the road, and consequently, roll with less resistance (see attached chart). So, although a few grams heavier, they roll faster, and are more comfortable, particularly on long rides.

So today, I swapped out the 23 mm tires on the Dura-Ace wheels to 25 mm Vittoria Rubino Pro folding tires. I want new tires and tubes for the upcoming Whistler Gran Fondo. There is no need to take more chances with a possible flat than is necessary.


2 thoughts on “What tire size?

    • Yeah. I used to inflate both of my tires to the recommended maximum until I learned about the 15% drop concept. It makes sense to inflate them differently given there is different weight on each. I experimented with different pressures until I found the combination that was both fast and comfortable. Good luck.

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