We’re a few days late due to an anticipated power outage in Northern California that didn’t actually come to pass, but rescheduling being what it is, we had to adjust.
This week Patrick takes a look at how tire size affects rolling resistance, grip and comfort, as well as how changes in tire width will affect a bike’s handling.
Patria takes a look at what riders need to know if they want to move into gravel riding. She looks at simple ways to make the transition without a big cash outlay.
Podcast: Play in new window | Download (Duration: 54:31 — 49.9MB)
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Great podcast!
Patrick: I was wondering your thoughts on the Sheldon Browne tire pressure discussions. Has his discussion and chart been rendered obselete?
I just went back and checked his site as I hadn’t looked at that particular page in sometime (but I’ve been recently enough that my browser autofilled “sheldonbrown.com” after I typed “she”). His guide based on a 70 lb. load is pretty on the money, though I don’t weigh 70 lbs. So you might say it needs some repurposing. I do take issue with some of what he’s written about tires; his bit about dishonesty is inaccurate; for a tire size to be off, all you need to do is mount that tire on a rim either wider or smaller than the one that the tire was rated on.
I would also add, Patria, that I’ve never actually taken my mini-tool and checked that it does everything I might need it to. That sounds like a fun experiment for this weekend!
There is this discussion about optimal tire deflection. I’m not endorsing what they say because I’m clueless.
https://bouldercyclingclub.org/2014/09/your-bike-tires-are-over-inflated-probably/
Great episode. Re: Tire pressures – many tire makers have guidance charts or calculators now. Look up at their website.
Enve has an excellent table for tubeless at https://www.enve.com/en/tirepressure/.
In regards to 650b tires I think you missed some major considerations Patrick. 650b tires are more forgiving for gravel riders who don’t have much mountain biking experience. This can be new riders or riders who have strictly ridden hard top. The extra width a 65ob allows helps riders to acclimate to loose surface riding. And 650b is more supple given proper pressures and tire construction. This can be important to the non competitive rider. 650b can also be better for shorter riders.
While I haven’t looked at all the recommendations of all the tire companies yet, I’ve noticed that a number of them are still surprisingly high.
I’m aware of some of the opinions about 650B, but some of the assertions don’t ring true to my experience. For instance, a 700C wheel is going to roll over things more easily than a 650B will; in places with rock or tree roots, that matters. Where traction is concerned, I’ll grant that a 650B x 50mm tire will have better traction than a 700C x 35mm tire, but I’m not convinced the grip is better than 700C x 40mm as the tire contact patch is very similar in area, if not shape; my experience says grip is a wash. On the better tires, construction doesn’t vary between the 700C and the 650B models, so in the case of those tires where both sizes are offered in a model, it’s false to say the 650B is better. I will, however, grant that 650B can be better for small riders as it gives a custom builder more options in terms of establishing good fit with appropriate handling.