Thursday, June 10, 2010

Race wheels, tubes, tires, ...

For those that know me well, you know I LOVE talking about equipment. I'd own 30 bikes if it was possible in any way. Having said that, one topic that's been on my mind a lot lately is trying to figure out what set of tires is best for a particular set of race wheels I have... thought I'd share some thoughts here on wheels, tires, and how they all relate to one another.

So, here's some random thoughts that hopefully could be of assistance as you consider your race wheel setup

- Aerodynamics, rolling resistance and weight are your key considerations... and in that order. Let's talk about each individually.

Generally, the deeper the wheel profile the more aero... i.e. a set of Zipp 1080s (~110mm rim profile depth) will offer a larger aerodynamic advantage concerning triathlon riding than a Zipp 404 (~60mm rim profile depth) would. There are many caveats here of course... two primary factors being rider weight and wind conditions. Deeper rim profiles can be more affected by wind conditions and lighter riders may have more difficulty handling them in stiff crosswinds. Being a taller guy, this isnt such a consideration for me, but may be for some. Personally, I race with a 60mm depth front wheel... while not being the ultimate in aerodynamics, it's a very versatile choice for many different types of wind conditions. I've raced with rim depths up to 90mm on the front, and have noticed a difference in crosswind bike handling, but nothing that would scare me away from using them again. Along with rim depth, choosing a tire that's well matched to the rim width you're using is a good call to ensure your best experience. If you're using Zipp wheels, use the zipp tires - they're designed to work together and work very well. Hed C2s use a 23mm width rim, so you have many great tire options available. I've heard of very good experiences with the Bontrager R4 aero tires - good rolling resistance, well matched to many popular aero wheels... make sure to get the width that most closely approximates your wheel rim width at the tire track.

Rolling resistance is basically the resistive forces against the tire (and by translation the bike and rider) generated by friction from tire to ground and from tube to tire within your wheel. A more complete description of rolling resistance can be found here ( A few years back, tubular tires/wheels were technically superior to their clincher counterparts concerning rolling resistance, but not so any longer - it's debatable how close they've become, but the data i've seen tells me that through use of a low rolling resistance clincher tire and a latex (not butyl) tube, clinchers can be from equal to superior to their tubular counterparts. Certainly this is a factor in buying decisions for wheelsets, given the far superior convenience of repairing flats that clinchers possess over tubulars. Personally, I've ridden both, but own only clinchers now. One flat in a race is all you'll need to make the switch like I did :) One additional factor is tire width... i'm not an expert on this topic by far, but have seen a good amount of anecdotal info that tells me you're best staying in the 21-23mm range... below that race rolling resistance becomes a large factor and above it aerodynamics become a concern.

Last but not least, weight. Yes, I agree with the viewpoint that both aero and rolling resistance trump weight. For 99% of triathletes, weight should be primarily lost on the athlete first and gear second. Concerning the gear specifically, I'm not going to launch into a large analysis of weight vs. aero or weight vs. rolling resistance (these topics has been well debated on the forums, I'd highly recommend you search there for more info)... I'm convinced that the 100 gram weight savings that costs an extra $1,000 is not justified. Weight is a consideration certainly, and lighter is always better... this one usually comes down to budget.

All said, my current recommendation is the Hed C2 series of wheels. I race with either a Hed C2 60 front and Hed C2 90 rear wheel, or a Hed C2 60 front and a Hed C2 disc rear wheel... with almost all racing using the disk (since aero always trumps other factors). I've been racing with Michelin Pro Race 3 tires - they're very low rolling resistance and offer decent flat tire protection. It's not the lowest rolling resistance tire out there, but it's one of the best and has served me well. Latex tubes of course.

Some measured values of tire rolling resistance can be found at the end of this article ( not exactly up to date, but recent enough to be helpful.

Hope this helps! Thanks for reading!

Those who want to 'See Tom Tri' :)