Both of those sites are great resources. I use the silca calculator for all my bikes. I still use it to optimize pressure for a type of ride and expected surface.
I do have to disagree with the go as wide as you can fit with your frame. Depending on your typical ride speed, body position, and your of bike, a wide tire may save ~1 watt, but at high speeds it will have a negative aero performance.
Canyon has changed their tire set up on their ‘race’ bikes to 28mm rear and 25mm front. You get the aero saving on the front and still comfort on the rear tire. The rear tire has less an effect on aero performance.
Wide tires also come with a weight penalty. Sure this is small, but it is also rotational weight.
We do not have enough hills around here for the weight savings to matter on climbs, but I think if you go too wide climbing will start to feel sluggish, like your wheels are absorbing your effort. (I may be wrong here so don’t take my word for it)
I would like to see an site that shows aero loses in watts at different speeds for various rim and tire widths.
All this said, this is what I enjoy about the sport. I find I’m constantly trying new things to see what works for me comfort and performance wise.
Thanks for the feedback folks! I ended up with a set of tubelss GP5’s in 32c. I’ll be honest, the main reason was the wider the tire the less out of place it’ll look on my gravel bike
I’ve only got in one ride with them so far, but the feel was pretty good. Definitely more comfort than the 25c’s at 110psi that I was previously riding.
Unfortunately its VERY hard to do proper research on a lot of this. I think I’d agree that a wider rear and narrower front tire is definitely the best combo. However, what little data there is suggests that moving to a 30mm tire is nothing but wins when it comes to aerodynamics:
Of course beyond this you have to consider issues like rim width vs tire width (105% rule) so I’m not ready to jump on the 34+ bandwagon.
You have a limited point on the climbing, but if you look at the work of people like Alex Dowsett, the amount of weight you have to drop to increase speed on anything but the steepest climbs is very considerable. Saving 100g off your wheels (granted rotating mass and everything) would only change your climbing times by seconds, while switching to an aero helmet or aerosuit would be way bigger of a difference. If you’re anything other than a skinny build climber type, you’re better off having one less beer a week and having tires with better traction, breaking and control than saving 100g from your tires/wheelset.
