I recently watched a GCN video that, besides the fact their choice of tires on the wheels wrecked the whole experiment, their comparison pitting an aero bike against a climber, then swapping out 40 mm and 80 mm wheels to see which combination was fastest surprised me in more than one way.
I’m going to give a spoiler alert in the next couple of paragraphs, so if you want to watch the video first, please do.
Okay, spoiler alert in 3… 2… 1…
First, I don’t think there’s anyone who would try to argue the old 25-ish mm deep alloy wheels are better than even low-end carbon fiber wheels. There’s simply no comparison there. I included them for thoroughness only. There’s no question, though; as good a wheel as you can get in alloy, even a low-end deep section carbon fiber wheel will be faster – and the difference is great enough you can feel it instantly and unquestionably, so that will be enough about that.
I had the opportunity to go all-in with 80’s for my Venge but I chose to go with 50’s, instead. There isn’t a moment that goes by that I wish I’d chosen differently. Wind, specifically crosswinds kept me from going deep-deep dish. A friend has 808’s and he is blown all over the place when it gets breezy. In fact, I prefer my Trek with 38’s when it gets windy and I’ll be riding in a group. The 38’s and round tubes are superior in crosswinds – the combo is a little less squirrely. Squirrels are great. For dinner. Not so much in a group ride pace-line, but I digress… humorously.
Let’s get to that spoiler. The deep-section aero wheels fared worst. The shallow 40’s did best. Now, there was a flaw in the experiment. They used different tires for the shallow-section and deep-section wheels. They used 25’s for the deeps and 28’s for the shallows – and, if that wasn’t bad enough, butyl tubes for the deeps and tubeless for the shallows. Now, having run 25’s and 28’s, I’d take the 25’s any day of the week. The 28’s roll smooth, sure, but I don’t like the bounce when it’s time to sprint. Best, I think Specialized Turbo Pro 26 mm tires are absolutely the pinnacle of the “best of both worlds”. Technically, the best of three worlds. Excellent rolling resistance, just enough road chatter absorption, and fantastic flat protection. They’re no Turbo Cotton, but I’d rather spend my time setting up for the sprint than fixing a tire on the side of the road.
In the GCN experiment, the best combo was the aero frame with 40’s, followed by a lightweight climber’s frame with the 40’s, followed by the aero frame with the 80’s and lightweight/80’s brought up the rear. Folks, this is where real world runs circles around the lab setup. Anyone who’s seen a friend on 80’s in a crosswind knows they suck the life right out of you. They’re pushed all over and the rider has to battle to keep their bike in line with every gust. That battle sucks watts (exact same principle as lower tire pressure with wider tires – the increase rolling resistance but smooth out the ride so you’re actually faster). Put 40’s on that same bike in those winds and fast is actually easier. Now, you put those same 80’s on for a still summer’s evening and you’ll straight up fly. Problem is, how many of those still summer’s evenings are there? Not many.
So, even though the GCN boys messed up the tires, I have a funny feeling they’ll get the same results when they fix the tire issue and try the experiment again. Of course, all one has to do is look at the pro peloton to “get it”. They all roll 40’s and 50’s. You’ll never see an 80 out there unless it’s in a time trial. But hey, it’s a fun video to watch, anyway.