This is UK ‘gravel’ so a bit of everything. My average speeds are normally around 13-15mph but faster when linking up the roads. I’ve narrowed it down to Scribe Gravel carbon wheels but they have a 23.5mm depth with an internal width of 25mm and a 40mm depth with an internal width of 24mm. I’m currently running 40mm tyres and they seem pretty good for the mix of road, mud, bridleway, tow path, gravel and everything I came across locally.
Might be faster
Pros of lightweight:
Wider tyres negative the benefits of aero (40mm) rims anyway
Wider rim for better tyre profile
More comfortable due to flex
Better crosswind handling, could easily ‘loose’ the aero time benefits by having to stop to take a jacket on and off.
Aero data can certainly vary depending on many variables, but I’ve seen a lot of data to support the notion that aero benefits of deeper rims still apply to tires that are 40mm wide & wider. Of course, it probably depends on rim profile!
If you are reading this and are interested, you can find some supporting data on the FLO website. Especially if you think lightweight wheels might be more comfortable. Give the FLO pitch on the ‘leafspring’ effect of deeper rims a read.
As an aside the first gravel wheels I got from FLO I put on my bike and raced…busted the crap out of them. Jon and I had a pretty tense couple of phone calls…he told me my tire setup was all wrong…I told him I took it off his aero drag data so actually HIS tire setup was all wrong…next week, new data, new chart, wider tire guidance. I got replacement wheels and haven’t had a problem since.
So I’m not an in-the-bag FLO supporter but I think there is a lot of good data on that site.
Awesome, I’ll check them out. Hunt, Swissside and Specialized win tunnel all have some data too. In a block headwind the difference is normally <5w which I’m not bothered about. Though they do all say it is more in crosswinds but difficult to quantify. A lot of the tests are done at 40-50kph, which is obviously so much significantly faster than I’m riding. Even Hunts modelling for Dk200 is done at 32kph!
With 28-32mm tires, the 3.4 is going to deliver a wattage savings of up to 10 watts at 20 mph over the G23 with the same tire. That doesn’t tell the entire story, however. As tire width increases beyond 32mm, the 3.4’s aero advantage diminishes. Going up to a 40mm tire, the two wheelsets would essentially be aerodynamically equal
Very interesting! These wheels will always be on the gravel bike as I have some Zipps for the road bike. I think if I ended up swapping wheels around and could only have one I’d got for the more aero set but for a dedicated gravel wheelset it becomes less clear.
That Enve article is similar to one I read from Rene Herse which essentially said the same. At a 40mm width tyre you’d need a very deep and wide rim and with aero ‘nearly aero’ isn’t a thing.
I own both the G23s and the 3.4ARs. I tend to favor the G23’s for gravel when riding on bigger tires (current 40 - 42 sizes are my go to on the routes and races I do). Along with being very light and feel really snappy climbing and descending, the provide a great dampening quality that makes them great on long days.
I tend to use the 3.4ARs more for dirty road routes where I’m running smaller 32 - 38c tires. They are also fantastic road wheels and handle crosswinds very well but they do have a hasher feel when things get rough.
Why not both? I just ordered a Farsports Gravel wheelset. Rear wheel is 40mm deep with 24mm internal, front wheel is 36mm deep with 26mm internal. Built with Carbon Ti hubs and Spain CX-ray spokes claimed weight is 1280g.
Shipping from China was crazy fast, and the wheels are actually here already though I am out of town at the moment so can’t weigh them myself. Will update here once I get my hands on them!
Mostly because of the cycle2work voucher (tax break on bike purchase) and the UK support.
From the Flo website it looks the G700 that is 55mm deep saved 5w per wheel (though I don’t see how that works as the back wheel sees so much less drag, looks like they just tested the wheel in isolation). Even so that adds up to 10w across all the yaw angles and that’s at 22mph, a speed I very rarely get to on UK ‘gravel’.
It does seem more and more that aero doesn’t work for gravel wheels.
I’d go lightweight. 13-15 mph isn’t likely to bag you any aero benefit … especially on 40mm tires. If you’re in a gravel race and clocking higher speeds, it’s likely that you’re in a group and, again, the aero won’t matter that much.
I ride Hunt carbon wheels on my gravel racer, and I’m a fan.