Yep! I was surprised that even 42mm pathfinders seem to almost sit flush with the outer section of the rim keeping them aero even with such large tires
I think you would be surprised with some of these really wide rims. I’ll bet even with 47’s you would gain a decent aero benefit.
CLX is not worth the extra $1K IMO. I’d look at CL if you want to stay in the Roval family. Otherwise can’t reccomend Reserve 40/44 enough.
1 Like
Assuming the sale is over but where did you see them for 30% off?
1 Like
Mikes Bikes? I had a chance to score the 3T Discus for 25% off at BTD.
2 Likes
Yup mikes bikes.
3 Likes
@Comomtb @tiptoppenguin What is the actual width of a 42 mm gravel tyre when installed on 40|44 GR wheels?
I have Aspero with two wheelsets and I think if you run fast gravel tires, road wheelset is pretty useless.
1 Like
Interested to hear more, my S-works Pathfinders roll quick, but I figure I’m giving up an extra 20-30 watts to keep em turning on flats vs a 28mm road tire, you disagree?
I disagree. I run 44 Rene Herse Extralite. Probably one if not the fastest Gravel tire on the road. I certainly feel the difference seated and standing while laying down power. Can’t tell if it’s the Berd spokes or the tire bouncing more than my stiff carbon spoked wheelset with Conti 5k TR S. But to say it doesn’t make a difference… I wouldn’t go that far.
1 Like
I still can’t think you would get any aero benefits riding 47s during gravel races that make deeper wheels a better choice than a more compliant/lighter wheel. I do ride aerobars and that does give a huge performance gain so I am looking to shed weight and add compliance/stability/ride quality.
Also, it seems like DJ is not even trying to optimize his aerodynamics around tires/wheels anymore. I think he mentioned he has another upcoming video, I would be curious to see what he decides is the fastest setup for Unbound.
1 Like
Here’s a 35mm G-one RS on a LB WG44 rim (30mm ID/40mm OD). This setup is pretty close to “rule of 105” compatible, though I’d be curious how it’d actually test in a wind tunnel. The shoulder tread yields a somewhat squared off leading edge, and I’m not smart enough to know if that’d be good or bad at yaw and with rotation.
1 Like
Wouldn’t you need 3x the diameter of the tire for the aerofoil shape so that the wind keeps attached. That would mean 141mm deep and 50mm wide front wheel. Or has my knowledge been superseded?
Here’s a 40mm G-one RS on the same (LB WG44) rim. Starting to overhang the rim a bit, but the ol’ eyeball wind tunnel suggests this would still have some aero benefits. I’d have to think this is about the widest you could go and have that sill be true though. FWIW the 35 and 40mm G-ones are about the same weight….
3 Likes
I have a tarmac and a crux. I’d say getting a cheaper used Tarmac on 28’s will be a better move.
Crux is high off the ground with BB way up there, shorter reach/higher stack more upright - all of those are aero penalties not only tire width/wheelset, if you want to be front of pack and descend fast.
Also to each its own of course and I have often considered going to one bike only, but the thought of spending a bunch of cash on Reserves for example plus matching cassette and rotors then having to swap for each ride, yet still paying the other penalties is not one I can commit to.
I would say halfway house simple solution is swap the chain ring slightly bigger 46/48 if need more top speed and use 38 S-works Pathfinders with smooth centerline. That gets you very close what you would get with a 2nd wheelset without actually getting a dedicated wheel set. And add FTP power 
My first thought would be more like 10 watts. 30 watts seems really high?
Road tires feels more efficient and I’m sure they are 10 watts faster etc., but is that worth +1000 usd… I haven’t been that impressed by the speed gains.
To be fair, I haven’t done any back to back testing with them.
I have Tufo Thundero 40 tires (42mm measured) set tubeless on LB WR45 wheelset and Conti GP5000’s 28mm (30mm measured) with latex tubes on a LB AR56 wheelset.
Do it! I have Trek Boones, 3 in total, all 3 for CX season, and in the summer it’s 1 for CX, 1 for Gravel and 1 for road (with a 2x added).
No more redundant bikes and just 3 sets of different tyres.
1 Like
What’s decent? 3 watts - 5 watts? Mavic used to have some data out there (like 5 years ago) indicating that a tire over 35mm with knobby edges just killed any aero benefit. Of course, they didn’t have 40mm wide rims back then but knobby tires will still kill the airflow.
Ben Delaney had a video out recently. He went with deeper gravel carbon rims and less knobby tires and got an 8 watt improvement.
The point of his video though is that he got twice the improvement by going with 2cm less bars.
The cheapest aero gains are going to be rider positioning, helmet, bars, jersey, aero hydration pack (hump), etc. A $2000 wheelset is probably dead last in gains if you are using wide knobby tires. But if one’s gravel is relatively smooth, you might be able to get away with a 35mm GP5000AS for a fast setup.
1 Like
