There’s a lot written about the versatility of having a couple of wheelsets for one bike. For example, a gravel bike can double or even triple up for winter, cx/gravel and summer duties.

Question; does sticking a set of summer 50mm section aero wheels on a boxy gravel frame give any advantage other than aesthetic? Yes I know elite cxers use deep sections but I thought that was to stop mud accumulation.

Stiffer?

Advantage? No.
Possible. Yes.
I use my 40mm carbon clinchers.

I’d also think about the rim and tyre profile as well. Modern rims are wide so would be fine with a 42mm tyre. Older rims might be narrow, probably be ok, but be worth checking it.

What I’m getting at is this;

Will an aero wheelset be more, less or equally effective if used on a bike not specifically designed to be aero? i.e gaping fork clearances and slab bottomed downtube.

I ‘think’ the wheel will decrease in resistance in a broadly similar fashion irrespective of the bike they are on. However the percentage resistance the wheels contribute to the total is less on a gravel bike than a full on aero road bike. That’s more to do with the ride position that it is to the shape of the other bike components though they will contribute too. So, a say 15% reduction in the air resistance of a pair of wheels will make less overall difference than it would on a full on road bike. Add to that to the fact that air resistance is exponential – double the speed and square the air resistance. As the gravel bike is probably being ridden at a slower average speed to a head down arse up road bike the impact of improved air resistance is also reduced.

gaping fork clearances

I thought aero wheels only had any effect when riding above something like 18mph if not more?

They will save the same amount of watts regardless of what bike they are are. The most important one is the front one which is not affected by frame design.

Yes they work, and don’t forget your aero helmet and water bottle too.

In theory yes BUT….. if you run wider tyres as you probably would do then you negate the aero gains as the most important part of an aero wheel is the tyre to rim transition and aero rims are designed to work with a specific width of tyre. So stick your large volume knobbly tyres on and bang goes most of the aero gains.

But on the flip side deep section rims see stiffer so there is potentially a benefit there.

I sold my carbon Spec. Roubaix when i bought my Reilly Gradient gravel bike as i found that i preferred having that with two wheelsets, got a set of Hunt wheels with road tyres for road riding.

One thing i found was that where the bars were slightly higher on Reilly, i used the drops rarely on Roubaix, but i use them a lot more on the Reilly as they are at a nice height for my flexibility and core strength and subsequently am probably are a bit efficient.

I used to use deep section road rims on my (non aero) road race bike. They gave a noticeable advantage once you got over about 25mph. It made keeping up with the bunch a lot less effort. Below 25mph they was no noticeable difference on the flat and up hill they were a bit slower (even carbon fibre weighs something).

Unless you are planning on riding everywhere at 20+ mph on your gravel bike, I would say stick to lighter non aero rims.

Not sure I agree with the figures used by somewhatslightlydazed – but agree with the principle.
Riding in a bunch, there is no noticeable benefit from aero wheels, the only benefit will be when you hit the front of the pack for your pull.
My 65mm carbon wheels are lighter than most aluminium wheels and my 40mm disc brake wheels are not much heavier.
But the principle of aero benefit on a gravel ride, unless you are riding very flat smooth gravel then there will be little benefit. And as I mentioned in my first post, depending on the rim, you may also notice a reduction in performance, but that will also be as minimal as any performance advantage would be at 16 or 17mph.
Personally, I’d say stick to what look the best!
In terms of the frame, aero wheels do not need an aero frame to get aero benefits. The frame makes up a surprisingly small amount of aero difference, unless you count your body position. But the aero wheels will give a performance benefit. The faster you go the more benefit you get. (but that’s a very general principle, and at the speeds you will likely be travelling, we are talking single digit watt differences)

If rim brakes I would think the potential for the pads + dust,grit,paste to really damage the carbon braking track would be enough to stop non sponsored riders from doing it.

I thought aero wheels only had any effect when riding above something like 18mph if not more?

I think they work at any speed. It’s about 9mph when the main force you are trying to overcome on a bike is wind resistance. There have been a few articles about how aero is actually more of an advantage to middling riders. The argument is you’re on your bike for longer over a given distance so you have more time you could gain.

I think the OP’s question is are aero wheels usefull on a non aero frame, not are aero wheels usefull for gravel/cx riding.

Yup. Probably even more so if the alternative is a fairly boxy rim.

The downside is I find the bike itself lacks zipp. You’re dropping the bb by ~20mm, the geometry is quite relaxed, the frames designed to be comfortable etc. I have a CAADX and a CAAD. The CAADX just doesn’t feel as engaging with 23mm tyres (and the CAAD is probably worth less than some people’s wheels!).

The frame is pretty much irrelevant though, from an aerodynamics point of view. Yes it makes a small difference, but not a huge amount.
The deep rim wheels will provide an aero advantage on any frame, but the amount will vary depending on the speed of the ride.
And then it is also possible that running wide tyres for gravel and cx have the potential to lose their aero benefits. But we really are talking single figure wattage benefits.

(I have an aero bike with 65mm rims and a non aero bike which runs shallow 30mm rims as well as 40mm rims – the difference isn’t the frame so much, it’s the position on the aero frame and the wheels that make the difference)
If the frame made that much of a difference we wouldn’t see any Supersix’s or TCRs and the like win stages. Madones and Venges would win everything.

To be clear I am talking about disc braked aero road wheels with road tyres for road riding, but just on a gravel frame.

For something so ultra scientific it’s such an opaque subject. The manufacturer’s all big-up their own rim shapes while throwing shade on the opposition. It’s impossible to tell. I think this is the only objective and fundamentally truthful guidance:

Personally, I’d say stick to what look the best!