Deeper wheels or lightweight wheels for gravel racing?

63 replies · 7,193 views

sgtrobo
155 posts
#1Mar 9, 2019, 11:55 PMedited
Looking to do some (semi)serious gravel racing, everything from gravel kermesse races (~30-35 miles) to longer 100+ mile races

So how do you roll? Lightweight wheels or deeper wheels?
Do the deeper, more aero wheels help that much more or would lightweight wheels be better?
I'm not talking about 60mm deep, just 35-40mm or possibly 50mm if it helps.
Interested in opinions, especially from those who have both.
Thanks.
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Koyote
288 posts
#2Mar 10, 2019, 7:53 AM
I'm not sure if gravel (vs road) has anything to do with it, as the same logic would apply. More aero wheels if you expect higher speeds, and shallower rims (which are lighter) if you expect more climbing. Unless there is something I'm missing?
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ljsmith
762 posts
#3Mar 10, 2019, 8:41 AM
From everything I have read, unless you are riding in the mountains aero trumps weight no matter what speed you ride. In fact some "experts" claim that the slower you go the more benefit you get since the yaw angles of wind increase the slower you go. The only caveat being the tire width need to be matched to the rim width. If you are running 40mm tires and the external rim width is 28mm, you really won't get any aero benefit. I am not aware of any aero rims with an external width of 40mm. I think the Reynolds ATR is probably the widest at 23mm internal and 30mm external.

To sum up, in theory aero would be better. But in reality there currently no aero rims wide enough (at least that I know of) to get much of an aero benefit with gravel width tires.
1
drwelby
531 posts
#4Mar 10, 2019, 10:27 AM
There's also the question of whether the knobs on your tires screw up the airflow enough to negate the airfoil benefits behind it. Another question is what's the aerodynamic drag of the knobs themselves. It might be that even a perfectly sized deep rim with a knobby tire is slower than a slicker one with a semi-aero rim. So I'd be wary about investing a lot of money into optimizing aerodynamics and maybe look for other places to make gains. (Though it's your money, feel free to spend as you like!)
1
SWGraveler
247 posts
#5Mar 10, 2019, 11:01 AM
I am fairly new to gravel but have been road riding for a long time and wheels are my "thing" as I consider them to be the most important part of a bike. I have had a lot of road wheelsets and can certainly say that they really do affect the ride of a given bike. Years ago when the road aero thing was getting started, Gerard Vroomen of Cervelo said that his data showed aero was relevant down to about 10mph. As others have said, the tire/wheel interface is critical to a real aero gain though so I'm not sure where that leaves it.
Lighter wheels will be more lively as they will accel/decal and change direction with less effort so responding to or attacking might be a bit easier. Not sure what gravel racing is like but this might be relevant. If you have access to some front wheels, hold a heavier one and have someone spin it up for you and try to move it around while it is spinning. Do the same with a lighter wheel. The difference will be very obvious. Factor in that even with an aggressive spin that the wheel might be spinning at 8-10 mph and you will understand how much of an affect rim(not wheel) weight has on the feel of a bike. The easiest/cheapest way for a manufacturer to make a light wheel is to lighten the hubs so explore and find rim weights as opposed to the just wheel weight. Hub weight is no more relevant than your stem.
I just pondered all of this and ended up buying Bontragrer XXX 2's; they ride nicely, are very responsive and have been issue free so far. Quite a bit cheaper than Enve G23s which are arguably the best all-around gravel wheelset on the market.
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drwelby
531 posts
#6Mar 10, 2019, 11:34 AM
Gravel will also expose you more to sharp rocks, pointy sticks, barbed wire, random pieces of farm equipment, abrasive mud, and other stuff that can render what is otherwise a strong wheel into wall art. The races might be in towns that don't have bike shops. If you're not a pro who gets them for free and has a team trailer with mechanics and spares you might want to go conservative.

But if speed is your thing, given a choice between two similar rims I'd go for the more aero one.
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Volsung
878 posts
#7Mar 10, 2019, 2:15 PMedited
Video from Specialized-
https://youtu.be/89KEevSRcGw

Basically yesterday aero is faster regardless of tire size, but if your tires dont fit your rims well you dont get as much of a benefit.

I think currently the widest aero wheels are 32mm (Bontrager and Reynolds EDIT- not sure how deep they are. There are some 30w 40d rims though). Not sure the width on the ones used in this video.
2
nellborg
142 posts
#8Mar 10, 2019, 8:45 PM
I've got a set of $700 Mavic elite Allroads but they haven't been used yet. I bought them thinking that they were likely a safe middle of the road wheel to start with. I can see a second set of wheels in my future, though. I'm with the original poster here in that I'm not sure whether to go more aero, lighter, carbon, or aluminum for the second set. With a budget of about 1k for the set, what's conservative? Hunt carbon? $1,000 alu wheels? I guess it's also unclear to me what the price point is, above which, there are diminishing returns for reliability and performance. $2500 for Enve's seems completely crazy to me, but what do I know....
1
Koyote
288 posts
#9Mar 10, 2019, 8:50 PMedited▲ Top
nellborg wrote: I guess it's also unclear to me what the price point is, above which, there are diminishing returns for reliability and performance. $2500 for Enve's seems completely crazy to me, but what do I know....

I’m willing to bet the diminishing returns kick in well before $2500!

Out where I am riding gravel, it is pretty common to have 100 feet of climbing per mile on average. And on the descents, I am often laying pretty hard on the brakes because speed would kill - the descents are too steep and rough. There is no way in hell that I would choose heavier deep section rims just because they might be more aerodynamic.
3
SWGraveler
247 posts
#10Mar 10, 2019, 9:40 PM
nellborg wrote: With a budget of about 1k for the set, what's conservative? Hunt carbon? $1,000 alu wheels? I guess it's also unclear to me what the price point is, above which, there are diminishing returns for reliability and performance. $2500 for Enve's seems completely crazy to me, but what do I know....

Not to repeat myself but I have had a lot of road wheelsets; I worked in a shop for years and took full advantage of industry pricing! I have had Lightweights and they are amazing. Honestly, the simple spin them in your hands exercise I mentioned earlier will be very revealing to you; wheel(rim!) weight matters. The difference between $750 wheels and $1000 wheels will be hard to notice. Honestly, if one wheelset is lighter than the other at those price points, the difference is probably in the hubs and won't show itself when riding.

$2500 for a set of wheels seems crazy until you ride them; on your bike on your routes where you will know the differences you feel are real. It is a rather scary and expensive experiment. Again, for me I used to buy at industry prices and I knew I could probably sell them for at least what I had paid if I was disappointed. That license allowed me to try things and I am absolutely convinced that in most cases you will see real gain for more money spent on wheels. Gain however is very subjective and everyone needs to evaluate what they see as a gain and also the conditions that they have overall. Your weight, where you ride and what matters to you. If you are climbing a lot and so have lower average ride speeds, the aero gain will taper off. Wheels take a beating off-road and anything can break. If absolute reliability matters to you, steer clear of the lighter offerings. When I saw the minimal weight difference but several hundred dollar price difference between the XXX2's and G23's, I figured a few more grams probably equated to a bit more reliability and as I weigh 180 I decided that was the wheelset for me; I have had them for about 6 weeks and they have been great so far but long enough to really express more than so far so good.

If I were buying wheels with a budget of $1k or so, I would probably buy Hed BE+ rims laced to a nice hub and just enjoy them. Unless you can double that budget, you won't realize much gain. If can go a bit beyond $1K but not $2.5K, my advice would be to buy lighter tires knowing you will replace them more often and maybe have fun with trying different ones. However, once you see the difference rim/perimeter weight makes you will want the G23's!
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sgtrobo
155 posts
#11Mar 10, 2019, 11:34 PM
Koyote wrote:
Out where I am riding gravel, it is pretty common to have 100 feet of climbing per mile on average. And on the descents, I am often laying pretty hard on the brakes because speed would kill - the descents are too steep and rough. There is no way in hell that I would choose heavier deep section rims just because they might be more aerodynamic.

with the wider tires I'm looking at running (probably 40c Maxxis Ramblers), I'm thinking that lightweight will matter a bit more because I'll be doing a lot of climbing myself.
The win tunnel said "12s over 40km" for the 42s.
That's on perfectly smooth, perfectly flat, rollers. I can't see that 12s providing nearly as much benefit on uneven gravel nearly as much as lightweight wheels which will be easier to handle and much easier for climbing.
More reading and research to do. Anyone else with some ideas, please feel free to chime in.
Thanks a ton for your responses!
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Koyote
288 posts
#12Mar 11, 2019, 6:43 AMedited
SWGraveler wrote:
If I were buying wheels with a budget of $1k or so, I would probably buy Hed BE+ rims laced to a nice hub and just enjoy them. Unless you can double that budget, you won't realize much gain. If can go a bit beyond $1K but not $2.5K, my advice would be to buy lighter tires knowing you will replace them more often and maybe have fun with trying different ones. However, once you see the difference rim/perimeter weight makes you will want the G23's!

I've having some wheels built soon, and asked the shop about the HED Belgium + rims. They recommended H+ Son Hydra as a slightly lower-priced alternative. Any opinion? I do know that the HED is expensive for alloy.

And for the OP: if you start with a solid rim like one of the above, add decent spokes (and enough of them) like DT Swiss Competition, Sapim Race, or Sapim CX-Ray (last one is very expensive, but light and strong), and lace 'em to DT 350 hubs, you will have a very good wheelset for under $800 (or around that price, depending on builder).

To get much lighter without sacrificing reliability, you'll have to move to cf rims - which will raise the price considerably. So, I think that is roughly where the diminishing returns kick in, at least for me.
0
oleritter
364 posts
#13Mar 11, 2019, 9:31 AM
Koyote wrote:

I've having some wheels built soon, and asked the shop about the HED Belgium + rims. They recommended H+ Son Hydra as a slightly lower-priced alternative. Any opinion? I do know that the HED is expensive for alloy.

And for the OP: if you start with a solid rim like one of the above, add decent spokes (and enough of them) like DT Swiss Competition, Sapim Race, or Sapim CX-Ray (last one is very expensive, but light and strong), and lace 'em to DT 350 hubs, you will have a very good wheelset for under $800 (or around that price, depending on builder).

To get much lighter without sacrificing reliability, you'll have to move to cf rims - which will raise the price considerably. So, I think that is roughly where the diminishing returns kick in, at least for me.

Hydras are good and 1/2 the price of Belgium's (for me at least). Pacenti Forza is also a good rim, and it is offset. Velocity Aileron's are nice too but unfortunately have gone up in price a little, but still less than Hed.

Also, some really good carbon rimmed wheels can be done for $850-1000, with sub 1500g possible. LB RG922 rims, DT 350 hubs, CX Ray spokes for $995. (shown with WI hubs)
1
chas
1,305 posts
#14Mar 11, 2019, 12:53 PM
I always wonder why gravel people care about aero wheels???
Doing a long gravel ride, weight is everything for me. I guess it matters where you ride, but for me I may be doing 25-40mph at the velodrome, but only 15mph on a rolling hills gravel ride. I don’t worry much about aero until I’m going over 20mph.
But, weight on rolling terrain makes a difference to me. I have no problem keeping up with a group on flat terrain, but hills and climbing seem to be where the group splits up. This is where I need the light weight and efficiency.
Deep aero wheels are not going to enable me to pull away from the group (or prevent me from getting dropped). Light weight wheels do sometimes prevent me from getting dropped when I need to accelerate hard to close a gap.
Gravel just isn’t fast enough for aero wheels to be much of a benefit for me. Not to mention that the wide tires (and knobs) we use aren’t going to help the airflow

GCN did an interesting test, and helmet and the clothes made much more of an aero difference than deep wheels. Based on their data, I’m not sure I could feel the difference in the deep wheel anyway.

P.S. loving the sub 1500g 23mm deep carbon wheels oleritter built for me similar to what he posted above.

2
Koyote
288 posts
#15Mar 11, 2019, 1:09 PM
chas wrote:GCN did an interesting test, and helmet and the clothes made much more of an aero difference than deep wheels. Based on their data, I’m not sure I could feel the difference in the deep wheel anyway.

But nice wheels get you more style points than a new jersey.
1
SWGraveler
247 posts
#16Mar 11, 2019, 2:01 PM
chas wrote:
I always wonder why gravel people care about aero wheels???
Doing a long gravel ride, weight is everything for me. I guess it matters where you ride, but for me I may be doing 25-40mph at the velodrome, but only 15mph on a rolling hills gravel ride. I don’t worry much about aero until I’m going over 20mph.
But, weight on rolling terrain makes a difference to me. I have no problem keeping up with a group on flat terrain, but hills and climbing seem to be where the group splits up. This is where I need the light weight and efficiency.
Deep aero wheels are not going to enable me to pull away from the group (or prevent me from getting dropped). Light weight wheels do sometimes prevent me from getting dropped when I need to accelerate hard to close a gap.
Gravel just isn’t fast enough for aero wheels to be much of a benefit for me. Not to mention that the wide tires (and knobs) we use aren’t going to help the airflow

GCN did an interesting test, and helmet and the clothes made much more of an aero difference than deep wheels. Based on their data, I’m not sure I could feel the difference in the deep wheel anyway.

P.S. loving the sub 1500g 23mm deep carbon wheels oleritter built for me similar to what he posted above.

I has been well known in the road world for a years that aero helmets etc offer the most aero gain for the buck as the rider is and always will be the least aero part of a bike. You can argue the validity of aero all day but repeated testing proves it to be relevant even at gravel speeds. Aero is a funny thing and very counterintuitive at times. Everyone assumes that wide gravel tires are so bad for aero but because you have to eventually flow the air over the rider, having a wider leading edge is not as harmful as folks think. Look at a LeMans winning race car such as the Porsche 919; they have an almost blunt front end but it works because once you punch a hole the size of the largest part, you can smoothly pass the air over the rest of the car and that is where the gains are realized. The widest part of the object is going to encounter the airflow at some point so the earlier it happens, the less overall drag you can achieve because all the nick-nacks are now out of the airflow. Again, the air has to pass over the rider at some point. That is why aero wheels have become wider in the last few years; they start the process. In the early days of aero wheels, mfg's were touting gain claims that were for the wheels themselves spinning in a wind tunnel and everything was skinny with almost sharp edges. Then someone else started advertising bike gains and reality set in and wide wheels were recognized as being better for a bike with a rider on it achieving better overall aero. If you didn't need a rider, bike aero would be very different..

Conversely, you claim that weight is significant to you but I would question that and what it is based on. If you weigh 165lbs and have an 18lb gravel bike vs you on a 16lb gravel bike, there is a 1.1% (.011)difference in the overall weight that is climbing up a hill. Can that even be detected by someone? Factor in some day/day variation in your weight and it quickly gets pretty gray..
ljsmith
762 posts
#17Mar 11, 2019, 6:50 PM
SWGraveler wrote:

Conversely, you claim that weight is significant to you but I would question that and what it is based on. If you weigh 165lbs and have an 18lb gravel bike vs you on a 16lb gravel bike, there is a 1.1% (.011)difference in the overall weight that is climbing up a hill. Can that even be detected by someone? Factor in some day/day variation in your weight and it quickly gets pretty gray..

I agree with everything you say. The thing is that lightweight wheels "feel" fast, so the rider perceives it as fast. Test after test have proven that lightening any part of the bike (including wheels and tires) really makes very little difference unless you are spending all day climbing mountains. But I will be the first to admit that my bike feels quicker with lighter tires and wheels and so I feel faster.
2
SWGraveler
247 posts
#18Mar 11, 2019, 11:01 PM
I think there is no doubt that a bike can feel faster with some changes, especially with light wheels because what you are feeling is responsiveness. Pumping your tires to a higher pressure will do the same(until you can't take the pounding anymore haha). Again, a spinning wheel has a lot of momentum and reducing that makes accelerations/decelerations and changes of direction much easier. I see a lot of data around pharma testing and a placebo effect is not fluff, it is real and truly has an affect on results. Back to when I was working at a bike shop; it was always a source of great humor when someone would buy a light stem or whatever and then come back in a few days later announcing that the stem helped them set a new PR on a hill. Given that a 181lb rider & bike weighs 82,174 grams, it is incredible that someone would actually believe that a savings of ~75 grams or .0009% caused them to climb faster..
IMHO, the "grass roots" aspect of gravel riding causes some folks to feel that acknowledging that aero/lightness/electronic shifting/etc is ok or relevant somehow dilutes the "purity" of this form of riding. There will always be those that are drawn to the latest gadget, those that want to win the group ride and those that just want to enjoy riding in the middle of nowhere. Me, on various days I am all of these people. All of these are good things in their own right and whatever motivates you to ride is a great thing. Embrace and embody what you believe in but don't bash those with a different view. Without all of us, we would not have all the great tire/bike/gear choices that we are enjoying.
2
Volsung
878 posts
#19Mar 12, 2019, 2:52 AM
I've been researching new rims too and kinda hate spending money so I'm trying to make the right decision. A few things I've picked up-

-Aero trumps weight on climbs less than 6%, which is most of the climbs I deal with
-Aero is apparently more beneficial at lower speeds and you get diminished returns at higher speeds.
-Never trust your feeling over actual data. 23mm tires FEEL fast, but aren't.
-I don't know if there's a certain point that light weight trumps aero

Anyway, I want light AND aero. The closest thing I've found are Far Sports rims that are 30w (24 internal) and 40 deep at 400g. On the other hand I could get some flyweight XC rims that are 24mm deep and 270g. Is 16mm worth 130 grams? Beats me.
1
Koyote
288 posts
#20Mar 12, 2019, 7:08 AM
Volsung wrote:
Anyway, I want light AND aero. The closest thing I've found are Far Sports rims that are 30w (24 internal) and 40 deep at 400g. On the other hand I could get some flyweight XC rims that are 24mm deep and 270g. Is 16mm worth 130 grams? Beats me.

I shudder to think of what will happen to those 270g rims when you bomb through a pothole.
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