Gloves or Pogies... what is faster for me on a gravel race?
/The TLDR version (you are welcome Mike M. š):
I performed a field aero test utilizing an Aeropod to see the potential differences between heavy gloves, Pogie Lites and Bar Mitts, with the following results:
For a 64.5 mile race (Cirrem), relative to gloves the Pogies Lites would cost me (be slower) 0:02:19, and using Bar Mitts would cost 0:02:10.
For a 152.5 mile race (SHGU150), relative to gloves the Pogies Lites would cost me 0:05:16, and using Bar Mitts would cost me 0:05:00.
For a 337.6 mile race (IAWAR), relative to gloves the Pogies Lites would cost 0:12:31, and using Bar Mitts would cost me 0:12:16.
These are based on my specific aerodynamics and may not be completely applicable to others, but it should give you a general frame of reference.
In 2017, one of my athletes asked about the potential time loss for using Bar Mitts (generically called pogies) for 330+ mile Trans Iowa gravel race. The temps were predicted to be very cold that year, and hypothermia was a big concern. At the time, I made some assumptions, did some back-of-the-napkin math, and conservatively estimated that over the course of the event it may cost them 20 minutes in total time**.
Recently I was taking photos at the Spotted Horse Gravel Ultra, and when reviewing the pics afterwards, I noticed the difference in handwear and once again wondered about the potential impact of gloves versus pogies.
Hand models, from the 150 miles Spotted Horse Gravel Ultra. Left to right, gloves, Bar Mitts and Pogie Lites.
So, I grabbed my gravel bike and headed to the Water Works Park in Des Moines, where there is a reasonably low traffic circle where I can do field aero testing. To perform the comparison, I utilized an Aeropod, which looks at real time air density, ground speed, wind speed, bike power and slope to estimate aero losses (assuming fixed rolling resistance and mechanical losses). The testing is pretty simpleā¦ you ride in your circular route, maintaining a fixed body position, with each of your different equipment options. You capture the data, and then analyze it using their software, to determine your CdA (Cd = Coefficient of Drag, A = Area). Your CdA directly impacts your overall aero drag, which is typically the biggest component of your overall bike power. This page does a nice job of describing the physics involved, if you want more information.
Bar Mitts top, Pogie Lites bottom and Gloves in the center.
The results of my testing were as follows:
Hoods CdA
Light Gloves 0.415
PI Lobster Gloves 0.414 reference
Bike Iowa Pogie Lites 0.431 (+0.017 / +4.11%)
Bar Mitts 0.435 (+0.021 / +5.07%)
So, the Pogie Lites and Bar Mitts do create a higher CdA (more drag) than using heavy gloves in my testing. Interestingly, the heavy gloves were about the same loss as the light gloves (numerically better, but I suspect the difference is below the test accuracy overall). Note that the Pogie Lites tested better than the Bar Mitts in this particular case, but I suspect they will be more variable in their CdA as they are made from a soft material that changes shape quite easily, which can change both the cross sectional area (A) and the coefficient of drag (Cd). As a whole, anything that flaps or moves in the wind creates a high coefficient of drag.
Not content for a single test, I did another test in another location with a much smaller circular loop. The day was windy (15 mph winds) and cold, which is less than ideal for aero testing as a whole. As such, I was bundled up with heavier clothing for this ride. Even though it was less than ideal conditions, I wanted to see if I saw any variance in the relationships with wind buffeting from different directions. The route was only Ā½ mile, so I did 10 loops for each option (with wind hitting from all sides then) to see how it impacted the results. In the second test, my CdA values were:
Hoods CdA
45 NRTH Heavy Gloves 0.496 reference
Bike Iowa Pogie Lites 0.514 (+0.018 /+3.63%)
Bar Mitts 0.506 (+0.010 / +2.02%)
In this case, all the CdA values looked a lot worse, and as such, the percentage change the pogies made looked smaller. We also see that the Bar Mitts tested better in this case than the priorā¦ possibly due to the rigid shape and semi-aero friendly profile overall (speculation).
For simplicity, if we average my two tests, assuming sometimes Iāll be wearing heavier clothing and dealing with more wind and sometimes Iāll be with slightly lighter clothing and less winds, we end up with the following CdA values:
Hoods CdA
Gloves 0.4550 reference
Pogie Lites 0.4725 +3.85%
Bar Mitts 0.4705 +3.41%
So, what does this actually meanā¦ how does it impact my race times?
Letās try three different local gravel race lengths, since I have my actual race data for Cirrem 100k in ā18, Spotted Horse Gravel Ultra 150 in ā16, and Iowa Wind and Rock 338 (IAWAR) in ā19. The actual temps may not have warranted pogies for these races, but it will provide a general idea of the impact over varying distances. I didnāt try to match my actual race times, but rather used my past data to put in realistic power data for the model. I also used the weather from the date of the race for the model as well.
First up, Cirrem. Total mileage 64.5 with around 3400ā of climb (per RWGPS which tends to understate elevation gains):
Cirrem model, with Gloves, Pogie Lites and Bar Mitts
Iām sure thereās a weight-weenies out there balking because I havenāt included the weight differences. Well, I can estimate that as well. My medium gloves, which Iād wear under the Pogie Lites or Bar Mitts, weight 3.88 oz, my Pogie Lites 3.46 oz, Bar Mitts 8.75 oz, and my heavy gloves (without pogies) are 5.82. Unfortunately, BBSās minimum weight change is 1 lb, so I re-ran the PL and BM options with an additional pound, which added 20s to the PL option and 19s to the BM run. Then taking the ratio of 0.09 x 20s is about a 2 second slower time for Pogie Lites and 0.43 x 19s or 8 seconds slower for the Bar Mitts.
For my 64.5 mile example, using Pogies Lites would cost me 2 minutes and 19 seconds, and using Bar Mitts would cost me 2 minutes and 10 seconds.
Next up, Spotted Horse Gravel Ultra 150. Total mileage 152.5, with 12,655 gain according to RWGPS.
Spotted Horses 150 model, with gloves, Pogie Lites and Bar Mitts.
Using the same method to compensate for weight differences discussed above, the Pogie Lites would be 4s slower than shown and the Bar Mitts 21s.
For my 152.5 mile example, using Pogies Lites would cost me 5 minutes and 16 seconds, and using Bar Mitts would cost me 5 minutes even.
The last example, from the Iowa Wind and Rock. Total mileage 337.6, with 27,323 gain according to RWGPS.
Iowa Wind and Rock 337, with Gloves, Pogie Lites and Bar Mitts.
Using the same method to compensate for weight differences discussed above, the Pogie Lites would be 18s slower than shown and the Bar Mitts 87s.
For my 337.6 mile example, using Pogies Lites would cost me 12 minutes and 31 seconds, and using Bar Mitts would cost me 12 minutes and 16 seconds.
Overall, it looks like my original guestimate was conservative and pogies would cost me less than 20 minutes for a long race like Trans Iowa or IAWAR.
Other important considerations:
1. This is all based on my aero test and doesnāt mean that wearing pogies for IAWAR will result in a 12-minute penalty for you (or other distances / times as discussed above), as your aerodynamics are different. I think it will likely get you in the general zip code, but you could do your own analysis, even without an Aeropod, as noted below. *
2. The Pogie Lites came out better than I expected in terms of aero losses. Soft material means more likely they will flap in the wind, which is bad for the coefficient of drag. That said, I have really big hands. In gloves, that means they fill up the Pogie Lites pretty well, which may make the Pogie Lites perform better on me than they would for someone with smaller hands. With the thicker neoprene construction, I doubt that hand size would have much of an impact with the Bar Mitts.
3. This analysis was based on a single position, riding on the hoods. Obviously if you take your hands out and put them on the tops or on aerobars, the aerodynamics change and the results may change as well. Yes, I did look at the impact when on aerobars (as I ride them frequently), but I need to keep some info privy for myself and my athletesā¦ right? I hope you understandā¦ š
4. This discussion is simply on aerodynamic loss estimates and not for suitability of the task. Outside of this context, I have the following thoughts on the alternatives:
a. Bar Mitts. These are my choice for cold weather training rides because they are the warmest for me and easiest to get my big hands in and out of when riding. Would I race in them? Doubtful. Even with a long race like IAWAR they are simply too big / bulky. More on this below.
b. Pogie Lites. Being light material, I find they are note as warm for me as Bar Mitts, but work well down to about 20 ā 25 degrees with my compromised hand and a decent glove (I have nerve damage in my hand from being run over by a careless driver). The flexible material makes it a little more challenge to get my fat hands into, but also provides the inherent advantage of being able to shift or brake right through / over the pogie itself, if you hand is outside of the pogie. They are also pretty light, pack small and are relatively easy / quick to get on and off. That means on a long race (e.g. IAWAR) you could put them on / take them off as needed, without taking up a lot of room in your bag. Would I race in them? Yes, I think they would be good for low predicted temps for IAWAR or comparable racesā¦ possibly even shorter races like Spotted Horse 150 or 200 again if the temps were cold enough.
c. Heavy Gloves. Generally, this is what Iād race in for shorter races like Cirrem. 2 minutes + is an eternity at the finish line, and Iād lose a lot of spots with the aero losses. It would take really cold temps for them to make more sense (where you are already bulked up with heavy clothes). The other factor is being able to eat with what you are wearing. If the gloves get too heavy / cumbersome, it somewhat restricts you (or me anyway) to a liquid diet, as they lack the dexterity to open food wrappers. Again, this is fine for shorter races, but less than ideal for longer events. In contrast, you can typically wear lighter gloves when using either the Pogie Lites or Bar Mitts.
* Soā¦ what if you want to do your own field testing?
Since the time I was asked the original question, Iāve had the chance to do some field aero testing. There are a few different methods that you can utilize, but a couple of the more popular are using the Chung method, via aerolab in the application Golden Cheetah. This is a free app to download and use, and with a basic understanding, the aerolab portion is pretty easy to use for simple aero tests. The second is a paid app, called Best Bike Split (BBS). BBS is a great tool for estimating race times, and also contains a feature to estimate aerodynamic losses as well. The third option is to use a device that estimates real time aerodynamic data, looking at power data, speed, wind speed, air density and slope (I use a product called Aeropod). The advantage of the device is that it sees the actual wind speeds that are occurring during your ride, which provides greater accuracy than the software application only methods. With all methods, you need to have a power meter, as they all utilize the power data to work backwards and estimate CdA based on speed and assumed rolling resistance and mechanical losses. Likewise, each works best if you have reasonably low and steady winds, steady temps, and a consistent road surface. Ideally your route is something that is loop where you can do multiple iterations to get any wind to hit from all sides, and also has low traffic for safety and riding consistency. I personally use one of the loops near Water Works Park in Des Moines. Once you have a good route, itās a matter of riding the loop with consistent body position and relatively constant power. Itās best if you can hold a reasonably brisk pace, say 18 mph or more if possible. You want to make sure whatever power level you choose, that you can hold it relatively closely for all of your test runs. Then itās a matter of testing your base option and then your remaining positions or gear that youād like to test. Iāve created how to videos for:
o Golden Cheetah / Aerolab. This is probably the most widely used option for field tests. Itās reasonably easy to use, and free. I show how to use it here.
o Best Bike Split. This is a paid program that does the race modeling used above, but also has an aero estimator as well. Itās easier to use than Golden Cheetah and also utilizes historic wind, temperature and humidity over the course of your ride, so I suspect itās possibly more accurate than Golden Cheetah. I show how to use it here.
** My original back-of-the-napkin estimate from 2017:
Assume a hand is roughly 6ā x 3ā without a mitt, 18 sq in
Assume a mitt adds 4ā to each dimension. This seems like a lot to meā¦ so this should be conservativeā¦ but again, I donāt know what they look like from the front on a road / gravel bike. 14ā x 11ā = 154 sq in. But, this may help compensate for the difference in drag coefficient, as a bar mitt would be more shaped like a block than an airfoil and probably reduces the drag coefficient as well.
Diff = 136 sq in x 2 hands = 272 sq inches
Or 1.888 sq ft, or 0.17547 sq meters
Throwing in 0.6 sq meters as the baseline into this calculator, making your weight 69 kg, bike 13 kg, and Crr 0.01, at 150w speed is 26.01 kph (https://www.gribble.org/cycling/power_v_speed.html )
Making the area 0.617547 to adjust for the mitts, the speed at the same power drops to 25.81 kph.
This translates to roughly 0.124 mph difference. At 30 hours, itās 3.72 miles difference, or around 20 minutes overall.
Letās say you get cold instead, and lose 10w over your average. This takes the speed (assuming no mitts) from 26.01 kph to 25.2 kphā¦ closer to 0.5 mphā¦ a much bigger deal than the aero loses of the mitts.