Gravel tire pressures tested!

[@jasonwills6694]

The surface shown looked firm and packed in places is a thought. Great job good video

[@JMCyclingVideos]

For sure it is mostly Hardpack with a few patches of loose gravel here and there. What boggles my mind is how the low pressures were faster than the mid pressures though if it being smoother was the case.

[@fiimble]

Hello, Thank you for your analysis. My preference is more comfort rather than a a bit more speed, particularly on a longer and more enjoyable ride. Cheers!

[@JMCyclingVideos]

Thanks for watching! I’m usually the opposite. I’ll sacrifice a little comfort for more speed. But, this test has shown me that perhaps going a little lower on pressure isn’t costing me much speed and gaining a lot of comfort.

[@Aragorn.Strider]

Well, a few months ago, I noticed when I start a ride, I'm in the blue zone and my muscles are not ready. My body temperature is a bit on the cold side. After say 2 kilometers I am ready though. There could also be some dust from the night before or other stuff, which after say 2 or 4 kilometers blows away. The solution for all this stuff is basically say, the first ride is a throw away round and after the last one you should do the first original setup again. Also be sure you are in same condition between each ride. So add say a one minute pause to get it more even. Also by increasing the distance makes the influence of inaccuracies diminishes. Up to 10 kilometers the influence of something weird is less.

[@JMCyclingVideos]

Thanks for the input. I definitely have some ideas for changing up the testing protocol, especially for tests like this that are relatively easy to make changes quickly in between tests.

[@MorganBrown]

interesting. i'm about to do one of these tests myself. I think I will definitely do a "squishy" test, maybe 15 psi, just to actually see the end members of the speed distribution. It's gonna be a lot of zone 2 tomorrow!

[@JMCyclingVideos]

Let me know what you find. I’m curious if someone else does something similar and gets different results. Be careful going too low on pressure. You don’t want to risk a rim strike on a big rock or something.

[@MorganBrown]

@@JMCyclingVideos will do. I actually run Vittoria foam inserts, which will keep you from bottoming out. Apparently they don't affect rolling resistance according to the BRR site.

[@MorganBrown]

@@JMCyclingVideos I think your philosophy is perfect. It's not that we're searching for the "perfect" tire pressure. We're searching for the lowest possible tire pressure that doesn't give away too much speed on the majority of the course.

[@Morehills840]

Thank you for the great report.

[@JMCyclingVideos]

Thanks! Even though the results weren’t what I was expecting, knowing I shouldn’t stress too much about pressures helps. And, knowing I can run lower pressures without as much concern is also good for long distance races

[@streddaz]

I've heard of a good way to test rolling resistance is to pick a hill to roll down and where you can come to a rolling stop on a flat. As long as you just let the brakes off to start from a marked position, don't pedal and keep the same body position, so the aero is the same, and you just have to mark where you finish rolling. Do this a few times to get an average. This removes any difference in power output.

[@JMCyclingVideos]

That’s a good thought from a pure rolling resistance consideration. But, there are plenty of resources to get rolling resistance data. Rolling resistance and real world usage data don’t always correlate.

[@Mati03x]

Hello ! I am from Argentina ! And I recently bought my first gravel bike, I have a lot of experience racing track bikes, and I wanted to get into this modality. At the moment I love it! And I congratulate you for your video!!! And I thank you for the time and work! My conclusion is that what the page recommends is just the necessary measure to make it comfortable and fast.

[@JMCyclingVideos]

Thanks for watching! Videos like this do take a lot of time and work but I enjoy doing it and hope they help others. I think prioritizing comfort is best for longer duration gravel rides and races.

[@elefantrising]

I think my fastest times have been when setting up the tires firmer although not as comfortable. I think it depends a lot on the terrain and the length of effort, short effort you can take more punishment longer effort you can less and so on. If I recall correctly the elite racers run pretty high pressures. With gravel seems to be many many variables.

[@JMCyclingVideos]

In ideal conditions, I do think higher pressures will probably be faster. But like you said, there’s so many variables in gravel and you’re likely to see a lot of different terrain over a long gravel ride/race. Makes it really tough to figure out one specific pressure that’s best for all.

[@riffmeisterkl]

What did you think about the compliance ? Was 10psi less a lot more comfortable ? Thanks for taking the time to do this methodically.

[@JMCyclingVideos]

It is actually a huge difference in comfort between each of the pressures. Even though the highest pressure was technically the fastest by my measure, I would never run that high of pressure for anything longer than maybe an hour. It was that bad. Whereas at the lowest pressure it super comfortable. I would just worry about pinch flats or rim strikes at that low of pressure. It’s really a balance everyone has to experiment to find.

[@riffmeisterkl]

@@JMCyclingVideos are you running tubeless? You can go even lower

[@JMCyclingVideos]

I am running tubeless. I know lower is possible, but with the 40mm I’m a little hesitant about striking my nice zipp wheels on a rock. With 45mm+ I’d probably try a little lower

[@MorganBrown]

here you go. kzbin.info/www/bejne/f4HJaHyMgN6im9k Silca told me 50 psi for "category 2" gravel, but I found that 30, 40, and 50 were roughly similar on smooth gravel. 20 psi was much slower. Though on the singletrack, 20 psi was the fastest. I am concluding 35-40 psi would work best for me for the typical "mostly smooth with chunky sections" course. And I am a large rider (215 lb/95 kg)

[@JMCyclingVideos]

Finally got around to viewing your video and left a comment. Great work on that and interesting findings!

[@erichouck9487]

what would you normally before you did this test?

[@JMCyclingVideos]

I would typically run what the Zipp tire pressure calculator said, although sometimes I’d go on the higher side of it due to the expectation that higher pressure were faster. Now I’ll definitely be running on the lower side due to comfort.

[@lovenottheworld5723]

A tire with a soft casing isn't that sensitive to pressure differences.

[@JMCyclingVideos]

That does make sense. But I really would’ve thought a 30-40% difference would see a bigger change.

[@nickconol1428]

Try same pressures on single track

[@JMCyclingVideos]

Good thought. Maybe I’ll try that. Which pressures do you think would be fastest on single track with a 40c tire?

[@nickconol1428]

@@JMCyclingVideos cyclocross pressures. Mid to high 20’s

[@Dov-ux8gk]

Interesting first half till music fatigue killed my will to make it to the end.

[@JMCyclingVideos]

Thanks for the input. Hopefully you at least skipped to the end to see the results.