Testing Gravel Bike Tire Pressure vs SPEED

[@JMCyclingVideos]

Great work on the test and really interesting findings! I like how you compared both single track and smooth gravel to find what would be an optimal pressure for a course with a mix of both. I know these videos are time consuming to produce to I appreciate the effort you put into it.

[@MorganBrown]

you of all people would know how time consuming they can be!!! I have a better single track course in mind for the next test. It's about 1 mile circumnavigating a lake, so flat. With rocks, roots, and ruts.

[@davidbee9563]

I tried the silca calculator for a couple of my bikes and found the suggestions 5 to 10 psi higher than I run on mixed surfaces. Also the weight balance they suggest is much higher for the front than I would expect. For road I think it is likely 40/60 F/R and they list 42/58 which seems quite aggressive to me. My combined weight varies from 125 to 130kg. Favourite tires are Gravel King standard or semi slick treads.

[@sonnybowman]

I run my 26" bike on the rail to trails(stone dust with hard-pack gravel) and count on increasing my speed by as much as three km/h when I increase the tire pressure from 25 psi(after 2 to 3 months of biking) to 60 psi.

[@MorganBrown]

That is pretty consistent with what I found. 20 psi was about 5% slower than 50 psi on the smooth stuff.

[@OskarAustegard]

Is 35 as wide as your bike fits? Considered 650s with something wider? My hypothesis is that it would allow a more consistent low pressure on both surfaces (and be more comfortable and possibly faster) 🤔

[@MorganBrown]

I have a Canyon Grizl. It is supposed to accommodate 50 mm or larger. I would have preferred the 40 mm version of this tire (Schwalbe G-one Super RS) but it was (is?) out of stock. I typically choose the fastest tires from the BRR list (www.bicyclerollingresistance.com/cx-gravel-reviews). I was able to get one(!) of the Caracal TLRs from Europe. The Schwalbe is the fastest tire with a meaningful tread. I've been happy with it so far; will race it next Saturday.

[@livinglifeontheedge4261]

When I tried 650b I found that at the same 35ish psi I was having good success on my terrain with on 40c 700c. They didn't ride as well at speed downhill that I attributed to the flex of the taller sidewalls? I also think that rim width has alot to do with the equation, I like a wider rim like an i28 or i30 even. Granted I am probably more concerned with comfort over speed........

[@MorganBrown]

yeah, when you start looking at rim/tire combos, unraveling the speed is really tricky. The rolling resistance tests are nice, but like you say, those tests don't ensure that a certain rim/tire combo will roll fast on real terrain, in real wind. From an aero perspective, I do like how these 35's mate with my Hunt Limitless wheels (I think outer rim width is 28 mm)

[@livinglifeontheedge4261]

@@MorganBrown I think that one thing we should all agree on is that no matter what "genre" of cycling one is doing it is best to test different psi on your terrain and bike(s). It doesn't take long and pays big dividends. Stuff like that Silica site just makes people lazy and not really get them what would best suit them. The best aspect of tire pressure I have seen is how it keeps going lower and proves to be as, if not more efficient overall. Tubeless also has a hand in that.

[@bikebudha01]

The real mistake in this video is putting "gravel" and "race" together. Ugh... racing gravel just kills what gravel should be about, getting out and hitting new roads that you normally wouldn't on a road/mountain bike. "Gravel + Grand Fondo" is the winning combo...

[@MorganBrown]

if it makes you feel any better, my "races" are usually solo time trials, since I don't climb well. But regardless, I will always take some free speed if I can get it. The incremental gains philosophy does appeal to my nerdy side. I'm not keen at all at the "pro-ification" of gravel riding. It's getting kinda silly and all the attention will inevitably draw more rules & regulations, which kind of defeats the original idea of gravel.

[@bikebudha01]

@@MorganBrown First off, thanks for posting the vid. Always interesting to see results of real world testing. Second, my comment was along the lines of what you say about "pro-ification" of gravel. I am old enough to remember Norba, and how 'low key' it was before they got all hot-to-trot to appease the UCI, and get into the olympics. If there was no such thing as 'pro mountain biking', moutain bike racing would be better for it. Same with gravel. I don't give 2 shits about who wins Unbound. I do give 2 shits about the event be fun and open to as many people as possible.

[@MorganBrown]

When the World Tour guys started showing up to these events en masse, it was the beginning of the end. That said, I'm "racing" Salida 76 this Saturday and it will be a blast. I measure an event by how many drink tickets you get. I think they gave 2 or 3 last year.

[@bikebudha01]

@@MorganBrown I like your way of measuring an event!