# Tubeless pressure for gravel racing?



## namaSSte (Jul 28, 2004)

I'm planning on running my HED Ardennes + wheels (25mm) and 40c WTB Nanos but not exactly sure what kind of pressure makes the most sense for gravel. For cross, i usually run them in the mid 20's but was thinking I might add some air for gravel but not so much that I sacrifice rolling resistance, traction, or too much comfort (although that is the lat of my considerations). Anyone have thoughts on this?


----------



## pretender (Sep 18, 2007)

There's a lot of variation in gravel. Like, if there were some steep descents, I'd be leery of setting the pressure super low. But if there were a lot of loose and scrabbly stuff, I'd want the tire pressure as low as possible. Mainly, whatever makes you feel comfortable and confident.


----------



## rcb78 (Jun 15, 2008)

Exactly, it depends on the course. As a 210lbs rider, I've gone as low as 25psi and as high as 45 on those same tires. For long rides that will cover varying terrain, I'll bring a small pressure gauge and make changes along they way if the course changes enough.


----------



## namaSSte (Jul 28, 2004)

Thanks guys. I'm going to err on the high side as its a race so I probably wont be able to make on the fly changes. I know there are several long fast decents (and of course, lots of loose stuff in between) so I guess its picking the lesser concern and setting pressure for the other. 40psi will be pretty hard (at 155lbs) so I amy opt for upper 30's but likely not lower it sounds like.


----------



## pretender (Sep 18, 2007)

That sounds sensible to me. I'd go mid-30s rear and lower 30s front.


----------



## Stoneman (Mar 1, 2009)

namaSSte said:


> Thanks guys. I'm going to err on the high side as its a race so I probably wont be able to make on the fly changes. I know there are several long fast decents (and of course, lots of loose stuff in between) so I guess its picking the lesser concern and setting pressure for the other. 40psi will be pretty hard (at 155lbs) so I amy opt for upper 30's but likely not lower it sounds like.


With those tires and at your weight I'd go 35 front / 37 rear. That should be plenty cautious.


----------



## single1x1 (Mar 26, 2005)

I ran 35 front 40 rear on 38 Spec triggers , want enough not to feel to slow on any pavement sections, but still have some cushion without hitting the rim on rough downhill sections. Had a friend last weekend running tubes on Clement MXp cross tires @ 40PSi and he pinch flatted the rear then pinch flatted again, but he was on a smaller tire with tubes and weighs more @ about in the 190# range, I'm just 165#


----------



## Roland44 (Mar 21, 2013)

single1x1 said:


> I ran 35 front 40 rear on 38 Spec triggers


That's the sweet spot for me as well. I did a lot of testing to figure out what works best for me and I suggest OP to do the same.


----------



## 4Crawler (Jul 13, 2011)

I don't race on mine, but I have 40mm Marathon Mondials I run tubeless and find 30R/27F is about as low as I can go on my gravel test trail. Its a hundred yards or so of golf ball to fist sized stone off the end of a paved trail. My test is to hit the gravel at speed and if I can clear that stretch w/o feeling the rims bottom out, that's good. If I drop below that pressure I'll burp the tires on that section. I usually run a few psi above that lower limit but I find no difference in pavement speed at 30psi or 35psi or even higher.


----------



## namaSSte (Jul 28, 2004)

I wound up going 35/38 and it worked out well. There were some really rough DH sections and even at speed, the tires never had any squirm let alone threatened a bottom out. The rest of the dirt sections were in remarkably great shape so having extra cushion really wasn't imperative. Race was really challenging with 4 categorized climbs each with multiple sections over 20% and none with flats where you could recover, just steady climbing to the top. The first 50k was a test, the second 50k felt like survival!


----------

