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Recreational Cyclocross and Gravelbiking This has to be the most physically intense sport ever invented. It's high speed bicycle racing on a short off road course or riding the off pavement rides on gravel like :The Dirty Kanza". We also have a dedicated Racing forum for the Cyclocross Hard Core Racers.

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Old 04-12-16, 09:07 PM   #1
garciawork
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Not finding a solid answer, even with lots of googling. Tire pressure for 35c?

I just got my new Traitor Wander built up, with a fresh set of 35c Schwalbe G One's set up tubeless. Its probably 4-5 miles from my house to the closest gravel, maybe 10-15 miles for the real long roads, so I want to find a pressure that will work ok for the ride to the gravel, and ok on the gravel. Anyone have any idea?
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Old 04-12-16, 09:41 PM   #2
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it's very subjective and has a lot to do with rider weight, riding style, and the type of terrain you're on. if you're "average weight" you can start around 40 psi and go lower if you're lighter, much lower if it's set up tubeless.
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Old 04-12-16, 09:43 PM   #3
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it's very subjective and has a lot to do with rider weight, riding style, and the type of terrain you're on. if you're "average weight" you can start around 40 psi and go lower if you're lighter, much lower if it's set up tubeless.
Good call... didn't even think about weight. I am 170 lbs currently. There will be a lot of pavement to start the rides off with, and... well, then hardpack and gravel. I have trouble wrapping my head around 40 psi on pavement, so I will probably try a ride at 50 and see what happens!
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Old 04-12-16, 11:31 PM   #4
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what is the pressure rating on your rims?

A couple of years ago, my gravel bike had Michelin CX tires, which are a very large 30mm tire. I loved those things at low pressures, like 30psi. I weigh somewhere between 180-200 pounds, depending on the rate at which I'm drinking beer. The only down side was pinch flats. But the handling was great. I never had any desire to go to higher pressures on the road. The tires I'm using now are very heavy, Schwalbe Marathon Cross 38mm. If I run them down at 30 pounds they squirm too much on the road. The issue is that the sidewalls are too stiff. So the answer really depends on the tire. I would go lower than 50, that's really high for gravel.
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Old 04-13-16, 06:27 AM   #5
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My 35 mm tires have stiff sidewalls. They are around 80 or 90 PSI for around town use, that feels good for now. When I go to do the Katy I wonder if I'll lower the pressure in these or go to the 29x2.0 the bicycle came with. I'm thinking it depends on if the trail is wet or dry.
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Old 04-13-16, 06:32 AM   #6
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I'd say start with the recommendation on the side of the tire. If it's 60, start there. If you know you're doing dirt and it just rained, start at maybe 45-50. If you'll be mostly road that ride, go back to 60, etc.
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Old 04-13-16, 06:39 AM   #7
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The Berto (15% drop) formulas put "optimal" pressure at about 50 PSI rear/35 PSI front for 35mm tires on a typical gravel bike with a 175 lb load (rider and gear). With tubeless you can probably get away with a couple PSI less. I find the Berto optimal is a little low for my taste, so in this case I'd probably start with the recommended 50R/35F (no adjustment for tubeless) and see how it feels. If rolling resistance feels too high on pavement, increase a couple PSI. If you're getting beaten up too bad on gravel, reduce a couple PSI. It's always going to be a bit of a compromise so you have to decide how much speed you're willing to give up on each surface.
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Old 04-13-16, 07:45 AM   #8
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I'd say start with the recommendation on the side of the tire. If it's 60, start there. If you know you're doing dirt and it just rained, start at maybe 45-50. If you'll be mostly road that ride, go back to 60, etc.
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Old 04-13-16, 08:47 AM   #9
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what is the pressure rating on your rims?

A couple of years ago, my gravel bike had Michelin CX tires, which are a very large 30mm tire. I loved those things at low pressures, like 30psi. I weigh somewhere between 180-200 pounds, depending on the rate at which I'm drinking beer. The only down side was pinch flats. But the handling was great. I never had any desire to go to higher pressures on the road. The tires I'm using now are very heavy, Schwalbe Marathon Cross 38mm. If I run them down at 30 pounds they squirm too much on the road. The issue is that the sidewalls are too stiff. So the answer really depends on the tire. I would go lower than 50, that's really high for gravel.
The rims are velocity Aileron's, which are fine for pretty much any road pressure. The tires are part of Schwalbe's latest salvo of tubeless rubber, and seem pretty supple in my experience.

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I'd say start with the recommendation on the side of the tire. If it's 60, start there. If you know you're doing dirt and it just rained, start at maybe 45-50. If you'll be mostly road that ride, go back to 60, etc.
The tire says up to 75 psi, which I know is way to high. I rode around the neighborhood at 60, and it felt fine for road, but was a little stiff on the slight bit of gravel I hit. I don't have a mini pump yet, so messing with pressure and actually testing it is a bit difficult.

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The Berto (15% drop) formulas put "optimal" pressure at about 50 PSI rear/35 PSI front for 35mm tires on a typical gravel bike with a 175 lb load (rider and gear). With tubeless you can probably get away with a couple PSI less. I find the Berto optimal is a little low for my taste, so in this case I'd probably start with the recommended 50R/35F (no adjustment for tubeless) and see how it feels. If rolling resistance feels too high on pavement, increase a couple PSI. If you're getting beaten up too bad on gravel, reduce a couple PSI. It's always going to be a bit of a compromise so you have to decide how much speed you're willing to give up on each surface.
Man, riding that low scares me! Not really, but it seems very bizarre from my experience. I think I am going to try somewhere in the neighborhood of 40-50psi and see how it goes. Still waiting on my sit bones to recover from my first ride of the season, as I remember why I prefer to not ever take this much time off the bike... ouch. So, I will get out and test tomorrow hopefully.
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Old 04-13-16, 10:03 AM   #10
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Man, riding that low scares me! Not really, but it seems very bizarre from my experience. I think I am going to try somewhere in the neighborhood of 40-50psi and see how it goes. Still waiting on my sit bones to recover from my first ride of the season, as I remember why I prefer to not ever take this much time off the bike... ouch. So, I will get out and test tomorrow hopefully.
Trust the physics, not your gut People typically run tire pressures that are higher than necessary even with normal 23/25mm road clinchers. Combine that with the fact that 35mm tires have over 230% the volume of a 23mm road tire and you'll see that those "scary" pressure numbers really aren't.

I've raced Cyclocross on 32mm clinchers (with tubes) at 28R/26F PSI. I race 32mm CX tubulars closer to 20 PSI. I do have a bit of a weight advantage, but unless you're really pushing the limits on the kind of terrain your bike was meant to ride, you'd be surprised just how low you can safely go on your setup. But there's certainly no harm in starting higher and working your way down. Just don't be afraid to push the low-end a bit -- hitting the sweet spot for tire pressure can really transform your off-pavement riding experience.
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Old 04-13-16, 10:17 AM   #11
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Trust the physics, not your gut People typically run tire pressures that are higher than necessary even with normal 23/25mm road clinchers. Combine that with the fact that 35mm tires have over 230% the volume of a 23mm road tire and you'll see that those "scary" pressure numbers really aren't.

I've raced Cyclocross on 32mm clinchers (with tubes) at 28R/26F PSI. I race 32mm CX tubulars closer to 20 PSI. I do have a bit of a weight advantage, but unless you're really pushing the limits on the kind of terrain your bike was meant to ride, you'd be surprised just how low you can safely go on your setup. But there's certainly no harm in starting higher and working your way down. Just don't be afraid to push the low-end a bit -- hitting the sweet spot for tire pressure can really transform your off-pavement riding experience.
I'll try haha. I am one of those who runs high pressure on 23's, I can't bring myself to go below 90, and I normally run 95-100, and know that I should try it out in the 80's. I should also buy some 25's or 28's... but that is another story.

I am working on selling an old Rockhopper of mine, once I do I will pick up a pump and gauge so I can do some experimenting and possible ride higher on pavement and drop the pressure accurately off.
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Old 04-13-16, 01:10 PM   #12
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Schwalbe's website says 45-70 psi for those. I'd start with the minimum number and adjust from there. Wouldn't worry about going somewhat below the minimum if I wanted to do that.
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Old 04-13-16, 01:43 PM   #13
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My cross bike has Stan's Iron Cross wheels which if you follow the rules have a 45psi limit so I run my 35mm slicks at 45psi. The pressure doesn't seem to slow me down any and rides real smooth. Also works fine for short burst on gravel and single track.
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Old 04-13-16, 01:44 PM   #14
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Originally Posted by garciawork View Post
I just got my new Traitor Wander built up, with a fresh set of 35c Schwalbe G One's set up tubeless. Its probably 4-5 miles from my house to the closest gravel, maybe 10-15 miles for the real long roads, so I want to find a pressure that will work ok for the ride to the gravel, and ok on the gravel. Anyone have any idea?
It varies by your weight and surface, take notes and experiment. With tubes and my weight ( 235 lbs), 700 x 35 mm on mavic A 719 touring rim, 55 psi front and 60 rear. Try this, sit on the bike, you want your tires to squish a little. Not scientific, but a good start.
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Old 04-13-16, 03:42 PM   #15
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I am slightly heavier than OP and run 40/50 on 38s. I'd probably go a little higher than that on 35s.
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Old 04-13-16, 07:19 PM   #16
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My 35 mm tires have stiff sidewalls. They are around 80 or 90 PSI for around town use, that feels good for now. When I go to do the Katy I wonder if I'll lower the pressure in these or go to the 29x2.0 the bicycle came with. I'm thinking it depends on if the trail is wet or dry.
I have 700x32s on my touring bike. I pump them up to 80 psi when on the road. For the Katy Trail, I put them at around 65 psi. I weigh 215 lbs and the bike another 30 lbs unloaded. I'd recommend going a little above the minimum pressure for those tires. Unless you and they bike weigh more than me, I think that the 35s will be just fine for the Katy.
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Old 04-13-16, 08:39 PM   #17
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I ride Michelin Protek Cross Max 700x40 on pavement and gravel. Michelin recommends around 75 psi for my weight, 165 lbs. But that feels too rough, jittery and skittish to me. I prefer 50-55 psi on the front (with a simple spring suspension fork) and 60-65 psi on the rigid rear. These tires have a thick, heavy puncture resistant integral liner and stiff sidewalls.

I go by how it feels on loose, deeper patches of soft sand/gravel and rock, washboard ruts and when I sideswipe larger gravel. If the bike feels stable I might add 5 psi and check again until it begins to feel skittish, then back off a bit.

It's about 4 miles on pavement to the nearest gravel paths or chipseal and rough asphalt roads. The ride feels a bit softer and squishier on pavement with the tires set for gravel, but checking splits on the app I use shows I'm not actually riding any slower. It's just a subjective feel.

I've run these tires even lower for really rough, damp open prairie and pasture without trails. No problems with pinch flats. I'm running tubes with sealant, not tubeless.

Regarding a portable gauge, the Nashbar dial gauge for $8 is good. It matches the built in gauge on my Earl Grey floor pump perfectly. While that doesn't mean it's accurate, at least it's consistent. The portable dial gauge has a bleed button which is handy for finessing the pressure downward after overfilling slightly.

I carry a Topeak Race Rocket HP on the bike. It's marginal for my 700x40 tires, and really better suited to skinny high pressure road tires, but I can pump these tires up to 40 psi without much effort so it's good enough for emergencies. And it has a built in hose just long enough to avoid damaging the valve stem. Good value, around $20 or less on sale. But there are more efficient portable pumps for a little more money.
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Old 04-14-16, 06:56 PM   #18
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I run 700x38s and on pavement run 70-75 in the front and 75-80 in the rear. Slightly lower if I'm on non pavement.
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Old 04-14-16, 07:58 PM   #19
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Originally Posted by Squeezebox View Post
My 35 mm tires have stiff sidewalls. They are around 80 or 90 PSI for around town use, that feels good for now. When I go to do the Katy I wonder if I'll lower the pressure in these or go to the 29x2.0 the bicycle came with. I'm thinking it depends on if the trail is wet or dry.
What does "feels good" mean to you? Unless you weigh 300 pounds, this is too high. You will be much more comfortable with lower pressures. For Cyclocross racing, I run 33mm clinchers at about 25psi front, 28psi rear and have only pinch flatted once in four full seasons. Go way lower for off road unless you ride like a brick and never unweight for bumps.
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Old 04-14-16, 08:52 PM   #20
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How are you liking that Traitor, by the way? that company seems to have appeared out of nowhere but I like their stuff.
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Old 04-14-16, 09:19 PM   #21
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How are you liking that Traitor, by the way? that company seems to have appeared out of nowhere but I like their stuff.
No earthly clue when they popped up, or how they are doing as a company, but I really like the bike with my limited experience with it thusfar. I have only ridden it a couple miles at 60 psi on pavement, and I could easily see riding it on a road ride. That said, I am not sure I would want to wear down a nice gravel tire in that manner, so I plan to eventually get another set of the same wheels it has now and throw on a set of... I think they are the plain ole' Schwalbe One in 25 or 28c. Standing up and sprinting a little felt great, my other road bike has a level top tube (custom steel bike), and I feel like this one "dances" a little more underneath me. Shimano will take a little getting used to, but the ergonomics feel like they will be plenty comfortable compared to Campy, although I can tell I will miss the 3 up 5 down of Ultrashift.

I plan to get out for a ride tomorrow that'll hit some gravel and plenty of pavement, probably shoot for 50f 55r for pressure, and post up a review of my thoughts. I can say, however, that for $280 the frame was an absolute steal so far.
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Old 04-15-16, 03:05 AM   #22
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