Tire pressure on gravel roads

[Catrin]

I need to do a little hard riding on the Jamis to break the seals on the rear suspension so lbs can customize it for my weight. They said gravel roads would do the job - and out in my corn fields there are some gravel roads that I've never been able to ride As wet as everything is that is my only option anyway - and they said road riding won't do it.

Should I lower the tire pressure any for gravel roads? Last week I ran the full 65 pounds pressure - but that was for pavement. I suspect these roads don't have fresh gravel on them - though I do want to look at them to make certain any flooding has subsided.

[Becky]

65?!? Way too much, IMO. I don't know too many riders who run even the minimum pressure listed on the side of the tire. My squishy bike's tires are rated for 35-60, and I don't think I've had more than 30 psi in there.

Too much pressure means less traction, as a rock-hard tire can't deform around obstacles for grip, and instead bounces off them. It's uncomfortable too. A too-soft tire runs the risk of pinch flats and feels like pedalling in wet cement.

The goal is to find the tire pressure that allows you a comfortable ride with plenty of traction, while not being so low that it causes/contributes to pinch flats. The right pressure varies by tire, bike, weight, and conditions.

I would start with the pressure on the high side, and let air out a little at a time until you find the pressure that works for your bike, your riding style, and the conditions. Carry a pump and don't be afraid to experiment

[Catrin]

I only had it so high because I was on total pavement for that ride. My favorite pump with a gauge doesn't seem to be made for schrader valves, though it has two heads so surely Am taking Ms. MG (the Jamis) to the LBS tomorrow so will take pump to and ask them about it. It was HARD to find one with a gauge!

[Becky]

Ahhh ok. The pavement part makes more sense. Off-road, you'll definitely want less.

As for the whole gauge thing, I pump up at home with my gauge-equipped floor pump and note my starting pressure. Then I let air off as I ride until I find nirvana, and check my final pressure when I get home.

If your pump has two heads, it must be able to do both presta and schrader valves. Do you have a link or a picture?

[Catrin]

It is this Crank Brother pump...

I may have figured it out, one of the "caps" at one end does appear to unscrew - that might be how I can use it for the schrader valve. My other bikes all have presta.

OOOOOH I see it now! There are little "symbols" for the two kinds of valve, one by each end. I've no idea why I couldn't make it work but I am quite sure it was user error - will try it again I would much prefer it be my error than to learn that I can't use my $30 pump on my mountain bike!

[Aggie_Ama]

For gravel on a mountain bike with tubes, I would stick around 30. For hard pack I would go up to 35. With tubes I had to run a higher pressure. But you don't want to pinch flat on tubes, so bottom line 30 or so. You need a firm tire but a little bit of squish in them for traction. Hope that makes sense, it will once you ride a little more. And since your LBS may know the exact trail ask them what they think as well.

[Catrin]

Thanks Aggie, it helps to have an idea. I suspect that someone at my LBS knows the gravel road/trail I am headed to so will ask. I also need to go look at the gravel trail and make certain it isn't flooded...

[SheFly]

Be careful with tire pressure - it's really an individual choice.

I am 5'10" and between 155 and 160 lbs on a given day. I run my MTB tires (with tubes) between 50 and 60 PSI ALWAYS, including racing. Too much, Becky says! Not so, say I. I haven't flatted on a ride or in a race in years - no fear of pinch flats (and in New England, everything is rocky and rooty).

I'm used to this tire pressure, and am comfortable with it. Riding with less makes me more timid and cautious while riding, thinking about getting a pinch flat.

My point is, that everyone needs to find their own ideal tire pressure, and run with that. I personally would NEVER run 30-35 lbs on a gravel road, but YMMV.

SheFly

[Catrin]

Be careful with tire pressure - it's really an individual choice....

My point is, that everyone needs to find their own ideal tire pressure, and run with that. I personally would NEVER run 30-35 lbs on a gravel road, but YMMV.

SheFly

Thanks SheFly, and I will speak with my LBS. I am 5'3 and weigh 133... I don't know what this trail/road actually looks like but will check it out prior to riding it.

[Aggie_Ama]

SheFly is correct there is no "rule" on pressure. Our trails are super rocky and we Texans run low pressure to compensate the fatigue on our bodies but I am talking "baby head" rock gardens not gravel. It is also constantly loose due to excess droughts. Having squish in my tires makes me feel like I am not bouncing off obstacles and get a grip. Plus with cactus and other prickly plants I know very few people who aren't tubeless here which also changes variables in tire pressure. I have been tubeless almost two years but it is only recently I stopped running very firm tires. I also didn't notice as much with a longer travel front fork (120 mm vs 100 mm now) and rear shock (5" now 4") on my Gary Fisher. So tire pressure isn't the only factor in how the ride feels.

Probably get a starting point and investigate different pressures. Run super high, run super low, run medium. Find your happy place.

[Catrin]

Interesting! The main purpose on this first off-pavement ride is to pop the seals on the rear suspension so my LBS can customize it to the weight of me and my gear - and of course to ride my lovely Jamis They can approximate it pretty darn well, but they explained it would be best to do it this way. They said to expect it to feel odd until we get things dialed in.

I've no idea how much travel I have on this bike, but we will see I am hoping the weather breaks while I am at my conference in Reno next week. I've been focusing on getting enough miles on my Gunnar this week for my fitting next Friday - and for the new bike tune-up. Will start working with the Jamis after my return when, hopefully, things will be a little warmer and drier So far I've only ridden Ms. MG once on pavement.

Depending on the kind/depth of the gravel on this trail, I will start my experiment at 60 psi and go from there.

[spokewench]

I need to do a little hard riding on the Jamis to break the seals on the rear suspension so lbs can customize it for my weight. They said gravel roads would do the job - and out in my corn fields there are some gravel roads that I've never been able to ride As wet as everything is that is my only option anyway - and they said road riding won't do it.

Should I lower the tire pressure any for gravel roads? Last week I ran the full 65 pounds pressure - but that was for pavement. I suspect these roads don't have fresh gravel on them - though I do want to look at them to make certain any flooding has subsided.

I think you are new to riding in the dirt, arent you? For rocky stuff where I ride here in Flag, I never ride with more than 35 in the front, 40 in the rear. I weigh 125 pounds. This will give you a softer ride; I do not think that you are trying to go fast per se, just ride the bike for the lbs and get the feel of it. The harder more air in your tires, the more they slide. I suspect that you would like a more stable feel for some of your first rides, so I would opt for no more than 45 on a dirt road for you.

[limewave]

You know what's funny, I have never, ever, put air in my mountain bike tires or checked the pressure.

Maybe I should start doin' that.

[Catrin]

I think you are new to riding in the dirt, arent you? .... I do not think that you are trying to go fast per se, just ride the bike for the lbs and get the feel of it...

Yes, and am looking forward to it very much! I had hoped to do this before my Reno trip, but that means a treat will be awaiting me upon my return

[Becky]

Be careful with tire pressure - it's really an individual choice.

I am 5'10" and between 155 and 160 lbs on a given day. I run my MTB tires (with tubes) between 50 and 60 PSI ALWAYS, including racing. Too much, Becky says! Not so, say I. I haven't flatted on a ride or in a race in years - no fear of pinch flats (and in New England, everything is rocky and rooty).

I started at 50 and worked my way down until I found the "sweet spot".

It's very much an individual thing and comprised of many variables.