Tube Tire Pressure recommendations
 

Hey, I was wondering if there was an easy way to figure out a ballpark estimate of what tire pressure I should be running. I run tube tires (though I may switch to tubeless sometime soon, but I'm just waiting until I can switch out some non-tubless compatible parts) on WTB Trail 29" tires 2.25 width and I weigh about 130-140lbs. I am honestly just trying to figure out what range I should be running in since I ride my bike quite hard. I'm also not sure what measurements are necessary for determining this so sorry if I overshared. (Also sorry that my questions are all so dumb, I'm just very new to the sport).

No dumb questions. As someone who has a much bigger frame and a full C-note heavier, don't apologize for sharing the details. More info will get you better answers. I'm new to mountain biking also, but what I've learned is that running tubes limits your options for tire pressures. I recommend making the switch as soon as you can. So, to your question: Tubes do all the work for keeping the rim off the ground, so you have to keep your pressures up. That doesn't mean you can't adjust a little, just not as much as tubeless. I would recommend following the numbers on the side wall, then experiment with lowering your pressures a pound or two at a time. You can also talk to your LBS (local bike shop). I'm sure they can give you some quality input.

The answer is "less" until you get a pinchflat. Start with 40.

LOL. Nobody rides a mountain bike on trails at 40 psi.

Milesf...at your weight ~20 psi would be a good starting point.

^This^ 40psi for a 130lb rider is insane. At 160lb I'd probably crash every other corner w/ 40.
ETA: The 'less til you pinchflat' is not the smartest thing either. You may find your best pressure results in a pinch flat or 2 on the most rough terrain but it's perfect the rest of the time. Don't over inflate to avoid pinch flats, you'll not be happy the 99.999% of the time you're not pinch flatting.

OP , try about 28-30.. you may be able to let a little out and run 25 at your weight. Tubeless you could get by with 18

I don't like to pinch flat or bang rims on hard objects so I keep my pressure high enough to avoid those things. I weigh as much as the OP and run about 15-20psi in a 2.2" tire.

he’s running tubes, not tubeless

The minimun number on the sidewall is to keep the tube & the tire from migrating in relation to eachother. So I wouldn't run lower than that no matter what the arbitrary recommendations of those on internet messege boards say.

I weigh 190 pounds. On 2.1 inch tires I've had good luck with 35 psi. I wouldn't run any higher than that unless I'm on paved, but for the most part it's squishy enough for good traction on terrain & speeds my 38c gravel friends get nervous about.

Since you are on 2.3's I should think around 25 to an upper bound of 30 ought to be well enough if you weighed the extra 50-60 pounds I do. So much depends on local hazards & how you ride it's tough to give a range for you.

Still though, heed the minimum sidewall pressure. A pulled out stem from tube migration is a tough thing to come back from.

That's even a little high for trail riding. At 190 lbs kitted up I'm at 22 rear and 20 front on both by my tubeless and tubed setups.

I'd start around 25/28 front/rear and then drop it a psi or two each ride until you get a pinch flat and then bump that tire up 2 psi. I am guessing at your weight you are going to end up around 23ish/26ish front rear.

It is literally the ONLY way to know.

I am ~180 with a pack, and I when I ran 2.25-2.3" tires in the rear tubed , I could not go lower than 28 psi or I would pinch-flat occasionally. Front with that size I'd run into issues under 24.

That advice has been roundly ignored for the history of people riding mountain bikes with no ill effects. In fact, several manufacturers have stopped listing a minimum pressure.

29er on 2.25tires at 140lbs, I think the correct pressure is somewhere around 20psi, probably a hair under. For reference, I ride 26x2.35 at 160lbs, and I run 18/22 tubeless. You're lighter with about the tire volume/contact patch.
Here's how to tune tire pressure. Find a good section of trail about 10min long. You want a mix of the type of riding you normally do. Some technical, some not. Having a good tire gauge is key.
Start at about 25psi, run a session, drop the pressure ~2psi, repeat. Initially, you'll bounce off rocks and traction suffers. Then as the pressure gets too low you'll get pinch flats and it'll feel sluggish. Once that happens stop and add a few psi, and you should be good.

Yeah, I also run tubes.

I forgot about the tire migrating on the rim until someone else mentioned it. Watch for it at low pressures or you could end up with a destroyed tube. It gets worse as the tires age and the (bead) rubber goes from tacky to slippery. This year I'm going to try using a bit of tubular glue on one set of wheels that always has problems. Simply raising the pressure is not an acceptable solution for me.

Wonder if that it's a function of tire type and tube? My hardtail has a 2.3" tire in the rear and it's stilled tubed (because I've been too lazy to set it up tubeless) and I'm ~190 and never have pinch flatted yet running it around ~22 psi. First set of tires were some Racing Ralphs and now I have a Continental Cross King in the back.

I don't know. I do think it is a little less likely to pinch on a HT because you are more aware of how hard the wheel is hitting and tend to ride more smoothly. But still, I could never get away with anything close to that on any sort of bike with tubes and that size.

I am surprised how low you are going without pinch flats. Back when we were all on tubes, I was on the low side of what most people I knew were running.

Even with Tubeless, I'd be denting rims with 2.3s at the pressures you are running.

That's why we all gotta find out what works for us.

Have to wonder if its something to do with compounds. Sidewall compuounds from the different tire manufacturers are all over the place these days. My Crosskings have the Chile compound, whatever that is, only made in Germany blah blah.

I haven't dented a rim yet. Outside rim width on those pressures I'm running is 29.5 mm.

Your traction will suffer and you'll bounce off rocks as you DROP pressure? Wrong.

No, you are just reading what he wrote wrong.

“Initially” here means before you start dropping the pressure.

25 front, 30 rear

The OP weighs 130-140, this is way too much pressure.

Is it really ok to go below 25 psi with tubes? I thought that to go lower than that without getting pinch flats, you needed to be running tubeless.

Depends on your weight, the terrain, and your riding style. For me, yes, it's definitely ok.

Lots of variables...rider weight, tire size/construction/rim width, terrain...there is no single pressure that defines needing tubeless or not.