Tire pressures for ROCKY terrain.

I feel like i'm beating a dead horse but i couldn't find exactly what i'm looking for.

I've never really payed much attention to my tire pressures but i keep hearing that finding the right pressure improves your cornering by ALOT, and my cornering traction isn't the greatest.

Usually i just run 45-50 PSI in both tires because i'm scared of pinch flats in the rear( WTB Dissent 2.5 on a Sun Single Track rim has already broken a tire jack)

I weigh 230, and ride a Transition Vagrant (hardtail) with a Kenda Kinetics 2.35 up front and a WTB Dissent 2.5 in the rear. Where i ride is chock full of fairly sharp rocks so i'm a bit scared to go lower.

Should i go lower? How much lower?

Thanks!

 

Go tubeless and drop your pressure a little....

 

ditto. seal them up and drop to 40, and then try 35. you've got 70 pounds on me, but i keep my "Stanitized" Maxxis 26ers at 25 - 30.

 

The tire pressure also depends on your weight, the weight of the bike, and the tire itself. Personally I'm a lighty, I weight about 125lbs and my bike only weights 22lbs (s-works ht). I run tubeless wheels (Mavic CrossTrails) with Specialized S-Works Fastrak 2bliss tires. I typically run 20 psi in the rear and 15 psi in the front and it's awesome. Rolls super fast and feel like I have suspension in the rear.

When I talked to Manny awhile back he was running a similiar setup on his sj ht. 20psi rear and 18psi front. He's also a light guy at around 130lbs and runs small block 8.

 

Have you considered tubeless? It will allow you to drop some pressure. The optimum tire pressure is usually around 25 to 40 pounds. I know of no one who rides over 40. It would take away all the benefits of the tire to run it that high. All the testing of the tires are done at their recommend pressures which are molded into the tire or sometimes stamped. They are designed to give you the best performance at these pressures and by over inflating them really doesn't help.

I used to think I'd have better riding if I stayed on the high side but once I went with a wider tire up front and dropped my pressure it was a lot better handling. I run 25 pounds up front and 30 in the back but I weigh 140 so these pressures probably won't be the best for you. If the ground is all hardpack I might change it up a little but not much.

 

well, i was gonna wait until i get new tires to go tubeless (i've used ghetto tubeless before and i love it)
so i'd like to stick to tubes until then. Also, if it makes a difference, i ride DH

 

duuude, if you ride DH you definitely wanna run LOW pressure. With DH tubes you dont have to worry about pinch flats as much since DH tubes are thick as hell. Get the Maxis DH tubes, i had them on my big hit awhile back and they will NOT flat!

 

Your Big Hit isn't a hardtail like what he says he rides.....even DH tubes are subject to pinch flats...saw it happen this weekend on SART and it wasn't in a really bad spot....

Tubeless is the way to go (still carry a tube as an emergency backup)
I weigh 205 w/o gear and I ran 30psi in my 2.35 Maxxis Ignitor's but I also have full suspension....
IF I was you....
I'd try 40 #'s in the rear tire to start....if you don't burp try dropping it to 35#'s....personally I wouldn't go much lower on a hardtail at 230 #'s

 

I run 2.35 Nevegal USTs at 30psi and weigh 230+. Full suspension though. My thinking with running high pressures is the sharp rocks will pierce the tire rather than the tire conform to the rock.

 

hmmmm... good point! ok, so here's a question, what if this trail is SOOOOO steep, that i can't really stop safely in the event of a flat?

 

Maybe dont ride it?

20-30LBS is where U want to be. HT with tubeless is OK. But U should be able to run mid low 30's with DH tire/tubes

 

this one is easy - drop pressure in 2psi increments and experiments. Costs you nothing but air.

personally, i ride as low as I can while still getting good traction and cornering, but not so low that pinch flatting is a problem. Usually 30-32 psi for me on 2.35s.

 

I'm about 230 with gear and I run a little over 35psi in the rear and a little under 35psi in the front. Looking at all these numbers I'm thinking i should run lower. I have only pinch flatted one and I was running 30psi at the time with regular tubes.

 

i just went in to wally world to pick up a couple of cheap tubes for my XC bike, and i saw a tube that Slime calls a "Smart tube." It has slime sealant in it, and it's friggin thick!!! i mean like REALLLLLYYY thick! it's supposed to stop thorns and the like but it seems like it would make a good DH tube for us clyde DHers that haven't yet gone tubeless. I also picked up a couple of 20" tubes for another ghetto tubeless conversion. But nobody around here has stans or wheel milk in stock

I'd do it without stans but the bead on my rear tire is so messed up that it won't hold air without it... that and it's full of holes

 

Super heavy and lots of rolling resistance...

 

I think those are the same tubes I bought for my single speed XC bike, picked them up at Jensons. I've been running them for almost a year, without a flat. Best move I've made. I used to get at least one flat a month due to pinch flats or thorns.

 

TR tubes are not any better, except for training.

I used to blow through those on a BMX, the rubber is thicker but not any harder and can still snakebite. Single track is a plenty wide rim, should work a DH tire just fine. An easy way to come up with you pressure is to just do some J-hops in front of your pad at like 32 PSI and listen to see if it bottoms out, rolling straight up a curb (without pulling up at all) works too but wont put as much stress on it. Front and rear should be within 5 (really 2) PSI so once you find the minimum for the rear adjust to taste.

 

Damn....you guys run a ton of pressure. I am 230 and run 25-30 psi, but I run DH casings on all of my bikes. Single plys and I are not friends....seems like I have to run so much pressure on singles that it feels like riding concrete wheels. I have ridden N* and Bootleg no problems with 30 psi or less. I was just having flat problems recently, but turns out it was a crappy batch of tubes that were all getting pinhole leaks at the seams. Got some different tubes and haven't had a problem. I don't run DH tubes either.

Really looking to get a tubeless setup on my next rig.

 

I run maxxis advantage 30psi and maxxis cross mark 35psi

 

well, i went out and hit the trail yesterday. the lower pressure made a HUGE difference!!! i was able to corner about 5 mph faster! my stopping distances were also greatly reduced (good thing, cause i cooked the fock out of my rear brake on the way down).

I only rarely feel like it will pinch flat, and it rolls much smoother with the lower pressure of 36 PSI in the rear and 35 in the front

Thanks for the advice!