Tire pressures for trails

Forums Mountain Bike Forum Tire pressures for trails

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    • #425009

      Hey Guys, had a heck of a time finding an entry bike with everything being sold out but did find a new GT Avalanche. It came with no info/manual etc. Looking for recommendations for tire pressures. I’ll be riding easier trails first then progressing but I’m getting a little older so nothing too crazy.

    • #425107

      ok

    • #425128

      Depends on tire  brand, width and your weight, also terrain and your personal preference can affect what you run. I weigh right at 200 lbs, and run 2.30 Maxxis Minions 22 to 25 PSI rear, a couple pounds less in the front.

    • #425213

      As Alvin said ,it depends on tire , weight of rider, conditions and more. I would search singletracks and see what others say but 20 – 25lbs is typically a good starting point. I find a half psi  or one psi makes a noticeable difference. Ya think about only  having 20psi then adding or taking a psi or two, its noticeable.

    • #425256

      Hopefully your tires are tubeless.  If so, Stan’s No Tubes has a good formula to use as  a starting point.

      Divide your weight, in pounds, by 7.  Add 2 psi for the rear tire and subtract 1 psi for the front.

       

       

    • #425351

      What is your tire size? (27.5×2.2, 29×2.6, etc)  What is your rim width?  (i25mm, i35mm, etc.)  How much do you weigh?  I can’t even begin to make a suggestion without knowing those 3 things.   I weigh 165 pounds with 29×2.6 tires front and rear on inner width i35mm rims and I run 17psi front and rear.

    • #425366

      As Bike Nerd said… Tire size, construction, rim width, rider weight, riding style etc. All add up to a recommendation. I run 10-14 with my 27.5 x 3.0’s dependent on terrain planned. Smoother, lower. Loose terrain, lower. Rocky, rooty, hard etc. higher. But, only high enough for a trialsy, light rider with a light riding style to not rim out while being appropriately finesseful.

      Piper99, we need details to give you a hand…

       

    • #425374

      2020 GT Avalanche, 200 lb. rider, 29×2.25″ tires with no brand name markings, 19mm inner rim width, tire pressure on sidewall 35-65 psi. light to moderate trail riding in Delaware state parks. Again, just a beginner. Appreciate the responses.

    • #425542

      Stan’s formula should be perfect for your tire and rim width.  At 200 lbs, you would be around 30 psi in the rear and 27 psi in the front – if your tires are tubeless.

      If you tires have inner tubes, you should be fine around 40 psi.

      Tire pressure is not that big of a deal when you are starting out.  You just want to run enough pressure to keep from pinch flatting.  As you gain experience you can start experimenting to find the pressure that works best for you.

       

    • #425654

      On very smooth trails 27psi might be fine but on rough rocky trails, you might need to go to 35psi.   In general, you want to run the lowest pressure you can without bottoming out your tire against the rim which would cause a pinch flat if you’re using tubes.  Bottoming out the tire could damage your rims.  You also don’t want to run such low pressure that the tire feels squirmy or floppy.  You want the tire to feel firm but not hard.  If it’s too hard, the tire bounces back or feels pin-bally when it hits bumps.  I think it’s best to run the same pressure front and rear.  Also, you would run the same pressure with tubes or when going tubeless.  Some think that you can run less pressure with a tubeless setup but anytime you bottom out a rim you risk damaging the rim.

    • #427670

      Yes, I’m running tubes. I finally got on a trail today running 40 psi F&R and it felt great until I hit a part of the trail with heavy tree roots. Definitely felt like the back tire was bottoming out. Other than that it was great. That’s for all the input.

    • #432986

      This is a good test:

      Take your wheel off, inflate to between 20 and 30 psi based on your best judgement. Grasp the tire with both hands, with the web of your thumb and forefinger of each hand overlaying the tread. With your full body weight, press down as hard as you can and try to feel the rim (without squeezing with your fingers). Given all your weight and strength, you should be able to just feel the rim. If its too easy, add a few lb/in² and try again. Too hard, let a small amount of air out.

      This should be the correct pressure for optimal traction with tubeless tires, without bottoming out on roots and rocks, given proper technique. If you are riding trails that are appropriate for your skill level this should be a good starting point, and only add pressure if you find yourself bottoming out.

      I find that for my weight of 160 lb, this is around 20 psi. Because I ride a hardtail or rocky terrain, I cheat a bit and put 18 in the front and 22 in the back, for a little extra grip up front and a little more rim protection out back.

    • #476406

      The myth of tubeless unicorn tires! While tubeless is awesome, rim cuts and severe rim damage are things that do occur. Burping some air happens…

      Carrying a pump is one must of many.

      Considerations for pressures…

      27/60/120 TPI.

      Single ply vs. 2 ply.

      Rider weight.

      Rider skill set.

      Terrain. (rocky/rooty or smooth/groomed)

      120 TPI 2.25, 200# rider, 40 to begin with margin to increase or decrease.

      60 TPI, same as above, 35… Being a starting point, give it a go in the neighborhood. Carve some turns, hop some curbs etc. to get a feel for the tires. Add if they feel squirmy or squishy. Let some out if they feel like a basketball or hard as a rock.

       

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