optimal tubeless psi

Viewing 13 reply threads
  • Author
    • #200820

      I have finally converted to tubeless, currently running Maxxis Ikon 29’s on Mavic XM119’s.  What is the optimal tubeless psi?  I ride in FL where we have lots of sugar sand and a TON of roots.  I’ve been using Stan’s method (rider weight/7 = x.  x-1 front pressure, x+2 rear pressure) which puts me at 25 front and 28 rear.  But I have been told by several people that I should be running much lower pressures tubeless.  I weigh 185lb.

      What tubeless pressures are you dudes/dudettes running?

    • #200822

      25/28psi sounds pretty reasonable to me. IMO, people seem to enjoy bragging about how low their pressures are, but in the end it comes down to rider preference. Lower pressures can certainly be advantageous, but only up to a point. Beyond that magical point, the disadvantages start to outweigh the advantages. Unfortunately the magic number is different for everyone so you’ll need to experiment.

      As a point of reference, I weigh less than you but generally run my tubeless tires in the low 30s.

    • #200848

      I weigh 200 and run my tube tires 25 psi here in Florida, I would say as low as you can get them without them feeling wobbly in corners.

    • #200857

      I play with low pressures to lend a bit of dampening to my somewhat lacking suspension. I tend to hover around 20/22 front/back. I’ve gone lower and I’ve only had an issue due to the low pressure once but it only takes one exciting instance of losing your front tire in a fast offcamber turn to add a bit of pressure to the tires.

    • #201221

      Good thread. I tend to follow the Stan’s guidelines too. One possible way to go lower and still avoid problems would be to use the Schwalbe Procore system. I’ve been thinking about it for a while but my current rims are just a little too narrow so it would require a new set of wheels for me. 🙁

    • #201252

      A few more factors besides rider weight and preference are the tires themselves. A stiff sidewall or just tire volume can all affect what 25 lbs feels like. Your rim width will affect tire pressure as well. This is why percieved pressure is so important, i.e. Squish it with your thumb and then go ride it. I find my pressure by starting in the high 20’s and then slowly letting out air on the ride. In Florida sand low pressure is probably a good thing.  Eventually the tire will start to squirm on turns and I’ll add a pound or so from there.

    • #201675

      Thanks for all the input!  I’m running Maxxis Ikons (2.25″) on 29″ Mavic XM119s.  I rode with bro-in-law last weekend and it’s been SUPER sandy in FLA with no rain for past month.  Graham Swamp was miserable!  He was riding 26″ Maxxis Ardents at 55 psi w/ tubes (which I think is ridiculously high but he likes it….been riding that way for 12 years) and I was noticeably faster in the lose sand.  Could be from PSI, or tubeless, or 29er, or more narrow tires?  Who knows.  What I do know is that, as a first-year novice, it felt damn good passing a seasoned vet in that sand!  Yew!

    • #201681

      tubeless tires come with a recommened psi rating but i have found that the factory settings suck . to get the best tire pressure first start with tires inflated to about 35 psi then ride the bike on your favorite trail and go down in pressure . keep going down 2 psi at a time until the tire starts to burp air after big jumps or hard cornering. once your tires starts burping air its time to start adding 1 psi at a time to find the sweet spot you will be able to feel when your tires flex and bite the ground better … i recommend using a digital pressure gauge to keep track of tire pressure i currently run 23psi in the rear and 20-19 psi in the front i ride a 27.5 plus bike with wtb trail blazer up front (19psi) and a wtb trail boss in the rear (23psi) .. noted that in wet conditions and really loose dirt i drop both tires 2 psi for the extra grip ……. hopefully this helps with your tire pressure situation

      watch this video to see how tire pressure makes your faster     https://www.youtube.com/watch?v=J5gt86RSIrs

    • #201871

      I also just converted over to tubeless along with a larger tire (29×2.3) and like Jeff said above it’s really a rider preference to which psi feels best as you ride, corner, etc. to find out the optimum pressure. I weigh approx 230lbs and ride with 23psi on the front and 26psi on the back. And still am not certain that I’m right where I need to be as of yet! But I think I’m fairly close!

    • #201942

      I run about 20psi in the front 25rear in most conditions locally (Charlotte NC) in Pisgah I bump it up a couple PSI to protect my rims so maybe 22f 27 rear. Keep in mind though I’m running rims that are 10mm wider and high volume tires with fairly stiff sidewalls.

      I’d guess your pressures are pretty good as they are. You can always knock them down one psi at a time until you start to get tire squirm. Lower pressures are helpful in soft conditions.

    • #201971

      Isn’t it half your age plus seven? Or am I thinking about something different?

    • #231072

      aron your thinking your (waight /7)-1 for front and +2 for rear

    • #231145

      So many factors to consider, but it really comes down to preference, terrain, and tires. Just experiment and you will find what is right for you. I have been running tubeless for nearly ten years now and until my recent bike, I would run 35 rear and 30 front for most of my bikes. Any lower and I would tend to burp tires or contact rims on rough downhills. My new trail bike, a 2018 Transition Scout, has Stans Flow Rims with Maxxis Minion 2.4″ and 2.5″ Wide Trail tires. In addition I am running Cush Core inserts. I am finding 25-28 in the back with 20-25 works great! Oh, and I weigh 178lbs.

    • #231229

      The only thing I have to add that hasn’t already been said in other replies is that you need to be careful if you ever decide you want to try higher pressures. This may be obvious to most but since the OP is new to tubeless this is worth mentioning.

      A 2.3″ 29er makes one heck of a kaboom when the bead lets go with 40 psi of pressure behind it.

Viewing 13 reply threads

You must be logged in to reply to this topic.