[miuan]

It seems for those who burp regularily at lower pressures, it is a good idea to use stans strips instead of UST rim interface as a means of tire insulation. All my stans setups hold air better than UST beads, that said, I weigh 170, run regular Maxxis DH tires only at 23-30 psi and I've never burped them.

 

[Jim Mac]

Jeebus, these tire pressures seem high compared to what I normally run - 24-26 F and usually 28 back - both trail and DH. In softer conditions in DH, I'll run 22 F and 24/26 back.

 

[DirtyMike]

I weigh 260, I run 30 front, and 45 rear on 2.5 clutch/chunder combo.

Remember the size of the tires makes a big difference as well. Only difference I notice on my bike with lower rear pressure is the rear end feels loose at 35-45 mph range, other than that, I dont notice any difference from dropping the pressure. I do ride in Socal which is always loose and sandy<aside from our rare days we get enough rain to keep it wet>. No loss in traction with 45 in the rear, 30 seems just perfect for the front.

Its all about how much weight is riding on each tire, so your front and rear combos will vary alot....if you ride front heavy, more in the front, rear heavy more in rear ETC ETC.

Every tire will deflect differently, every tire will support loads differently as well. I know here in the bicycle world its not really an issue, but there is a reason for min and max inflation on tires.

 

[bizutch]

The only pro advise I've ever been privy to was Steve at the Michelin tent said most all his Michelin pros at the time were running 2.5's with 28psi. The 2.8 they would run at 22-25psi. That was with Michelin DH tubes. This is however...old news.

Oh, and I forgot to vote:
You're only as awesome as your last post.

 

[Ithnu]

I hear some people who say the run low 20s. For a while I thought I was running 30 all the time. Then I realized my pump read 5-10 psi low. I bet most people's pumps are inaccurate. So I use a separate gauge now.

I'm 205 without gear (I haven't armored up and stood on a scale, apparently you guys do). I change based on tracks, but find I like 30 +/-2 front and 35+/-2 in the rear. I do hear the rim bang on rocks once in a while (front and rear).

I'm on 823s with UST High Rollers.

 

[dump]

I run it until it deflects a bit with thumb pressure. Hope that helps everyone!

 

[SylentK]

I don't think you'll find anyone "fast" who runs super hard pressure. Probably cuz you reach a point of diminishing returns when you run too much. Meaning it just doesn't help you past a certain point.

There was an interview w/ Fabian Barel this summer that said he runs around 1.9-2.0 bars. So 27.5-29psi. He's prolly around 180lbs?

That probably doesn't help your argument to run higher pressures does it?

 

[frorider]

It seems for those who burp regularily at lower pressures, it is a good idea to use stans strips instead of UST rim interface as a means of tire insulation. All my stans setups hold air better than UST beads, that said, I weigh 170, run regular Maxxis DH tires only at 23-30 psi and I've never burped them.

i tend to agree.

i like having a rubber rim strip / tire bead interface. as a test in the garage, i like to drop the pressure down very low (12 psi or so) so I can roll the tire body (practically off the rim) and check that there is no burping.

on the subject of speed---it's been documented that in general very high tire pressure does not equate to higher speed on rough ground (e.g. that schwalbe study that has been posted a thousand times on every bike forum). tires that deform / absorb rocks help preserve forward momentum, as physics would predict. i don't have much contact any more with xc pro racers, but from what i hear they've mostly stopped drinking the super high tire pressure koolaid.

however in the case of DH tires/casings, the tradeoff might be different. sure seems that moderately high (say, 35 psi) feels better when pedalling on a fire road than 25 psi.

 

[BikeFan84]

super thick intense DH tubes, minion 2.5" 42a, 33rear, 23 front, sometimes I increase the front to 28 (when riding rocks) No flats in 5+ years.

 

[SCARY]

I keep 2 gauges of the same make to keep them in check.MX tire pressure is even more picky cuz they heat up so quick,and we're down in the 12-13psi range.

Jesus Christ Bullcrew!238?! I hope you're 6'7.

I'm so happy Ive started a thread that's lasted 4pages(sniff)I can't believe I've reached such a milestone. Happy and proud





I guess if you ask a question that sounds like a survey,everyone can feel important and wanted.And then you can get multiple pages......but still.

 

[bullcrew]

I keep 2 gauges of the same make to keep them in check.MX tire pressure is even more picky cuz they heat up so quick,and we're down in the 12-13psi range.

Jesus Christ Bullcrew!238?! I hope you're 6'7.
I'm so happy Ive started a thread that's lasted 4pages(sniff)I can't believe I've reached such a milestone. Happy and proud





I guess if you ask a question that sounds like a survey,everyone can feel important and wanted.And then you can get multiple pages......but still.

6'3" lol 34-36 waist... Yeah I feel the same way but its having spent too much time in the gym when I was younger.


Theres alot of good info here, I started seeing all the crazy high PSI's and started having flashbacks to the bike deflecting off pebbles and small animals... Good to know its not just me but its intresting to see the views and differences... A good thread!!!

 

[Bikael Molton]

I don't run UST or XC tubes, so I can get away with about 30psi rear and 28psi front on Minion DH3Cs at Diablo; I'm 160 in gear. All the guys I know who run high pressure (35+) have to do it because they choose to run light tubes or are big clydesdales.

I think there are certain conditions where mid-to-high 30s pressures might work well: loamy forests like in Santa Cruz or muddy days on hills that don't have many rocks/roots.

As far as UST goes, if we are talking pro racers, I thought the Pinkbike (or was it Vital?) WC poll already settled it: zero pros run UST.

 

[DirtyMike]

You know its funny talking about rolling resistance redundancy for dh...... Thought that was only something I was going to hear in the roadie world.

Thats a very true statement, Take a road rider for example, running a diamonte pro so they can run 150 PSI front and rear to get better rollign resistance..... well say they only weigh in at a buck 30...... that means all they have done is kill ride quality......

 

[SCARY]

6'3" lol 34-36 waist... Yeah I feel the same way but its having spent too much time in the gym when I was younger.


You know you're suppose back off the eating too,when put the weights down,right?

 

[bullcrew]

6'3" lol 34-36 waist... Yeah I feel the same way but its having spent too much time in the gym when I was younger.


You know you're suppose back off the eating too,when put the weights down,right?

LOL... thats the best part....
Lift the twinky to the dome and down 1, lift the twinky to the dome and down 2...

No I still work out regularly, just not for bulk anymore.

 

[aznick]

65 psi front and rear I goes real fast

 

[karpi]

24-26 front
26-28 back
180ish with gear
Any higher than that, to much loss in traction

 

[richgardiner]

I once ran 8 psi in my front wheel (kaiser with dh tubes) in the uk and survived the whole day, despite ludicrous amounts of tyre flex/ rollage in corners. We didnt have a pump with us so i was stuck with it for the day. Pretty grippy on wet roots though!

I then managed to get 3 front punctures in a row out of the 4 times i rode champery dh track this summer when we visited, when running about 25 psi, it was a true fml moment!

 

[BmxConvert]

24-26 front
26-28 back
180ish with gear
Any higher than that, to much loss in traction

I'm at the same pressures; but I'm 150lbs and slow... It works well for me in our rainy/wet/sloppy roots 75% of the year. 3 months of dry and we're dry slick so the same lower pressures help hang onto the roots.

I do find that I have more traction at places like Ski Bowl when it gets duffy bumping to 33-35psi up front. I leave the rear alone as I very rarely flat. and traction is fine.

 

[SCARY]

65 psi front and rear I goes real fast

no,you're not allowed in here,you're an xc racer,stick boy

 

[karpi]

I'm at the same pressures; but I'm 150lbs and slow... It works well for me in our rainy/wet/sloppy roots 75% of the year. 3 months of dry and we're dry slick so the same lower pressures help hang onto the roots.

I do find that I have more traction at places like Ski Bowl when it gets duffy bumping to 33-35psi up front. I leave the rear alone as I very rarely flat. and traction is fine.

Yeah, depending on track and conditions you always wanna play around with air pressure. Some people forget how important it really is. Its kinda crazy when you inlfate past the 30 psi how much your speed goes up.