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Old 07-07-09, 02:06 PM   #26
power182
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2.1 front and rear.

150 lbs

40 PSI in back and 35 PSI in front.

Ride in Phoenix AZ... very rocky terrain and anything less results in bent rims (this is tubeless and I still require higher PSI).

I don't know if I am a hard rider or what but anything less (while the traction is awesome) and I go through rims like candy.
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Old 07-08-09, 08:58 AM   #27
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Fluctuating between 206-210lbs

26x2.14 WTB Mutano Raptors - hardpack and a fast trail, I'll run 40; lots of climbing/rock gardens, roots 35-37psi, depending on the conditions. I don't ride this rig, urban, I have a dedicated commuter for that.

I suppose I should add East Coast conditions, none of that sandy stuff and goatheads you get out West.
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Old 07-08-09, 12:12 PM   #28
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Let's not forget that rim width also factors into the equation. And to all you noobs and hacks who run these outrageously high tire pressures: you don't know what you're missing.
Given what I'm reading here I'm going to go a lot softer on my ride tomorrow. I may not be a noob but I'm most definitely a hack.
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Old 07-08-09, 12:46 PM   #29
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I am 145 or 155-160lbs geared up. I ride smooth singletrack and some with lots of roots and rocks. I love rock gardens. I like to try and pop off of everything I can find. My rims are 30mm wide and I use tubes. When I run my Mutano Raptor 2.4, I use about 30-32psi. If I switch to my Prowler MX 2.3 and Stout 2.3 combo, I run a bit lower because of the slightly thicker sidewalls, 26-28psi. I have gone as low as 20 on certain occasions and was once down around 7psi in deep snow. Never have had a pinch flat.
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Old 07-09-09, 03:06 PM   #30
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Im a dj biker so run between 32-36 psi, Im also really light, im 5.10 weighing in at 143, But still growing.
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Old 07-09-09, 03:34 PM   #31
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165 lbs, 2.25 intense Sys 4 (running tubeless) on an Epic comp, 30 lbs front, 34 lbs rear. Ridden on rocky, dusty, sandy, very dry fireroad and singletrak
They still feel plenty hard to me, but not bouncy and ride just fine on assfault.
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Old 07-09-09, 04:17 PM   #32
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Man I'm jealous of the low pressures here. 210# rider weight. 38# rear 2.35". 35# front 2.4". Rocky, rooty and drops too. Heavier duty tubes (not DH). Very rare pinch flat, usually on a drop. Maybe I need to lose a pound or two or ten.
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Old 07-09-09, 04:24 PM   #33
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Tires: 29x2.2 Specialized Capt. Control (tubeless on Arch rims)
PSI: 22 front/26 rear

Tires: 26x2.0 Specialized Capt. Control (tubeless on Mavic 819)
PSI: 32 front/35 rear

Terrain: Mostly smooth single track, some rocks, some roots, brake ruts I don't jump, take drops, etc. I'm an XC'er

Weight: 200 lbs is safe - 190 towards end of summer, 205 towards spring
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Old 07-09-09, 06:36 PM   #34
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Instead of answering this question, I'm going to ask one- because I recently started mountain biking, and am not sure.

I weigh 110#, and my tires are 2.1.
Ride single track: rooty, rocks, small drops, little sandy here and there...

so, what PSI?
The developing take home message in this thread seems to be to run MTB tires at relatively low pressure offroad. It's hard to quote an exact figure because ideally, you'll vary it according to terrain, riding surface, and the type of tires you have. With the kind of riding you describe and being near my weight- as a rule of thumb I'll keep the tires soft enough to push them in about a quarter inch using FIRM pressure of a finger. On my tires that's not much more than 20 lbs. You want them soft enough to get good contact in the rough stuff, but firm them up for road or other hard surface riding or your bike will feel like an anchor. I write this assuming you aren't carrying a heavy load on the bike when you ride; otherwise taking my advice will lead to pinch flats and bent rims!

Last edited by rnorris; 07-09-09 at 06:46 PM.
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Old 07-09-09, 07:24 PM   #35
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The developing take home message in this thread seems to be to run MTB tires at relatively low pressure offroad. It's hard to quote an exact figure because ideally, you'll vary it according to terrain, riding surface, and the type of tires you have. With the kind of riding you describe and being near my weight- as a rule of thumb I'll keep the tires soft enough to push them in about a quarter inch using FIRM pressure of a finger. On my tires that's not much more than 20 lbs. You want them soft enough to get good contact in the rough stuff, but firm them up for road or other hard surface riding or your bike will feel like an anchor. I write this assuming you aren't carrying a heavy load on the bike when you ride; otherwise taking my advice will lead to pinch flats and bent rims!
Thanks for the input! This thread has been incredibly useful- as a road rider, I can't imagine running on tires that soft, but its clear the 55 I have been putting in is quite high. I'll work my way down until I find the right fit.
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Old 07-09-09, 07:33 PM   #36
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26x2.35/25-30psi up front, 33psi in the back for rough terrain. 35 psi up front and 40 in the back for hardpack. 195 at the moment.
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Old 07-09-09, 08:51 PM   #37
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Tires: 2.1 Panaracer Fire F 2.1 Nevegal R
PSI: 40 F 35-40 R
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Trails: Lots of roots, climbs, technical... biggest drops 3 or 4 feet, nothing insane. I also need to ride to trails, so no crazy low pressure.
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Old 07-09-09, 10:36 PM   #38
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I should have qualified my earlier post by saying I have full suspension, which means I can run lower tire pressures than I would risk with a hardtail.

edit: Got called away and left that dangling. Meant to say with my dual suspension softened up (say, 50 lbs. in the rear shock, the front is an elastomer) I feel more confident running lower tire pressures because the suspension takes some of the impact off the tires. On my old hardtail, running the rear at 20 lbs. made me a bit nervous for my rim.

Last edited by rnorris; 07-10-09 at 11:25 AM.
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Old 07-09-09, 10:39 PM   #39
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I should have qualified my earlier post by saying I have full suspension, which means I can run lower tire pressures than I would risk with a hardtail.
Huh?
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Old 07-10-09, 11:48 PM   #40
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I am running WTB V-raptors. I am now down to 125lbs from 160. But being a fat *****. My rear has been set at 50 and my front at 40-45.
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Old 09-15-09, 05:11 PM   #41
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*bump*

215# on a FS MTB

Maxxis Crossmark 2.1 f/40 psi r/45 psi (5 psi less based on conditions...). Great & really fast XC tire.


Just picked up a pair of Maxxis Ignitor 2.35's and will mount them this weekend. I have heard very good things about these tires. Anyone else ride these?
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Old 09-16-09, 04:28 AM   #42
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If you are riding on a FS, you should post the psi of both your front and rear shock as well.
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Old 09-16-09, 05:57 AM   #43
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If you are riding on a FS, you should post the psi of both your front and rear shock as well.
I disagree...different leverage ratios of suspension designs requre different amt. of air for the same weight rider...making it immaterial. Not to mention the coil sprung / air assist forks.

Tire's only please.
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Old 09-16-09, 10:15 AM   #44
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2.1 on the FS, 2.35 on the HT.
30-35 psi. If I had tubeless, it would be less.
110 lbs, give or take 5 lbs, without gear.
Rocks, hardpack, loose stuff. Don't like mud as much, but I'll ride it. I avoid sand like the plague.
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Old 09-16-09, 12:16 PM   #45
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2.1 on the FS, 2.35 on the HT.
30-35 psi. If I had tubeless, it would be less.
110 lbs, give or take 5 lbs, without gear.
Rocks, hardpack, loose stuff. Don't like mud as much, but I'll ride it. I avoid sand like the plague.
30-35 at only 110lbs? I bet you can go lower.

Last week, I pulled into the trailhead and saw a friend just starting the trail. I didn't have time to check my PSI because I wanted to catch him. First thing I noticed, my steering had a 1/4 second delay. Ran into 3 trees. I also slid out in 2 corners because the tire just folded over at max lean. Weird feeling. Hadn't found my friend yet, so I kept going. For anyone in Ohio, I was at West Branch. Eventually I did Bit O Honey and the expert section twice. Still no friend. Got back to the trailhead and checked my tires. 13PSI in the front, 15 in the rear. WOW! No pinch flats, didn't lose my tire and rims were still true. This was with my Spank Subrosa rims and WTB Prowler MX 2.3/Stout 2.3 combo.

Learned that my rims do a great job of holding the tire bead. Also makes me realize I can run low low pressure. Won't ever go that low again unless there is snow, but I'm not gonna die if I'm below 30PSI. Don't be afraid to experiment!
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Old 09-16-09, 12:24 PM   #46
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200#

Velociraptors 2.1 F/R @ 30-35# w/tubes

Roots, rocks, smaller drops.
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Old 09-16-09, 01:47 PM   #47
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I disagree...different leverage ratios of suspension designs requre different amt. of air for the same weight rider...making it immaterial. Not to mention the coil sprung / air assist forks.

Tire's only please.
It might be interesting if owners of the same fork could compare the tuning, but not on this thread. Especially forks like Fox where you can dial in sag, rebound, and compression and lockout.

For example, if someone started a thread just for Fox TALAS RLC owners... might be interesting to hear how different people set those up.
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Old 09-16-09, 09:04 PM   #48
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215 lb rider on mixed conditions, but very XC type of stuff. FS ride in the sig.
Bontrager tubeless setup on bontrager 29 jones and xdx.
40psi front and back. Maybe a tad lower on the front.
I tried higher and a tire blew off. Probably defective but I'm too nervous to go any higher now.
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Old 09-16-09, 09:49 PM   #49
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215 lb rider on mixed conditions, but very XC type of stuff. FS ride in the sig.
Bontrager tubeless setup on bontrager 29 jones and xdx.
40psi front and back. Maybe a tad lower on the front.
I tried higher and a tire blew off. Probably defective but I'm too nervous to go any higher now.
Try it lower and see how you like it. I did.
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Old 09-19-09, 07:36 PM   #50
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150lb rider + pack/tools/water. Rigid bike. IRC Trailbear 2.5's front and rear running +/-25-27lbs with tubes. Very technical XC terrain, never a problem in three years. Knock on wood.
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