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Old 01-09-2019, 09:03 AM   #1
XXshawnXX
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PSI per terrain - What do you run?

For some reason, the question of tire pressure keeps pestering my brain amidst watching the Dakar and all of the Moto participants' IG videos of them riding 5 different types of terrain in either a full day or within 10-15 miles.

My question - What have you guys either experienced, keep consistent, general rule of thumb or do you just "run what you brung" and don't bother to do anything in regards to your PSI when you ride the following terrains:
  • Dirt
  • Sand
  • Mud
  • Heavily Rocked
  • That slimy, Slippery Mud
  • Fuck you talkin' bout Willis?

I typically try to air down on my Africa Twin (Tubed) quite significantly during rides in either inclement weather or dirt/sand to about 12F/15R but I am also on a 500lb bike and I am significantly heavier than your normal dude @ 300lbs. However, my riding buddy doesn't give a shit and keeps his tires right around 42F/44R which I found to be super sketchy in the Nevada desert a few months back.
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Old 01-09-2019, 09:10 AM   #2
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I drop the pressure of my XR650L to about 15 psi off road when things are loose. The big KTM to maybe 20. I don't always bother dropping pressure on the KTM, depending on where I'm headed.

I carry an air pump with me and normally air back up as soon as I get to pavement. On pavement, the XR gets 33/36 and the KTM might get the recommended 38/42 or I might not go that high depending on how long I want to wait for the air coming out of my tiny Slime pump.
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Old 01-09-2019, 09:35 AM   #3
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Oh man, 12/15 on an Africa Twin sounds like a pinch flat or bent rim or both gonna ruin your day. I rarely go below 25 (cold) f & r on my Tiger. Carry a mini-compressor to air back up when returning to pavement....
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Old 01-09-2019, 09:44 AM   #4
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Oh man, 12/15 on an Africa Twin sounds like a pinch flat or bent rim or both gonna ruin your day. I rarely go below 25 (cold) f & r on my Tiger. Carry a mini-compressor to air back up when returning to pavement....
It does sound like a bent rim/pinch but *knock on wood* only thing that has happened is that I have broken 2 spokes.

Incredible traction though! or atleast I experienced significant improvements in the desert running such low pressure.
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Old 01-09-2019, 09:45 AM   #5
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Originally Posted by ScottRNelson View Post
I drop the pressure of my XR650L to about 15 psi off road when things are loose. The big KTM to maybe 20. I don't always bother dropping pressure on the KTM, depending on where I'm headed.

I carry an air pump with me and normally air back up as soon as I get to pavement. On pavement, the XR gets 33/36 and the KTM might get the recommended 38/42 or I might not go that high depending on how long I want to wait for the air coming out of my tiny Slime pump.
Scott - by loose stuff, would you run the same 15 PSI or 20 PSI if it was loose DRY dirt vs. loose mud?

Does it matter or am I reading too much into tire pressure and the compression of the actual tire vs contact area/grip?
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Old 01-09-2019, 12:01 PM   #6
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Scott - by loose stuff, would you run the same 15 PSI or 20 PSI if it was loose DRY dirt vs. loose mud?

Does it matter or am I reading too much into tire pressure and the compression of the actual tire vs contact area/grip?
I don't do mud.

I don't analyze what type of low traction environment I'm going into, either the bike will do better with lower pressure or it won't and that's about as far as I go. And I don't really ride fast enough to worry too much about pinch flats as was mentioned in one of the other posts.
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Old 01-09-2019, 12:11 PM   #7
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I have adopted 1 tire pressure. I keep it around 22psi even with rim locks. Particularly on the front because if you ride in really rocky terrain the wheels get bent pretty easily at anything less. It makes the ride worse but I'd rather not have bent rims.

It's a compromise. We rode this rocky road in Baja and I aired down to 18 and bent the crap out of my rim. But it felt like it handles the rocks better despite bashing the crap out of my rims. If you have tubless tire even more reason to keep the tire pressure up because if you bend the rim it won't even hold air.

At 22psi it's a good medium and I'm not having to add more pressure when I hit a long slab section. That's what I used for LAB2V 2018 also.

It depends on the weight of the bike, the heaver the bike the more PSI you will want.
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Old 01-09-2019, 12:19 PM   #8
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I have adopted 1 tire pressure. I keep it around 22psi even with rim locks.
That is the air pressure that Honda recommends to run all the time for the XR650L. I like more when I'm riding the twisty roads.

Should I be concerned about running lower pressures if I'm going to be cruising at 90 mph for 20 minutes or more on country highways with big sweeping curves?
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Old 01-10-2019, 03:34 AM   #9
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I don't cruise at 90mph but I've done 80mph on and off road no problem. Everybike is different and depends on your load also. I'm sure the AT you probably want to run higher that's a heavy beast.

Only thing I'm worried are rocks at lower pressures. Other than that I would welcome lower tire pressures. But the terrain is always changing O_o'

If you were riding a lot of sand or dunes and have trouble hooking up lowering tire pressure helps. Might help in mud a bit but if your tires get packed with mud you're kind of SOL. I ran into snotty mud on the final section of the Nevada BDR and decided to turn around because it's so hard to control when the tires get packed up with mud, it's pretty much a slick. A more knobby tire would help in the mud.

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Old 01-10-2019, 06:52 AM   #10
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I'd be worried about cruising at that speed at low pressure.
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Old 01-10-2019, 07:20 AM   #11
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I'd be worried about cruising at that speed at low pressure.
And that's why I don't do it. And why I won't be running just 22 psi all the time.
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Old 01-10-2019, 08:20 AM   #12
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Originally Posted by XXshawnXX View Post
I typically try to air down on my Africa Twin (Tubed) quite significantly during rides in either inclement weather or dirt/sand to about 12F/15R but I am also on a 500lb bike and I am significantly heavier than your normal dude @ 300lbs.
As mentioned (or inferred) by others that is way too low of pressure unless you are trying to extricate or traverse a very soft sandy section.
Especially with the combined bike and your weight.
Yeah, the traction will feel improved but the risk of bending a rim, pinch flatting or spinning the tire on the wheel (and thus pulling the stem off the tube) is much higher. Does the AT have rim lock(s)?

Normal pressure (for most tires) for the big ADV bikes would be between 28 - 34 front and 35 to 42 rear.
The above mentioned 22/22 is a good compromise in pressure as long as your not blasting rocky sections, or get surprised by "that rock".
It'll feel squirrelly on the hardpack/road though. That's why refilling upon return to pavement is a fairly common practice.

What tires are you running on your AT?
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Old 01-10-2019, 08:56 AM   #13
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As mentioned (or inferred) by others that is way too low of pressure unless you are trying to extricate or traverse a very soft sandy section.
Especially with the combined bike and your weight.
Yeah, the traction will feel improved but the risk of bending a rim, pinch flatting or spinning the tire on the wheel (and thus pulling the stem off the tube) is much higher. Does the AT have rim lock(s)?

Normal pressure (for most tires) for the big ADV bikes would be between 28 - 34 front and 35 to 42 rear.
The above mentioned 22/22 is a good compromise in pressure as long as your not blasting rocky sections, or get surprised by "that rock".
It'll feel squirrelly on the hardpack/road though. That's why refilling upon return to pavement is a fairly common practice.

What tires are you running on your AT?
Currently running TKC 80's

Many surprise rocks have been encountered even with 12/15 and nothing has happened. I definitely don't take it easy on that bike and I haven't experienced a tube pinch. I did bend the front rim by some fucking phantom rock up by Rumsey and reiff road but that was on the pavement in which the tire had 35 psi in.

I do carry an auxiliary pump to air up once I reach pavement.

Should be riding this weekend if the weather turns out and will try the magical combo of 22/22 and see what happens!
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Old 01-10-2019, 11:32 AM   #14
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It does sound like a bent rim/pinch but *knock on wood* only thing that has happened is that I have broken 2 spokes.

Incredible traction though! or atleast I experienced significant improvements in the desert running such low pressure.
I only run the pressures you are on my dedicated two stroke dirt bike offroad. 11-12 lbs in most conditions in NorCal and a couple lbs higher in the desert with higher speeds. Thats a 225lb dirt bike with me at 230lbs with gear.

In the desert on a heavier thumper, I run 18lbs front and rear to avoid pinch flats. Thats rock, deep sand, whatever the desert throws at me and its more than enough traction on a 290lb bike.

I have NEVER broken a spoke. I have however bent the shit out of a number rims.

In picking the brain of a former pro Honda Baja racer in Catavina over beer one year, he told me 18lbs is what the top teams are running with tubes. Obviously lower with mousses now, but they are different animals.

Quote:
Originally Posted by ScottRNelson View Post
That is the air pressure that Honda recommends to run all the time for the XR650L. I like more when I'm riding the twisty roads.

Should I be concerned about running lower pressures if I'm going to be cruising at 90 mph for 20 minutes or more on country highways with big sweeping curves?
I always air back up on the pavement when I can. Even at 60-70 mph I start to chunk or tear knobs. Its only 45 miles between Viscaino and San Ignacio (pavement section in Baja), but thats enough to chunk or tear a knob in my experience. 28-30 lbs on pavement to save my knobs.

Its the heat generated. I dont claim to know the science of tires, heat, pavement, and speed...... but my experience has proven to me they chunk or tear fast even in the low 20's pressure. Closer to 30 saves them.

Quote:
Originally Posted by m0t0_ryder View Post
As mentioned (or inferred) by others that is way too low of pressure unless you are trying to extricate or traverse a very soft sandy section.
Especially with the combined bike and your weight.
Yeah, the traction will feel improved but the risk of bending a rim, pinch flatting or spinning the tire on the wheel (and thus pulling the stem off the tube) is much higher. Does the AT have rim lock(s)?

Normal pressure (for most tires) for the big ADV bikes would be between 28 - 34 front and 35 to 42 rear.
The above mentioned 22/22 is a good compromise in pressure as long as your not blasting rocky sections, or get surprised by "that rock".
It'll feel squirrelly on the hardpack/road though. That's why refilling upon return to pavement is a fairly common practice.

What tires are you running on your AT?
+++++ John knows his shit!

Just my experience and opinion, I'm no expert or pro. I also dont ride 500lb adventure bikes. Others may vary.
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