ADVrider

Go Back   ADVrider > Riding > The perfect line and other riding myths
User Name
Password
Register Inmates Photos Site Rules Search Today's Posts Mark Forums Read

Reply
 
Thread Tools Search this Thread Display Modes
Old 04-13-2015, 04:22 AM   #1
MichaelJ OP
Beastly Adventurer
 
MichaelJ's Avatar
 
Joined: Jul 2003
Location: Sterling, Virginia, USA
Oddometer: 2,369
Reducing tire pressure - how much?

The title pretty much sums it up.

I know that one should reduce tire pressure when riding on loose surfaces, but by how much?

The bikes in question are a DL1000 and a Tiger Explorer. Both big, heavy and set up for touring with cast wheels & tubeless tires - usually either Anakees or Tourances.

The bikes are primarily (98%?) pavement, but I do like the occasional foray onto dirt roads - of varying surface quality. It's been 45 years since I've done any serious dirt riding and I wasn't all than good at it then.

TIA for any wisdom.
__________________
Michael J. - IBA #3901
Ten years in the Alps (so far)
Alpine Trip Reports: 2006, 2007, 2009
Pictures, pictures and more pictures
MichaelJ is offline   Reply With Quote
Old 04-13-2015, 05:10 AM   #2
windblown101
Studly Adventurer
 
Joined: May 2010
Location: Star Tannery, VA
Oddometer: 914
For dirt roads I wouldn't bother reducing pressure. Like you said: Big heavy bikes with cast wheels, and 98% on-road use.

Not saying you couldn't take a little pressure off. However having damaged cast wheels off-road on heavy bikes I lean towards protecting the rims over the slight increase in traction achieved by airing down a street tire.

YMMV. :)

Edit to add: However I rarely run max pressure in my street tires. If you tend to run 40+ lbs of pressure you could certainly take it down a bit if you wanted without undue risk to the rims.
windblown101 is offline   Reply With Quote
Old 04-13-2015, 08:41 AM   #3
MichaelJ OP
Beastly Adventurer
 
MichaelJ's Avatar
 
Joined: Jul 2003
Location: Sterling, Virginia, USA
Oddometer: 2,369
Quote:
Originally Posted by windblown101 View Post
Edit to add: However I rarely run max pressure in my street tires. If you tend to run 40+ lbs of pressure you could certainly take it down a bit if you wanted without undue risk to the rims.
38/42. Bike, 250 (or so) lbs of me plus luggage.

This sort of road (this is one of the better sections):

__________________
Michael J. - IBA #3901
Ten years in the Alps (so far)
Alpine Trip Reports: 2006, 2007, 2009
Pictures, pictures and more pictures
MichaelJ is offline   Reply With Quote
Old 04-13-2015, 08:48 AM   #4
Pecha72
Beastly Adventurer
 
Joined: May 2008
Location: Helsinki, Finland
Oddometer: 4,180
Quote:
Originally Posted by windblown101 View Post
Big heavy bikes with cast wheels
....should not really be run on lower tyre pressures, unless you want to damage those wheels. DL1K and TEX are basically road bikes.

Actually this is how the stories of how the "wheels were made out of cheese" mostly come from (not all, but many): Air down, then ride stupid fast onto some rocks with a big load on board, then blame the equipment
__________________
Countries ridden FIN SWE NOR DK EE LV LT POL SK HU RO BG GR IT AT DE CZ CH SMR LIE NL BE FR AND ES GBR LUX SI HR BIH SRB MK TR IR PAK IND TH KH LA MY ID AUS CR USA ZA LS SWZ MZ NA BW ZM ZW
Pecha72 is online now   Reply With Quote
Old 04-13-2015, 09:44 AM   #5
MichaelJ OP
Beastly Adventurer
 
MichaelJ's Avatar
 
Joined: Jul 2003
Location: Sterling, Virginia, USA
Oddometer: 2,369
Thanks, guys. The "stupid fast" part wouldn't apply to me - more of a "just fast enough not to fall over" speed.

But yeah - the rest does apply. I may drop them by 5psi after I see if I have any issues at "normal" pressure. I carry a compressor, so it's not much of a hassle going back.
__________________
Michael J. - IBA #3901
Ten years in the Alps (so far)
Alpine Trip Reports: 2006, 2007, 2009
Pictures, pictures and more pictures
MichaelJ is offline   Reply With Quote
Old 04-14-2015, 02:52 AM   #6
Jud
Beastly Adventurer
 
Jud's Avatar
 
Joined: Dec 2007
Location: N.E. Ga. USA
Oddometer: 2,454
I've rode a lot of dirt road mileage on heavy bikes. My first "adv" bike was a FJR1300 which has probably done close to around a thousand miles of off tarmac riding from Alaska to Baja.




My fairly well modded DL650 has probably done much more, everything from Canadian dirt roads including the Trans Lab to sugar sand in S. Ga. and Florida and the rough, rutted and sometimes rocky forest roads in my local N. Ga. area.



Off tarmac in the Keys-

Even found a good bit of dirt in Hawaii-

The Tenere hasn't seen near as much dirt as the other two but that's because I just bought it in January of this year. Even so, the 600 mile ride home included at around 50 miles of N. Ga. forestry roads then immediately went south to Mexico and while in Texas and in Mexico I hit a lot of sand and mud {that brand new bike looked like pure hell with-in 3 days of buying it!}.


I have bent two front wheels on my DL650, never a rear. One time was just riding rough, rutted and rocky sections at times probably ridden too fast. That was just a small bend that I pretty much fixed with a hammer and a 2x4. The second actually happen on tarmac when I came hauling ass around a corner to find a limb about ten inches in diameter. I was not aired down either time. I would not advise airing down too much with a big heavy bike with cast wheels in rocky stuff.

If it's muddy or sandy,,,, air down. In Baja with me on my FJR and my friend on his GSXR,,,, we aired down big time when we hit the sandy sections. If memory serves, I was running something like 15-20lbs in the front and around 10-15lbs in the rear. We pumped back up to the low to middlin 30s when we hit the rocky stuff. Roughly the same on my DL650 when on the Trans Lab and in sugar sand down south.

I have not aired down the Tenere not once but if I hit a lot of sand I will.
__________________
Pics- http://s563.photobucket.com/albums/s...eon/?start=all
Places visited on two- http://s563.photobucket.com/albums/s...0two%20wheels/
Endeavor to Persevere
Blue Skies Coming
Jud is offline   Reply With Quote
Old 04-14-2015, 09:12 AM   #7
scottrnelson
Team Orange
 
scottrnelson's Avatar
 
Joined: Apr 2006
Location: Folsom, CA
Oddometer: 1,496
I'll drop the tire pressure on my KTM down to about 20 psi for loose stuff and it helps quite a bit.

On the XR650L I'll go as low as 15 for tight trails and stuff. Anything less and you'll need rim locks - you might even be pushing your luck at 15 psi.

Even with full pressure you can still pinch a tube if you hit a rock just right. I ran over a rock on the road on my KTM at about 50 mph and had a flat front tire a few seconds later. I was very lucky to keep it upright and stopped without running off the road.

Lower tire pressure helps with traction on loose dirt and rocks.
__________________
__Scott R. Nelson, 2008 KTM 990 Adventure, 2001 Honda XR650L, Folsom, CA
scottrnelson is offline   Reply With Quote
Old 04-14-2015, 09:52 AM   #8
MichaelJ OP
Beastly Adventurer
 
MichaelJ's Avatar
 
Joined: Jul 2003
Location: Sterling, Virginia, USA
Oddometer: 2,369
Quote:
Originally Posted by scottrnelson View Post
Even with full pressure you can still pinch a tube...
Tube? Whazzat?
__________________
Michael J. - IBA #3901
Ten years in the Alps (so far)
Alpine Trip Reports: 2006, 2007, 2009
Pictures, pictures and more pictures
MichaelJ is offline   Reply With Quote
Old 04-14-2015, 09:53 AM   #9
scottrnelson
Team Orange
 
scottrnelson's Avatar
 
Joined: Apr 2006
Location: Folsom, CA
Oddometer: 1,496
Quote:
Originally Posted by MichaelJ View Post
Tube? Whazzat?
You must ride a BMW or something.
__________________
__Scott R. Nelson, 2008 KTM 990 Adventure, 2001 Honda XR650L, Folsom, CA
scottrnelson is offline   Reply With Quote
Old 04-16-2015, 08:47 AM   #10
markk53
jack of all trades...
 
markk53's Avatar
 
Joined: Dec 2007
Location: Delaware Ohio
Oddometer: 8,900
Just start letting some air out...


A bit more...



wait, wait, wait...



STOP!

That's perfect.
__________________
Ever get lost? You know, that good kind of lost - come to a dirt road intersection and you have no idea where you are or which way to turn? I like when that happens!

Mark - klx678
95 KLX650C w/Vulcan piston bigbore, Now an 09 KLX250S, selling my 90 Zephyr 550
markk53 is offline   Reply With Quote
Old 04-16-2015, 10:49 AM   #11
Sparrowhawk
Beastly Adventurer
 
Sparrowhawk's Avatar
 
Joined: Sep 2005
Location: Eastern Washington, USA
Oddometer: 2,233
As Scott mentioned, 20 psi is a good starting point for heavier bikes off pavement and 15 psi for a big thumper.

That's a starting point and will work well at moderate speeds in most conditions. If you are riding over large, sharp edged rocks, carrying a big load or two up, or riding faster than, say 30 mph, you would be well served to add another 5 psi of pressure.

Lowering pressure makes a bike way more controllable. Carry a mountain bike hand pump to air back up when the dirt ends or bring an electric one if your a wuss.
Sparrowhawk is offline   Reply With Quote
Old 04-16-2015, 11:25 AM   #12
eatpasta
Lawnmower Target
 
eatpasta's Avatar
 
Joined: Jul 2006
Location: Santa Barbara, Ca
Oddometer: 10,851
Holy shit - is this the road from San Felipe through Coco's Corner back to the main highway??



even if not - respect!!



I have an FJR and I've done that road on an 1150GS - I wouldnt want to do it on an FJR.....




as far as airing down goes, personally I never did it on my big bikes. Honestly, I dont really think it helps much. You're not going to get that much more grip and popping a bead out in the middle of nowhere doesn't sound like too much fun. Plus how fast are you really going to be going anyways?
On Dirtbikes I always run relatively low pressure though....
__________________
We shall not cease from exploration, and the end of all our exploring will be to arrive where we started and know the place for the first time.
T. S. Eliot
Quote:
Originally Posted by Burnszilla
I was SO high, I could have hunted duck with a rake
Quote:
Originally Posted by VxZeroKnots View Post
MX stuff isn't my cup of tea, but falling down the side of a mountain is
eatpasta is offline   Reply With Quote
Old 04-16-2015, 01:08 PM   #13
scottrnelson
Team Orange
 
scottrnelson's Avatar
 
Joined: Apr 2006
Location: Folsom, CA
Oddometer: 1,496
Quote:
Originally Posted by eatpasta View Post
as far as airing down goes, personally I never did it on my big bikes. Honestly, I dont really think it helps much. You're not going to get that much more grip and popping a bead out in the middle of nowhere doesn't sound like too much fun. Plus how fast are you really going to be going anyways?
On Dirtbikes I always run relatively low pressure though....
On the dirt roads in the Sierras it makes a significant difference in how my KTM steers.

After coming through this road I dropped the pressure and immediately noticed a big improvement.
__________________
__Scott R. Nelson, 2008 KTM 990 Adventure, 2001 Honda XR650L, Folsom, CA
scottrnelson is offline   Reply With Quote
Old 04-16-2015, 01:35 PM   #14
eatpasta
Lawnmower Target
 
eatpasta's Avatar
 
Joined: Jul 2006
Location: Santa Barbara, Ca
Oddometer: 10,851
Quote:
Originally Posted by scottrnelson View Post
On the dirt roads in the Sierras it makes a significant difference in how my KTM steers.

After coming through this road I dropped the pressure and immediately noticed a big improvement.
the 950/990 doesnt count



that bike shouldnt be able to do about 1/2 the things that it does...someday Id love to have one. More importantly I would like to have a reason to have one...
__________________
We shall not cease from exploration, and the end of all our exploring will be to arrive where we started and know the place for the first time.
T. S. Eliot
Quote:
Originally Posted by Burnszilla
I was SO high, I could have hunted duck with a rake
Quote:
Originally Posted by VxZeroKnots View Post
MX stuff isn't my cup of tea, but falling down the side of a mountain is
eatpasta is offline   Reply With Quote
Old 04-16-2015, 01:44 PM   #15
scottrnelson
Team Orange
 
scottrnelson's Avatar
 
Joined: Apr 2006
Location: Folsom, CA
Oddometer: 1,496
Quote:
Originally Posted by eatpasta View Post
the 950/990 doesnt count



that bike shouldnt be able to do about 1/2 the things that it does...someday Id love to have one. More importantly I would like to have a reason to have one...
I bought mine because I took a test ride on it. I didn't have to go far before I moved it to the top of my list of next bikes to own. I was instantly thinking "I need to get me one of these!"

It's a great bike for everything except when you need a lighter/smaller bike. Riding twisty roads, going long distances on the freeway, most dirt. I've almost never regretted buying it.
__________________
__Scott R. Nelson, 2008 KTM 990 Adventure, 2001 Honda XR650L, Folsom, CA
scottrnelson is offline   Reply With Quote
Reply

Share

Thread Tools Search this Thread
Search this Thread:

.
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On

Forum Jump


Times are GMT -7.   It's 11:39 AM.


Powered by vBulletin® Version 3.8.5
Copyright ©2000 - 2015, Jelsoft Enterprises Ltd.
Copyright ADVrider 2011-2015