Running tires at the sidewall max PSI

[Tripped1]

Originally Posted by corndog67

No, goobers like you. There are conflicting stories on here about what to run. Some are pure bullshit, and probably dangerous on top of that. Which are which? So that makes all of them bullshit. Do what the manufacturers of the tires say. Not what some old guy had on his bike in the 50s. The same guy that thinks carbs are the way to go. And ignition points.



Not when it's conflicting bullshit. Could get somebody killed.

Call him a goober all you like but go pull the recommended pressures for pretty much ever common sport or hyper-sport tire and you will find a 10% difference between the manufacturer recommend hot and cold pressures. The 10% rule has been pushed by the tire guys at the track for at least 15 years that I can think of. Maybe before that but I was too young to give a shit. The guy next to me said set it like this and I listened.

Pretty much all of the tire makers say the same thing, for STREET use follow the bike maker's recommendation for pressure i.e. it doesn't matter.

For track use they are much more specific, and it varies wildly for example the recommended cold pressures on my Diablo Rosso Corsas is 26f/28r 29/31 hot Dunlop Q2s want significantly higher pressure at ~32 front and rear as a start, guess what the teller is......10%

Now would I run max PSI settings? I certainly have, I used to run 35,000+ miles a year on roads that had surface temperatures in the 160* range, so yeah, I didn't want any excess heat for commuting. I'd just air them down when I went anywhere with a corner. I've also set the tire pressures high as hell because I was running two up on a loaded down 850lbs bike and a little napkin math said that I was going to be pretty close to the load rating.

[LilGreenBooger]

Air your tires to get the desired handling depending on terrain and load. too squirrelly on road? air them up. too squirrelly off road? air them down.

it's your bike, it's your ride, and your bike, load and ride are different than everyone else's, so adjust your pressure accordingly.

[anotherguy]

I run 41R/35F on the Tuono all the time. There's no need to run track day pressures riding to work or even on strafing runs on my favorite mountain roads. If I need the extra grip slowing down is a good idea.

[390beretta]

Motoghost in Phoenix, my favorite BMW mechanical shop recommends running ROAD tires at 2psi less than the max load pressure on the tire, especially in Summer. They have several tires in their showroom that have failed due to excessive heat caused by running too low pressure along with a chart indicating how much hotter your tires run AT SPEED, with increments of only 2 pounds less pressure. The Phoenix Police Dept. runs their moto tires at Maximum pressure. I know this is not a universally popular practice, but I will continue to follow it. A tire that is being run AT SPEED, let's say 70-90 mph for extended periods and which is 7-10 psi under inflated, will eventually reach nearly the same temperature as when it comes out of the mold.....especially when the ambient temp is 100 degrees plus and the road surface is quite a bit hotter. I think motorcycle tires are one of the least understood and most neglected parts of a bike by many riders.

[BanjoBoy]

Originally Posted by Barry

I read one post only. The first one. The answer is the sidewall PSI is the max for the TIRE. Period. It is Not the appropriate PSI for all motorcycles and load that the tire will fit on. If you are going by the sidewall, you are an idiot.

Public Service Announcement - the above response is accurate, but fueled by Vodka.

Barry

Purdie much ^THIS^
I gotz an FJR which I run 43R/41F on PRIIs, and I have enough grip ta get ta the edge of the tires, & drag pegs.
I run the same size tires/rims on mah little FZ6 dirtbike, butt I run much lower pressures 36R/34F (And I'm still experimenting) cuz the bike weighs much less. I do run higher pressures (I'm gonna die!!!!) than most to get better tire life, 'n it actually makes the big pig feel "lighter.".
It all depends on the bike, the weight, the power, the kind of tires, the rider, the roads, 2 up w/ gear; common sense goes a long way with this shit. Don't listen ta anythang "track guys" do, (Unless yer ride'in on the track) cuz the street is a whole 'nother world. The roads 'round here are much shitier than the tracks 'round here.

[the Pheasant]

Inspired by this thread, I checked the rubber on my Yam 900 Diversion - Bridgestone Battlax BT021s. The rear says that maximum load is (x) lb at 42psi, which ties in with what has been noted here previously; that what is stated in this way is not the maximum pressure the tyre will take, but the pressure at which it can support its maximum load - presumably at up to its maximum rated speed.
Since the pressure in the rear tyre after a period of high-speed riding will be around 10percent higher than 42psi, this cannot be its maximum pressure rating. FWIW, cycle tyres have a max. pressure rating moulded on the sidewall, but that's 'cos a narrow clincher inflated to 160psi might either blow clean off the rim or, if the rim is worn, break the rim by cracking the sidewalls away at the braking surface. It is invariably way higher than the highest recommended riding pressure.
I run 36/42 on the Diversion in all circumstances. The manual says this is right for for two-up and high-speed riding and says 33/36 otherwise but, since I never know when I might venture onto a fast stretch of road, I prefer to stick with 36/42 day-to-day.
In any case, there's enough grip in the dry to scrape the footpeg hero blobs and reach the edge of the rear tyre tread. Also, the higher pressure reduces the bike's tendency to self-steer in road depressions. For solo riding I have tried 33/36 and 37/43 pressures and even some in between; why not experiment a bit to find the exact pressure that suits?
Off-road? Yup, I air-down, albeit not as much as some suggest here but that's 'cos I hate the idea of a pinch flat. Still makes a big difference to grip.

[randyo]

Originally Posted by PT Rider

The tire sidewall in the pic does give the max pressure for that tire. It is the minimum pressure required to carry the max load that tire can carry, according to the Federal Motor Vehicle Safety Standard 119.
http://www.gpo.gov/fdsys/pkg/CFR-199...-119-id524.xml

Here's Avon's inflation pressure recommendations:
http://www.avonmoto.com/tech/tire-pressure-guidelines

Here's Metzeler's blurb:
" ...Over inflation or extreme tire pressure will impair your riding comfort and decrease the size of the contact patch of the tire with the road....You will find the correct pressure in the operating manual of the motorcycle."
http://www.metzeler.com/site/us/tech...intenance.html

James Davis writes some very good, very important stuff, then he writes some stuff that is just goofy. As others have said, try to reason with him at your own peril.

no, the tire does NOT give the max pressure, it give max load rating and the pressure that is necessary to acheive max load but nowhere does it say that its also max air pressure

nor does the federal regulation require or say anything about max air pressure, only max load and the corresponding pressure that supports max load

(d) The maximum load rating and corresponding inflation pressure of the tire, shown as follows:
(MARK ON TIRES RATED FOR SINGLE AND DUAL LOAD): MAX LOAD SINGLE XXKG (XXLB) AT XXKPA (XXPSI) COLD. MAX LOAD DUAL XXKG (XXLB) AT XXKPA (XXPSI) COLD.
(MARK ON TIRES RATED ONLY FOR SINGLE LOAD): MAX LOAD XXKG (XXLB) AT XXKPA (XXPSI) COLD.

further I am apalled at Metzlers blurb when I questioned Metzlers own recommendation to run a Karoo T at 41psi on the rear of a V-strom when the sidewall psi is only 35 for max load