what I learned about tire pressure





WWJD

Donating Member
Registered
#1
Track days. Can't beat them. Yeah, yeah, they seem expensive at first but the money stops mattering after your first one. I am almost completely done riding on the street. My eyes are now opened to the real dangers of traffic and all that, but that is not what this thread is about.

TIRE PRESSURE! Check it daily. If ya don't you could get lucky.... so why not just remove LUCK from the equasion? you gotta let your engine warm up first thing anyway, right? RIGHT? A couple minutes of warmup of the engine is perfect time to check your tire pressure.

For the n00bs: stock busa recommends 42 front and rear. And that works most of the time. But if you wonder how rossi, hayden and the rest do it, well, they have super special super stickie tires with tire warmers and you can't run those compounds on the street... effectively. Frist trackday, I learned to lower my PSI to 30 - tires heat up and PSI goes to 34-35 range. still less than 42, bigger contact patch, more rubber getting heated up and stickie due to all those rotating contortions. Great. I run 36 on the street usually, and although the turning feels a little heavier, it's awesome at speed and feels planted.

But what to do what it's cold out? Well, I'm rattling on so I can share my recent experiences on that topic. Cold day at the track. Here's how it went:

It was cold maybe 40s- 50s like, and I lowered my tires to 30 like normal thinking okay they wil heat up fine in a few laps. Nope. I grannied them too much and they only went up 2 PSI. AND the track was cold, tires were not heating up, I felt some ugly sliding happening and was not pleased. So I lowered them to 27 in hopes that would make them heat up a little better, giving me some grip, and increasing the PSI a tad. only went up about 2 again and grip was no better. I sat out a session and messed around on the computer thinking the tires would drop back down to 27 and maybe that is the best I can do on this crappy day. I checked the PSI before the next session and they had DROPPED to 26!! Maybe cuz it was getting colder as the day progressed. Anywho, I thought, screw it, let's give it a shot and hit the track.

It was almost dangerously low for me. The bike took on a brand new experience that must be similar to having a flat. It pushed to the outside of EVERY turn and and that is scarey on a slick track! I backed off and went in after only 3 laps. It sucked! Now I know what the lowest limits if PSI I should run on a twistie track - and I would NEVER run that on bumpy standard roads - track surface is very different, smoother, a lot more trust worthy.

I bumped them up to 32 and my busa went back to railing on the turns and feeling much more planted. I don't know what I was thinking, but it was a great learning experience I wanted to pass on

Anywho, I don't recommend it. Unless you are going in a strait line on a drag strip. That's completely different

42 - high speed, long touring, high way, commuting
36 - having fun on any surface, heating up and sticking
30 - trackdays

you mileage may very

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#2
Yeah whatever. I call BS on anyone that thinks they can out think the multitude of engineers of a huge multinational corporation with no empiraical data. It's always some subjective, qualitative argument which means zero without data. And yet no one can ever provide any data to support a claim. Oh wait I got it. maybe all those engineers of those big companies with huge R&D budgets are just trying to trick us normal guys. bah!
 

Tufbusa

Track Coach / TufPoodle Coach
Registered
#3
(psalm69 @ Sep. 28 2006,20:14) Yeah whatever. I call BS on anyone that thinks they can out think the multitude of engineers of a huge multinational corporation with no empiraical data. It's always some subjective, qualitative argument which means zero without data. And yet no one can ever provide any data to support a claim. Oh wait I got it. maybe all those engineers of those big companies with huge R&D budgets are just trying to trick us normal guys. bah!
And your point is?
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Shibumi

Donating Member
Registered
#4
(psalm69 @ Sep. 28 2006,22:14) Yeah whatever. I call BS on anyone that thinks they can out think the multitude of engineers of a huge multinational corporation with no empiraical data. It's always some subjective, qualitative argument which means zero without data. And yet no one can ever provide any data to support a claim. Oh wait I got it. maybe all those engineers of those big companies with huge R&D budgets are just trying to trick us normal guys. bah!
So I take it that you are disagreeing with WWJD, who actually takes his bike out on a track and finds out the result of differing pressures on cornering? If so, have you taken yours to the track to verify/refute the results, or are you just disagreeing based on ignorance?
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Jet Li

What is the AWESOME????
Donating Member
Registered
#5
Thanks for the low down WWJD. I should have lowered my pressure last weekend at the gap.
 
#6
Used to run adjustable bleeders on the oval cars. You can set the tires to the desired pressure when cold & do not have to worry about track temps or the # of laps you are running. Install them 180* from the tire valve. Installation requires drilling the wheel.
 

WWJD

Donating Member
Registered
#7
Engineers? I never found riding at the track. I'll look harder next time, and consult him when I find him. Until then, I'll listen to the droves of multi-year experienced track riders, racers, instructors and professionals. They'll have to do in a pinch.
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My numbers are by NO MEANS the ULTIMATE for everybody. They work for me. Any many people have no idea they can and should lower their PSI for better grip at hard lean. You COULD stay upright just fine at 42, but why not tilt the odds in your favor? My mian point was TOO LOW gets weird. I never experienced it before, now I have, so I'm passing it on

There's the whole "Nitrogen filled" thing where the tire pressure doesn't change from heat... but I'm not that sophisticated
 

vman1300

Never Forgotten
#9
I might have missed it but what tires were you running?

Great points and I learned alot last November at Road Atlanta, temps in the 30's for the 1st two sessions.
 
#10
(WWJD @ Sep. 29 2006,05:28) Engineers?  I never found riding at the track.  I'll look harder next time, and consult him when I find him.   Until then, I'll listen to the droves of multi-year experienced track riders, racers, instructors and professionals.  They'll have to do in a pinch.  
smile.gif


My numbers are by NO MEANS the ULTIMATE for everybody.  They work for me.  Any many people have no idea they can and should lower their PSI for better grip at hard lean.  You COULD stay upright just fine at 42, but why not tilt the odds in your favor?  My mian point was TOO LOW gets weird.  I never experienced it before, now I have, so I'm passing it on

There's the whole "Nitrogen filled" thing where the tire pressure doesn't change from heat... but I'm not that sophisticated
Nitrogen won't change pressure in spite of temperature? WTF? I'm not sure what planet you are living on, but clearly the physics there don't apply. Consult your clearly unused highschool chemistry book for the answer to that one. Let me give you a hint it's called Charles' law. The only reason N2 is used in tires to to prevent a moisture build up from condensation thereby negating any balance problems at high speeds or in the case of aircraft to prevent unwanted corrosion. You clearly do not know what you are talking about. It is that kind of misinformation that gets guys hurt. No you really aren't that sophisticated.

My point? Unless you have data that backs up an assertion it is just an opinion. Don't present it for more than it is.
 

TIMMYDUCK

Head Woodchuck
Donating Member
Registered
#11
I run Pilot Powers at the track.
28lbs up front and 30lbs out back works great for me.
Plus they have that fancy nitrogen to load them with courtesy of Moto-X.
 
#12
(psalm69 @ Sep. 29 2006,10:40)
(WWJD @ Sep. 29 2006,05:28) Engineers?  I never found riding at the track.  I'll look harder next time, and consult him when I find him.   Until then, I'll listen to the droves of multi-year experienced track riders, racers, instructors and professionals.  They'll have to do in a pinch.  
smile.gif


My numbers are by NO MEANS the ULTIMATE for everybody.  They work for me.  Any many people have no idea they can and should lower their PSI for better grip at hard lean.  You COULD stay upright just fine at 42, but why not tilt the odds in your favor?  My mian point was TOO LOW gets weird.  I never experienced it before, now I have, so I'm passing it on

There's the whole "Nitrogen filled" thing where the tire pressure doesn't change from heat... but I'm not that sophisticated
Nitrogen won't change pressure in spite of temperature? WTF? I'm not sure what planet you are living on, but clearly the physics there don't apply. Consult your clearly unused highschool chemistry book for the answer to that one. Let me give you a hint it's called Charles' law. The only reason N2 is used in tires to to prevent a moisture build up from condensation thereby negating any balance problems at high speeds or in the case of aircraft to prevent unwanted corrosion. You clearly do not know what you are talking about. It is that kind of misinformation that gets guys hurt. No you really aren't that sophisticated.

My point? Unless you have data that backs up an assertion it is just an opinion. Don't present it for more than it is.

and stop the
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fasttoys1

Donating Member
Registered
#13
I believe WWJD was posting something he noticed and what seemed to work for him in his opinion. I like seeing what everyone does and what they find when they do it. This is a place to exchange info. I like to take all the info., make a reasonable deduction of what seems to work and build on that. PS I see and have worked with way too many highly payed engineers who couldn't figure out how a paper clip works. Not all of them, but more than you'ld think. Thanks WWJD I've been running 37-38. It does feel a little dungy at 1st but very positive at speed esp. on those roads of ? pavements.
 

Sloto200

Off we go, into the wild blue yonder...
Donating Member
Registered
#14
(psalm69 @ Sep. 29 2006,10:40)
(WWJD @ Sep. 29 2006,05:28) Engineers?  I never found riding at the track.  I'll look harder next time, and consult him when I find him.   Until then, I'll listen to the droves of multi-year experienced track riders, racers, instructors and professionals.  They'll have to do in a pinch.  
smile.gif


My numbers are by NO MEANS the ULTIMATE for everybody.  They work for me.  Any many people have no idea they can and should lower their PSI for better grip at hard lean.  You COULD stay upright just fine at 42, but why not tilt the odds in your favor?  My mian point was TOO LOW gets weird.  I never experienced it before, now I have, so I'm passing it on

There's the whole "Nitrogen filled" thing where the tire pressure doesn't change from heat... but I'm not that sophisticated
Nitrogen won't change pressure in spite of temperature? WTF? I'm not sure what planet you are living on, but clearly the physics there don't apply. Consult your clearly unused highschool chemistry book for the answer to that one. Let me give you a hint it's called Charles' law. The only reason N2 is used in tires to to prevent a moisture build up from condensation thereby negating any balance problems at high speeds or in the case of aircraft to prevent unwanted corrosion. You clearly do not know what you are talking about. It is that kind of misinformation that gets guys hurt. No you really aren't that sophisticated.

My point? Unless you have data that backs up an assertion it is just an opinion. Don't present it for more than it is.
Nothing like getting on the board and flaming someone for sharing their experience with others so that they might learn something from it. It was something that WWJD tried and worked for him. Did he say that this is what everyone needs to do when at the track or riding on the street? I must have missed that part, but me and the rest of us surely didnt miss yours...
 

Tufbusa

Track Coach / TufPoodle Coach
Registered
#15
(psalm69 @ Sep. 29 2006,08:40)
(WWJD @ Sep. 29 2006,05:28) Engineers?  I never found riding at the track.  I'll look harder next time, and consult him when I find him.   Until then, I'll listen to the droves of multi-year experienced track riders, racers, instructors and professionals.  They'll have to do in a pinch.  
smile.gif


My numbers are by NO MEANS the ULTIMATE for everybody.  They work for me.  Any many people have no idea they can and should lower their PSI for better grip at hard lean.  You COULD stay upright just fine at 42, but why not tilt the odds in your favor?  My mian point was TOO LOW gets weird.  I never experienced it before, now I have, so I'm passing it on

There's the whole "Nitrogen filled" thing where the tire pressure doesn't change from heat... but I'm not that sophisticated
Nitrogen won't change pressure in spite of temperature? WTF? I'm not sure what planet you are living on, but clearly the physics there don't apply. Consult your clearly unused highschool chemistry book for the answer to that one. Let me give you a hint it's called Charles' law. The only reason N2 is used in tires to to prevent a moisture build up from condensation thereby negating any balance problems at high speeds or in the case of aircraft to prevent unwanted corrosion. You clearly do not know what you are talking about. It is that kind of misinformation that gets guys hurt. No you really aren't that sophisticated.

My point? Unless you have data that backs up an assertion it is just an opinion. Don't present it for more than it is.
OMG we have the infamous tire GURU (IamANerection) with us
bowdown.gif
He is very reluctant to share any of his profound knowledge but quick to criticise. We simply must team up and offer this genus of the motorcycle world large sums of money to give up the info only "HE"
has embedded in his gray matter!

I am making my donation of fifty cents! If all of you will participate with equal amounts, I'm sure we can get our money's worth?
 

mjn

Hillbilly Deluxe
Donating Member
Registered
#16
Wow PS69....way to intruduce yourself to the board. A whopping 80 posts and you are already flaming WWJD?

How much track time do you have? I recommend doing a bit more reading prior to climbing on you soapbox in the future.

WWJD, thanks for the additional insight.. I have played with several different pressures on the street and have come to find that, for my riding style, the 36lb area is indeed about the best on an average day.

Wish I had more time to spend on the track.......
 

tjdobb

Donating Member
Registered
#17
Maybe psalm69 is too smart for us dumb Busa riders on the board. I work with a lot of engineers in the highway building industry and a lot of them are very smart with no common sense. I will take advice from experience and common sense over book smarts any day. Thanks for the info WWJD, I will use it, along with all other sorts of non-educated but very rider experienced information that this board brings to share with us. Thanks again and good luck at you next track day.
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ozz

Donating Member
Registered
#18
good info WWJD Tufbusa, i wil donate a nickle...i would kick in with .50 but so far i havent even seen that much thats worth it
 

WWJD

Donating Member
Registered
#20
hahahahah this took an ugly detour didn't it? I posted this to share experience like everyone else here, and because when I started riding, NOBODY told me anything about tire pressure. I respect engineers a lot, but would definitely trust someone in the field USING the products more. Sounds like others are running around the 36 PSI on the streets. Maybe I'm on to something
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IN combining information, it's interesting to note the tires MAX PSI rating, the vehicles manufacturing reccomendation, and the tire makers recommendation for the vehicle. On my Metzeler M3s, max PSI is 42, Busa manual says 42, but Metzeler's website says 36. hmmmmm do you trust the vehicle maker or the maker Tires it's riding on? Who's engineers are right now?

p69, I have too much fun riding rather than gathering stats and documenting experiments. I hate accounting. Feel free to post up your finidings

Actually, I'll challenge you to go ahead and post up some FACTS proving that I stated anything that is wrong or dangerous to anybody.
 

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