Determaning best ct tire pressure

A concern came up about me using too low pressure in my CT on my Bike by 00 Doc.
I gave a simple answer but I did just drop it.
I started reading more and more and yes; I need to be on the bike more.

1. Long story short, how does a Manufacturer determine tire pressure on any vehicle?
Total vehicle weight dived by 100. I.e. (2576 lbs Miata comes out to 26 psi + or – 4 psi.)
If I do that on my Stryker, it would be 6.5 psi. Obviously that will not work.

2. Another engineer’s tire forum addresses targeted heat and pressure on racecars.
The engineer’s again say each tire and track is different. But they are doing what I have been doing and that is run the tire to a set pressure and Temperature and bleed it down” hot”.

3. I “didn’t” find the definitive answer here either and maybe someone can help.
“Standard Tire Pressure” I read is, between 20 psi and 44psi. Does this mean most tires can run these pressures?

Now on a mc we are pretty much on our own here.
Ok here is what I do, I determine the footprint of the tire, I then see how well it rides, and adjust the pressure “Hot” to the best handling and most footprint. I also have been using a infrared pyrometer to check the outside temperature of the tread after about a half hours usage.
Again, increase weight increase pressure. Yes then you can throw into the mix sidewall stiffness.
Right now, I am running 26 psi with a targeted hot temperature of 30 psi, on a Tire with a stiffer sidewall, and it is doing well. Towards the middle of the summer, I will bleed it down Hot more if needed.
A different tire I would have to start all over, this even true on a car.

I drove truck for 25 years and I don't care what the air pressure is as long as the tire stays at the right temperature. To cool and you don't get max traction or wear, to hot and you lose the tire(see all the blown tire rubber on the road) or when it gets to hot you lose a lot of traction.
As for race cars they go by the temperature of the tire and they adjust the temperature of the tire by adding or subtracting the air pressure in the tire. Every time a tire comes off a race car they check the temperature of the tire at multiple spots across the face of the tire.

I run the rear tire at around 120* at the tread and that is 36 psi for my 175/75-16 tire.

ROD

Isn't the temperature also determined by the tire itself, the rubber compounds used and by the temperature of the individual tire handling characteristics?
Doesn’t a race tire use extremely sticky compounds that we would not get on tires like All Season Radials? Again, track tires, drag tires.
What size is the tire you are using, how does the temperature relate to the ridden footprint, or tread width.
On my BFGoodrich radial TA, I tested it at 104 degrees ambient temp. and it was 138 degrees at the tread with air at 32 psi. My wear pattern was flat. My tire was a small 175/80-15.( this tire is not made anymore) I am trying to remember if it was 120-125 degrees when ambient was around 75 degrees.
I have to get a new pyrometer and see what this new tire is running at.
Got back with a new Pyrometer and 67 ambient I got 97 degrees on the tire with it being 30 psi "hot".
Do you think it should run lower pressure to increase the heat?

I think manufacturer's suggested pressures have nothing whatsoever to do with our application. I'd like to agree with Mr. Rounds assessment, but
that only goes a short ways as well, being as we're not on race tires, nor racing nonstop for the most part. But yeah, you don't want that sucker heating
up too much - my 175/75/16 running 36 lbs. on hot Georgia asphalt with a load usually only gets to 114-120 degrees F. I'd say that is a GOOD thing.

Barring all that, the 2 methods I prefer are first to try different pressures, looking for the point where it wallows (too low) and tracks (too high). Your
sweet spot is directly between these two. Being solo or 2up seems not to make any difference on my black balloon back there.

Temperature be hanged unless it's too hot.

edit: forgot to put the other method in: riding away from the sun, with a friend following. Hit some sweepers and friend tells you when you have half the tire contacting.

Right now the tire I am trying to find the "sweet spot" (good term) is a 225/45-18.

You should be able to run a lot less air pressure than I do, first because your sidewall is a lot stiffer than mine and the second is, I most likely put more weight on my rear tire than most do. My wife and I weigh about 480 geared up.

ROD

Oh one more thing, I would not want a street tire to get hotter than around 175*F. On my BiL's race car, his tires would be 200*F to 215*F when he came off of the track, any hotter and the road racing slicks would lose traction, but he had to get them up over 150*F before he could go balls to the wall.
On my 18 wheeler I would take my hand and touch each tire and could tell by the temp if I had a tire that was low. My hand was way better at telling me if I had a low tire than my bump bar(a short bar that you hit the tire with and listen to the sound it made).

ROD

I did get to the sweet spot on my tire and it was not any thing to do with my reasoning and going lower in pressure. I reread an earlier recommendation a darksider here named “Darkfury” and he was spot on for this tire. I needed to increase my pressure to 41 psi. The high-speed handling was phenomenal and the rut chasing disappeared. The tire heat is completely lower, after a half hour of high speed running I only saw 78 degrees and pressure only went up to 42 psi. Anything that I tried made it worse especially lowering pressure on this wide tire.
This is shacking up anything I have read on tires and inflations when it comes to MC on bikes. It seems what works on one bike and its tire load and anther bike, which is a different load and tire, are all different pressures and temps.

saber wrote:I did get to the sweet spot on my tire and it was not any thing to do with my reasoning and going lower in pressure. I reread an earlier recommendation a darksider here named “Darkfury” and he was spot on for this tire. I needed to increase my pressure to 41 psi. The high-speed handling was phenomenal and the rut chasing disappeared. The tire heat is completely lower, after a half hour of high speed running I only saw 78 degrees and pressure only went up to 42 psi. Anything that I tried made it worse especially lowering pressure on this wide tire.
This is shacking up anything I have read on tires and inflations when it comes to MC on bikes. It seems what works on one bike and its tire load and anther bike, which is a different load and tire, are all different pressures and temps.

Awesome! Glad something I said could help.

Huh? Wadjoo say?

I told him to say that....

I'm going riding.
Thanks all.