What the heck, let's talk tire pressure....

[Harald]

I've never had TPMS on a bike, so haven't monitored temps. But I do know about temps from feel on my F350 hauling a very large truck camper.

Having extensively researched tire types and pressures to ensure i don't have a blow out with that rig, I learned a lot. Remember the Ford Explorer Firestone tire fiasco? Passenger car tires on those vehicles had recommended pressures from Ford that resulted in a cushy ride, but should have been higher. When people let the pressure drop too low, the excessive flexing of the underinflated tire caused it to get very hot and blow. It's a simple formula: less tire pressure results in more flex, which results in more heat, which results in higher pressures.

Passenger car tires usually have a MAX pressure on them and the recommended pressure is spec'd by the vehicle manufacturer based on vehicle weight and normal usage. When you're talking about larger pickup trucks, they usually have Light Truck tires installed that don't have a MAX pressure listed on the tire - they only list MAX load. You need to consult a tire inflation chart to set pressures based on loading on that axle. Many weigh stations near me leave their scales on when closed to allow you to pull in and check your weights by axle.

Sure, Ford puts a inflation chart in the door jamb but if you never haul a load in the bed of the truck you'll have less traction, more risk of damage when hitting potholes or rocks and poor wear if you follow that chart for your back tires. On the other hand, if you haul a huge camper with a single rear wheel (SRW) truck you better check the tire inflation table and set pressures based on the actual weight on that rear axle. Most SRW trucks with a big camper are probably overloading their rear tires and should bump up the pressure above the pressure listed for max load on the tire. I ran 90 psi in my SRW truck rears until I upgraded the truck to a dually for the safety of my family. The tires on that SRW truck would get pretty hot to the touch, but the dually spreads the load over 4 tires so no problems there.

I gotta wonder about the guy that keeps blowing tires. Perhaps he's got them pumped up so stiff with little load that they can't withstand hitting a pothole or debris on the road? Or he's buying tires that don't have enough capacity for his loading? Nobody can be that unlucky, can they?

[philharmonic]

Air is 79% nitrogen and 21% oxygen,

If I fill my tires with air to 40 psi and over time, all the 21% of oxygen leaks out, the pressure would then be around 32 psi. This wouldn't happen all at once, but a few PSI at a time.

If I put the lost 8 psi of air back in I would now have tires with about 4 % oxygen which seems to be OK even for airplanes. LOL

This would work out especially well for Car Tires, as they are on the bikes, or cars, for 2 or 3 times as long as MT's' and would have leaked out the oxygen and been reinflated more times.

Heck, maybe I need to suck out the "mostly nitrogen' gas out of my tires when I change them and then reintroduce it into my new tires.

Better yet, gas stations can get one of those freon sucking pumps and steal all the nitrogen out of everyones tires when they come to the shop for service or new tires and then sell it BACK to the customers for 8 bucks a tire.

I am going to be RICH!!!

[hillbilly]

Stuff, in no particular order:

Tire pressure changes at ~ 1 psi for every 10° of temperature change (motorcycle tires are considered light duty 30 - 50 psi tires so the 2% rule applies)

Tire pressure will change with the sun on the tires. Youse guys that change your own tires know the power of the sun.

Properly inflated tires will slowly drift up ~5 psi after ~ 20 minutes riding.

Tires with too little inflation will have temperature go up faster and higher than a properly inflated tire. A large temperature rise is an indication of an under inflated tire.

Inflate your tires to your preferred pressure before riding, riding just 5 minutes first will result in false pressure settings. If possible use the same pressure gauge so you get consistent settings.

Complicated Stuff (Phuck Charles & Boyle and their laws):

Tires filled with nitrogen will have a more stable tire pressure. A compressor with an air dryer will also allow stable tire pressures. Nitrogen is a 'dry' gas. Compressed air will have a lot of moisture entrained unless a dryer/desiccator is used. It is the moisture which contributes to tire pressure variation.

And, here is the space for FJRoss to correct/add to/ridicule my post: Begin:

Just to point out that the atmosphere is 78 percent nitrogen. You may be onto something with the moisture in compressed air though...

[Pterodactyl]

Spousal Unit and I both have new 2017 R1200GS/GSAs and they are the first bikes we have owned with TPMS. Watching tire pressure change is very interesting. I have yet to see a 5 PSI change. Typically it is around 2 PSI. On my bike the rear tire changes faster and to a greater degree and the front may not change at all.

[Powerman]

I'll buy nitrogen for planes, not for cars. The tire company tech expert at the road race track gave us a pressure correction chart for nitrogen vs compressed air, threw it in the trash with my ice cream wrapper. You have to pull the car off the track and quickly make multiple temp readings across the width of the tire. (wide ass slicks) Used nitrogen for air tools so we didn't bring a compressor for tires.

I think the correct fart gas is Unicorn farts, according to an Albanian study.

[Hppants]

Josh and I have learned why Hwy 341 in Arkansas is called Push Mountain Road.

Because as sure as I am typing this, that road is gonna push your tires to the limit!!!

[wheatonFJR]

Josh and I have learned why Hwy 341 in Arkansas is called Push Mountain Road.

Because as sure as I am typing this, that road is gonna push your tires to the limit!!!

If it doesn't grind your tire carcass off first.

[Festus]

Josh and I have learned why Hwy 341 in Arkansas is called Push Mountain Road.

Because as sure as I am typing this, that road is gonna push your tires to the limit!!!

If it doesn't grind your tire carcass off first.

Yeah, but to be fair, you left home with only the carcass

[raYzerman]

I never thought the AR roads were particularly grinding when I was there and I was pushing..... not the norm for sure but OK on my tars I thought...

[Poolboy2]

I go to Arkansas with new tires and I get home with junk tires. I set the psi when I leave home and they are junk when I get home. Maybe it's because I ride with Pants and Josh !!!!!!!

I go to Georgia with new Tires and come home with junk tires I think I'm starting to see a pattern here. Only took me 5 years to figure this out.

[SLK50]

The last time I went to Arkansas, I didn’t have enough
tire left to make it back home.
I had to replace a set of Angels with only 4,150 miles
on them.
Arkansas is pure evil. Stay away. You’ve been warned.

[wheatonFJR]

Yeah, all you guys wearing out tires probably have your tire pressures too low!

[Cav47]

Those of you that may recall, I had a nearly flat tire on Push Mountain the first time that I rode it. I thought something was wrong with the suspension the way my bike was acting (and not acting) Long story short, my rear had somewhere between 9-14psi in it. I bring this up to ponder what was the temperature in that tire after trying to ride it up and down Push Mt? I bet it was not good. Additionally, I think that tire handled okay once it was repaired and pumped back up. BUT, it never quite felt the same as I recall before. It was not long after that I began understanding the suspension was getting tired. Getting a new tire made it good. Getting a Penske made it even better. Getting a Gen 3 ES made it best.

That day chasing Allen, Joey, and Jonjon quite possibly was the most frustrating day of riding in my life. They were faster than me, but the bike clearly would not do what I was asking it to do. I have never rode drunk, but I bet that is what it feels like.

It all leads back to the tire pressure thing. Having it wrong makes for some really intrepid moments. You likely will never see me not checking before we head out for a ride.

Being slower because others are better is what it is. Being slower because equipement is not right is stupid

[Redfish]

As I read through this entire thread I am now forced to add my own thoughts on this.

1. HotRodZilla actually made sense and I agree with him. That's depressing.
2. I am Very Happy that Ionbeam is contributing over here. Mean as he is, I still like him.
3. It does not matter how much the pressures fluctuate. As 'Zilla said, that's why the manufacturers stamp the word "COLD" next to the recommended tire pressures. The tire manufacturers know how much pressure and temperature are expected to change and they build in a safety factor when they decide what numbers to mold into the sidewall of the tires.
4. The whole N2 vs. Air thing for a passenger vehicle is ridiculous to me. Obviously for aircraft and a few other specialty applications N2 is beneficial. The average driver only knows if the tire is flat or not.

Let me throw some more confusion and BS into the discussion:
What about the difference between my Sea Level air vs. Zilla's New Mexico air? My air has more moisture and all sorts of carcinogens from our local factories.

What exactly is COLD? If I inflate my tires to 41 psi and the "cold" temp is 98F is that the same as Pterodactyl inflating his tires to the same pressure at 20F?

And what about the difference in the pressure OUTSIDE the tire? Sea level ambient pressure vs. high altitude pressure? What if I set my tire pressures here at 24 feet above sea level and ride directly to the top of Pike's Peak? There is a local potato chip company that bags their chips at something less than 20 feet above sea level. Those bags will be INFLATED as the truck climbs up to the summit of Pike's Peak. Some will explode. Really.

Regarding trailer tires and blowouts: I tow a lot of heavy stuff around. In my experience an underinflated trailer tire is a HOT trailer tire. (This was mentioned earlier by another poster) A hot trailer tire wants to fail. Inflate a trailer tire to the pressure stamped on the sidewall BEFORE the trailer ever moves and the tire is actually "Cold". Another factor that has not been discussed is the driving/turning forces. Aggressive parking lot maneuvers, sharper turns put enormous stresses on the carcass of a multi axle trailer tire. Take a look at the tires on a tandem axle trailer during a tight turn in a parking lot. Throw in some heat, some axle misalignment...

[gixxerjasen]

Did anyone else audibly groan in pain when they read this?

I am now forced to add my own thoughts on this.

[HotRodZilla]

My F250 came with Micheline LTX-AT tires. They're load rated E. They have a max PSI of 80 at full load of 3640lbs. When we pull our camper or the horses I fill them to 75PSI. Never had an issue, and they tow well. A dual wheel rear axle is way more stable, but I'm not towing enough weight, or frequently enough to pay for the extra tires.

As far as the guy blowing trailer tires, he's doing something drastically wrong. I've been towing trailers since I was a kid. Everything from horses, cows, hay, campers, boats, tractors, cars etc. Those have all been on flatbeds, stock trailers, horse trailers, goose necks, bumper pulls, boat trailers car haulers, low boys, etc. I've blown two, maybe 3 trailer tires in my entire life and every one of those was due to dry-rot. I have NEVER seen a viable trailer tire blow.

Proper tires are different from automobile tires. When they're rated for weight, most are bias play, to reduce friction and make towing easier. They're usually higher ply than auto tires and can take a lot of weight. If someone's blowing trailer tires on a regular basis, something's up. I'm 99.9% sure it's not the tires' fault.

[HotRodZilla]

Did anyone else audibly groan in pain when they read this?

I am now forced to add my own thoughts on this.

No, but I was typing when he posted. Lol.

[wheatonFJR]

Did anyone else audibly groan in pain when they read this?

I am now forced to add my own thoughts on this.

[Hppants]

I've got almost 150,000 miles on FJRs. That doesn't make me an expert, but along the way, I've developed 2 theories.

The first one, which I've held for quite a long time, is ..... The FJR EATS tires. On the Gen 1, I was amazed at how fast it would go through a set of PR2s. I expressed concern (to many of you people, in fact) and the unicorn rainbows started to appear. Reading some of you boast 15,000 miles on a rear tire made my head itch. I'd get all lathered up over it and that would cause indigestion. At one point, I seriously considered counseling. Over the years, I've tried everything. Wrong tire pressure. Wrong tire. Wrong roads. Wrong throttle. Wrong beer. Too much weight. Too little weight. Holding the fart instead of expelling it mid-curve. Too high cholesterol. Forgetting to apply the fairy dust before seating the bead.

In the end - all bullshit. The FJR just eats tires.

Then, relatively recently, a new theory started to appear. When PANTS rides the FJR, the FJR EATS tires. I don't think I'm overly aggressive with the bike, but my riding style is harder on tires. I accelerate harder on the Gen 3 than I did with the Gen 1. I love to lean the bike and will often alter my lane position, speed, and other factors to force me to lean more. In aggressive twisties, I flat out ABUSE the front tire. Much of the time, I'm fully loaded with my camping and cooking crap. And let's face it: It's a big 'ole heavy bike with 145 hp and shaft drive and I'm weak. A better Pants would hold his right wrist in check. A better Pants would show restraint and moderation. But I'm weak. The 1st step is admitting you have a problem.

So I buy a lot of tires. It's money but I'm willing to spend it. The bigger picture problem now is that my trips are getting much longer in miles. Now, it's not enough to leave on a fresh set of shoes. I've got to find one of your guys to host me mid-trip like some kind of NASCAR pit crew. It's a tough job, mind you. But somebody's gotta do it......

Now - in spite of all of this dribble and vomit..... Arkansas roads are the worst. The grip on that chip seal is incredible. In the wet or gritty, you'd still have to work pretty hard to exercise the traction control. In the dry and clean, dam near impossible.

[NTXFJR]

Joe, looks like you have some great concepts going on there. I wonder if I might add a slight bit?

The fjr does not eat tires, period. So, I respectfully have to disagree with your conclusion here.

Unless of course said fjr is subjected to the likes of chip seal pavement such as that in NW Arkansas, coupled with a gifted twisties rider like, say, ummm, Oface, or Wheatie, or Intech, etc, etc. Or, gasp!...HPPants.

With that extra bit added in, I'd have to say it's closer to being spot on. But then maybe you've already touched on this.

Perhaps the more pertinent question here, at least in my mind, is the therapy that's involved. While some of us pine away, languishing about our tire's tread life, some of us are out there enjoying every single mile we can get out of them while being engaged in these said twisties.

Would we rather be releasing the tensions of life's issues while paying for seat time in the office of some Freudian (fraudian) (sp??) educated counselor, or from the seat of our trusty feej while paying for that periodic new rubber? I'd say that bang for buck, we have the better bargain as this type of therapy treatment is more thoroughly satisfying and complete.

The only issue I've found with this twistie's therapy so far, is that it tends to be an addictive venture, requiring many, many follow up treatments.

Stay theraputic my friends!!