Tire Pressure question

[Steve]

Well, I really hate to bring it up, but I'm going to do it anywyay.

One of the best guidelines I have seen concerning tire pressure is to look for a 10% rise when the tire is warm. For example: set the pressure at 30 psi (or your personal favorite pressure). Go for a good ride to warm up the tires. 25 miles of spirited riding should suffice. Check the pressure. If it is less than 33 psi, the tire did not flex enough to warm up and increase the pressure, so drop it about 2 psi before your next ride. If it went up to more than 33 psi, it flexed too much, so add 2 psi before your next ride. Don't adjust pressure until the tire is cold (basically the next day). It may take more that a couple of rides (oh, darn) to get the pressures dialed in, but then you will know what works for your tires and your bike. If you frequently carry a passenger, you will have to do it again, as the additional load of the passenger will require a higher inflation pressure.

And then, just 12 hours later, Billy Ricks posts this as his definitive way.

Here is the right way to adjust tire pressure, throw all the other crap out. Check your tires cold before you ride first thing. Then ride for about 10 minutes to heat the tires up. When you recheck you want to see 3 lbs more pressure. If you see more pressure you need a little more air so the tire will run cooler. If you find less than a 3 lb change you are running too much air. That doesn't let the tire get to a good operating temp. I'd be willing to bet if you are running the max pressure stamped on the tire you aren't getting the tire heated properly.

In my puny little mind it just seems that a 3 psi increase is dangerously close to a 10% increase. Gee, where did I hear that number before?

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[Billy Ricks]

Well, I really hate to bring it up, but I'm going to do it anywyay.
And then, just 12 hours later, Billy Ricks posts this as his definitive way.


In my puny little mind it just seems that a 3 psi increase is dangerously close to a 10% increase. Gee, where did I hear that number before?

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I never got to your reply before posting mine. It could get critical when running heavy loads at higher pressures. 3 lbs is always what I've seen quoted as the increase you want to see between cold and hot.

And why the attitude? People respond all the time in threads without reading further and finding a similar answer has already been given.

[Billy Ricks]

This actually shows you want to see a higher increase but it is on race tires and conditions. No reason it shouldn't carry over to the street though.

http://www.factorypro.com/tech/tire_pressure_risez.html

[nert]

One set of tires i bought was the recommended tire model for that manufacturer by application (82 gs1100gl). And they...the manufacturer recommended tire pressures for that model tire on my bike. Thats the way it should be.. They designed the tire, they know the bike, and weights (application determined). So they know best the pressure for their tires. Eliminates guess work, optimizes tire and safety. Now which tire was it??? Maybe check the tire manufacturers web site for your particular bike and tire. (application) To me, a tire manufacturer who provides this information, has done his homework, knows his product, is serious about his product, and earns my purchase support. And as others have stated, the max pressure stamped on the tire is what is needed to support the max load (lbs), also stated on the tire. It is NOT the recommended tire pressure, unless you're actual axle weights are equal to the max weight stamped on the tire.

[Steve]

And why the attitude?

Sorry, it wasn't meant as an attitude, but I can see how it came across that way.
I was merely showing that there are many ways to state the same thing. 8-[

In the link in your next post, it approximates the same thing, but looks for a higher pressure increase for track use. I think that if we were to do the 10% or 3 psi increase on the street, then ran the same tires at the same pressures on the track, we would probably see 5-6 psi increase with the additional load of the track, too.

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[twistedwankel]

One set of tires i bought was the recommended tire model for that manufacturer by application (82 gs1100gl). And they...the manufacturer recommended tire pressures for that model tire on my bike. Thats the way it should be.. They designed the tire, they know the bike, and weights (application determined). So they know best the pressure for their tires. Eliminates guess work, optimizes tire and safety. Now which tire was it??? Maybe check the tire manufacturers web site for your particular bike and tire. (application) To me, a tire manufacturer who provides this information, has done his homework, knows his product, is serious about his product, and earns my purchase support. And as others have stated, the max pressure stamped on the tire is what is needed to support the max load (lbs), also stated on the tire. It is NOT the recommended tire pressure, unless you're actual axle weights are equal to the max weight stamped on the tire.

Remember when Ford put pressures on the Explorer tire pressure stickers for a soft ride much lower than Firestone recommended for safety and in hot climates the tread separated and they rolled over?

Firestone almost went out of business on that one but it was Ford's mistake. I would always take the instuctions of the tire manufacture over the vehicle manufacturer. (But I also would find it hard to believe that Suzuki would be that stupid on it's bikes where blowouts are associated with serious injuries/deaths. I've always found their recommendations to be ultra conservative.)

[nert]

maybe i used too many "theys" and it got confusing. That is what i was saying, go to the tire manufacturers website, look up by application chart for the correct tire, and the pressures for that tire as recommended by the tire manufacturer. I think reliable, responsible tire people will provide year/make/model application recommendations and tire pressures.

[bleeble]

I just happened to stumble up this today: http://www.factorypro.com/tech/tire_pressure_risez.html

[Steve]

Good "stumble".

Billy Ricks posted that on 5/4 in post #18.

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[simon kuether]

I run 34 psi front and 38 psi rear.I check my pressures cold ,usually every second tank of fuel.I find that if my pressures are getting a bit low,the bike will start to "walk" when I ride along any irregularities that run along (not across) the road surface.It should ride over the top of them without any "wiggling".This might be a bit different for you Yanks as we ride upside down and on the wrong of the road compared to you.Cheers,Simon.:-D

[twistedwankel]

Nitrogen

Anyone running nitrogen yet? It's gaining popularity with vehicles here in the South as pressure stays the same cold to hot.

I don't know what you'd do on a trip unless you had a small bottle of gas with you?

[catbed]

i was thinking about running nitrogen in my car tires and might switch later. would be interesting to see.

[Steve]

Anyone running nitrogen yet? It's gaining popularity with vehicles here in the South as pressure stays the same cold to hot.

The place where I get my car tires brags about filling ONLY with nitrogen. In other words, it's standard, not an extra-pay option.

I have checked my tire pressure cold, then warm, within a day after leaving the shop with new tires. Yes, I verify proper pressure just to make sure that the tires sealed to the rim. You can forget any of that hooey about pressures remaining the same when warm. The pressure goes up just like it did before. Without tabulating all the variables, I can't say for sure that it might have gone up a bit less than before, but the pressure rise will be different depending on whether I have anything in the back of the van, changing the load.

"Nitrogen atoms are bigger than air". Guess what? Normal air is already over 78% Nitrogen, so 'pure' Nitrogen isn't going to be that much of an advantage. Also...did they seat the bead, then apply a vacuum pump to get all the air (with its small atoms) out, then replace it with just Nitrogen? Nah, I didn't think so. That means that it starts with a fair amount of non-Nitrogen already in there when they mount the tire to the wheel, so just adding more Nitrogen is not all that big an advantage.

They will brag about race teams using Nitrogen because of the consistency. My personal opinion (hey, you asked for it) is that they use Nitrogen because it does not absorb moisture the way regular air can. It is the dryness that is the advantage, not the Nitrogen.

Oh, almost forgot to answer your question...I don't think they used Nitrogen in the bike tires. At least they didn't say so.
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[Zooks]

Bike workshops here use nitrogen. It's got more to do with preventing corrosion than anything else I think.

[bleeble]

Good "stumble".

Billy Ricks posted that on 5/4 in post #18.

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Well, clearly I missed that. 8-[