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I just installed new tires and want to get the best performance, gas mileage and wear. That means maintaining the proper tire pressure and an accurate tire gauge. I already have a digital tire gauge and the Kawasaki VN750 tool kit pencil gauge. Both gauges produce similar results, but I wondered how accurate those results were. So, I visited the local motorcycle performance shop and had the gauges tested on a calibrated master gauge (available at tire shops and some truck stops). Both gauges tested -2.0 pounds off. So, it appears that I have been under inflating my vehicle tires. The 2.0 pounds is not critical and is consistent with my research on tire gauge accuracy, but it is nice to know. Now, I can adjust for the inaccuracy by letting the gauges read 2.0 pounds over the reading I'm looking for (i.e., if the gauge reads 42lbs, then the actual pressure is 40lbs).

So, carry your tire gauge(s) with you and stop by a tire shop. Ask if they have a 'calibrated master gauge' for testing tire gauges and have them test your gauges. Bring a Sharpie to mark the gauge with any adjustments needed and the date it was tested. Note that some shops may claim to have a master gauge, but a master gauge must be calibrated at least annually in order to labeled certified. Usually no worries with a performance/racing shop (auto or motorcycle) since they need spot-on tire pressure accuracy.

Also, I would replace any gauge that was more than a few pounds inaccurate.
 

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I have a Snap-On (almost all my tools are Snap On) TPGP50 pencil tire gauge for general use, and feel it is pretty accurate. It is calibrated 10-50 psi. I also have a super low pressure dial type gauge (just don't like digital) for my quad and my race car slicks.

I believe there are to things that are super important to long tire life. One is keeping them inflated to the proper pressure, and two, that the proper pressure is what is marked on the sidewall by the tire manufacturer, not what it may say somewhere on the bike, or in the manual.


The manual that came with my new EX500, which still has the stock tires, says 28 psi front, 32 psi rear. But on the tire sidewalls, it says 41 psi front and rear, and that is precisely what the tires are inflated to. Now, I've done some pretty hardcore (for me) sport riding on this bike, and the tires have performed very well for stock tires. I will get something better when they wear out. The last thing I want while doing aggressive sport riding is half inflated tires. Jerry.
 

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Here's my take on the PSI printed on the tire:

The PSI printed on the tire is the maximum pressure. The optimum pressure should be adjusted down from there based on how much weight you're hauling.

When you look at how the edges of your tires are wearing you can see if you're putting too much air (sides still look new). Ideally, you want to use some of that edge.

Mark
 

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Tire pressure

Here's my take on the PSI printed on the tire:

The PSI printed on the tire is the maximum pressure. The optimum pressure should be adjusted down from there based on how much weight you're hauling.

When you look at how the edges of your tires are wearing you can see if you're putting too much air (sides still look new). Ideally, you want to use some of that edge.

Mark
I have to agree. On my 1 ton truck the tire pressure on the side of the tires is 85 psi. The duals in the rear I keep at 45 psi. if I'm not hauliing heavy. I adjust by the contact patch of the tire. At full pressure only the center of the tire touches the pavement, and the tire will wear the centers off and leave the edges unworn. By adjusting to the contact patch I got 89,000 miles from my bridgstones on a one ton dually truck.
Motorcycle tires as you know, are a completely different animal but, adjusting pressure to the load still applies and I think the suggested pressures in the manual and on the bike are a great place to start.
Checking calibration against a master guage is a great idea for accuracy too.

That's my 2 cents.
 

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True, the rating on the tire is the maximum rating for that tire for maximum load carrying capacity. Useful for trailering, towing, etc.

Almost never inflate any vehicle tires to that, normally much to harsh a ride. The owners manual for whatever the vehicle is the best source for correct tire pressure.
 

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While it is listed as the "max" pressure, tire companies tend to be a bit conservative about such things, so even at the "max" recommended pressure, you still have some room to play with, at least on the high side. You don't have to worry about the tires being overinflated if you have them at the sidewall pressure. Almost every vehicle that comes into our shop (about 30 a day) has drastically underinflated tires, and when they leave, they all have the tires inflated to the pressure on the sidewall. I have gotten 20,000 miles out of the stock Bridgestones running them at the pressure on the sidewall. I can see no advantage to underinflating a tire, other than maybe for a softer ride.

My '66 Ford F100 pickup has 16.5x8.75 10 ply commercial tires on it (I got a killer deal on the tires and wheels, it has an 8 lug Dana rear axle and 8 lug front discs) and the tires (Firestone Trans Force HT) say 81 psi on the sidewall. And that is exactly what they are inflated to. As close as I can reasonably get to it anyway. 45 psi would be half flat. Of course it has a bumpy ride, with a 3/4 ton suspension and commercial tires, but I never intended it to be a Cadillac. I'll bet those tires never wear out. Jerry.
 

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True, the rating on the tire is the maximum rating for that tire for maximum load carrying capacity. Useful for trailering, towing, etc.

Almost never inflate any vehicle tires to that, normally much to harsh a ride. The owners manual for whatever the vehicle is the best source for correct tire pressure.
Ah yes, the "harsh" ride thing again. Like I said, a "soft" ride is the "only" reason for inflating tires under their recommended inflation pressure, and it comes at a high price. Underinflated tires not only wear out much faster, but they don't handle very well either. Tire companies are fanatics about safety. They have to be. They probably get sued more often than any other company that makes vehicle parts. Do you really think they would put that pressure on their tire if they felt it was not safe? Not likely.


If I remember correctly, the big Ford Explorer/Firestone tire fiasco happened mostly because Explorer owners were seriously underinflating their tires, by following the recommendations in the "manual". There was nothing actually wrong with either the Explorer or the Firestone tires. Jerry.
 

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I'm getting ready to buy a set of Metzlers and when I did reviews on them most people said they need to be over inflated from what the factory recomends for their bikes. Any truth to this?
 

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If I remember correctly, the big Ford Explorer/Firestone tire fiasco happened mostly because Explorer owners were seriously underinflating their tires, by following the recommendations in the "manual". There was nothing actually wrong with either the Explorer or the Firestone tires. Jerry.
You are right, Exploder owners complained about how hard the vehicles rode so Ford took action, lowered the recommended TP to compensate for two things, too hard a suspension and too cheap a tire. Ford told Firestone we will pay you $8 a tire, no more, so that's what they got, an $8 tire. They were both as at fault as each other.

Tires should be inflated to generate the correct contact patch when at temp under the maximum TP rating. This obviously will vary greatly with driving conditions, temperature, highway, local, etc. It will always be a compromise.

Jon
 

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I'm not going to get into another long drawn out argument here either. Obviously owners are free to inflate their tires to whatever pressure they want, and they are the ones who will deal with the consequences, if any.

I have always inflated all my tires, including bicycle tires, and even the tire on my wheelbarrow, to the pressure on the sidewall, and have never had any problems doing so, either with handling or tire wear. So, I know it is safe to do it that way. I'm not one of those that likes a mushy ride, so that is not an issue for me.


As for the Ford/Firestone thing, I can't help but think that had owners inflated their tires to the pressure on the sidewall, none of that would have happened.


Here's the way I see it. Inflate the tires to the pressure on the sidewall, and everything will be ok. Anything else is a gamble. Jerry.
 

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I'm not going to get into another long drawn out argument here either. Obviously owners are free to inflate their tires to whatever pressure they want, and they are the ones who will deal with the consequences, if any.

I have always inflated all my tires, including bicycle tires, and even the tire on my wheelbarrow, to the pressure on the sidewall, and have never had any problems doing so, either with handling or tire wear. So, I know it is safe to do it that way. I'm not one of those that likes a mushy ride, so that is not an issue for me.


As for the Ford/Firestone thing, I can't help but think that had owners inflated their tires to the pressure on the sidewall, none of that would have happened.


Here's the way I see it. Inflate the tires to the pressure on the sidewall, and everything will be ok. Anything else is a gamble. Jerry.
It's possible that higher pressure may have lessened the Explodeer issue, but Ford still pressured Firestone to take cost out of the tires, so who knows.

Another benefit to the sidewall rating is better gas mileage, less rolling resistance than at any lower pressures.

BTW, it's not an arguement, it's a discussion.

Jon
 

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It's possible that higher pressure may have lessened the Explodeer issue, but Ford still pressured Firestone to take cost out of the tires, so who knows.

Another benefit to the sidewall rating is better gas mileage, less rolling resistance than at any lower pressures.

BTW, it's not an arguement, it's a discussion.

Jon
No problem with a discussion. That is what the forum is for, IMO. It's just that several "discussions" that I have gotten involved in here did turn into arguments, pointless arguments in which nobody really had enough information to argue intelligently about the subject. They were really arguments based on opinions, and you know what they say about opinions. As long as a discussion stays civil, then I have no problem with it. But I will only argue about something if I have absolute facts to back up my statements. Otherwise, it is all opinions.

The statement about not getting into an argument over this was not meant to offend anyone who sees this as a discussion, and was not directed at you.


Gotta get back to work here, will be back later. Jerry.
 

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I can understand peoples concerns with keeping a car tire inflated to max pressure because the tire might wear more in the center, as car tires always remain flat on the road. If that happens, back down slightly on your tire pressure. But a motorcycle tire rides on the edges of the tread as well as the center. I would think keeping higher pressure in those tires (up to the max pressure stated on the sidewall) can only improve traction and decrease the likelihood of a blowout. In fact, the more you lean the more even the tire wear would be if your inflation pressure was on the high side. Even slight underinflation could severely wear a motorcycle tire's treads along the edge. I'm with Jerry on this one. I'm going to add some air to my Pirelli's to bring them up to max pressure.
 

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Max pressure is the most pressure that one can safely put into the tire. The way I see it is a car tire carries about 8 hundred to 1k lbs per tire. The bike only wieghs 5 hundred to 1 k with riders. I have run as low as 20 psi on the rear and 25 to 30 psi in the front. It is all preference. More pressure less drag on the tire, better gas mileage. It also makes for a rougher ride.
 

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One reason they say to inflate your tire lower then what is recommended on the side wall of the tire is the tire will increase in pressure as you drive. That is why they tell you to check pressure on a cold tire where it will increase pressure when warm. I have checked pressure on my bikes when the tire is cold around 32psi and after a few hard driving miles I have rechecked and it was up about 4 to 5psi making it around 36 to 37psi. So basically if you leave your tire a bit under pressure it will go up. So if you use the pressure on the sidewall of the tire you will actually be over pressure after a few miles which makes the tire harder and you get a rough ride. This is especially true for people in southern states with hotter temps and the road surface much hotter. Plus if the ride gets harder, adjust your shocks to smooth it out again.

I allways run my tire at 28psi front and 32psi rear (both are rated for 42psi)and bump it up a couple pounds when with a passanger because I know it is going to increase pressure as I drive.
 

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I'm getting ready to buy a set of Metzlers and when I did reviews on them most people said they need to be over inflated from what the factory recomends for their bikes. Any truth to this?
Factory recommendations are for original equipment. Inflate according to the tire not the bike's manufacturer.
 

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Discussion Starter #17
I love this forum. Here I post a tip on tire gauge calibration and the entire thread is taken over by a 'my favorite tire pressure' topic.

I'm glad that I'm not the only one here with ADH....hey, look a squirrel!

Anyone have a tire gauge relate tip to share; Brand X is the best most accurate, pencil vs gauge vs electronic, calibration tips, etc.?
 

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I love this forum. Here I post a tip on tire gauge calibration and the entire thread is taken over by a 'my favorite tire pressure' topic.

I'm glad that I'm not the only one here with ADH....hey, look a squirrel!

Anyone have a tire gauge relate tip to share; Brand X is the best most accurate, pencil vs gauge vs electronic, calibration tips, etc.?
I'll wade in I have an accugauge brand dial type with hose that holds the reading until I press the button,no bumping into things and having to recheck as with the pencil type I tried one of the digitals and it was alright but just not very durable looking.Oh yeah I forgot I go on reserve at 120 miles;)
 
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