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I have a question. I don't actually need the answer, as I already have the right answer for me, but this came up on another forum, and there is a bit of a controversy about. it. Say you have a bike, car, truck, whatever, and it no longer has the stock tires on it, they have been replaced with another brand. Most vehicles say in the owners manual and on the vehicle what the tire pressure should be. But remember, these are not the original tires. Should you use what is shown in the vehicle manual and on the vehicle itself, or should you go by what the tire manufacturer put on the tire sidewall? I need some opinions. Thanks, Jerry.
 

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i myself go by the tires at first, ill adjust the pressure as the tires wears so i can get the best life span out of them. and of course proper maintenance on the vehicle, and on the tires, plays i big part in it too.
 

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OH...and dont forget, larger vehicles, such as trucks, have 5 tires, not 4. yes, my spare tire is in my rotation of tires. dont want to be stuck with a flat, dry rotted spare on the side of the road. yea..been there, done that, not fun.. of course that was before cell phones. lesson learned the fist time.
 

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I run a few pounds under the rated max pressure on the tires, not the book.

DT
 

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Bikers garage told me to do 36 in the front 38 in the back. I have metzler 880's. Fort Worth, Texas....
 

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I bought the dial in air compressor. You just attach it to the tire...it digitally shows the pressure..you turn the knob to the number you want and hit the button. It stops when adequate air pressure is achieved. Then detach and go!
 

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...Should you use what is shown in the vehicle manual and on the vehicle itself, or should you go by what the tire manufacturer put on the tire sidewall? I need some opinions. Thanks, Jerry.
Personally I do neither.

For after market tires (i.e., not OEM) I refer to the tire manufacturer recommendation for my specific vehicle. It is my understanding that max tire pressure printed on the sidewall is just that, a max. for the tire regardless of application and that tire pressure should be set according to load, vehicle design, handling characteristics, etc., etc.. However, some tire manufacturers list a generic pressure for a group of vehicles (which may or may not be the max printed on the sidewall). In this case I use both the manufacturer recommendation and owner's manual, IF the owner's manual lists separate pressure for each axle as follows;

1. Cross out the highest tire pressure listed in the owner's manual and replace it with the tire manufacturer's generic number.

2. Calculate the lowest tire pressure percentage (based on the original OEM tire pressure). This is usually just a few pounds difference

Of course, I skip the above entirely if I have a tire dealer who knows their stuff and can recommend the right pressure for my vehicle.
 

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Some of the tire mfg websites have charts and will state recommended pressures for each bike, but I think with everyone's weight and gear being different, it seems like the pressure needs to be somewhere in between the bike maker's specs and the tire mfg specs. Only solid rule I can think of is never exceed the max psi listed on the sidewall of the tire, and you're probably not going to need quite that much in the tire.

I typically use the sidewall psi stamp as a basis to calculate what should be in the tire, according to the weight of the bike, my weight and approximately what my accessories weigh. Then I add a few lbs to make sure I'm above that number, and usually I'm getting within a few lbs of the max psi on the tires.
 

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This is true for me: If my front PSI is below 32, the handling is slow and mushy. I'm 250 lbs with some extra gear on every ride (always be ready for rain in the NW).

Anyone else experience this? I've felt the same with IRC, Dunlops, and Shinko.

DT
 

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Discussion Starter #12
Ok, thanks for all the information, really appreciate it. If you want to keep this thread going for the benefit of Vulcan 750 riders, great. It is a subject I never even considered before. I have ridden all kinds of bikes, including full on crotch rockets. I have always used the pressure marked on the sidewall of the tire, and will continue to. That goes for car and truck tires as well. While it is technically a "maximum pressure" number, tire manufacturers are always on the conservative side, so there is a built in safety margin if you should exceed this pressure by a bit. I can't think of a single disadvantage to having your tires inflated to this pressure. I have never had a single problem with it. I want my tires inflated to the max safe pressure, just like I want my engine oil level to be all the way to the full mark. Jerry.
 

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Jerry, I agree with you except I CAN think of a possible disadvantage of using the max pressure. If you find you tire wear is indicating too much pressure in the tire (excessive wear in the center of the treads), you need to back off of the pressure. This can occur if the total weight on the tire (vehicle and rider) is LOW in comparison to what the tire was designed for. If this is the case, not only will your tire wear indicate as such, but you're more at risk for skidding out of control on fast turns and quick stops. So a tire designed for a heavy Harley, being used on a light weight Kawi, being driven by a skinny little rider, probably shouldn't be inflated to max pressure.
 
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