Tire Pressure - exact to spec or + a pound or two?

For years I have read and been told to inflate auto tires a few pounds over the specified pressure for long trips and high speed driving. Does the same hold true for motorcycles?
I'm going on a 500 mile (each way) trip - mostly high speed slab with some state routes. I usually adjust the tire pressure to exactly 42 lbs front and rear per Honda's spec. But this time I had some second thoughts.

Is it a good idea to go to 43 lbs taking a page from the recommendations for cars? All pressures are of course adjusted cold.

I would just continue running 42/42. That is what I have been doing for 10 years on all types of roads, speeds and temps on motorcycle specific tires on my ST1300 motorcycle. Mostly Bridgestone 020/023s. No wear issues.

I try to run motorcycle tires near max pressure for the tires. Many tires in our bikes size are rated at 42. I would not over inflate any tire.

IIRC car tires had their MAX pressure shown on the side wall but the normal operating pressure was in the owner's manual and later on the door jam. That pressure was usually lower than the MAX air pressure. IIRC. When you added extra cargo you upped the tire pressure not to exceed the MAX.

I didn't know that some tires had a MAX pressure of 42lbs. Is that the case for the factory tires?

I'd go with the listed pressure of 42 from mother Honda... if you crank it up much higher you'll just wear out the center on the slab quicker

42/42 here too. Cornering, highway speeds, curves, etc... it's all good.


Those in the know use Tapatalk Pro.

Thank you all. 42/42 it is. And, I sure wouldnt want to wear out that concrete any faster than the cages do......

In the spirit of this thread and all air pressure threads what is a good, the best, the most used/liked/easiest to use/most durable etc. gauge used by the collective, I need to buy a new one?

I have a Joes racing gage that I like alot. Its analog and has a glow in the dark face.

SMSW said:

I usually adjust the tire pressure to exactly 42 lbs front and rear per Honda's spec. ... Is it a good idea to go to 43 lbs taking a page from the recommendations for cars?

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Your tire gauge isn't going to be accurate enough that exactly 42 or exactly 43 is going to be possible. Unless your bike is stored and operated in an environment where the temperature is precisely controlled, it isn't going to make a difference. If you set the pressure in the garage, roll it outside into the sun and start it up, the temperature will probably increase by 5 degrees before you take off and you're already up 0.5 PSI.

It's not an exact science. The tire and motorcycle manufacturers know this. Fill them to whatever 42 on your tire gauge actually means and ride.

I'm not sure where the idea that overinflating tires that are going to be used at high speeds came from, but it's bogus.

--Mark

Blrfl said:

I'm not sure where the idea that overinflating tires that are going to be used at high speeds came from, but it's bogus.

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have to agree with mark tire pressures increase as you ride anyway from a pound or to to several PSI Fillyour tires to the factory recommended setting and just ride.

I heard somewhere that a 7% increase in psi from cold to hot indicated that you are st the correct psi.
anyone have a comment on that?

drrod said:

I heard somewhere that a 7% increase in psi from cold to hot indicated that you are st the correct psi

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Similar idea discussed here.

General consensus was that it's old tale.

There is quite an increase in heat and PSI as you ride. The front less so than the rear I have started out at 42 front and rear and can see the increase on the TPMS The rear van go up as much as 6-8 PSI as long as it doesn;t go over the max PSI of the tire its all good.

spotz said:

In the spirit of this thread and all air pressure threads what is a good, the best, the most used/liked/easiest to use/most durable etc. gauge used by the collective, I need to buy a new one?

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I just got one of those digital talking gauges from Road Gear. I like it a lot. Just push and hold till you hear the pressure. STILL........
I don't know if it's accurate. My last 2 digital gauges died so I can't compare. THEN still I won't KNOW which is right.

Pete in PA said:

My last 2 digital gauges died so I can't compare. THEN still I won't KNOW which is right.

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Just go by with majority rules.

Grab all of your gauges, and a friends if available, see what you get.

The "correct" pressure for any vehicle is the one listed on the door jamb (cage) or manual (cage or bike). The same size tire can be used on anything from a compact car to a light pickup, and the pressures vary depending on the vehicle, so using the sidewall rating won't apply for your specific vehicle. That is simply the safe working pressure of the TIRE, not what is best for the VEHICLE. So if you are in a compact car and set the pressure the same as a loaded pickup would use, you will be WAY over inflated. The same for a bike- do you think the same tire used on an ST1300 would use the same pressure as it would on a bike that weighs 200 lbs less, rarely has a passenger, and has no luggage carrying capacity?

With that said, I tend to set tires to 1 to 2 lbs. over what the suggest pressure says. This takes into account:
-Variation of tire gauges. It is better to have a tire 2 lbs. over than 2 lbs. low
-Loading/weight of the vehicle- especially with our STs, it is very common to overload them well above what Honda rates them for. Add a big rider, a good sized passenger, and a weekend's gear and you will be well over the STs limit, and the weight the tire pressures were set for.
-Fluctuation of tire temp- Proper pressure check is done "cold". The pressure will increase as the tire is used and warms up. But what is "cold"? Parked in your sunny driveway on an 80 degree day? Or in your unheated 40 degree garage on a cool spring morning? Setting the pressures 1-2 lbs. higher on a cooler morning means you will be close to the mfg's rating on their "average" cold day. And having it set 1-2 lbs. over on a normal day means your tires will be at a safer pressure on a cold day.
-You lose pressure every time you check your tires. Having them a couple lbs. higher means you can check your tires more times before you end up having to add a couple lbs. And we all know most of us don't pull out the compressor for being a lb. low, so this keeps us at (or above) the rated pressure longer.

A good exception for all this are high performance tires used on the track. 1 lb. makes a difference there, and pressures are set according to track conditions, not any specific rating.