Tire Pressures

[CruisnGrrl]

I was having this discussion with a friend about tire pressures. On track days we're given suggested tire pressures for the day for the brand, model and kind of tire we have based on the temperature we're experiencing, which are no where near the maximum tire pressure listed on the side of the tire. In my bike manual I see other tire pressures that don't match the maximum listed on the side of the tire...

My friend fills his tires up to the maximum pressure on the side of the tire. I think the maximum is just that, a maximum, not a goal and probably something you should only hit fully loaded with camping gear and 2up. What I don't know is how to figure out what pressure I should be running for my daily stuff, sometimes with about 50 pounds of stuff with me (I go shopping on my bike) and at various times of the day.

[Skurj]

If you look up the manufacturer of the tire, it will state the recommended pressure.

There is a sticker on my bike that recommends the pressure based on the load as well. (pretty much 36psi)

For street and daily stuff it will be higher than the track, and will extend the life of the tire.

[Wogger]

You are right about the maximum tire pressure on the side of the tire. That is the maximum for safety reasons, not at all a recomended pressure.

Follow the owners manual.

[Basketcase]

I would expect that it has a lot to do with the amount of weight on the front tire vs the back tire. Normally you're looking in the mid 30's for the tire psi on a car or bike but my Jetta wagon hs 45 psi in the back and 36 on the front. Bicycle tires are like 60 psi for the road and 45 for off road.
My dirt bikes ar 15 - 18 for both the front and back.
And like you said the load make a difference. Note that stickers on bikes usually quote a number for riding solo and a higher psi for two up. Check your manual.
I've noticed that being out by a couple of psi really seemed to make a difference in the handling of my SV650-S.
I've heard that shorter people lower the rear of the bike so they can reach the ground more easily and they have to match that by lowering the front end too in order to maintain he same handling. I wonder if you could just lower the back end and use tire pressure to fix the handling?

[thisischris]

You are right about the maximum tire pressure on the side of the tire. That is the maximum for safety reasons, not at all a recomended pressure.

Follow the owners manual.

This guy is speaking the truth. Use the recommended pressure for the bike- not the max listed on the tire. Some manuals will give a pressure for a single rider and for 2up.

My new (to me) bike cbr400 recommeds front 33psi; rear 33 psi. Or with a passenger front 33 psi; rear 36psi.

[reciprocity]

This guy is speaking the truth. Use the recommended pressure for the bike- not the max listed on the tire. Some manuals will give a pressure for a single rider and for 2up.

.

How can this be the truth at all times?

Each tire manufacturer and tire type will have different pressure values for different configurations(2up etc)

The manual will have information for the original tire only.

If a different tire is installed after the original wears out, the manual is no longer relevant.

the TIRE manufacturers recommendation is the only correct information to use.

[nippondecker]

Most bikes on the road are running way too soft as people don't bother to check their pressure regularily.
Ask any bike mechanic, most bikes that come into the shop are underinflated, often grossly. ie by 10psi
If you run recommended press and CHECK IT occasionally, you won't go far wrong.

[nippondecker]

How can this be the truth at all times?

Each tire manufacturer and tire type will have different pressure values for different configurations(2up etc)

The manual will have information for the original tire only.

If a different tire is installed after the original wears out, the manual is no longer relevant.

the TIRE manufacturers recommendation is the only correct information to use.

If you can find a recommendation for that particular tire on that particular bike, perhaps, yes.
manuals sometimes list an optional tire brand.
But if you're putting knobbies on yer gixxer.......

[reciprocity]

If you can find a recommendation for that particular tire on that particular bike, perhaps, yes.
manuals sometimes list an optional tire brand.
But if you're putting knobbies on yer gixxer.......

If you can find one??

EVERY tire manufacturer has a "CONTACT US" email link and phone number.

[Brian P]

reciprocity, the *race* tire distributors can give you tire pressure recommendations for whatever conditions at whatever track, but for *street* tires you are unlikely to get any recommendation other than to use the pressure recommended in the owner's manual or on the information label of the bike. You *might* get a set of outer boundaries (an absolute min and an absolute max) and it's up to you to figure out where to be within those boundaries.

The pressure that you want to use when riding on the street on twisty roads (relatively low, to get it to a somewhat acceptable amount of grip, but not TOO low, to maintain stability) is different from the (higher) pressure you want to use when going straight at highway speed (to avoid overheating the tire) and that's different from what the drag racers want to do (maximum straight line grip with essentially no concern for tire life or steering characteristics).

The maximum inflation pressure printed on the sidewall is almost certainly going to be too high for any foreseeable riding condition.

I go more-or-less by the temperature of the tire. If it's way too low, I reduce the pressure but only to a lower limit (that I've established MYSELF) governed by steering feel - too low will make steering response too sluggish. If it's way too high, I increase the pressure, but again, not beyond limits.

I had the opportunity to test ride a street bike belonging to a member of this forum (and long time rider) who shall go nameless. I'm not one to be sliding bikes all over the place, but this one it felt like the tire was spinning at will. "What pressure is in those tires" - "what it says in the owner's book". JEEZ no wonder it was spinning. I have the same tires on my ZX10R right now, and although I'd have to say that they are not my favourites (I won't use them again) they are not THAT bad if the pressure is 32-ish psi rather than 37 ...

[reciprocity]

reciprocity, the *race* tire distributors can give you tire pressure recommendations for whatever conditions at whatever track, but for *street* tires you are unlikely to get any recommendation other than to use the pressure recommended in the owner's manual or on the information label of the bike. You *might* get a set of outer boundaries (an absolute min and an absolute max) and it's up to you to figure out where to be within those boundaries.

...

Most manufacturers do list this information on their motorcycle tire websites, but if you can't find it, the "CONTACT US" link on the same site will get you an answer and its rarely what is listed in the owners manual.

a few years ago, you'd never get a response but these companies have gotten much better at dealing with email questions.

I install a lot of tires and keep the email information I've received close at hand when tire install customers start asking about pressures as many are convinced anything besides 36 front, 42 rear is going to cause them to highside rolling out of my driveway.

[CruisnGrrl]

bleh tried to contact michelin, but they only want to hear from americans about motorcycles and the site crashes when i try to fill in the form

[Skurj]

are convinced anything besides 36 front, 42 rear is going to cause them to highside rolling out of my driveway.

Hey now.. that's what the suggested pressures were for the SV1000 on bridgestones, and the Michelin roads it came with I believe.

[AGAVE]

the TIRE manufacturers recommendation is the only correct information to use.

Exactly.
Max pressure is written on the side of a street tire.
It should be close to max pressure for everyday riding.
The main reason is to keep the tire round and not have a wave rolling through it at the contact patch, this causes tires to breakdown and fail early.

Racing tires have their own recommendations based on research for optimum grip, contact patch with the track. A serious professional will calculate the weight of the bike and rider, compare track temperatures etc..... it can be very complicated.

This article is quite informative. I selected it specifically because it pertains to sportbikes and i don't wanna hear any HD wise cracks.

In short > If you aren't going racing, fill up your damn tires!

http://www.sportrider.com/tech/tires...ure/index.html

[MotoStark]

I read from a well respected magazine on this subject that the Tire Manufacturers typically overstate the required pressures to keep the lawyers happy. They have no idea how heavy you are or if you are carrying pillion, so they typically suggest a standard "safe" pressure is 36/42.

For known solo riding, this same article suggested 34/36 for the street.


.

[KJM]

I was having this discussion with a friend about tire pressures. On track days we're given suggested tire pressures for the day for the brand, model and kind of tire we have based on the temperature we're experiencing, which are no where near the maximum tire pressure listed on the side of the tire. In my bike manual I see other tire pressures that don't match the maximum listed on the side of the tire...

My friend fills his tires up to the maximum pressure on the side of the tire. I think the maximum is just that, a maximum, not a goal and probably something you should only hit fully loaded with camping gear and 2up. What I don't know is how to figure out what pressure I should be running for my daily stuff, sometimes with about 50 pounds of stuff with me (I go shopping on my bike) and at various times of the day.

You're really concerned about altering your tire pressure on your streetbike for different times of the day?

[Franko!]

If you are really worried about tire pressure, make sure you have a good air gauge. Some can be out as much as 5 psi.

Air Gauge Review: http://www.mcnews.com/mcn/technical/200511gauges.pdf

[murf]

Exactly.
Max pressure is written on the side of a street tire.
It should be close to max pressure for everyday riding.
The main reason is to keep the tire round and not have a wave rolling through it at the contact patch, this causes tires to breakdown and fail early.

Racing tires have their own recommendations based on research for optimum grip, contact patch with the track. A serious professional will calculate the weight of the bike and rider, compare track temperatures etc..... it can be very complicated.

This article is quite informative. I selected it specifically because it pertains to sportbikes and i don't wanna hear any HD wise cracks.

In short > If you aren't going racing, fill up your damn tires!

http://www.sportrider.com/tech/tires...ure/index.html

interesting article, I run about the same pressure on the street as on the track, sometime I add a couple pounds. I figure if they aren't overheating at the track at an average speed of 150 km/hr plus, it would be impossible to overheat them on the street as that article states.

[toysareforboys]

28 front, 32 rear on my Diablo Corsa III's (got 13,000km's out of them, and abused them hard) and my new Power Pure's at 32 also. 2up = 36 rear.

-Jamie M.

[iconix]

I contacted Michelin awhile back when this question came up before and this is what they said:

Hi Steve,

Thank you for your email. We welcome the opportunity to serve you.

Michelin recommends you go by the pressure recommendation as specified by
the bike manufacturer. They have determined the optimal pressure given the
application. The pressure marking on the sidewall of the tire indicates the
carrying capacity for the maximum pressure tire pressure.

It is our goal to ensure that your issue has been resolved or your question
answered to your satisfaction. If we can assist you further, please respond
to this email or call us at 1-800-847-3435 (toll free) between 8:00AM and
8:00PM Eastern Time Monday through Friday or between 8:30AM and 4:30PM
Eastern Time on Saturday.

Thank you. We appreciate your business!

Gregg

Michelin North America
Consumer Care Department

SO I still dont know who to follow, the tire or the manual.