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Old 03-03-2014, 05:48 PM   #16
cycleman2
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Originally Posted by craigincali View Post
is the load index the same on motorcycles as it is on cars. Meaning: you multiply the tires max load X 4 on a car to come up with the true max load. Do you multiply a motorcycles max load X 2 ?? or add them or what?

Does this even make sense?
Short answer is no. The tire load is totally different than the Total GVW of the vehicle. The stamps on the tires represent the maximum load that tire will carry with the max air pressure at 42 lbs. That air pressure is not to be exceeded. The bike manufacture sets the recommended tire pressure and I've yet to see one that was over 41 lbs ( rear tire on my 08 Heritage Softail ), most are in the range of 36-40 lbs.

All bikes will have a sticker somewhere on them that will tell you the GVW, the dry weight etc. As a general rule if you put both the rider (220 lbs )and the passenger( 150 lbs ) , both with gear, on a typical bike with a GVW of 940 lbs, then you are going to have about 40 lbs maximum load carrying capacity left which includes the weight of saddlebags, trunk etc. Not a lot of carrying capacity and most bikes you'll see on the road are overloaded, especially if you are travelling 2up.

So you can see that the rear tire might have a 900 lb max load and the front tire might have a 700 lb load. You can't add them together and come up with how much weight the bike can carry. You always have to load the bike to its manufactures specs not its tire specs.
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Old 03-03-2014, 07:42 PM   #17
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Originally Posted by cycleman2 View Post
Short answer is no. The tire load is totally different than the Total GVW of the vehicle. The stamps on the tires represent the maximum load that tire will carry with the max air pressure at 42 lbs. That air pressure is not to be exceeded. The bike manufacture sets the recommended tire pressure and I've yet to see one that was over 41 lbs ( rear tire on my 08 Heritage Softail ), most are in the range of 36-40 lbs.
partially correct

the maximum load that the tire can safely carry along with the air pressure necessary pressure to carry that load

the air pressure is not the maximum not to be exceeded

for instance, the stamp on a Metzeler Karoo II says
"Max Load 716 lbs. @ 33psi" next, go to the Metzeler website or e-mail Metzeler yourself and ask what the recommended pressure is for running that tire on the back of a V-strom and they will tell you 41psi (but its still only safe for 716 lbs)

for some tires, the air pressure is max, but for others it is not,
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Old 03-05-2014, 09:02 AM   #18
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Not trying to start a tire war, but we all should honour what the tire manufactures put on the sidewall of their tires as it relates to max load and cold air temp. Those small tire contact pieces are our lifeline.

The tire manufacture sets the maximum load and air pressure on the tire. The bike manufacture sets its maximum load based on the tire manufactures recommendation for the tire they are recommending for their bike, which includes the design limits of the motorcycle and it is always going to be below the 42 lb max cold pressure.

Last year I sat in on a presentation by Michelin on their motorcycle tires and the engineers giving the presentation said that you should never exceed the 42 lb cold pressure on the tires that carry that label. All tires heat up in use and the air pressure goes up. According to them if you exceed the cold recommended pressure you are asking for problems with the tire as you've exceeded its design limits. The conversation was around Michelins Anakee's, Pilot roads etc.

There certainly can be lower max cold temps on tires as the tire manufacture sets that based on the tires intend use. Whatever that label says is what you should follow. Suzuki doesn't recommend the Metzler Karoo II tire for the Vstom, therefore they are unaware of any of the design specs for that tire. This is based on Suzuki's tire recommendation in their owners and service manual. The 2up loaded recommendation for cold tire air pressure is 41 lbs for the 2013 VStrom on their spec tire. As a side note my 08 Harley also carried a 41 lbs air pressure max for 2up load on the tire they recommended for their bikes.
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Old 03-05-2014, 10:22 AM   #19
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Originally Posted by cycleman2 View Post
Not trying to start a tire war, but we all should honour what the tire manufactures put on the sidewall of their tires as it relates to max load and cold air temp. Those small tire contact pieces are our lifeline.

The tire manufacture sets the maximum load and air pressure on the tire. The bike manufacture sets its maximum load based on the tire manufactures recommendation for the tire they are recommending for their bike, which includes the design limits of the motorcycle and it is always going to be below the 42 lb max cold pressure.

Last year I sat in on a presentation by Michelin on their motorcycle tires and the engineers giving the presentation said that you should never exceed the 42 lb cold pressure on the tires that carry that label. All tires heat up in use and the air pressure goes up. According to them if you exceed the cold recommended pressure you are asking for problems with the tire as you've exceeded its design limits. The conversation was around Michelins Anakee's, Pilot roads etc.

There certainly can be lower max cold temps on tires as the tire manufacture sets that based on the tires intend use. Whatever that label says is what you should follow. Suzuki doesn't recommend the Metzler Karoo II tire for the Vstom, therefore they are unaware of any of the design specs for that tire. This is based on Suzuki's tire recommendation in their owners and service manual. The 2up loaded recommendation for cold tire air pressure is 41 lbs for the 2013 VStrom on their spec tire. As a side note my 08 Harley also carried a 41 lbs air pressure max for 2up load on the tire they recommended for their bikes.
I was speaking of Metzelers recommendation to exceed their own sidewall, not Suzuki ,

some manufactures have a max air pressure, others don't, just an air pressure that you need to support max load
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Old 03-05-2014, 03:42 PM   #20
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They stamp the tire with a max psi and load because they are required to.

Don't rely on it as the end all do all.

Don't think that they actually tested it at that pressure and load for every test.
Or that it is equivalent to the actual rigorous testing you will put it through. It certainly is not.

It doesn't allow for any added friction or sidewall flex that tires are subjected to. No additional g forces or real road hazards. No acceleraiting or braking. No 140 tarmac or chipsealed road surfaces..
It's done on a 67" steel drum. Minimal friction compared to the real world.

The strength test is supposed to simulate road hazzards. For MC It is a 5/16 steel rod pushed into the tire at a blistering rate of......two inches per minute.
It can pop, but not fail the test after a formula consisting of the steel rod psi, and tire pressure, plies, rated load ect.ect.. is followed.

For cars and light trucks it's a bigger steel rod, 3/4" I think.

Like i said above, It's a joke...

The endurance test for cars and light truck tires has been revised.. It puts 85% of the rated load on the tire for three 30 minute periods. At 3 speeds up to 97? mph.

Motorcycle tires are still tested the same way that they were in the 70's. They have revised the testing for other types of tires though.

You can look it up if you are bored.
NHTSA FMVSS 109, 119, 139



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Old 03-06-2014, 09:53 AM   #21
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I was bored yesterday so I did lookup them FMVSS numbers I took off the "for testing purposes" tire up there. Looks like his may have escaped the testing and made its way to the market if what I read on some Goodyear papers is correct as I think it is. I hope it escaped the testing.....

Still, I'll listen to Michelin just as I did back then when my dad was a Michelin dealer. Only got a one day course out of that but worthwile. Relevant then in the 70's and looks like it still is, same testing procedures.

I don't piddle much with changing the manufacturer's recommended tire pressures on my bikes. Always tought that was the wrong way to compensate for other faults with the bikes, some suspension related and some maybe even riding habits. As in how do you break them dual compounds? Twisties or straight highways???

Different story with the car....that pig needs a little induced oversteer.
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Old 03-06-2014, 10:00 AM   #22
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Originally Posted by H96669 View Post
I was bored yesterday so I did lookup them FMVSS numbers I took off the "for testing purposes" tire up there. Looks like his may have escaped the testing and made its way to the market if what I read on some Goodyear papers is correct as I think it is. I hope it escaped the testing.....
I looked at a couple of older tires I have hanging around, they have the "for testing purposes" in the sidewall stamp, none of my newer tires have it

I think there may have been a change in the required wording 7 or 8 years ago
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Old 03-08-2014, 10:49 AM   #23
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The date code on that tire is 1911. So it's less than three years old.


Pretty sure it's just a disclaimer. They must ride at Avon and don't want people on their asses because they aired their tires up to what is "reccomended" on the sidewall. Honestly, there are many folks who abide by it, especially on four wheeled vehicles.

Fact is, a motorcycle tire is designed to flex when cornering so the tire can wrap around the rim and stay connected.

42psi cold is not going to allow that. The myth that you can "run out of tire" when cornering may be true.

42psi cold at sea level and 40f will inflate to 50psi or more at 6,000 feet when the tire is warmed up.

I run them at 24 front 26 rear on a light bike and they are by no means underinflated.

KTM recommends 1.5 bar front and 2.0 bar rear for my supermoto.
It translates to 22/29 psi. They only use .5 bar increments for some dumb reason, even on the dirt bikes. It's the one metric standard that isn't better.


Said tire is an Avon Distanzia 160/60 R-17

It's a widely available dualsport tire. It does very well on wet and dirty pavement, and offers decent traction in the dirt when new.

They make it in 17, 18, 19 and 21" sizes.
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Old 03-08-2014, 11:28 AM   #24
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The tire load is totally different than the Total GVW of the vehicle.
Yup, and we don't know exactly what is the weak link in the weight carrying limitations of the vehicle. It might be the wheel, or the bolts, or the frame...or the brakes to get'er stopped. Every GVWR placard I've seen has the total GVWR less than the sum of the front axle GVWR and rear axle GVWR which also is usually less than the combined max load of the tires on that axle.

The tire's Load Index is a two or three digit code for the max weight the tire can carry at the specified inflation pressure. For example, my rear tire has 69V among the info on the sidewall. 69 = 717# @ 42 psi. V is the speed rating, and actually tells us more about the stability of the tire carcass than its limitations for the speeds I'll ride.
http://en.wikipedia.org/wiki/Tire_code#Load_index
http://www.barrystiretech.com/speedratings.html

Bar of pressure is a metric measure of pressure. It is about one "barometer" of pressure which converts to 14.50377... pounds per square inch.

For those who don't know, the date of manufacture is impressed into the tire's sidewall. The last four digits of the DOT code are the week and year the tire was made. 0314 = third week of 2014.

Depending on the type of tire, the pressure on the sidewall is either the max allowable cold inflation pressure (see the posting above about Michelin info) or the minimum pressure required to carry the max weight the tire is rated to carry. Motorcycle tires and passenger car tires usually have the max allowable pressure on the sidewall. Truck tires have different wording showing the latter. A truck tire with a min pressure of 80 to carry its max load can safely be inflated to 90 psi cold to increase the max allowable speed of that tire. From a Goodyear truck load/inflation table:
"LIGHT TRUCK TIRES
The inflations shown in the load tables are minimum cold pressures for the various loads listed. Higher pressures should be used as follows:
A. When required by the speed/load table, table 1 on Page L-2.
B. When higher pressures are desirable to obtain improved operating performance.
The combined increases of A and B should not exceed 10 PSI above the inflation specified for the maximum load of the tire.
THE MAXIMUM LOAD AND INFLATION CAPACITY OF THE RIM MUST NOT BE EXCEEDED."
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Old 03-08-2014, 11:51 AM   #25
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Originally Posted by Idle View Post
Perhaps you are being misled by the manufacturers of your 24 tires.

I have two tires on my bike and 4 bald ones with the same disclaimer. Maybe you are right. I bought them from some guy in a white van at the gas station. He first offered to fix a dent in my truck for $150, then tried to sell me some speakers.
Lol. Funny stuff.
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Old 03-10-2014, 11:58 AM   #26
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Originally Posted by randyo View Post
I looked at a couple of older tires I have hanging around, they have the "for testing purposes" in the sidewall stamp, none of my newer tires have it

I think there may have been a change in the required wording 7 or 8 years ago
Let me put my boots on....I have some oldish Avon Gripsters here. Back in a minute.....both 09s and no "for testing purpose" markings. But I did test them Gripsters myself before and had more than one developping cracks in the threads almost from new.

Out the door and to the scrap pile go the ones I have here, at the age limit lots of thread left but the sidewall cracks don't look good. Hard to see but they sure are there "as found" 2 years ago.
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Old 03-10-2014, 06:59 PM   #27
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Originally Posted by craigincali View Post
Okay. I guess this is where I am confused. I have Scorpions on the 990 and the rear load weight is around 730. I weight 230 plus the bike makes it close to 730 so does that mean I cant load up the bike without being over the max load for the tire???
The whole KTM 990 Adventure weights around 460 lb dry.
Your geared body plus bike's fluids add about 260 lbs.
That is a total weight of 720 lb.

Let's assume your rear is carrying 60~65% of that total weight, then your rear is carrying around 455 lb.

If you add luggage on the tail, that extra weight goes mainly onto the rear tire.

If your tire is marked with a load index, use this chart for the max load at recommended pressure and max speed.

If you must temporarily overload the tire, just put some more pressure and ride slower.

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Old 03-12-2014, 07:50 PM   #28
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Originally Posted by cycleman2 View Post
Short answer is no. The tire load is totally different than the Total GVW of the vehicle. The stamps on the tires represent the maximum load that tire will carry with the max air pressure at 42 lbs. That air pressure is not to be exceeded. The bike manufacture sets the recommended tire pressure and I've yet to see one that was over 41 lbs ( rear tire on my 08 Heritage Softail ), most are in the range of 36-40 lbs.

All bikes will have a sticker somewhere on them that will tell you the GVW, the dry weight etc. As a general rule if you put both the rider (220 lbs )and the passenger( 150 lbs ) , both with gear, on a typical bike with a GVW of 940 lbs, then you are going to have about 40 lbs maximum load carrying capacity left which includes the weight of saddlebags, trunk etc. Not a lot of carrying capacity and most bikes you'll see on the road are overloaded, especially if you are travelling 2up.

So you can see that the rear tire might have a 900 lb max load and the front tire might have a 700 lb load. You can't add them together and come up with how much weight the bike can carry. You always have to load the bike to its manufactures specs not its tire specs.
Thank you for explaining that in language I can understand! Great answer.
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