Tire pressure Michelin Commander 2
Cruiser
Joined: Aug 2016
Posts: 181
Likes: 44
From: Toronto, Ontario
XRX is right. The maximum pressure on the side of the tire is the correct pressure if you're loading the tire to its maximum weight rating. Anything less and you end up with less than the optimal contact area. For every pound under the max the contact patch gets smaller. With a lightly loaded tire at its maximum pressure it's like riding on a ball bearing instead of a tire.
A very rough way to arrive at a reasonable pressure is to take the weight rating of the tire and divide it by the maximum pressure, then multiply the result by the actual load on the tire.
A very rough way to arrive at a reasonable pressure is to take the weight rating of the tire and divide it by the maximum pressure, then multiply the result by the actual load on the tire.
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Road Captain
Joined: May 2016
Posts: 506
Likes: 82
From: Southern NH
Here is another forum that says more heat lower pressure https://www.*****************/forums...r-cupping.html do a search on the internet, then state what you have learned.
Grand HDF Member
Joined: Nov 2012
Posts: 3,515
Likes: 887
From: Upstate New York
Just run your tires at the pressure that your manual says and check them often. If you are going to be riding 2 up or camping and have extra weight then add some more air but don`t go over the max that is printed on the tire. I use a bicycle pump for adding 1 or 2 lbs. of air when needed. Geez, some people make the simplest things more difficult.
Grand HDF Member
Joined: Nov 2012
Posts: 3,515
Likes: 887
From: Upstate New York
That's bad "advice".
The manufacturers tend to recommend higher pressures than optimal for a very good reason.
If you run tire pressures that are too high, and the resulting reduction in traction results in a crash, you can't sue anyone, because the motorcycle didn't fail, and the tire didn't fail- YOU put too much air in the tire and operated the motorcycle beyond it's reduced capabilities.
If you run the tire pressure too low (like only having 5 PSI cold) and the tire fails, then that opens the door for the question of whether the tire failed because of a defect in manufacturing or design. They can't question the tire pressure, because there's no way to measure air that exited the failed tire and left the scene of the crash.
The manufacturers tend to recommend higher pressures than optimal for a very good reason.
If you run tire pressures that are too high, and the resulting reduction in traction results in a crash, you can't sue anyone, because the motorcycle didn't fail, and the tire didn't fail- YOU put too much air in the tire and operated the motorcycle beyond it's reduced capabilities.
If you run the tire pressure too low (like only having 5 PSI cold) and the tire fails, then that opens the door for the question of whether the tire failed because of a defect in manufacturing or design. They can't question the tire pressure, because there's no way to measure air that exited the failed tire and left the scene of the crash.
Road Captain
Joined: Aug 2018
Posts: 690
Likes: 121
From: On my motorcycle
XRX is right. The maximum pressure on the side of the tire is the correct pressure if you're loading the tire to its maximum weight rating. Anything less and you end up with less than the optimal contact area. For every pound under the max the contact patch gets [larger]. With a lightly loaded tire at its maximum pressure it's like riding on a ball bearing instead of a tire.
Just run your tires at the pressure that your manual says and check them often. If you are going to be riding 2 up or camping and have extra weight then add some more air but don`t go over the max that is printed on the tire. I use a bicycle pump for adding 1 or 2 lbs. of air when needed. Geez, some people make the simplest things more difficult.
The manufacturers tend to recommend higher pressures than optimal for a very good reason.
If you run tire pressures that are too high, and the resulting reduction in traction results in a crash, you can't sue anyone, because the motorcycle didn't fail, and the tire didn't fail- YOU put too much air in the tire and operated the motorcycle beyond it's reduced capabilities.
If you run the tire pressure too low (like only having 5 PSI cold) and the tire fails, then that opens the door for the question of whether the tire failed because of a defect in manufacturing or design. They can't question the tire pressure, because there's no way to measure air that exited the failed tire and left the scene of the crash.
Are you trying to say that setting your cold tire pressures low enough to allow the tires to come up to proper operating temperature, is somehow a bad idea?
In this case, yes, it is bad "advice". There is no single arbitrary tire pressure that is correct for every rider, on every tire, in every riding circumstance.
That's why I took the time to type out the information on determining correct cold tire inflation pressures based upon pressure rise from cold to hot.
Where did I say in my post to put more than the recommended amount of air in the tire?
Let's say that you're shooting for a 4 PSI pressure rise from cold to hot. The first morning, your tire pressures are 30F/30R cold, and you end up with 40F/40R hot. That's a 10 PSI increase- that's too much.
So the second day, you try 33F/33R cold, and end up with 38F/38R hot. That's a 5 PSI increase. You're getting closer.
On the third day, you try 34F/34R, and end up with 38F/38R hot. That's a 4 PSI pressure rise from cold to hot, which is what you were shooting for.
Last edited by ChickinOnaChain; Sep 20, 2018 at 09:37 AM.
Extreme HDF Member
Joined: Jun 2014
Posts: 11,448
Likes: 2,299
From: NW Ohio
Without knowing the proper operating temperature (or pressure after this arbitrary "rise"), it's all random numbers anyway.
Lets not even get into having good measurement equipment and using it correctly. Then we need to discuss what gas goes into the tire...dry nitrogen, dry air, wet air, argon, CO2... Check the charts for them. They all react differently.
Yawn.
Lets not even get into having good measurement equipment and using it correctly. Then we need to discuss what gas goes into the tire...dry nitrogen, dry air, wet air, argon, CO2... Check the charts for them. They all react differently.
Yawn.
Last edited by cggorman; Sep 17, 2018 at 03:13 AM.
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Advanced
Joined: Jul 2018
Posts: 73
Likes: 19
From: NC
Best advice is to follow the recommended tire pressures set by the manufacturer for that specific tire. Most tire companies will list these on their website. I get to see and change a lot of motorcycle tires. Low tire pressure is THE number one culprit in motorcycle tire wear/failure for the regular rider. Most bikes come into the shop with tires way under pressure. I have been to several training seminars by the big names in motorcycle tires and they all recommend to keep it within 5% of max. but not over max.
Under pressure motorcycle tires ( especially the rear) get very hot. I have seen one particular brand chunk and come apart if they get to hot while running low pressure. Most just wear to quickly or very evenly. Harleys usually have one wheel that leaks more than the other and on mine its the front. I make it a point to check tire pressure several times a week.
As cggorman said you also need a good way to measure the tire pressure. Invest in a good dial gauge. Like many of us I keep a cheap pencil type gauge on the bike for quick checks but those are notoriously inaccurate.
IMO if your bike rides to harsh with tires set at proper pressures you need different tires or better suspension.
Back to the OP's question. I would set that tire to 40psi in rear and 30psi front for your bike with CMII 's.
WOW.... to much coffee
Under pressure motorcycle tires ( especially the rear) get very hot. I have seen one particular brand chunk and come apart if they get to hot while running low pressure. Most just wear to quickly or very evenly. Harleys usually have one wheel that leaks more than the other and on mine its the front. I make it a point to check tire pressure several times a week.
As cggorman said you also need a good way to measure the tire pressure. Invest in a good dial gauge. Like many of us I keep a cheap pencil type gauge on the bike for quick checks but those are notoriously inaccurate.
IMO if your bike rides to harsh with tires set at proper pressures you need different tires or better suspension.
Back to the OP's question. I would set that tire to 40psi in rear and 30psi front for your bike with CMII 's.
WOW.... to much coffee
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