The pressure, the pressure! Yet another tire tread.

[sq61708]

Hi folks

I've been running my 91 Connie on the tried and true  Avon Storm2 / Azarro combo for the last 5 sets of tires and I am very satisfied with them except that  they just don't last long enough for my money.  So I just ordered a Michelin PR3 / Shinko 777 set from my local tire shop.  I've searched the forums and this seems to be a good choice according to many of you. A good mix of performance, traction in the wet ( I ride in any weather ) and durability. Should be getting them installed this week.

So here is my question.  For those of you who have used these tires together, what tire pressure do you run them at.  I usually set my Storm front at 40 psi and my Azarro rear at 42. 
I  do mostly solo riding with a mix of 80 percent highway and 20 percent city streets with the occasionnal two up riding on weekends on back roads.

Thanks for your 2 cents.

[XR6]

Set your tyre pressures go for a ride and get the tyres warm. stop and check the tyre pressure frt and rear, the reading should be 4 psi more, the tyres should be warm to touch and if you rode on to some stones on the pavement they should stick to the tyres. Eg the tyres are now warm and grippy.

If you only get 2psi lift in the front, drop your tyre pressures until you get the 4 psi lift. ( tyre too cold)
Do this for both tyres and you will get the best grip no matter what tyre combinations you use.
When you get home and let the tyre cool ( next morning) check the cold pressure and then always start with those cold pressures before each ride. This should be the best settings for YOU. 

This will not work on a freezing cold day

NB.  If you change a suspension setting eg sag or ride preload, ride height etc  you will upset the 4 psi test. So then start again until you get the 4psi lift in pressure in both tyres.
 This info was shared with me by a very good tyre tech.

[Jim __]

I've got the same combo and have settled at 38 psi front and 42 psi rear.  I was more concerned with matching the load rating on the front tire compared to the OEM tire set to 36 psi.

XR6,
That is an interesting procedure for setting up tire pressure.  I was wondering how close your settings are to the 36/42 psi.  Also, how much difference have you seen in pressure increase between flat, straight highway and rolling through the twisties?  I guess I'd be more concerned about running the tires under inflated than over inflated.
Thanks

[works4me]

The advantage of XR6's method is it doesn't require
an accurate tire gauge, only a consistent one.

[XR6]

The advantage of XR6's method is it doesn't require
an accurate tire gauge, only a consistent one.

Good point, Yes,  make sure you use the same gauge ALL the time

[Steve in Sunny Fla]

XR6's method is based on the 10% rule.  The idea is to set the cold pressure so that the tire gains 10% pressure as it comes to full warm running temp. During particularly warm weather, you may actually have to raise the cold pressure in order to keep the 10% gain, as going higher than 10% will result in much more rapid tire wear. HTH, Steve

[sq61708]

Thanks for the info. 
I just learned that the tires a out of stock so my order is delayed another 2 or 3 weeks. Oh well, no big deal, the weatherman is calling for snow tonight in my neck of the woods.

XR6  your method sounds a bit complex and now with SISF reply I don't know if I will get it right. Probably will start with the numbers Jim gave and will keep an eye on how much it changes after a good ride.

If anyone wants to add a comment I still have a couple of weeks before I try them out.

[SteveJ.]

I also run the PR3/Shinko combo, about 5 or 5 sets now. I also have an after market TPS setup that also includes tire temp.

I've found that anywhere between 38 and 42 in the front raises tire temp about 20* or so in front and about 3-4 lbs tire pressure, more if hammering on the slab in full sun, especially on black top.

The rear is more difficult, to the point that I quit using the 4 lb rule. I think it's cuz it's bias, and bias seem to run warmer. I was getting about a 6-8lb increase, even after hiking the cold pressure to 450lbs. All this resulted in is ruining the rear sensor due to pressures rising well into the mid 50 range. JMO.


It is interesting to note the swing in cold tire pressure due to ambient temp. For approx every 6*F, the tire will gain/loose a pound. A forty degree swing in ambient will change the pressure by about 6*. Interesting when you consider living out west, it's pretty normal to have that swing on a daily basis, not even counting cold/warm fronts.

Anyhow, having said all that, I've settle on about 40 in front and 42 in back. I'm not sure how the new HD tire will deal with the same pressure.

[timsatx]

The rear is more difficult, to the point that I quit using the 4 lb rule. I think it's cuz it's bias, and bias seem to run warmer. I was getting about a 6-8lb increase, even after hiking the cold pressure to 450lbs. All this resulted in is ruining the rear sensor due to pressures rising well into the mid 50 range. JMO.

Wow, I didn't think you could put that much pressure in them