Purchased Pirelli P7s

[Fish64]

Purchased Pirelli P7s

After my Toyo OEMs (225-55-R19) wore out after only 43,943 km (I am an engineer, I cant help but measure everything), I found a reasonable sale at Canadian Tire for the Pirelli P7s. The local dealer matched the sale, plus I will receive a $70 rebate (MasterCard?) which apparently takes 3 months to arrive in the mail. The P7s have been installed for 3 weeks now and are performing well. At first I found them a bit soft in the corners, not as stiff as the Toyos. I checked the tire pressure cold, and the dealer had set them at 34 psi. I increased it to 36 psi and it has made a difference, it is now more stiff when cornering, closer to the Toyo feel, which I really liked.

Regarding road noise, they seem quiet, but I cant really compare to the Toyos. Due to a bad rear diff (see my other thread), unfortunately road noise had been an issue for a while which I mistakenly attributed to the Toyos premature wear.

I had them for an extended period on the highway this weekend, and they did well at highway speeds (100-130 km/hr), still responsive, but maybe not as solid feeling as the Toyos. Someone else had mentioned in another thread that the P7s have softer sidewalls, so increasing the tire pressure to 40 psi may help. I may try it at 38 psi in a week or so to see if there is any noticeable improvement.

Hopefully these will last longer than the OEMs!

 

[yrwei52]

Purchased Pirelli P7s

Check the maximum inflation pressure on the sidewall of your new Pirelli Cinturato P7. It should be at only 44 psi instead of 51 psi on OEM Toyo A23's. So you really don't want to put too much air into your P7 other than the spec at 36 psi cold. This lower spec on maximum inflation pressure at 44 psi on Pirelli Cinturato P7 and Michelin Premier LTX is the reason I have reserves getting these two tires. I'll get tires with 51 psi maximum inflation pressure like the OEM Toyo A23 is having.

 

[brillo54]

Check the maximum inflation pressure on the sidewall of your new Pirelli Cinturato P7. It should be at only 44 psi instead of 51 psi on OEM Toyo A23's. So you really don't want to put too much air into your P7 other than the spec at 36 psi cold. This lower spec on maximum inflation pressure at 44 psi on Pirelli Cinturato P7 and Michelin Premier LTX is the reason I have reserves getting these two tires. I'll get tires with 51 psi maximum inflation pressure like the OEM Toyo A23 is having.

According to tirerack.com "A tire's maximum inflation pressure is the highest "cold" inflation pressure that the tire is designed to contain." More info on the subject here: http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=196 So a 38 psi cold setting would be 13.6% below a 44 psi max., which is enough of a safety margin for me.

I hope the OP will give us updates as time goes on.

 

[Fish64]

Thanks for the info yrwei52, I knew about the 44 psi max, so I was thinking that 38 psi would be as high as I would go. Also, I don't want to create an opportunity for uneven wear; after having the Toyos crap out after only 44,00 km, I want the P7's to last.

And yes brillo54, I will provide another update, probably mid summer, after a few roads trips.

 

[yrwei52]

Purchased Pirelli P7s

According to tirerack.com "A tire's maximum inflation pressure is the highest "cold" inflation pressure that the tire is designed to contain." More info on the subject here: http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=196 So a 38 psi cold setting would be 13.6% below a 44 psi max., which is enough of a safety margin for me.

OP mentioned people were suggesting 40 psi due to the softer sidewall of Pirelli Cinturato P7. So as many people here are putting 40 psi in their OEM Toyo A23's. Now for 40 psi the safety margin is only ~9% for tires with only 44 psi maximum inflation pressure. Either way, I'd think getting tires with 51 psi MIP like the OEM Toyo A23 is a lot safer than 44 psi MIP tires as we all want bigger safety margin. I also believe 51 psi MIP tires are newer designed and better constructed for strength and efficiency. And there're lots of excellent 225/55R19 tires with 51 psi MIP you can choose.

In addition, the maximum load is closely related to maximum inflation pressure. While a tire's maximum load is the most weight the tire is designed to carry, its load carrying capacity at lower inflation pressures is proportional to how much inflation pressure is used. Pirelli Cinturato P7 has maximum load 1,709 lbs. at 44 psi maximum inflation pressure; whereas Toyo A23 has the same maximum load 1,709 lbs. at 51 psi maximum inflation pressure. When we put the same factory specified 36 psi for these two tires, the load carrying capacity between the two are totally different. So as the patch contact to the ground hence affecting the wear pattern.

That's why I prefer my next set of 225/55R19 99H/V tires are having 51 psi maximum inflation pressure like the OEM Toyo A23 tires.

 

[yrwei52]

Purchased Pirelli P7s

Thanks for the info yrwei52, I knew about the 44 psi max, so I was thinking that 38 psi would be as high as I would go. Also, I don't want to create an opportunity for uneven wear; after having the Toyos crap out after only 44,00 km, I want the P7's to last.

If you care about the wear pattern, try to use factory spec 36 psi first instead of 38 psi as explained above since Pirelli Cinturato P7 has lower maximum inflation pressure than the factory tires. P7's softness is its nature and by adding more air pressure to offset it may have other side effects such as uneven wear - most likely wearing faster in the center thread. You just have to experiment it out gradually.