Calivette2003

I have a 2014 GLK-350 with the 20" AMG rims (not what it came with stock). I just got replacement Toyo Prezza 245/45/20 replacing the Pirellis of same size. Of course the gas filler cap and inside drivers door tire ratings only applies to the original 19' rim/tire combo the car originally came with. After leaving the tire store I noticed a huge split between the tire pressures on the monitor LF-44, RF-47, LR-41, RR-39. For now I set a nominal 41 cold/ 44 hot (like the Pirelli's) but want to know the proper pressure, not a guess. The 35/39 for a stock 245/50/19 tire will result in the premature wear of the outer edge of the tires in front (too low).


This answer is nowhere on the Toyo website nor on the internet.

Calivette2003

AzCamel

I normally run 36f/38r cold and it will be 39f/41r hot. If your concerned about longevity then look at your alignment specs, MB and most European cars are aggressive with their toe and camber for performance handling, I changed mine to all toe at .01-.03 and front camber at 1.0 and rear at 1.25. Your turn in will not be as quick but your tires will last longer and wear even. I run more aggressive spec on my fun car, the GLK is the wife's daily driver so mileage is the paramount concern.

If your only getting outer edge wear then I would look at your alignment, typical center wear will indicate over inflation and outer wear (both sides) indicate under inflation. Abnormal wear like only one side or chopping indicates alignment issues and or suspension issues.

Calivette2003

You never mentioned but I'm assuming your wife has a standard 19 inch rim tire combo correct not the 20 inch AMG rims with the low-profile tires what I be correct in asking that ?

as for the where it was one on both outer edges underinflation and that's at 40 psi which is why am running these at 41 right now I believe the 3639 you're quoting is for your standard 50 to 70 series tire on the low-profile tires they require a better bigger pressure but I don't know exactly what that number is

just like your wife's car this is just a daily driver I have a Corvette and a Hayabusa from my fun vehicles

Calivette2003

I just read a couple articles on current driver and another Internet site stating that the low-profile tires require 40 PSI or greater because of the sidewall for whatever reason the little profiles were choir over 40 but no one gives me that exact number the max PSI is 50 as written on the tire the tire shop I got the work done said it should be set at 45

bop11

Anywhere between 38 and 48. It is up to you and your driving style. Obviously the higher the pressure the harder the ride. Check for wear in the center vs edge. Your normal load and style is different than mine that is one reason I stick with the 19". But there is no perfect answer for everyone.