sexyRTboi Posted July 7, 2014 Report Share Posted July 7, 2014 So as many know, I have replaced my worn out tires with 235/55/19 Conti TrueContact's. Couldnt be more pleased however Im abit confused. My MPG became worse since having them put on and one of the tires has been alil off from the others PSI. So I went to put air in them the other day, read the sidewall and it said MAX PSI 51 ............. when I checked what they were, the tires were only at 34 all around (36 on the one) .... So Ive put them all at around 48 PSI and have noticed a GREAT improvement in driving, rolling resistance and fuel econ ... went from 14.5L/100km down to 10.1 and holding ........ the ride is alil firmer, but I expected that. So my question, when I was talking about this to some friends, people were divided. Some said 48 PSI is way to high and Im going to wear out the tires very quickly .... while others, including myself, felt that 34 PSI was WAY WAY to low for these tires which explained all the earlier issues (mpg, rolling resistance etc) ---- So .... what do you all think? what are yours set at? whats your opinions? Quote Link to comment Share on other sites More sharing options...
bigtsr Posted July 7, 2014 Report Share Posted July 7, 2014 I have found that for the ride I like and an acceptable mpg I have always set pressure 2 lbs greater than suggested on door sticker. While it's nice for mpg you will experience greater tire wear along with increased brake wear, as the DJ has great roll to in stock configuration. Journey_SeXT 1 Quote Link to comment Share on other sites More sharing options...
2late4u Posted July 8, 2014 Report Share Posted July 8, 2014 48 psi is really high and if that is when they are cold then when they heat up they will rise to 50 -51 psi . i have never heard of psi that high i always run around 36 -37 psi. true running that high will get you better mpg but you run the risk of having your tires ove-rinflated and risk having a blow out at hi-way speeds. and also your tires will wear out faster in the middle of the tire . with less traction during wet weather.its your choice as to what you want to do but i would let the psi down at least to 40-41 at the most...goood luck and keep it between the ditches....... Journey_SeXT 1 Quote Link to comment Share on other sites More sharing options...
sexyRTboi Posted July 8, 2014 Author Report Share Posted July 8, 2014 well damn ....... you just made me lose the bet with my fiance .... thanks alot guys ! ... lol .... okay, I get what youre saying .... with gas prices as high as they are, I will shed a tear as I let them down to 38-40 PSI thanks for you help guys ! once again, the DJ community is quick to reply and faster to help me lose bets .... damn. lol jkeaton 1 Quote Link to comment Share on other sites More sharing options...
bramfrank Posted July 8, 2014 Report Share Posted July 8, 2014 (edited) There is a serious trade off between tire grip and gas mileage. The sidewall rating is the MNIIMUM the tire is guaranteed to hold without BURSTING - it is NOT intended as an inflation value. Besides, over-inflating the tires will lead to the tire bulging and the center of the tread will wear out VERY quickly. You will find the proper inflation value for the vehicle on the sticker inside the front door well - by the way, for the DJ the factory rating is 36 psi all around (the spare is another story) regardless of tire size - tires are inflated when COLD (at local ambient temperature, noting that tires heated by the sun are not considered to be cold) - do not drive to a fill station unless you have measured the pressure when cold, and then take into account the pressure rise from that drive for each tire and factor that into the amount of air you fill - if it has gone up 2 psi, then fill 2 psi higher than what you desire - but only if the tires remain warm. Do not go too far above the specified pressure because pressure rises with tire temperature - and on hot days, running on a highway it goes up a LOT. Invest in a GOOD pressure gauge - decent electronic gauges offer the best accuracy and repeatability, since friction plays no part in their operation. I inflate to 37 psi. Edited July 8, 2014 by bramfrank Quote Link to comment Share on other sites More sharing options...
Windancer Posted July 8, 2014 Report Share Posted July 8, 2014 I inflate to 37 psi. I certainly not saying you are wrong, IMO this seems a weeeee bit to high for my liking but to each his own. It would definately help the mileage aspect of it. Maybe it's just all the potholes around here that would make me worry about such pressures. I have a Saturn Sky with 245/45/18 tires and I know I wouldn't go any lower with regards to aspect ratio with our roads. Terry Quote Link to comment Share on other sites More sharing options...
bramfrank Posted July 8, 2014 Report Share Posted July 8, 2014 37 psi is only one pound over the manufacturer spec, which tends to run a it on the soft side, It is also within the margin of error for the vast majority of mechanical pressure gauges, so no issues with safety doing that. Quote Link to comment Share on other sites More sharing options...
Windancer Posted July 8, 2014 Report Share Posted July 8, 2014 37 psi is only one pound over the manufacturer spec, which tends to run a it on the soft side, It is also within the margin of error for the vast majority of mechanical pressure gauges, so no issues with safety doing that. After I wrote that post I thought that 36 was on the door tag, sorry Bramfrank. I am at work and wasn't close to my Journey to see what was specified. Terry Quote Link to comment Share on other sites More sharing options...
rolly Posted July 8, 2014 Report Share Posted July 8, 2014 I hope you people out west are safe from all the flooding out there. It's been a crazy year for weather! Quote Link to comment Share on other sites More sharing options...
Windancer Posted July 8, 2014 Report Share Posted July 8, 2014 (edited) Thanks Rolly, personally I have been spared, luckily, but you are correct, it has been a weird year weather wise out here. We have had so much rain and tornadoes that we are really worried about things. A little known fact is that Regina is still home to Canada's deadliest tornado, (28 dead) way back in 1912. There are numerous photos on Facebook as well as all the news sites of the conditions here at the moment. Terry Edited July 8, 2014 by Windancer Quote Link to comment Share on other sites More sharing options...
Bubba Posted July 9, 2014 Report Share Posted July 9, 2014 The max pressure of 51 psi is for when they are installing the tire on the rim . ( setting the bead ) Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.