Higher tire pressure

[higheroctave32]

so I took the advice that I have seen here regarding raising the tire pressure to improve mileage. I raised the pressure up to 40 psi this morning and noticed a little bit more of a firm ride which is more than fine with me, but more than that I noticed that when I go around a reasonably fast long turn such as on a freeway onramp, before the car had what I can only describe as a slight shimmy, now that sensation seems to have disappeared. Now to monitor any improvement in MPG.

[GrySql]

Makes sense to me.

I ran 42 psi in my OEM 18" GY LS2 Eagles and now run 40 psi in my 235/45R-18 Continental PureContact with EcoPlus Technology
tires. I prefer a firm and controlled ride and felt the OEM tire pressure on the door was too low. I did not have any issues, those are both 51 psi rated tires.

[acdii]

I just checked mine the other day, I have one tire with a slow leak. They were all over the place, now they are at 42 each and the ride is improved. They still thump, and need to be replaced.

[higheroctave32]

I prefer firm and controlled also. The stock tire pressure is definitely too low. Resulted in lower response and a little unsettled feeling. Much better at 40. I was little surprised at the 51psi rating on the tire.

[GrySql]

Usually the Low Rolling Resistance (LRR) tires have higher psi ratings, I think some members run their tire pressure even higher than I do.

I tried as much as 50 psi and after testing various pressures settled on the ride quality I liked at the psi I mentioned earlier.

 

I had the PCM Recall done the other day at my local Dealer, the final Work Order had a box checked that my tires were set to OEM spec's (34 PSI).

When I got home they were still at 40 psi, i suppose the Tech either just waved the air pressure gauge over the tire or checked and left it alone, which was okay with me.

[Texasota]

I was little surprised at the 51psi rating on the tire.

 

From Tirerack:

 

 

The pounds per square inch (psi) pressure number branded on the tire's sidewall identifies the maximum cold inflation pressure that specific tire is rated to hold. However, the tire's maximum pressure is not necessarily the correct pressure for every vehicle upon which the tire can be used (almost all vehicle manufacturers' recommended tire inflation pressures are less than the tires' maximum pressure).

[SteveB_TX]

Usually the Low Rolling Resistance (LRR) tires have higher psi ratings, I think some members run their tire pressure even higher than I do.

I tried as much as 50 psi and after testing various pressures settled on the ride quality I liked at the psi I mentioned earlier.

 

I had the PCM Recall done the other day at my local Dealer, the final Work Order had a box checked that my tires were set to OEM spec's (34 PSI).

When I got home they were still at 40 psi, i suppose the Tech either just waved the air pressure gauge over the tire or checked and left it alone, which was okay with me.

 

When I had my oil/filter done on the Z at the Ford dealership, the multi-point inspection sheet showed the spare tire was good, which is miraculous since I do not have one of those precious gems. :)

[corncobs]

 

When I had my oil/filter done on the Z at the Ford dealership, the multi-point inspection sheet showed the spare tire was good, which is miraculous since I do not have one of those precious gems. :)

Maybe the checked the fixa flat stuff instead for the expiration date.

Otherwise it's pretty hilarious ;)

[HybridDragon]

Another interesting tip - use a slightly higher tire pressure

 

Just pumped mine (225/50-17) up to 40 psi

I definitely like the handling/feel quality better

 

Will run like this for a while and see how it goes

[Sleddog]

I run mine at the recommend pressure. The ride is fine and my mileage is great. My trip are usually 53 to 60 mpg each way, depending on conditions and traffic.

[Waldo]

The biggest downside to the higher pressure (if you like the ride) is longer stopping distances. All of you saying "everything is fine" haven't had to make any panic stops obviously. It might be a rare occurrence, but that extra foot or two the lower tire pressure gives you could make the difference between a crash and not.

[tr7driver]

I have settled on 42 as the best for ride/mpg combination. There is a guy on the C-max energi site that claims 51 will increase the tire life of the Michelins. I haven't gone that high. At 45 the ride gets a little to harsh for me with the G 18's.

[acdii]

The biggest downside to the higher pressure (if you like the ride) is longer stopping distances. All of you saying "everything is fine" haven't had to make any panic stops obviously. It might be a rare occurrence, but that extra foot or two the lower tire pressure gives you could make the difference between a crash and not.

Just the fact its a hybrid can make panic stops longer since the pads and rotors barely have any wear on them, at times they act as newly installed brakes. Had that happen a few times now. Takes much greater pedal pressure to lock them up than on either of my non hybrids. I find myself overshooting the stop line at times when I have to stop fast due to stupid lights at the bottom of a hill. The only times braking seems to be really good is when they are damp.

[GrySql]

In the driving around here my hybrid brakes are nicely bedded, and try as I might, near full lockups happen.

There is also load to consider and the type of roads you frequent, we have lots of twisty mountain roads and my FFH carries more that just one person most of the time.

Weather conditions and road surface material also affect stopping efficiency.

We're not all using the same tires either, my new Cont tires do not react the same as the OEM GY LS2's.

I'd like to see some modern braking distances data with various PSI in the same tire. The NHTSA has a older data sheet with some examples, it's interesting to read.

 

The door sticker cannot be correct for every tire or car load situation, more likely it is a compromise of various factors.

A tire load/inflation table is something that can help determine your safe & correct tire pressure under different situations.

The Toyo table is included here:

LoadInflation_Table_P-LT_102913.pdf

 

[Waldo]

The door sticker cannot be correct for every tire or car load situation, more likely it is a compromise of various factors.

A tire load/inflation table is something that can help determine your safe & correct tire pressure under different situations.

The Toyo table is included here:

LoadInflation_Table_P-LT_102913.pdf

 

 

The door sticker is never "correct". There is no such thing as a "correct" tire pressure, it's always a compromise of different factors. There is a "correct" tire pressure for optimal stopping distance, there is a "correct" pressure for best fuel economy and there is a minimum pressure for a given load requirement. But the chances that those three all line up to the same pressure is pretty much zero. The door sticker is just what Ford chose as the best compromise for what it figured customers would want. Sometimes the door sticker is set at the minimum load, which means going any lower could be dangerous - that's why you should never go lower than the sticker - but especially now with CAFE requirements, the tire pressure is raised a few psi above the minimum for fuel economy considerations.

 

Note the load table you link to is really a fairly generic thing. The Tire and Rim association sets minimum requirements for pressure/load/size that all tires must meet. But not all tires are the same, certainly some will exceed the load tables by quite a bit while others will just barely make it.

[md13ffhguy]

Just the fact its a hybrid can make panic stops longer since the pads and rotors barely have any wear on them, at times they act as newly installed brakes. Had that happen a few times now. Takes much greater pedal pressure to lock them up than on either of my non hybrids. I find myself overshooting the stop line at times when I have to stop fast due to stupid lights at the bottom of a hill. The only times braking seems to be really good is when they are damp.

On the other hand, because I happily drive it more gently than any car I've previously owned, I've yet to have to make any "panicked" stops. Btw, I've noticed when my brakes are a little damp, they tend to grab more suddenly than expected.

[acdii]

Yep, new brake pads tend to do that when damp too. The lighter you are on the brakes, the longer they take to get a good bedding. Thats what I find with my car. 33K miles and they still feel like brand new brakes.

[corncobs]

Yep, new brake pads tend to do that when damp too. The lighter you are on the brakes, the longer they take to get a good bedding. Thats what I find with my car. 33K miles and they still feel like brand new brakes.

Except for going downhill and hitting a red light at the bottom (and avoid maniacs) you never really use the mechanical part of the brakes.

[GrySql]

Moved to the Wheels & Tires Forum. There is some good info for that Topic.

[md13ffhguy]

Yep, new brake pads tend to do that when damp too. The lighter you are on the brakes, the longer they take to get a good bedding. Thats what I find with my car. 33K miles and they still feel like brand new brakes.

Little to no brake dust is a plus, too!

Still, I'm with Sleddog - I'm keeping my tire inflation pressure at the "recommendation" on the door frame. I don't feel like I need to squeeze out too many more MPGs.

[acdii]

Mine is raised for handling. I prefer a firm tight car over mush. I set the MKT to Comfort once, once.

[TonyHzNV]

Makes sense to me.

I ran 42 psi in my OEM 18" GY LS2 Eagles and now run 40 psi in my 235/45R-18 Continental PureContact with EcoPlus Technology

tires. I prefer a firm and controlled ride and felt the OEM tire pressure on the door was too low. I did not have any issues, those are both 51 psi rated tires.

Question: At what point (miles) did you change out your OEM GY's for the Conti's? Did you wear out the OEM tires first, or did you feel it was worth the price for a better tire? If you DID wear out the originals, how many miles did you get out of them? Just curious. I have the same 18" GY's on my '14 FFH and at least now I can bump up the pressure knowing that it wasn't a problem for you or others. I thought 34 was a little on the low side myself. I'm going to bump them up tomorrow. Looking forward to feeling the difference and maybe a little more MPG. Thanks again for the tip.

[GrySql]

Question: At what point (miles) did you change out your OEM GY's for the Conti's? Did you wear out the OEM tires first, or did you feel it was worth the price for a better tire? If you DID wear out the originals, how many miles did you get out of them? Just curious. I have the same 18" GY's on my '14 FFH and at least now I can bump up the pressure knowing that it wasn't a problem for you or others. I thought 34 was a little on the low side myself. I'm going to bump them up tomorrow. Looking forward to feeling the difference and maybe a little more MPG. Thanks again for the tip.

Some of your answers are here, plus other comments in each Topic that might interest you:

 

http://fordfusionhybridforum.com/topic/8542-tire-life/?p=86018

 

http://fordfusionhybridforum.com/topic/9232-lrr-tires-18/?p=86778

[TonyHzNV]

Some of your answers are here, plus other comments in each Topic that might interest you:

 

http://fordfusionhybridforum.com/topic/8542-tire-life/?p=86018

 

http://fordfusionhybridforum.com/topic/9232-lrr-tires-18/?p=86778

You were right. My answers were there and then some. Thanks for the info! I guess I need to dig a little deeper into these here forums! :) There is a lot of useful information in those threads so now I know about the tread wear indicators on those Conti's and the proper way to rotate tires, thanks to the video link. Now I'm convinced that my personal decision to rotate the tires at 5000 miles is a good idea. I'm just getting started here, but already I have gained so much information from these forums and I really appreciate the hospitality I have been shown by you and many others. Thanks again for the links and Happy Hybriding!

Edited December 29, 2014 by TonyHzNV

[TonyHzNV]

Well, I did get around to bumping up the pressure on my stock GY LS2s today. Set them at 40 PSI and I have to say, I DO like the ride much better. Maybe I'll even take them up to 42 eventually, but for now I'm going to ride around at 40 and get used to the new feeling. Someone mentioned that it felt like being "on rails" and I have to admit, I kind of felt that too! Once again, the Forum has provided excellent advice and I look forward to many happy miles on my new "shoes". That is, until I get those Conti's! :) Happy Hybriding!