HCH II-Specific Discussions Model Years 2006-2011

Tire inflation and gas mileage

Thread Tools
 
Search this Thread
 
  #11  
Old 04-08-2008, 07:02 PM
cbibbs's Avatar
Active Enthusiast
Join Date: Sep 2007
Location: Detroit, MI
Posts: 200
Default Re: Tire inflation and gas mileage

Originally Posted by mmrmnhrm
Keep in mind that our tires are smaller than a Crown Vic's.

Bugger nash for beating me to the punch... I love linking that article when people start getting all uppity about my tires
Look, there a lot of guys running Civics in the street classes at SCCA autocross events. That's probably a better starting place to judge what would give optimal grip on your HCH than a police article on Crown Vics, no? As you've pointed out, you're not running the same size tire nor is the car the same size.

What you run your tires at is your choice and I'm not going to tell you to lower the pressure, but you have to concede you've made a sacrifice.
 
  #12  
Old 04-08-2008, 08:03 PM
msantos's Avatar
Eco Accelerometrist
Join Date: Jun 2006
Location: Winnipeg, MB
Posts: 1,191
Default Re: Tire inflation and gas mileage

Originally Posted by cbibbs
...
What you run your tires at is your choice and I'm not going to tell you to lower the pressure, but you have to concede you've made a sacrifice.
Not many of us will concede to that. This issue has been beaten to death over and over again... for years already.

It would be a net sacrifice if the negatives outweighed the positives. Let's see:

Undeniable positives of running higher tire pressures:
- awesome fuel economy potential due to lowest road resistance.
- tires wear better and last longer
- improved handling
- greater safety under many adverse situations - hydroplaning , etc.
- lower tire temperatures. A cooler tire is a safer tire.

Possible negative(s):
- harsher ride.


Cheers;

MSantos
 
  #13  
Old 04-08-2008, 11:07 PM
ElanC's Avatar
Ridiculously Active Enthusiast
Thread Starter
Join Date: Oct 2005
Location: El Cerrito, CA
Posts: 700
Default Re: Tire inflation and gas mileage

40 psi isn't over-inflation. It's well within the safety margin of the tires.

Talk to a real pro at a tire store. He'll never tell you to inflate more than the manufacturer's spec because he doesn't want to be responsible for moving you out of spec. But tell him you're inflating to forty and you'll see him nod in approval. The only reason cars in America are spec'ed at 32 psi is because the manufacturers think we're all soft in the tush. 32 psi is about low as you can go without starting to squish the tires.

Improving the MPG by 10% means that the gas savings will pay for my replacement tires as long as I own the car. And as a byproduct it means I'm driving a greener car. Any HCH owner should appreciate that.
 

Last edited by ElanC; 04-08-2008 at 11:11 PM. Reason: Added a sentence.
  #14  
Old 04-09-2008, 06:02 AM
spinner's Avatar
Pretty Darn Active Enthusiast
Join Date: Oct 2007
Posts: 467
Default Re: Tire inflation and gas mileage

Originally Posted by msantos
Possible negative(s):
- harsher ride.
- At high speed, tires run hotter, increasing the tire pressure and the chance of damage
- Easier to damage by potholes or debris
- Can't isolate road irregularities. Uncomfortable ride and more noise
- Could be found at fault in an insurance claim on the grounds of operating the vehicle outside of manufacturer's recommendations


Questions: Why do you always remind everyone of the cyclic nature of the forum? Why not put your energy instead towards getting topics merged? Have you tried navigating all the search results of redundant topics?
 
  #15  
Old 04-09-2008, 06:34 AM
medicmike's Avatar
Pretty Darn Active Enthusiast
Join Date: Mar 2006
Location: Lake Zurich, IL
Posts: 300
Default Re: Tire inflation and gas mileage

Originally Posted by cbibbs
I don't know what to tell you. That's much higher than what any tire guy would recommend. Are you saying it handles better because it feels good to you or because you can perform a cone weave faster? 50psi would be high for autocross and daily driving should certainly be lower than that.
Keep in mind that the Dunlops, at least, are rated for 45 psi(?) max cold. 50 is still high, obviously, but the 32 that is recommended is too soft and the tires handle poorly. On the flip side, I noticed a marked decrease in traction this winter with my tires at 40-42 psi.
 
  #16  
Old 04-09-2008, 07:03 AM
cbibbs's Avatar
Active Enthusiast
Join Date: Sep 2007
Location: Detroit, MI
Posts: 200
Default Re: Tire inflation and gas mileage

Originally Posted by medicmike
Keep in mind that the Dunlops, at least, are rated for 45 psi(?) max cold. 50 is still high, obviously, but the 32 that is recommended is too soft and the tires handle poorly. On the flip side, I noticed a marked decrease in traction this winter with my tires at 40-42 psi.
32 is definitely below ideal high-speed performance or fuel economy psi for normal temperatures.

Getting tires up to operating temperature in cold weather is tricky business. If you don't drop a few psi, you'll find you never get quite the right amount of friction or keying.
 
  #17  
Old 04-09-2008, 07:39 AM
msantos's Avatar
Eco Accelerometrist
Join Date: Jun 2006
Location: Winnipeg, MB
Posts: 1,191
Default Re: Tire inflation and gas mileage

Originally Posted by spinner
- At high speed, tires run hotter, increasing the tire pressure and the chance of damage
Good points spinner.

But since you brought it up and to be more specific: all tires will run hotter at higher legal speeds. However, the ones that sport lower inflation values will consistently run hotter due to the added friction.
So even if speed is factored in, the probability of tire failure due to heat build-up remains statistically higher with lower tire pressures. That is why I simply love direct TPMS systems since that seems to be what's need to reduce many of the tire failures that occur in our highways.

Yes and yes. A "harsher ride" will implicitly mean that the road imperfections will be transmitted to the suspension components and those in turn will work harder and less effectively in reducing road noise and comfort. If one drives on many cobble-stone roads or roads loaded with pot-holes then running the tires at Max Pressure is not going to be nice at all. That is why we often recommend people raise the pressures gradually until they find a good balance of FE and comfort that is suitable to them.

The "insurability" and liability aspect is a good one, but that too is not a universal concern for everyone. As an example, my provincially managed insurance policy does not regard higher tire inflations as being a meaningful determinant for failure. Notice my use of the word "higher". However it does refer to under inflated tires as a significant attribute impacting safety and even liability.
While there are definitely limits as to how "high" is too high, the best approach for most folks is not to exceed the max pressure rating for the tire. Calling your insurance company and asking does not hurt either.

The good thing about these forums is that we all have the opportunity to discuss, debate and share knowledge that while useful to some may not necessarily apply to everybody. If you notice, my previous post was not qualified by "all-inclusiveness" either.


Cheers;

MSantos
 
  #18  
Old 04-09-2008, 09:33 AM
mmrmnhrm's Avatar
Wo ai Zheng!
Join Date: Apr 2006
Location: Columbus, OH
Posts: 654
Default Re: Tire inflation and gas mileage

Originally Posted by spinner
Why not put your energy instead towards getting topics merged?
Because people are lazy and would just start a new thread anyways.
 
  #19  
Old 04-11-2008, 04:46 PM
spinner's Avatar
Pretty Darn Active Enthusiast
Join Date: Oct 2007
Posts: 467
Default Re: Tire inflation and gas mileage

Suspecting that my tires came back from the dealership with low pressure, plus thinking tire pressure might be accounting for a little rear wiggle, I have been pumping it up a bit. My 12V portable says 40psi. Tires feel a little more wooden but still plenty comfortable.
 
  #20  
Old 04-11-2008, 06:34 PM
holicow's Avatar
Active Enthusiast
Join Date: Jun 2004
Location: Turtle Jxn, NC
Posts: 139
Default Re: Tire inflation and gas mileage

Originally Posted by spinner
- At high speed, tires run hotter, increasing the tire pressure and the chance of damage
- Easier to damage by potholes or debris
- Can't isolate road irregularities. Uncomfortable ride and more noise
- Could be found at fault in an insurance claim on the grounds of operating the vehicle outside of manufacturer's recommendations


Questions: Why do you always remind everyone of the cyclic nature of the forum? Why not put your energy instead towards getting topics merged? Have you tried navigating all the search results of redundant topics?
More sidewall flex at lower psi will cause higher pressure changes due to the heat generated (and the fatigue generated.)

I would rather hit a pothole at 50 psi than at 30. The lower pressure will probably cause more damage to the tire, and is much, much more likely to damage the wheel itself.
 


Quick Reply: Tire inflation and gas mileage


Contact Us -

  • Manage Preferences
  • Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Your Privacy Choices -

    When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.

    © 2024 MH Sub I, LLC dba Internet Brands


    All times are GMT -7. The time now is 03:41 PM.