Go Back   EcoModder Forum > EcoModding > EcoModding Central
Register Now
 Register Now
 

Reply  Post New Thread
 
Submit Tools LinkBack Thread Tools
Old 01-01-2009, 12:43 PM   #21 (permalink)
93 Metro Streamliner
 
Join Date: Oct 2008
Location: Oregon
Posts: 180

AeroMetro - '93 Geo Metro
Thanks: 1
Thanked 14 Times in 7 Posts
I just check my odometer at a mile post on the highway, then check it again 30 or 40 miles later and see what the discrepancy is.

  Reply With Quote
Alt Today
Popular topics

Other popular topics in this forum...

   
Old 01-01-2009, 03:30 PM   #22 (permalink)
Tire Geek
 
CapriRacer's Avatar
 
Join Date: May 2008
Location: Let's just say I'm in the US
Posts: 796
Thanks: 4
Thanked 393 Times in 240 Posts
And the Clarifying continues:

Quote:
Originally Posted by Jim Allen View Post
Capri: Is that,
"Interesting, that's the dumbest thing I've ever seen!"
or
"Interesting, cool way to do it!" ( : < )
Actually, my reaction was "I wouldn't have thought anyone would do it that way, even though that's a pretty good way to do it."

Quote:
Originally Posted by Jim Allen View Post
..........

Either way, it's not my idea. It's how the programmer wanted you to find the circumference. Easy to do. I though it was cool. My other method is to measure the loaded radius with the tire inflated to the pressure I will use.
No!! The loaded radius is not the way to do this. BTW, this is called the Static Loaded Radius and it only affects ride height - which is why some find it a useful statistic to have.

Long story, but the short version is that the axle is off center both from the top and the bottom of the tire. The tire kind of hangs from the top and pushes down on the bottom.

Quote:
Originally Posted by Jim Allen View Post

..........

If you have other methods, would love to hear about them!

As to centrifugal forces, a tire engineer told me regarding one particular tire (a big, high profile, 38 inch diameter, 15 inch rim, mudder) that the tire grew in circumference by several mm at high speed (he did not define "high"). I never did get to question him further to see if this was a general phenomenon, or something found just on that tire, or others like it. That's why I asked you about it.

This is probably a bias ply tire - and yes, those types of tires will grow. You can see this phenomenon in drag racing - especially Top Fuel where the speeds are high and the tires are exposed.

But we are talking about radial tires with a belt which restricts the growth. In fact, growth of this nature is such a problem for radial tires that higher speed rated tires will have a circumferential overlay which further restricts the growth.
__________________
CapriRacer

Visit my website: www.BarrysTireTech.com
New Content every month!
  Reply With Quote
Old 01-01-2009, 05:28 PM   #23 (permalink)
NightKnight
 
NachtRitter's Avatar
 
Join Date: Dec 2008
Location: Placerville, CA
Posts: 1,595

Helga - '00 Volkswagen Jetta TDI
TEAM VW AUDI Group
Diesel
90 day: 54.39 mpg (US)

Mathilde - '99 Volkswagen Eurovan Camper
90 day: 16.87 mpg (US)
Thanks: 315
Thanked 314 Times in 187 Posts
Quote:
Originally Posted by CapriRacer View Post
Actually, my reaction was "I wouldn't have thought anyone would do it that way, even though that's a pretty good way to do it."
Folks that are into bicycling (as I am) that need to calibrate bike computers will measure this way too (rather than use a tape measure around the circumference)... not that bike computers need to be all that precise, but still the same idea. I usually use chalk on the tread which then leaves a mark on the pavement for several revolutions before becoming too faded, and then measure between the marks.
  Reply With Quote
Old 01-01-2009, 06:45 PM   #24 (permalink)
EcoModding Apprentice
 
Join Date: Oct 2008
Location: Indiana
Posts: 131

Impala - '04 Chevrolet Impala base
90 day: 32.84 mpg (US)
Thanks: 0
Thanked 2 Times in 2 Posts
All tires are subject to the centrifugal force which can make them bulge slightly while rotating. The faster the rotation, the greater the chance of distortion/bulge.
__________________
  Reply With Quote
Old 04-11-2009, 09:43 PM   #25 (permalink)
Master EcoModder
 
NeilBlanchard's Avatar
 
Join Date: May 2008
Location: Maynard, MA Eaarth
Posts: 7,908

Mica Blue - '05 Scion xA RS 2.0
Team Toyota
90 day: 42.48 mpg (US)

Forest - '15 Nissan Leaf S
Team Nissan
90 day: 156.46 mpg (US)

Number 7 - '15 VW e-Golf SEL
TEAM VW AUDI Group
90 day: 155.81 mpg (US)
Thanks: 3,475
Thanked 2,952 Times in 1,845 Posts
Hi,

I recently got a TireRack.com catalog in the mail and they actually have a blurb on low rolling resistance, and they list three tires that are low(er) rolling resistance:

Michelin "HydroEdge Green X" (UTQG Rating 800 A B)
Goodyear "Assurance Fuel Max" (UTQG rating 580 A A)
Bridgestone "Ecopia EP100" (UTQG rating 400 A B)

Has anybody tried any of these, or have you heard anything about them?
__________________
Sincerely, Neil

http://neilblanchard.blogspot.com/
  Reply With Quote
Old 04-12-2009, 03:58 AM   #26 (permalink)
Ernie Rogers
 
Join Date: Feb 2008
Location: Pleasant Grove, Utah
Posts: 133
Thanks: 0
Thanked 20 Times in 12 Posts
Accuracy of speedometer and odometer? Why not just check them with a GPS?

If you are comparing fuel economy, best to make sure both cars are going the same speed, otherwise, what have you proved? With my car, a one mph error in speed makes a one mpg change. I apply corrections to both speed and odometer when it's important to know.

If you increase tire diameter, fuel economy will usually increase, but it will SEEM to go down unless you correct for guage changes.

/Ernie Rogers
  Reply With Quote
Old 04-12-2009, 04:47 AM   #27 (permalink)
Pokémoderator
 
cfg83's Avatar
 
Join Date: Dec 2007
Location: Southern California
Posts: 5,864

1999 Saturn SW2 - '99 Saturn SW2 Wagon
Team Saturn
90 day: 40.49 mpg (US)
Thanks: 439
Thanked 532 Times in 358 Posts
Ernie -

Yeah, I periodically use a GPS correction for my one-size-up-from-stock tires :

http://ecomodder.com/forum/showthrea...ires-2642.html

I apply the correction to my fuel log, so it's like a mini-bonus.

CarloSW2
__________________

What's your EPA MPG? Go Here and find out!
American Solar Energy Society
  Reply With Quote
Old 04-17-2009, 04:46 AM   #28 (permalink)
93 Metro Streamliner
 
Join Date: Oct 2008
Location: Oregon
Posts: 180

AeroMetro - '93 Geo Metro
Thanks: 1
Thanked 14 Times in 7 Posts
Quote:
Originally Posted by NeilBlanchard View Post
Hi,
Has anybody tried any of these, or have you heard anything about them?
I contacted Michelin directly a few months ago, and they recommended the Hydroedge.

Another one that looks good is Nokian i3.
  Reply With Quote
Old 07-30-2009, 11:53 PM   #29 (permalink)
Master EcoModder
 
chuckm's Avatar
 
Join Date: Aug 2008
Location: Monroe, LA
Posts: 308

Exploder - '02 Ford Explorer xlt

Rolla - '02 Toyota Corolla ce
Team Toyota
90 day: 44.43 mpg (US)
Thanks: 11
Thanked 13 Times in 12 Posts
What do you think the rolling resistance is on these?
__________________
"Jesus didn't bring 'Natty Lite' to the party. He brought the good stuff."
  Reply With Quote
Old 08-01-2009, 05:20 AM   #30 (permalink)
93 Metro Streamliner
 
Join Date: Oct 2008
Location: Oregon
Posts: 180

AeroMetro - '93 Geo Metro
Thanks: 1
Thanked 14 Times in 7 Posts
I contacted Nokian also, and they said the i3 is good but the H is better.

  Reply With Quote
Reply  Post New Thread




Similar Threads
Thread Thread Starter Forum Replies Last Post
Hyperinflating tires CapriRacer Hypermiling / EcoDriver's Ed 276 03-14-2022 04:51 AM
List of Low Rolling Resistance Tires Daox EcoModding Central 57 05-13-2019 02:17 AM
Top 5 most fuel efficient tires (Lowest Rolling resistance: LRR) blackjackel General Efficiency Discussion 144 01-26-2016 12:39 AM
Calculating Rolling Resistance SVOboy EcoModding Central 2 02-15-2012 09:43 PM
Busting the non believers trikkonceptz Success Stories 30 09-28-2008 06:51 PM



Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Content Relevant URLs by vBSEO 3.5.2
All content copyright EcoModder.com