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

Reply  Post New Thread
 
Submit Tools LinkBack Thread Tools
Old 04-11-2013, 11:28 PM   #101 (permalink)
EcoModding Wannabee
 
LioNiNoiL's Avatar
 
Join Date: Sep 2011
Location: fabulous Las Vegas
Posts: 14
Thanks: 6
Thanked 7 Times in 5 Posts
Thumbs up data analysis

Quote:
Originally Posted by MetroMPG View Post
More inflation vs. rolling resistance data for the pile.
Thank you for your diligence and care. Since data analysis (especially small-sample analysis) comprised the second half of my professional career (from which I am now retired) I entertained myself tonight by exercising some remaining brain cells with my own spreadsheet (OpenOffice Calc) analysis of these data, verified with software by Richard Lowry at Vassar:

Spearman rank correlation* (SRC) between 70psi and 60psi of feet travelled is -0.488, a weak (insignificant) decrease of feet above 60psi.
Including the 50psi data gives a SRC of +0.133, a very weak (insignificant) increase of feet above 50psi.
Including the 40psi data gives a SRC of +0.644, a strong (significant at 0.012 level) increase of feet above 40psi.
It's therefore clear that increasing pressure above 40psi results in an increase in feet, and that increasing pressure above 50psi does not.

*chosen because the data are non-linearly related.

__________________
"There's no tellin' where the money went"
-- Robert Palmer, "Simply Irresistible" (1988)
  Reply With Quote
The Following User Says Thank You to LioNiNoiL For This Useful Post:
MetroMPG (04-12-2013)
Alt Today
Popular topics

Other popular topics in this forum...

   
Old 04-12-2013, 03:15 PM   #102 (permalink)
Batman Junior
 
MetroMPG's Avatar
 
Join Date: Nov 2007
Location: 1000 Islands, Ontario, Canada
Posts: 22,513

Blackfly - '98 Geo Metro
Team Metro
Last 3: 70.09 mpg (US)

MPGiata - '90 Mazda Miata
90 day: 52.71 mpg (US)

Even Fancier Metro - '14 Mitsubishi Mirage top spec
90 day: 70.75 mpg (US)

Appliance car - '14 Mitsubishi Mirage ES (base)
90 day: 60.16 mpg (US)
Thanks: 4,058
Thanked 6,957 Times in 3,602 Posts
Thanks for the analysis! I don't suppose you'd care to turn your skills to this related test ...

Also tested Oct 13, 2011... Bridgestone RE92 tires, multiple runs at pressures from 20-70 PSI. See this post: Experiment: coast down distances (rolling resistance) @ various tire pressures
__________________
Project MPGiata! Mods for getting 50+ MPG from a 1990 Miata
Honda mods: Ecomodding my $800 Honda Fit 5-speed beater
Mitsu mods: 70 MPG in my ecomodded, dirt cheap, 3-cylinder Mirage.
Ecodriving test: Manual vs. automatic transmission MPG showdown



EcoModder
has launched a forum for the efficient new Mitsubishi Mirage
www.MetroMPG.com - fuel efficiency info for Geo Metro owners
www.ForkenSwift.com - electric car conversion on a beer budget
  Reply With Quote
Old 04-14-2013, 02:03 AM   #103 (permalink)
EcoModding Wannabee
 
LioNiNoiL's Avatar
 
Join Date: Sep 2011
Location: fabulous Las Vegas
Posts: 14
Thanks: 6
Thanked 7 Times in 5 Posts
more data analysis

psi feet

20 568
20 570
30 662
30 672
40 677
40 679
50 667
50 679
60 681
60 692

The same type of analysis of these earlier data is a bit more interesting than the previous analysis, because of the high SRC (+0.8944) between 60psi and 50psi, which has low significance (at 0.167 level) due to small sample size of only four pairs of data.
Including the 40psi data reduces the SRC to +0.667 with greater significance (at 0.074 level) because of more data.
Including the 30psi data increases the SRC to +0.761 significant at 0.014 level.
Including the 20psi data further increases the SRC to +0.877 highly significant at 0.0004 level.
In these data, it appears that increasing pressure to 60psi may result in an increase in feet (unlike the previous data) but the significance is low enough to diminish our confidence in this result. As is stated nearly always in such cases, we need more data.
__________________
"There's no tellin' where the money went"
-- Robert Palmer, "Simply Irresistible" (1988)
  Reply With Quote
The Following 2 Users Say Thank You to LioNiNoiL For This Useful Post:
MetroMPG (04-15-2013), mikeyjd (05-19-2013)
Old 05-19-2013, 08:28 AM   #104 (permalink)
Master EcoModder
 
mikeyjd's Avatar
 
Join Date: Mar 2013
Location: Grand Rapids, MI
Posts: 838

Matchbox - '93 Ford Festiva L
Team Ford
Last 3: 70.16 mpg (US)

Salamander - '99 Chrysler Concorde LXI
Team Dodge
90 day: 30.3 mpg (US)

Urquhart - '97 Toyota Tacoma 4x4 V6 3.4L DLX
Pickups
90 day: 25.81 mpg (US)

Smudge - '98 Toyota Tacoma
90 day: 40.65 mpg (US)

Calebro - '15 Renault Trafic 1.25 dci
90 day: 39.39 mpg (US)
Thanks: 1,380
Thanked 209 Times in 155 Posts
Thanks allot!

Quote:
Originally Posted by LioNiNoiL View Post
psi feet

20 568
20 570
30 662
30 672
40 677
40 679
50 667
50 679
60 681
60 692

The same type of analysis of these earlier data is a bit more interesting than the previous analysis, because of the high SRC (+0.8944) between 60psi and 50psi, which has low significance (at 0.167 level) due to small sample size of only four pairs of data.
Including the 40psi data reduces the SRC to +0.667 with greater significance (at 0.074 level) because of more data.
Including the 30psi data increases the SRC to +0.761 significant at 0.014 level.
Including the 20psi data further increases the SRC to +0.877 highly significant at 0.0004 level.
In these data, it appears that increasing pressure to 60psi may result in an increase in feet (unlike the previous data) but the significance is low enough to diminish our confidence in this result. As is stated nearly always in such cases, we need more data.
Thank you for optimizing our understanding of the existing data. I've been rocking 55-60 psi on my cars since I came across this thread and I've been happy with the balance between ride comfort and rolling resistance. Thanks to everyone who added to this thread.
  Reply With Quote
Old 05-20-2013, 02:02 AM   #105 (permalink)
EcoModding Wannabee
 
LioNiNoiL's Avatar
 
Join Date: Sep 2011
Location: fabulous Las Vegas
Posts: 14
Thanks: 6
Thanked 7 Times in 5 Posts
I do a lot of hiking, and a fellow hiker has a Ford Excursion (huge SUV) who routinely has 65psi in his tyres (recommended for 45psi) having measured an increase in fuel economy by ½ mpg (more than that at 45psi) which for him is about 5%
__________________
"There's no tellin' where the money went"
-- Robert Palmer, "Simply Irresistible" (1988)
  Reply With Quote
Old 05-21-2013, 01:24 PM   #106 (permalink)
Master EcoModder
 
Jakins's Avatar
 
Join Date: Sep 2012
Location: Texas
Posts: 252

hX-TREME!!! - '97 Honda Civic HX
90 day: 54.75 mpg (US)

450sX-TREME!!! - '95 Nissan V8 240sx

chodercycle - '06 kawasaki ninja zx6r 636
Thanks: 18
Thanked 43 Times in 23 Posts
on a past road trip i stopped at a truck stop and cranked my PSI waay up. idk how much because i didnt have a gauge but it felt alot different. way more rough and easyer to stear without power steering. but when i got home the car was hopping. the tires bulged out and were ruined. so now im afraid of pumping them up real high. who knows. maybe i cranked them up like over 70 psi or something dangerous. they were real old tires too.
  Reply With Quote
Old 05-21-2013, 02:05 PM   #107 (permalink)
Master EcoModder
 
justme1969's Avatar
 
Join Date: Dec 2012
Location: ff
Posts: 459
Thanks: 59
Thanked 38 Times in 30 Posts
yep

Quote:
Originally Posted by Jakins View Post
on a past road trip i stopped at a truck stop and cranked my PSI waay up. idk how much because i didnt have a gauge but it felt alot different. way more rough and easyer to stear without power steering. but when i got home the car was hopping. the tires bulged out and were ruined. so now im afraid of pumping them up real high. who knows. maybe i cranked them up like over 70 psi or something dangerous. they were real old tires too.
Ive said it many times tires dont survive over airing like back in 80s/90s
I did same the did it again just to be sure I was stupid! lol
dont take car tires past max inflation.
  Reply With Quote
Old 08-12-2013, 01:15 PM   #108 (permalink)
Master EcoModder
 
Joggernot's Avatar
 
Join Date: Jun 2013
Location: Texas
Posts: 449
Thanks: 1,748
Thanked 126 Times in 105 Posts
Long ago people were putting "airplane" tires that could be pumped to 300 psi on their cars for best mileage. Has anyone here done this? Has anyone checked to see if airplane tires would fit a 15 or 16 rim?

Joggernot
  Reply With Quote
Old 08-12-2013, 02:13 PM   #109 (permalink)
Pishtaco
 
SentraSE-R's Avatar
 
Join Date: Jun 2009
Location: Bay Area, California
Posts: 1,485

Mean Green Toaster Machine - '06 Scion xB
Team Toyota
90 day: 48.92 mpg (US)
Thanks: 56
Thanked 286 Times in 181 Posts
Aircraft tires aren't DOT approved, ergo not street-legal. You'd have to run them at ~200 psi, and fill them with water if you wanted to overinflate them.
__________________
Darrell

Boycotting Exxon since 1989, BP since 2010
Have you ever noticed that anybody driving slower than you is an idiot, and anyone going faster than you is a maniac? George Carlin
Mean Green Toaster Machine
49.5 mpg avg over 53,000 miles. 176% of '08 EPA
Best flat drive 94.5 mpg for 10.1 mi
Longest tank 1033 km (642 mi) on 10.56 gal = 60.8 mpg
  Reply With Quote
The Following User Says Thank You to SentraSE-R For This Useful Post:
Pawtuckett (08-12-2013)
Old 08-12-2013, 05:08 PM   #110 (permalink)
Master EcoModder
 
Join Date: Oct 2008
Location: Mid-Atlantic
Posts: 491

OurInsight - '06 Honda Insight
Thanks: 170
Thanked 69 Times in 44 Posts
Quote:
Originally Posted by justme1969 View Post
Ive said it many times tires dont survive over airing like back in 80s/90s
I did same the did it again just to be sure I was stupid! lol
dont take car tires past max inflation.
It probably depends some on the tire brand and model. Insight owners have been very successful running 80 psi in the Bridgestone RE-92. There are lots of examples, with no recorded examples of damage, that I am aware of. I do suspect that damage would be more likely with old tires.

However, the gains in MPG at 60psi+ are very small if any. The Insight is a very difficult car on which to make such measurements, so it is a bit difficult to really know

  Reply With Quote
Reply  Post New Thread


Thread Tools


Similar Threads
Thread Thread Starter Forum Replies Last Post
Hyperinflating tires CapriRacer Hypermiling / EcoDriver's Ed 276 03-14-2022 03:51 AM
Tire Engineer here - concerned about hyperinflating tires CapriRacer Introductions 48 09-26-2009 09:25 PM
Tire pressure (of winter tires) tasdrouille General Efficiency Discussion 20 08-12-2009 01:38 AM



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