[ausev] EV tires

[Brian Lasseter]

On Fri, Dec 12, 2008 at 9:05 AM, Derek Bridges <bridges at ieee.org> wrote:
>    The online Greenseal report on LRR tires that Brian mentioned has
> several pages of material on of LRR background and test methodology and
> it culminates in a scatter graph of test results without anywhere
> mentioning specific brands and models of tires.  It includes a URL to a
> 55 page report from the California Energy Commission that again avoids
> mention of specific brands and models. The Greenseal report does say
> that manufacturers sometimes publish artificially poor LRR numbers on
> their cheap tires to make their expensive tires look better.
>    Brian, where did you get the numbers that led you to choose the
> Sumitomo tire?  What easy-[for lazy people]-to-find information
> resources are out there?

I'm sorry... I didn't check  my link too carefully... it looks like
Green Seal deleted their table of tire rolling resistances.   Notice
how the last half of "page 5" is just missing, there was a table there
of rolling resistance:
http://www.greenseal.org/resources/reports/CGR_tire_rollingresistance.pdf

Anyways... I have a copy of their report that I downloaded in
October... so I'll reprint it here for your convenience (or laziness).
 You will note that half of these tires are OEM (like the CH95's) and
the other half of these tires are snow tires (like the Artic Alpine
XL).  Here is where I got the Sumitomo HTR 200 info:
  TABLE 1: RECOMMENDED TIRE MODELS
  BRAND MODEL SIZE RRC AVERAGE
  Bridgestone B381 185/70R14 0.0062
  Nokian NRT2 185/70R14 0.0085
  Sumitomo HTR 200 185/70R14 0.0092
  Dunlop Graspic DS-1 185/70R14 0.0092
  Dunlop SP40 A/S 185/70R14 0.0103
  Bridgestone Blizzak WS-50 185/70R14 0.0103
  Goodyear VIVA 2 185/70R14 0.0104
  Continental ContiTouring Contact CH95 205/55R16 0.0083
  Michelin Pilot Alpine 205/55R16 0.0090
  Michelin EnergyMXV4 Plus 205/55R16 0.0090
  Dunlop SP Witnter Sport M2 205/55R16 0.0102
  Michelin Arctic AlpineXL 235/75R15 0.0081
  Dunlop Axiom Plus WS 235/75R15 0.0088
  BF Goodrich Long Trail T/A 245/75R16 0.0092
  Michelin XPS Rib LT245/75R16 0.0101
  Michelin LTX M/S 245/75R16 0.0103
  Bridgestone Dueler A/T D693 245/75R16 0.0103
NOTE: The lower the rolling resistance coefficent (RRC), the more
efficient is the tire; all tires listed here meet Green Seal's
criterion for rolling resistance of less than
0.0105 and are among the most efficient available in the market today.
(c)2003, Green Seal Inc. Use of this table for commercial purposes is
prohibited.


This government report also has scads of RRC measurements for tires
made between 1982 and 2005:
http://onlinepubs.trb.org/onlinepubs/sr/sr286.pdf   Consumer reports
also "rates" tires based on rolling resistance, but you have to pay
for the report (which I have not done) and their report only gives
relative rankings... not RRC composite measurements.


Certainly as Dustin mentions... almost all OEM tires also have a very
low LRR.  It helps car makers eek out that last little bit of MPG
efficiency for the EPA window stickers.  While Prius and Honda Insight
OEM tires have a particularly low rolling resistance, they are also
particularly small.  I believe they are both 13" rims?  I am unwilling
to put 13" tires on my car.


-- 
TTFN,
Brian "Lasso" Lasseter

"No Sane man will dance."   -Cicero (106-43 B.C.)