# [EVDL] New crop of LRR tires



## EVDL List (Jul 27, 2007)

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From: "John M. Salmon III" <[email protected]>
Sent: Sunday, May 24, 2009 1:20 PM
To: "Electric Vehicle Discussion List" <[email protected]>
Subject: [EVDL] New crop of LRR tires

> Please correct me if I'm wrong. These LRR tires do not provide the same
> stopping performance or handling as the standard tires. My recollection
> is that Consumer Reports tested two version of the Prius and did not
> recommend the LRR tires from a safety aspect. I haven't seen any one
> selling auto insurance that brings you back from the dead. Prevention
> is still worth a thought.

There is always a compromise. The tires that will handle best are race or 
near race, but in general we don't run those because they wear out too 
quickly, so there is always a compromise.

In theory, there is little difference in performance between rolling 
resistance levels. In practice, the difference can be substantial and the 
more known methods of achieving low rolling resistance also decrease the 
performance of the tire. The most recent generation of LRR tire should offer 
small enough performance change that the difference in too small for most 
drivers to realize, so they should be equally safe for most drivers. Not 
only will your mileage vary, but literally your mileage will vary.
Joe 

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## EVDL List (Jul 27, 2007)

Note that the difference between a crash and timely stopping
can in many accidents be measured in single MPHs difference,
so if you are so concerned about crashing then simply driving a
few MPH slower will prevent many a crash.
That and keeping a watchful eye, another large part of crashes
are when the driver was temporarily distracted.
Believe me - I have been behind drivers who were flipping
though their phone book with one hand (and two eyes) while
bouncing back and forth between crossing the double solid lines
and almost hitting the guardrail, no joke.

Careful driving practices make a much large difference than
those minor differences in vehicle performance so quit being
focused on the equipment to get the last few inches shorter 
stopping distance from your tires and focus on the nut behind
the wheel whose driving behavior and reaction speed makes many 
yards of distance of difference.

Regards,

Cor van de Water
Director HW & Systems Architecture Group
Proxim Wireless Corporation http://www.proxim.com
Email: [email protected] Private: http://www.cvandewater.com
Skype: cor_van_de_water IM: [email protected]
Tel: +1 408 383 7626 magicJack: +1 408 844 3932
Tel: +91 (040)23117400 x203 XoIP: +31877841130

Please consider the environment before printing this e-mail.
-----Original Message-----
From: xxx[email protected] [mailto:[email protected]] On
Behalf Of Joseph Ashwood
Sent: Monday, May 25, 2009 4:27 AM
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] New crop of LRR tires

--------------------------------------------------
From: "John M. Salmon III" <[email protected]>
Sent: Sunday, May 24, 2009 1:20 PM
To: "Electric Vehicle Discussion List" <[email protected]>
Subject: [EVDL] New crop of LRR tires

> Please correct me if I'm wrong. These LRR tires do not provide the
same
> stopping performance or handling as the standard tires. My
recollection
> is that Consumer Reports tested two version of the Prius and did not
> recommend the LRR tires from a safety aspect. I haven't seen any one
> selling auto insurance that brings you back from the dead. Prevention
> is still worth a thought.

There is always a compromise. The tires that will handle best are race
or 
near race, but in general we don't run those because they wear out too 
quickly, so there is always a compromise.

In theory, there is little difference in performance between rolling 
resistance levels. In practice, the difference can be substantial and
the 
more known methods of achieving low rolling resistance also decrease the

performance of the tire. The most recent generation of LRR tire should
offer 
small enough performance change that the difference in too small for
most 
drivers to realize, so they should be equally safe for most drivers. Not

only will your mileage vary, but literally your mileage will vary.
Joe 

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## EVDL List (Jul 27, 2007)

John
Have you been reading the Tire Rack drivel on LRR tires?


When you say " these LRR tires" you're grouping together a bunch of
completely different tire designs, that happen to have one characteristic in
common. There is no clear grouping of "LRR" tires and "standard" tires.
Some tires just happen to be designed well enough to have relatively low
rolling resistance - and, are not even advertised as LRR tires.

Sure - there are some tires designed specifically for LRR that undoubtedly
have somewhat compromised performance at the limits of handling. But many
tires- like the Sumitomo HTR 200 - may just be good tires that happen to
have low rolling resistance. These are listed as having 0.0092 rolling
resistance ( third best in the GreenSeal Report ) , but are certainly
performance-oriented. Check out this description and the user surveys for
this tire:

http://www.tirerack.com/tires/tires.jsp?tireMake=Sumitomo&tireModel=HTR+200#Survey


The Dunlop Graspic DS-1 tires are a similar case. It would surprise me if
they were specifically designed for LRR (who cares about snow tire RR?) ,
but they are tied for third best RR (in the same Greenseal Report) and
happen to be one of the best snow and ice tires available. I've been using
them on two different ICE cars for a couple of years. To me, the low
rolling resistance is just a bonus.


So, even if you're particularly sensitive to less-than-optimum handling and
braking performance, don't give up on any tire just because it has low
rolling resistance. Similarly, buying a tire just because it has very high
rolling resistance ( in the hopes of better performance) wouldn't be real
smart, either.


Phil Marino





> John M. Salmon III <[email protected]>wrote:
> 
> > Please correct me if I'm wrong. These LRR tires do not provide the same
> > stopping performance or handling as the standard tires. My recollection
> ...


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## EVDL List (Jul 27, 2007)

Are y'all finding rolling resistance data on Tirerack? If so, where?

-- 
Willie, ONWARD! Through the fog!
http://counter.li.org Linux registered user #228836 since 1995
Debian3.1/GNU/Linux system uptime 527 days 3 hours 46 minutes

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## EVDL List (Jul 27, 2007)

Yes, and where can you get a copy of that Green Seal report?

There seems to be an abstract/snip here:
http://www.greenseal.org/resources/reports.cfm

But where are the results?




> Willie McKemie <[email protected]>wrote:
> 
> > Are y'all finding rolling resistance data on Tirerack? If so, where?
> >
> ...


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## EVDL List (Jul 27, 2007)

I've never seen actual RR values on Tirerack or any other tire sales
website. It is my understanding that the tire manufacturers do NOT measure
(or at least don't openly advertise) RR values. Not totally sure why.

Here's a link to the Green Seal report:

http://www.greenseal.org/resources/reports/CGR_tire_rollingresistance.pdf

Here's a related link (note that these are 2002 data):

http://books.nap.edu/openbook.php?record_id=11620&page=60


I've not seen anything more recent than these two.

Peter Flipsen Jr
http://www.evalbum.com/1974







> Nicolas Drouin <[email protected]>wrote:
> 
> > Yes, and where can you get a copy of that Green Seal report?
> >
> ...


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## EVDL List (Jul 27, 2007)

Somebody needs to invent a shape changing wheel that could alter the contact
patch;

Coasting down a hill ? the tires get skinnier
Need better 0-60 ? About to carve a corner ? Sport mode changes wheel
camber, and the tires get a bit fatter.

Alright, fantasy, but so was the microwave oven 70 years ago. 

Anybody know of someone working on something like this ?
I know theres lots of work being done on 'sideways' wheels.
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## EVDL List (Jul 27, 2007)

Willie - TireRack doesn't sort their tires by rolling resistance, or include
any rolling resistance data.
But if you're looking for a particular LRR tire, you can find it the way you
find any tire at TireRack.

For instance, to find the Bridgestone B381, which is the lowest RR tire that
I have seen hard data for: select "Bridgestone" and then look at the list
for "B381" and, then click on it.
Phil Marino



> Willie McKemie <[email protected]>wrote:
> 
> > Are y'all finding rolling resistance data on Tirerack? If so, where?
> >
> ...


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## EVDL List (Jul 27, 2007)

Dave - that would be cool, except that narrower tires ( at the same
pressure, and with the same materials, etc) have higher rolling resistance
than wider tires. So, you want them to be wide all the time.
Phil Marino



> Dave Hymers <[email protected]> wrote:
> 
> > Somebody needs to invent a shape changing wheel that could alter the
> > contact
> ...


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## EVDL List (Jul 27, 2007)

Tires, A fickle beast, but it is getting better.

I use to run a BFG R1 for autocrosses or the Yokahama equivilant.

These are what we call DOT rubber. It is a Department of Transportation
approved tire, but has a really soft compound on it. In order to make
the tire last longer and give us more grip, the first thing we did was
but the balanced tire on a lathe and cut off half the tread! (the raised
sections deflected less and we got rid of the rubber contaminated with
mold release)

Anyhow the reason we went with such soft rubber is that in an autocross,
you were hard pressed to get the tire up to temperature fast enough to
get the stick you needed.

Rolling resistance has less to do with the compound and more to do with
the carcass construction.
Thread count, bias angle, side wall stiffness. A high thread count
(actually 3 kevlar cords woven into one is best I've seen) and a near 45
degree angle gives you the strength to handle the inflation but makes a
soft sidewall that uses less energy to flex and unflex as the tire
rotates. There are also three major divisions in the type of carcas
construction, 2 of which we use in passenger tires. Although you will
find a continuum between them. 

Stiff inner sidewall (yokahama)
Under heavy load in a corner, the tread bunches up and wrinkles a
little and you feel this as a smooth transition into understeer
Stiff outer sidewall. (BFG R1)
Under load the tread is stretched in tension and has a much sharper
transition to understeer as it lifts all at once off the surface.

As a beginner, I liked the Yokahamas as I gained experience, I could eak
a little more out of the BFGs.

Stopping test for both tires were interesting(stop-box test). I learned
that suspension design is very important and if you have antilock
brakes, it can hide a problem. Just like tuning a process on a molding
machine. Take it out of closed loop, adjust as good as possible, and
only then re-enable the closed loop control. Antilock brakes can keep
you on the edge of locking the tires, but what is the number and which
wheel is the limit?

As you break, load transfers from the rear to the front. Good anti dive
geometry reduces this weight transfer and biasing the brakes correctly
also is important. During this instance, you can overload the front
tires capacity and start to slide and of course not get the stopping
power from the back at all. I was able to reduce my stopping distance
from 60 mph from over 60 feet to an eye popping 20 something feet (I
think 24). (At that point, a wide 5 point harness is essential, you
can't maintain control of your body position at those G's )

I am rambling a bit, but the point is there are a lot of variables and
just changing a tire may go outside what the engineer for the vehicle
considered. More changes may be needed to take care of it.

Things are getting better because they have improved their materials,
Learning to make a rubber that is like an alloy is to metals. It wears
off slowly but still has grip. As it is forced, and pushed off, it
increases it's resistance to dusting. They now have much wider areas of
operation for load and temperature than they did 10 years ago. They also
are able to resist drying out and ozone damage better. They also have
learned alot about the carcus design.

Not all manufactures bother, we are talking about performance tires here.

But things are getting worse too. most after-market Rim manufactures
sell after rims that are heavy, I have seen 50+ lbs. The kids buy them
and put them on their honda and the wheel skips like a stone on a pond
as it encounters irregularities in the roadway. They are lucky if they
maintain contact with the road 50% of the time. I give them a wide
bearth as I have seen them make spontanous lane changes. At least with
an EV we are pretty sure we don't have that problem 

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## EVDL List (Jul 27, 2007)

> Phil Marino wrote:
> > Willie - TireRack doesn't sort their tires by rolling resistance, or include
> > any rolling resistance data.
> > But if you're looking for a particular LRR tire, you can find it the way you
> ...


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## EVDL List (Jul 27, 2007)

I have seen research into tires with harder inner compounds (towards the middle of the car), and the outer edge is actually off the road when going straight. When cornering, the tire rolls onto the formerly airborne shoulder, with softer rubber, so it grips better for turning. A similar idea I have seen is to have 2 wheels side-by-side, the outer one is just slightly smaller so it only comes into play during hard cornering.

Another idea is a Hummer H1 can change its tire pressure while driving. Maybe you could have a tire that changes characteristics via air pressure change.




________________________________
From: Dave Hymers <[email protected]>
To: Electric Vehicle Discussion List <[email protected]>
Sent: Monday, May 25, 2009 12:43:27 PM
Subject: Re: [EVDL] New crop of LRR tires

Somebody needs to invent a shape changing wheel that could alter the contact
patch;

Coasting down a hill ? the tires get skinnier
Need better 0-60 ? About to carve a corner ? Sport mode changes wheel
camber, and the tires get a bit fatter.

Alright, fantasy, but so was the microwave oven 70 years ago. 

Anybody know of someone working on something like this ?
I know theres lots of work being done on 'sideways' wheels.
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## EVDL List (Jul 27, 2007)

I emailed Green Seal regarding a new list of lrr tires. It appears we must do our own research. LR

Hello Lawrence:

Thank you for your interest in Green Seal. The Choose Green Reports were
originally developed as guidance document for people relatively new to
environmental purchasing. Since their publication, there have been many
innovations in manufacturing technology and variety products, making the
reference tables in these reports obsolete.

When Green Seal has the resources to revise these reports they will be,
but this is not planned in the near future.

Sincerely,
Green Seal Staff 


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