Autocross/Street Tires

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From: cstwcam_REMOVE_828162_THIS_@yahoo.com


> > Even if I do not drive on gravel roads, will I chip the paint on
the
> > sides of my old Cosworth? Also, won't using a "205" tire cause
interference at the
> left
> > rear inside fender well?
> I had to reshim my Panhard bar to give more clearance on the RH
>side Since the axle moves slightly to the left in jounce, RH
>clearance is
> reduced over a bump. Unfortunately, the '75s do not have
>the '76's
> shim adjustement for the Panhard bar.

Clark you can also check out Cooper tires they still have 175 70,
185 70, 195 70, and 205 60, 13 inch tires

<a href="http://www.coopertires.com/tire_cooper/passenger.asp?id=11">http://www.coopertires.com/tire_cooper/passenger.asp?id=11</a>

as for stone chips you can go to a local body shop supply or GM body
shop ask is they have the clear film that is put on bodies behind
the wheels to protect the paint from chips. It is also sold in balk
supply you may be able to go to a local graphic striper they may
have clear vinyl that could be used to protect the paint also.
Last there is a tech sheet reguarding adjusting the 75 rear track
bar in will need to be removed but it does work I did it on 1451 I
used a chain hooked on each end and a port a power in the middle
with the v shaped attachment to keep it on the bar you push with the
bend to increase bend to make it shorter or aganist the bend to
make it longer I adjusted to give equal distance side to side. It is
a trial and error though and may have to be done more than once to
get the results you are looking for.
Art




[This is message #9717 by user cstwcam on Yahoo! Group Cosworth Vegas: http://groups.yahoo.com/group/cosworthvegas ]

[h-bot]

From: cstwcam_REMOVE_596071_THIS_@yahoo.com

I forgot to say that when you go to the link you can see all the
cobra tires in different size also there is a dealer locater on the
left side I have been riding on 195/70R-13's for about 4 years on
the Cosworth and I have the new SLE's on my 95 audi A90 this spring
I will be putting the SLE on my 98 AWD Grand Caravan as I have
snows on all four corners of the Caravanfor winter.
--- In <a href="/group/cosworthvegas/post?protectID=219233066105193209050199029077192253163098100046209130">cosworthvegas@y...</a>, cstwcam <<a href="/group/cosworthvegas/post?protectID=091233212180056219138097203245129208071">no_reply@y...</a>> wrote:
>
> > > Even if I do not drive on gravel roads, will I chip the paint
on
> the
> > > sides of my old Cosworth? Also, won't using a "205" tire
cause
> interference at the
> > left
> > > rear inside fender well?
> > I had to reshim my Panhard bar to give more clearance on the RH
> >side Since the axle moves slightly to the left in jounce, RH
> >clearance is
> > reduced over a bump. Unfortunately, the '75s do not have
> >the '76's
> > shim adjustement for the Panhard bar.
>
> Clark you can also check out Cooper tires they still have 175 70,
> 185 70, 195 70, and 205 60, 13 inch tires
>
> <a href="http://www.coopertires.com/tire_cooper/passenger.asp?id=11">http://www.coopertires.com/tire_cooper/passenger.asp?id=11</a>
>
> as for stone chips you can go to a local body shop supply or GM
body
> shop ask is they have the clear film that is put on bodies behind
> the wheels to protect the paint from chips. It is also sold in
balk
> supply you may be able to go to a local graphic striper they may
> have clear vinyl that could be used to protect the paint also.
> Last there is a tech sheet reguarding adjusting the 75 rear track
> bar in will need to be removed but it does work I did it on 1451 I
> used a chain hooked on each end and a port a power in the middle
> with the v shaped attachment to keep it on the bar you push with
the
> bend to increase bend to make it shorter or aganist the bend to
> make it longer I adjusted to give equal distance side to side. It
is
> a trial and error though and may have to be done more than once to
> get the results you are looking for.
> Art




[This is message #9718 by user cstwcam on Yahoo! Group Cosworth Vegas: http://groups.yahoo.com/group/cosworthvegas ]

[h-bot]

From: doctorduke_REMOVE_707279_THIS_@yahoo.com


> Last there is a tech sheet reguarding adjusting the 75 rear track
> bar in will need to be removed but it does work I did it on 1451 I
> used a chain hooked on each end and a port a power in the middle
> with the v shaped attachment to keep it on the bar you push with the
> bend to increase bend to make it shorter or aganist the bend to
> make it longer I adjusted to give equal distance side to side. It is
> a trial and error though and may have to be done more than once to
> get the results you are looking for.
> Art

If you don't want wide tires to interfere, you need MORE RH clearance
at normal ride height. this is because the axle moves to the left in
jounce, which reduces RH clearance and increases LH clearance.

Duke




[This is message #9719 by user doctorduke on Yahoo! Group Cosworth Vegas: http://groups.yahoo.com/group/cosworthvegas ]

[h-bot]

From: longg01_REMOVE_691607_THIS_@yahoo.com

Kumhos Victoracers are not good street tires... no rain traction.
What you should do for an autocross is buy a set of cheap wheels
mounted with the Kumho Victoracers, Toyo Proxy R1, Hoosier, or any
other sticky tire. Just change wheels per event. If you do deside
to go with Kumho (Our family is a Kumho fan) try the new sicky
Ecsta. They're lighter, stickier, and last longer than the
Victoracers.
~CHRIS




[This is message #9720 by user longg01 on Yahoo! Group Cosworth Vegas: http://groups.yahoo.com/group/cosworthvegas ]

[h-bot]

From: cosworth0078_REMOVE_324976_THIS_@yahoo.com

Duke, you run a Cosworth competively, don't you? I need your advice.
I am in the market for a good street/autocross tire and am leaning
towards a 205/60VR-13 Kuhmo VictoRacer. You have previously stated
that there are very few good 13 inch performance tires. I usually
stick to Goodyear but they have "nothing" in my size. What I am
wondering about is whether I should buy these Kumhos even though they
have a reputation for "throwing gravel". What is your opinion of
this tire for occasional street driving and once a year autocrossing?
Even if I do not drive on gravel roads, will I chip the paint on the
sides of my old Cosworth? Also, if I go with this size and aspect
ratio, won't it cause "speedometer error"? I remember Karl at
Hutton's in the early 90's changing out the tranny's "speedo gear"
because it was the wrong one for my stock size (BR70-13) tires
(having been changed first in the 70's when I ran wider autocross
tires). Also, won't using a "205" tire cause interference at the left
rear inside fender well? I remember using an aluminum spacer in the
70's and 80's when I ran wider than stock tires.
Clark




[This is message #9715 by user cosworth0078 on Yahoo! Group Cosworth Vegas: http://groups.yahoo.com/group/cosworthvegas ]

[h-bot]

From: doctorduke_REMOVE_384846_THIS_@yahoo.com

--- In <a href="/group/cosworthvegas/post?protectID=219233066105193209050199029077192253163098100046209130">cosworthvegas@y...</a>, cosworth0078 <<a href="/group/cosworthvegas/post?protectID=091233212180056219138097203245129208071">no_reply@y...</a>> wrote:
> Duke, you run a Cosworth competively, don't you? I need your
advice.
> I am in the market for a good street/autocross tire and am leaning
> towards a 205/60VR-13 Kuhmo VictoRacer. You have previously stated
> that there are very few good 13 inch performance tires. I usually
> stick to Goodyear but they have "nothing" in my size. What I am
> wondering about is whether I should buy these Kumhos even though
they
> have a reputation for "throwing gravel". What is your opinion of
> this tire for occasional street driving and once a year
autocrossing?
> Even if I do not drive on gravel roads, will I chip the paint on the
> sides of my old Cosworth? Also, if I go with this size and aspect
> ratio, won't it cause "speedometer error"? I remember Karl at
> Hutton's in the early 90's changing out the tranny's "speedo gear"
> because it was the wrong one for my stock size (BR70-13) tires
> (having been changed first in the 70's when I ran wider autocross
> tires). Also, won't using a "205" tire cause interference at the
left
> rear inside fender well? I remember using an aluminum spacer in the
> 70's and 80's when I ran wider than stock tires.
> Clark

In addition to the Kumho, you can buy the Toyo Proxes RA-1 in the
205/60R-13 size (V-rated). This is the tire I am now running. I
can't give you a blow by blow comparison of the Victoracer and RA-1 as
I have never compared them back to back. The Toyo is basically a road
racing tire and needs some heat to work really well. Even at normal
highway running temps in mild to warm weather these tires have
exceptionally high grip, but they don't get sticky enough to pick-up
and throw pebbles unless you are hot lapping a track at which point
they can pickup debris when you slow down and go through the paddock,
but they are like driving on flypaper and generate an easy 1.0+ g of
lateral grip. I overfill my oil by one quart when I track the car,
and I am running 2 degrees negative front camber with 1 1/16"/7/8"
front and rear bars with poly bushings on the front links.

The 205/60R-13 size will make your speedo/odo about 5 percent
optimistic. A couple of ways to correct this is to either install a
properly geared adaptor or, what I did was have my speedo recalibrated
by decreasing it's gain by 5 percent. A speedometer shop can do this
by altering the magnetic flux of the head, but the odo will still be
high. If you have a four-speed you might be able to get a 24T
driven gear that will replace the 23T original and mesh properly with
the drive gear. The five speed has a 25T driven gear, and I am not
aware of any 26T driven gears that exist.

I had to reshim my Panhard bar to give more clearance on the RH side.
Since the axle moves slightly to the left in jounce, RH clearance is
reduced over a bump. If I approach or depart a steep ramp at an
angle, I can get still get slight interference on the RH inside, but
one only accomplishes these manuevers at low speed. I keep the RH
wheel wheel chalked to check for interference, but I have never had
any in normal driving. Unfortunately, the '75s do not have the '76's
shim adjustement for the Panhard bar.

The Toyos have a DOT wear rating of 40, but I project normal street
driving mileage of at least 10,000. A once a year autocross won't
reduce this by a significant amount, but 150 miles a day on a race
track sure will if you do that a lot.

I'm very happy with the Toyos and recommend them to all, but there is
one downside. They are very harsh riding because of the steel
stiffener in the sidewall. This give fabulous steering response, but
at the cost of ride harshness, especially on old patched pavement.

I think the Victoracer might be a better autocross tire. You should
go to some local events and see what guys who run the 205/60R-13 size
are using. I know the RA-1 is a spec tire for an RX-7 road racing
series, but I'm not sure if it's popular in autocross.

Duke






[This is message #9716 by user doctorduke on Yahoo! Group Cosworth Vegas: http://groups.yahoo.com/group/cosworthvegas ]

[h-bot]

From: markrock_REMOVE_790502_THIS_@yahoo.com

Autocross tires put you on a slippery slope. They are the mere tip of
the $$$ iceberg. To start with, they put you in a different class.

If you purchase the "best" (i.e. stickiest) tires, they will wear out
the fastest. The second step, as already noted, is the purchase of a
additional set of wheels.

Further, wheels and tires alone won't guarantee victory. Anybody can
buy sticky tires. To extract the last bit of performance today's
tires are capable of providing, many modifications will be required.
Others competing will have already made some or all of these
modifications, so if you want driver skill to be the determining
factor, then you need to start out on an equal footing. Larger sway
bars. Poly sway bar bushings. Spax shocks. Fresh positraction.
Heavier/lower springs. Poly control arm bushings. Poly trailing arm
bushings. Poly panhard bar bushings. Special track only alignment
specs. Bigger front brakes. Big back brakes on the 75's. Quick
ratio steering box.

Expensive if you do the work yourself. Very expensive if you have to
pay to have it done.

Of course we haven't mentioned at all the engine and exhaust
performance modifications that will enable you to take better
advantage of all this newfound grip. Engine modifications to increase
horsepower are even more expensive than suspension modifications for
comparable performance gains.

How fast do you want to go? How much money do you have?

Almost all of these modifications make the car ever less pleasant to
drive on the street. And of course most of them render it non-stock.

Oh, and I forgot, you will need a vehicle to haul around the race
tires if you want to drive the Cosworth to events, or a trailer and a
tow vehicle to haul around the car with the autocross tires
permanently mounted. You really don't want to drive around with a
set of autocross tires inside your Cosworth. They are big and ugly,
and they stink monstrously of rubber when they are in the passenger
compartment with you.

On the other hand, once you've driven a Cosworth with autocross or
race tires, you'll never want to look back!

Mark








[This is message #9721 by user markrock on Yahoo! Group Cosworth Vegas: http://groups.yahoo.com/group/cosworthvegas ]

[h-bot]

From: doctorduke_REMOVE_121904_THIS_@yahoo.com

If you normally don't drive your CV in the rain, use it just for
fun weekend driving, don't put more than a few hundred
to a few thousand miles a year on the car, and you want the
highest possible grip, I highly recommend DOT legal racing
tires as the place to start.

I took a thousand mile trip on my RA-1s to Monterey and back in
August. It was a terror on Highway 1! I couldn't even detect any
wear from the trip. They started out at 8/32" tread depth when I
installed them, new, in 1996 and currently have 4/32" with about 6000
total miles, so I'll probably need a new set by 2006 or 7, or maybe I
can stretch them to 2008.

I will run them until cord shows!

Duke





[This is message #9722 by user doctorduke on Yahoo! Group Cosworth Vegas: http://groups.yahoo.com/group/cosworthvegas ]

[h-bot]

From: kiva5198_REMOVE_443776_THIS_@yahoo.com

Clark if you are looking for grip, Grassroots Motorsports magazine
last month did a competition of the available DOT "race" tires.
This issue may still be on the shelves. They ranked in the
following order:

1. Hoosier (about $139 ea.)
2. Kuhmo V700 Victoracer ($97 ea.)
3. Kuhmo V700 ECSTA ($95 ea. in a 215/50/13)
4. Toyo RA-1 ($119 ea.)

The Kuhmos interestingly were only tenths of a second apart. I use my
Kuhmo Victoracers on the street, and I don't think they throw too much
gravel on the paint although they will make some noise in the
wheelwells. I have done two track days in the rain, heavy Oregon rain,
and they were still predictable enough to drive on the street. They
are also are by far the best bang-for-the-buck. You could easily get
10,000 miles out of a set of Kuhmo tires with a car as light as the
Vega. Have them shaved if you really want to grip, you'd think they
wouldn't last as long, but Kuhmo says that the heat dissapates faster
so they don't wear as quickly.

Britt




--- In <a href="/group/cosworthvegas/post?protectID=219233066105193209050199029077192253163098100046209130">cosworthvegas@y...</a>, doctorduke <<a href="/group/cosworthvegas/post?protectID=091233212180056219138097203245129208071">no_reply@y...</a>> wrote:
> If you normally don't drive your CV in the rain, use it just for
> fun weekend driving, don't put more than a few hundred
> to a few thousand miles a year on the car, and you want the
> highest possible grip, I highly recommend DOT legal racing
> tires as the place to start.
>
> I took a thousand mile trip on my RA-1s to Monterey and back in
> August. It was a terror on Highway 1! I couldn't even detect any
> wear from the trip. They started out at 8/32" tread depth when I
> installed them, new, in 1996 and currently have 4/32" with about
6000
> total miles, so I'll probably need a new set by 2006 or 7, or maybe
I
> can stretch them to 2008.
>
> I will run them until cord shows!
>
> Duke




[This is message #9728 by user kiva5198 on Yahoo! Group Cosworth Vegas: http://groups.yahoo.com/group/cosworthvegas ]

[h-bot]

From: doctorduke_REMOVE_591858_THIS_@yahoo.com

--- In <a href="/group/cosworthvegas/post?protectID=219233066105193209050199029077192253163098100046209130">cosworthvegas@y...</a>, "Britt" <<a href="/group/cosworthvegas/post?protectID=200176018237235197240138203004129208071">kiva5198@h...</a>> wrote:
> Clark if you are looking for grip, Grassroots Motorsports magazine
> last month did a competition of the available DOT "race" tires.
> This issue may still be on the shelves. They ranked in the
> following order:
>
> 1. Hoosier (about $139 ea.)
> 2. Kuhmo V700 Victoracer ($97 ea.)
> 3. Kuhmo V700 ECSTA ($95 ea. in a 215/50/13)
> 4. Toyo RA-1 ($119 ea.)


Was this test done in an autocross or road racing environment? If the
latter what was the course length and average speed?

Also, did they test the 205/60R-13 size, what kind of car
did they use, and was it production or modified?

Duke




[This is message #9738 by user doctorduke on Yahoo! Group Cosworth Vegas: http://groups.yahoo.com/group/cosworthvegas ]

[h-bot]

From: cosworth0078_REMOVE_258716_THIS_@yahoo.com

Britt, thanks for the magazine information. The only Hoosier
brand tires that I found in "my" size were slicks. I must have (1)
street legal (DOT) tires and (2) they must fit onto my stock Cosworth
wheels. This limits me to a maximum of 205/60-13 size, I believe,
though 195/70-13 would be more like the stock BR-70-13 tires.
-Clark

"Britt" wrote:
Clark if you are looking for grip, Grassroots Motorsports magazine
last month did a comparison of the available DOT "race" tires.
This issue may still be on the shelves. They ranked in the
following order:
1. Hoosier (about $139 ea.)
2. Kuhmo V700 Victoracer ($97 ea.)
3. Kuhmo V700 ECSTA ($95 ea. in a 215/50/13)
4. Toyo RA-1 ($119 ea.)





[This is message #9739 by user cosworth0078 on Yahoo! Group Cosworth Vegas: http://groups.yahoo.com/group/cosworthvegas ]