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Old 01-05-2006, 23:01   #1 (permalink)
66 6F HCS
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Understeer and fixes

Since the '69 has no powersteering, it's a PITA to get it to "point and
shoot" if you guys know what I mean. Everything I've heard is that the early
'Stangs had terrible understeer, which from my own experience is correct. Is
there a quick fix for this? add rear sway bar? thicker front sway bar? extra
leaf in the rear springs? stiffer shocks?

I really want to take this thing to the circle track drags this next season,
but not if I'm gonna put it in the wall.

--
Scott W.
'66 HCS Mustang 289
'68 Ranchero 500 302
'69 Mustang Sportsroof 351W
ThunderSnake #57
http://home.comcast.net/~vanguard92/


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Old 01-05-2006, 23:01   #2 (permalink)
Spike
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Re: Understeer and fixes

On Thu, 5 Jan 2006 23:44:42 -0700, "66 6F HCS"
<69ta_mustang@comcast.net> wrote:

>Since the '69 has no powersteering, it's a PITA to get it to "point and
>shoot" if you guys know what I mean. Everything I've heard is that the early
>'Stangs had terrible understeer, which from my own experience is correct. Is
>there a quick fix for this? add rear sway bar? thicker front sway bar? extra
>leaf in the rear springs? stiffer shocks?
>
>I really want to take this thing to the circle track drags this next season,
>but not if I'm gonna put it in the wall.

is understeer the same as bump steer? If so... from what I have been
told... FWIW.... if you are running radials, it's not generally a
problem. If you do have a problem with what I call bump steer... there
are kits which lower the mount points of the anti-sway bar...

For the problem I'm thinking of, go to the mustangs plus site
(www.mustangsplus.com) and do a search for "bump steer" and read the
description and see if it's what I think you're speaking of. (If
not... disregard all of this as the ramblings of someone who has had a
long day...: 0 )

My 65 is manual steering and I'm running radials. Also have a negative
wedge kit installed. I don't seem to have any problems with it, and
the guys from the engine shop, and the wheel and brake shop have had
it out for test drives and said it was fine, though pretty tight since
the whole front suspension has less than 25 miles on it.
--

Spike
1965 Ford Mustang Fastback 2+2, Vintage Burgundy
w/Black Std Interior, A Code 289 C4 Trac-Lok;
Vintage 40 16" rims w/225/50ZR16 KDWS BF Goodrich
gForce Radial T/As, Cobra drop; surround sound
audio-video...
See my ride at....
Feb 2004- http://207.36.208.198/albums/86810/003_May_21_3004.jpg
Feb 2004- http://207.36.208.198/albums/86810/005_May_21_2004.jpg
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Old 01-06-2006, 01:01   #3 (permalink)
66 6F HCS
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Re: Understeer and fixes


"Spike" <jma@snowcrest.net> wrote
> is understeer the same as bump steer?


No it's not. understeer would be what the NASCAR guys call "push". The
tendency for a car to "push" to the outside of a turn no matter how hard you
pull on the wheel. As opposed to loose, where the front end dives into the
corner more easily than is preferred.

To make it simple, in an understeer car, the front wheels lose traction
before the rear, causing the car to slide to the outside of a turn. Kinda
like what happens on ice when you're braking hard and you go straight
forward, no matter what direction the front wheels are facing. The front
tires have no more traction so you go where the rear tires "push" you.
AFAIK, all cars are manufactured with built in understeer.

In oversteer (or loose), the rear wheels lose traction before the front in a
turn, causing the rear wheels to slide to the outside of a turn, forcing the
car to "oversteer" into a corner. In many cases the rear tires cause the car
to completely spin out.

My problem is understeer, or push.
--
Scott W.
'66 HCS Mustang 289
'68 Ranchero 500 302
'69 Mustang Sportsroof 351W
ThunderSnake #57
http://home.comcast.net/~vanguard92/


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Old 01-06-2006, 13:01   #4 (permalink)
Wound Up
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Re: Understeer and fixes

66 6F HCS wrote:
> "Spike" <jma@snowcrest.net> wrote
>
>>is understeer the same as bump steer?

>
>
> No it's not. understeer would be what the NASCAR guys call "push". The
> tendency for a car to "push" to the outside of a turn no matter how hard you
> pull on the wheel. As opposed to loose, where the front end dives into the
> corner more easily than is preferred.
>
> To make it simple, in an understeer car, the front wheels lose traction
> before the rear, causing the car to slide to the outside of a turn. Kinda
> like what happens on ice when you're braking hard and you go straight
> forward, no matter what direction the front wheels are facing. The front
> tires have no more traction so you go where the rear tires "push" you.
> AFAIK, all cars are manufactured with built in understeer.
>


This is true. Some touring sedans and sports cars are quite close to
neutrality, but they are all dialed in with a bit of understeer for
safety of the masses...

> In oversteer (or loose), the rear wheels lose traction before the front in a
> turn, causing the rear wheels to slide to the outside of a turn, forcing the
> car to "oversteer" into a corner. In many cases the rear tires cause the car
> to completely spin out.
>
> My problem is understeer, or push.


Maybe Bill S. can weigh in on this, but as far as I know and can tell,
all early Mustangs tend to have significant understeer, followed by the
well-known sudden oversteer. I've only really leaned on mine a few
times, but this is what I feel.

I prefer manual steering for the feedback it gives. I also have them
dial in 1 degree of positive castor to improve the car's tracking. An
old hot rodder recommended this. It increases low-speed steering effort
on manuals, but it does make the car track better.

--
Wound Up
ThunderSnake #65

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Old 01-06-2006, 14:01   #5 (permalink)
fast Ed
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Re: Understeer and fixes

What are you working with? Stock suspension, or modified? List your mods
if you have any. Tire and wheel type and sizes?

Help us help you !!!! ;-)


cheers
Ed N.
TS # 27
--
Super Coupe Club of Ontario : www.sccoa.com/sccoo
SCCoA message boards : www.sccoa.com/forums
Great Lakes Cougar Club : www.greatlakescougarclub.com
Greater Toronto Area Mustang Club : www.gtamc.com





"66 6F HCS" <69ta_mustang@comcast.net> wrote in message
news:P-SdnSyQrKkHjCPeRVn-jw@comcast.com...
> Since the '69 has no powersteering, it's a PITA to get it to "point and
> shoot" if you guys know what I mean. Everything I've heard is that the

early
> 'Stangs had terrible understeer, which from my own experience is correct.

Is
> there a quick fix for this? add rear sway bar? thicker front sway bar?

extra
> leaf in the rear springs? stiffer shocks?
>
> I really want to take this thing to the circle track drags this next

season,
> but not if I'm gonna put it in the wall.
>
> --
> Scott W.
> '66 HCS Mustang 289
> '68 Ranchero 500 302
> '69 Mustang Sportsroof 351W
> ThunderSnake #57
> http://home.comcast.net/~vanguard92/
>
>



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Old 01-06-2006, 18:01   #6 (permalink)
66 6F HCS
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Re: Understeer and fixes


"fast Ed" <fast_ed@spamania.ca> wrote
> What are you working with? Stock suspension, or modified? List your mods
> if you have any. Tire and wheel type and sizes?
>
> Help us help you !!!! ;-)


Yeah I probably shoulda been ore descriptive. Everything I have is stock
other than the wheels and tires. Currently on the car are 15x7 Minilite
copies from WesternWheel. I will be running 235/60's on all corners. however
right now there are 225/65 on the front and 245/60 on the rear.
--
Scott W.
'66 HCS Mustang 289
'68 Ranchero 500 302
'69 Mustang Sportsroof 351W
ThunderSnake #57
http://home.comcast.net/~vanguard92/


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Old 01-06-2006, 20:01   #7 (permalink)
66 6F HCS
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Re: Understeer and fixes


"66 6F HCS" <69ta_mustang@comcast.net> wrote
>Currently on the car are 15x7 Minilite copies from WesternWheel. I will be
>running 235/60's on all corners. however right now there are 225/65 on the
>front and 245/60 on the rear.


Crap, I just remembered they're 15x7 in front and 15x8 in back. Dump the
235/60 all around deal. I'll probably end up with 255/55's in back and
235/60's on front. I had 295/50's in back at one point and they rubbed
REALLY bad, but they HOOKED!

The suspension is bone stock although I'm going to put KYB's all around and
am considering the Shelby drop. Stock front sway bar, no rear sway bar.
--
Scott W.
'66 HCS Mustang 289
'68 Ranchero 500 302
'69 Mustang Sportsroof 351W
ThunderSnake #57
http://home.comcast.net/~vanguard92/


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Old 01-07-2006, 01:01   #8 (permalink)
keller428@hotmail.com
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Re: Understeer and fixes


I ran my big block '69 Mach at Watkins Glen for open track days for 10
years.....with no power steering.

These cars are not Honda Civics....there's no chance of having a
'point and shoot' early Mustang. You MIGHT get close with a gutted race
only 65-66 with R+P steering and all the cool tubular control arms and
such....but a street oriented, more or less stock suspended '69 is a
load. I run an SVT Focus at Watkins Glen now.....Not many early stangs
can do what that car does on a road course.....so your best bet is to
shoot for a "I can pretty much ask the Mustang to go kinda where I'd
like it to go on a good day" car rather than a true point and shoot
deal.

Get a new (or atleast a rebuilt) steering box if yours is still the
original.

Relocate the upper control arms. Use the stock arms and drop them an
inch (ala Shelby) or better yet get the negative wedge kits that
reposition a new HD ball joint on the control arm that allows you to
drop the upper control arm pick up point two inches. Use a 1" front
sway bar with the stiffest bushings you can get (Urethane, aluminum,
etc). Try a stock big block spring at first up front.

Urethane (or better yet Del-a-Lum) bushings everywhere you can put
them....**especially** in the rear spring eyes and shackles. Stiffer
rear spings will help (get a set spec'd for a 428CJ convertable). Use a
rear sway bar at the track only if you really have to (I didn't with
mine but many like to use them).

Edelbrock Performer IAS shocks. Edelbrock Performer IAS shocks.
Edelbrock Performer IAS shocks. Edelbrock Performer IAS shocks.

Anything from a 235-60-15 to a 265-50-15 should fit with minimal front
fender rubbing. Check carefully.

It'll still push somewhat (your not in a Corvette or Porsche here),
you will need to throttle steer the car.

Most importantly....LEARN TO DRIVE THE CAR CORRECTLY. Get and
experienced instructor (or atleast another racing buddy whos been in a
similar car on that track) in the car with you and work your way up to
the cars limits step by step.

Good luck with it.

-Mike.

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Old 01-07-2006, 01:01   #9 (permalink)
keller428@hotmail.com
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Re: Understeer and fixes


I thought my last (lengthly) reply made it through....of well.

You don't get a "point and shoot" early Mustang. These are not Honda
Civics. I drove my big block Mach (with no power steering) at Watkins
Glen for ten years. I now drive an SVT Focus on Watkins Glen, so I can
tell you first hand you've got an up-hill battle here with the early
car.

First off, go buy Herb Adams book, Chassis Engineering. It covers
many of the basics you'll need. Another, more involved, book is called
Race Car Engineering & Mechanics by Paul Van Valkenburgh. It takes the
basics Adams starts with and expands on them.

If money is no object then a full load of tubular control arms, solid
mount strut rods, Koni adjustable shocks, a rack and pinion swap, and
adjustable sway bars will get you close.

Here's the basics of getting an early Mustang to rotate better in a
corner.......Sub-frame connectors, monte-carlo bar and export brace are
mandatory for a track car and don't hurt on the street either. Next on
the list is a negative wedge kit, urethane (or better yet, Dela-a-Lum)
bushings EVERYWHERE except the strut rod bushings, more rear spring,
more front swaybar (1"), better shocks, bigger tires. If you have money
get a R+P swap for the car otherwise get a blueprinted manual steering
box. If you've followed the lambs to slaughter and are running
620lbs/inch springs up front pull them out and swap in some big block
springs instead.

I ran 265-60-15 Goodyears on my Mach with a 1" front swaybar.
Relocated upper control arms (ala Shelby), urethane on the front sway
bar, new but stock big block front springs, Boss 429 rear springs with
urethane in the spring eyes and shackles. No rear swaybar. KYB
Gas-a-Just shocks on all four corners. Manual steering box and
center-link from my Boss 302 for the last six years of running it at
the Glen.

It did quite OK for many years.

It would have been much better with better bushings everywhere, better
tires, bigger brakes and much better shocks. Edelbrock Performer IAS
shocks are my only choice when Konis are out of financial reach. They
work VERY well.

E-mail me if you have more specific questions.

Good luck with it.

-Mike.

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Old 01-07-2006, 14:01   #10 (permalink)
fast Ed
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Re: Understeer and fixes

Keep in mind that genuine performance 15" tires (at least ones sized to fit
larger cars) are getting very scarce these days. I don't think the 255-55
size you're thinking of even exists. There used to be some decent 245-50-15
and 265-50-15 tires available, which were a good fit for 15 x 7 and a15 x 8
on a classic. BFG Comp T/A, GY Eagle VR could be had, but now it's mostly
"cruiser" stuff like Radial T/As, or a drag radial tire. Dunlop still has
245-50-15 in the Sport 8000 line, which is a decent tire.

I've been looking at wheel and tire options for my Cougar, and am running
into the same thing. I scrapped the idea of running 18" Marauder wheels,
and am considering lots of other ideas. If you have the budget to up to
16", your choice expands quite a bit. With 16 x 8 all around, you can go
with 245-50-16 at all 4 corners, or a 245-50 / 255-50 staggered combo. Lots
of good stuff available in those sizes. I'd say to stay pretty close with
front and rear tire sizes. Remember that adding grip to the rear (with
larger tires), is going to increase understeer. Great tires will make the
most difference to your car IMO. I'd rather have a car with good tires and
shit suspension, than the other way around.

As far as the suspension goes, Mike covered the basics. It depends on your
budget really. My Cougar has KYB Gas-A-Just shocks, generic 620 lb. front
springs, 1" control arm relocate, and stock rear springs with lowering
blocks. Rear shackle bushings are being replaced this spring. The car is a
decent handler, other than the random worn-out factory power steering. LOL
It currently has 225-60-15 Firehawk SZ50 tires (Firestone's old top line
Z-rated performance model), mounted on 15 x 7 69 Shelby wheels. I was
trying to find a source for re-rimming or replacing the Shelby wheels, to go
up to 16" or 17". But so far, all I can find is 15 x 7 or 15 x 8. I'd
happily go with the 15 x 8, if there was any tire choice left.


cheers
TS # 27



"66 6F HCS" <69ta_mustang@comcast.net> wrote in message
news:zu6dnVxrI62MqiLenZ2dnUVZ_s-dnZ2d@comcast.com...
>
> "66 6F HCS" <69ta_mustang@comcast.net> wrote
> >Currently on the car are 15x7 Minilite copies from WesternWheel. I will

be
> >running 235/60's on all corners. however right now there are 225/65 on

the
> >front and 245/60 on the rear.

>
> Crap, I just remembered they're 15x7 in front and 15x8 in back. Dump the
> 235/60 all around deal. I'll probably end up with 255/55's in back and
> 235/60's on front. I had 295/50's in back at one point and they rubbed
> REALLY bad, but they HOOKED!
>
> The suspension is bone stock although I'm going to put KYB's all around

and
> am considering the Shelby drop. Stock front sway bar, no rear sway bar.
> --
> Scott W.
> '66 HCS Mustang 289
> '68 Ranchero 500 302
> '69 Mustang Sportsroof 351W
> ThunderSnake #57
> http://home.comcast.net/~vanguard92/
>
>



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