Bumpsteer, What is it?

[Robert M]

I bought these tie rod ends from Shelby during one of their sales. I thought they looked Cool and planned on installing them with some tubed lower control arms and a couple of other suspension parts from the Shelby Store. Now it is time to do the install, and I am wondering, what do these tie rod ends do in addition to attaching the rack to the spindles????

I figured if any group would know, it would be the R Forum...........

Thanks, R

 

[r82of250]

Wiki-Wiki says
[ame=http://en.wikipedia.org/wiki/Bump_steer]Bump steer - Wikipedia, the free encyclopedia[/ame]

 

[cobrakidz]

Nice looking parts.

 

[Jimmysidecarr]

They extend the attachment points of the tie rods up so that lowered cars can have less pull or push on the wheel they control during the arc of travel of the steering links. The ends would be angled up otherwise.

If the steering links adjusted they will steer one side wheel or the other as they go through the travel.

When are centered in the arc that they travel in they move in and out less.

There is a small window of movement in that arc that does not steer the wheel with suspension travel.

 

[Robert M]

They extend the attachment points of the tie rods up so that lowered cars can have parallel to the ground steering links. The ends would be angled up otherwise.

If the steering links are not level with the ground they will steer one side wheel or the other as they go through the travel.

When they are level they are centered in the arc that they travel in.

There is a small window of movement in that arc that does not steer the wheel with suspension travel.

Thank you Jimmy!! Yes that is right, I forgot that the discription said "recommended for cars that have been lowered". I knew that they looked like nice parts, but I forgot about the lowered recommendation.

My car was lowered as part of the Super Snake conversion, but still retains its original tie rod ends. I am going to lower the Eibach coil overs about 1/2" more on the front, or what ever it takes to closely match the rear, now that I am done with the tire/wheel upgrade. I did not want to bring those tie rod ends to the dealership for installation during the alignment and them laugh at me for having something that is not of functional use on my car.

R

 

[flattrack53]

The supersnake looks great Robert. The bumpsteer kit looks like it should be a bar tap with how pretty it is.

 

[grape]

Dangerous information above....... to do bump correctly you have to have the car in the air with suspension loaded at height, get a reference point, then get the springs out so you can travel the front end up and down from your reference point with a bumpsteer gauge. LEVEL WITH THE GROUND IS BAD, if you are just guessing and not doing it the correct way, get the tie rod angle equal to the lower control arm angle at ride height, better than nothing

 

[Jimmysidecarr]

Sorry I was just roughing out the general idea.:shrug:

I edited it. It is best to not wing this kind of stuff.

 

[SPEEDRACER88]

Get a gauge and set it...

Longacre Racing Products 79150 - Longacre Bump Steer Gauges - Overview - SummitRacing.com

 

[grape]

i would highly doubt if anybody on this site besides Gary and myself own a bumpsteer gauge. Plan on spending a day to get it right, if you know what you are doing. And remember, you can only get a strut car so close because of the un-natural roll center migration.

 

[Powershift03]

Bumpsteer Gauge [MMT-4] : Maximum Motorsports, the Latemodel Mustang Performance Suspension Leader!

 

[Robert M]

The supersnake looks great Robert. The bumpsteer kit looks like it should be a bar tap with how pretty it is.

Thanks Scott!!^^^^^^

WOW, this bumpsteer thing is getting deep, I thought I was just installing a couple of bar taps........, you know, use a level, adjust accordingly, drive away proud. I guess not...........:shrug:

I may just have them install the tubed lower control arms, align the front, hopefully without the need to install my Shelby CC plates, but I also have them if needed, and leave the bumpsteer ends for another project. There is no use in installing them wrong, they weren't cheap.

R

 

[SPEEDRACER88]

i would highly doubt if anybody on this site besides Gary and myself own a bumpsteer gauge. Plan on spending a day to get it right, if you know what you are doing. And remember, you can only get a strut car so close because of the un-natural roll center migration.

I'm ordering the one from Summit tomorrow

 

[ac427cobra]

i would highly doubt if anybody on this site besides Gary and myself own a bumpsteer gauge. Plan on spending a day to get it right, if you know what you are doing. And remember, you can only get a strut car so close because of the un-natural roll center migration.

Not only do I own a bumpsteer gauge, I also made a video because there are so many people that don't understand it.

Bumpsteer explained

I use a Longacre bumpsteer gauge:

Longacre Racing - Online Catalog: Electronic Wheel Scales, Gauges, Pyrometers, Chassis Setup and More!

Trying to help Mustang owners pass Z06's since 2006. ;-)



:thumbsup::coolman::beer:

 

[Jimmysidecarr]

Trying to help Mustang owners pass Z06's since 2006.

THAT should probably be a permanent fixture in your sig!!!:rockon::beer:

 

[Saleenrose]

Some of us do run our cars as Ford thought they should be used. I also own a Dyno, can you say that?

 

[grape]

yes, stuska water wheel with depac software, my business is exhaust systems for professional motorsports :-D

 

[1995COBRA-R]

I may just have them install the tubed lower control arms, align the front, hopefully without the need to install my Shelby CC plates, but I also have them if needed, and leave the bumpsteer ends for another project. There is no use in installing them wrong, they weren't cheap.

I'd try that first.

Simply, a car that suffers from bump steer finds the front suspension dialing in slight unwanted steering when going over a bump. ;-) It can be a little unnerving at Sebring when going thru T-1 at 100+ Mph.

I doubt that you will experience it on a street car with just a small amount of lowering. Did Shelby install suspension bushings with a higher durometer index (more rigid)? Mustang GT's come with OEM "softer" bushings and would be replaced in a race car with rigid bushings. The more rigid the bushings; the more it pronounces any bump steer. Polyurethane bushings are often used to replace "rubber" bushings.

As mentioned, you must find a very knowledgeable guy (probably one that works in a race shop) to set it up properly. You have to go back and forth between the two sides numerous time to get it right. The labor rate could run $500+.

IMO, the S197 cars have much more complicated suspensions (that's why they work so well) than the SN95s. Then Ford has made adjustments during its current production cycle. There is a lot of new engineering stuff going on underneath. Be careful.

BTW, It is a beautiful Snake.

I am going to lower the Eibach coil overs about 1/2" more on the front, or what ever it takes to closely match the rear, now that I am done with the tire/wheel upgrade.

Robert,
You didn't ask this question, but I'll give you my opinion, anyway. :-D

I'd leave it just as it sits. :-D

My theory: Shelby has already lowered it once. They have probably already lowered it just enough to keep it compliant with the suspension components. :shrug:

After you pass this line, you will probably need camber/caster plates (they install under the shock tower; the SN95 C/C plates install easily above the shock towers) to keep from wearing out the front tires. You may need new coilovers (shocks) because they may not work well after a car is lowered beyond a certain point. And don't get me started on the five different steering calibrations on the S197. ;-)

Just saying: My suspension file on my computer is two paragraphs for a 1965/1966 car. It's a page and a half on the SN95. It's 5 pages and growing on a S197.

 

[SDW Racing]

Not really related...but I gotta tell this story anyway....

A good friend was instructing at an HPDE school at Watkins Glen some years ago....a guy in a Cobra roadster was driving, my buddy the instructor in the passenger seat.

This guy...we'll call him Baby Huey cuz thats who he looked like.....starting jerking the steering wheel back and forth going thru the 'toe of the boot' at The Glen.

When my instructor buddy asked him what he was doing....he said.....

I'M BUMP STEERING!!!!!
True story...can't make this stuff up. :rolling::banana::lol:

 

[Robert M]

I'd try that first.

Simply, a car that suffers from bump steer finds the front suspension dialing in slight unwanted steering when going over a bump. ;-) It can be a little unnerving at Sebring when going thru T-1 at 100+ Mph.

I doubt that you will experience it on a street car with just a small amount of lowering. Did Shelby install suspension bushings with a higher durometer index (more rigid)? Mustang GT's come with OEM "softer" bushings and would be replaced in a race car with rigid bushings. The more rigid the bushings; the more it pronounces any bump steer. Polyurethane bushings are often used to replace "rubber" bushings.

As mentioned, you must find a very knowledgeable guy (probably one that works in a race shop) to set it up properly. You have to go back and forth between the two sides numerous time to get it right. The labor rate could run $500+.

IMO, the S197 cars have much more complicated suspensions (that's why they work so well) than the SN95s. Then Ford has made adjustments during its current production cycle. There is a lot of new engineering stuff going on underneath. Be careful.

BTW, It is a beautiful Snake.


Robert,
You didn't ask this question, but I'll give you my opinion, anyway. :-D

I'd leave it just as it sits. :-D


My theory: Shelby has already lowered it once. They have probably already lowered it just enough to keep it compliant with the suspension components. :shrug:

After you pass this line, you will probably need camber/caster plates (they install under the shock tower; the SN95 C/C plates install easily above the shock towers) to keep from wearing out the front tires. You may need new coilovers (shocks) because they may not work well after a car is lowered beyond a certain point. And don't get me started on the five different steering calibrations on the S197. ;-)

Just saying: My suspension file on my computer is two paragraphs for a 1965/1966 car. It's a page and a half on the SN95. It's 5 pages and growing on a S197.

Doc - Thank you for the compliment.

This car has the optional Eibach adjustable coil overs, I guess the bushing are what ever comes with them? or are the OEM bushings re-used?

My only thought when installing these tie rod ends was to adjust the ends so that they are straight instead of angled as it relates to the rack vs. the spindle. I have not even looked at the car when it is sitting on level ground, maybe the angle is fine. Originally this car had 255/35's on the front as part of the conversion. I have upgraded the tire size to 275/35, but still have the same 9" Alcoa rim on the front. The reason I was going to lower it just a little more was to close up the gap (slightly) between the top of the tire and the fender lip and make it more closely match the rear. I do have Shelby CC plates that are new in the box. The guy at the dealership said to bring them along with me and leave then with him while he aligns the car.

The main reason for the alignment is to pull the passenger side tire in at the top. Instead of leaning in slightly as the drivers side does, the right side stands straight up. The tire sticks out a little bit because of this, it has since the conversion. I don't know if the Eibach coil overs are slotted for adjustment, but the Ford shop manual instructs the lower two holds in the strut to be slotted to achieve the proper alignment. I am hoping this same process can be preformed on the Eibachs as it would be on the OEM struts and not use the CC plates?

One other question.................my Shelby tubed lower control arms have poly bushings, am I making a mistake by installing these? The reason why I ask is that I know the poly bushing are harder than the OEM rubber bushings on the OEM lower control arms, are these poly bushings going to beat me to death?

Here is a rear view of my car now with the 335/30 Viper size tires (except in 20"). This car still over powers these tires without much effort!?!?

Another view...........There is no room at all to move these 335/30's inward.

R