what did the c5 have?
With .7" more suspension travel bump steer could
raise its ugly head. They must have kept it low
to get 186 mph, however.
I've read that the viper was the only street car
designed with zero bump steer.

 

 

he had terrible bump steer in his c3 at 130 mph.
something like 1-3 inches
quick steering corrections were needed
He built some special parts and eliminated
it
i'm thinking without the erratic steering that the c3's had, the c5-6 could stiffen the responses at speed since quick corrections aren't necessary.
BUT, i read numerous reports that the FUN TO DRIVE factor is dissappointing in the c5 compared to early vettes. I SUSPECT the stiffening of the responses are at least partly to blame.

 

Oh, I get it. Wing Cow!

 

there is no way any stock suspension front end could have 3" of toe. this guy is full of it. i have build race cars and i know what causes "toe steer"

 

I don't think you can convince Matt.

From his earlier thread on Magnasteer and C6 Corvette steering in general:

.... "I'll believe the C6 (steering) is as good as my 67 ford when i see and drive it. and if it isn't, i'll fix it to my satisfaction. .... "

From my own standpoint, the steering on my C5 is at least as good as the steering on my 70 Ford. I would expect the C6 not to be much worse.


http://forums.corvetteforum.com/show...0&page=2&pp=20

post #22

 

clem
i said do a search as i don't remember, i think
it was somewhere between 1-3".
he built spindle extentions and tie rod spacers
AS I RECALL.
very interesting story, worth looking up
HIS CAR IS STABLE NOW @130
i've read c6's are stable at 186

 

i tried to e-mail you as i could send you a fish scale so you could put a number on it.

clem, u missed the entire point of my post

 

matt what is your point, i must have missed it my point is this guy is full is excrement if he says a stock corvette front end has 3" of toe steer. i bet the orignal 53 corvette with a front end from a chevy sedan delivery did not have 3" of toe steer. we change the steering geometry on race cars to add or subtract bump steer depending on the track. 1/8" makes a big difference. the whole front suspension on the C-6 is changed from the C-5 so adding more travel to it has caused the suspension points to be changed. none of the front parts are interchangable with a C-5

 

 

clem
this version above might be clearer. if you are too lazy to look up the story just imagine the bump steer on
a c3 compared to a c5 or c6. do you see an improvement? that is the point.

 

"bump steer" has nothing to do with bumps, it is cause when turning at speed and the suspension is compressed and the toe changes. i never owned a C-3 but owned 4 C-2 which had the same front suspension and drove them on road race tracks with out any problems that would cause me to crash. the only time you should have a bump steer problem with a stock corvette would be if you lowered the car and then the tie rods attaching points would need to be repositioned. any time you plan on driving at very high speeds you should set the toe to 1/16"-1/8" toe out to prevent wandering at high speed.

 

"bump steer has nothing to do with bumps"
clem.
do you have any other words of wisdom?
thanks for giving me a big smile today!
Good to read my 72 has as good a suspension as the c6
Do fill us in on why the c4,5,6 suspension was redesigned without any improvement over the c3?
and what \how many/ are you drinking/smoking?
Good to see you can still party at your age!

 

if you are driving over bumps that compress the suspension enought to change the toe in you must must be off road. i never said that your suspension was as good as a later vette but i will bet that GM did not send your 72 out the door with 3" of bump steer. the main reason the C-4 was changed they went to rack and pinion and of course they changed the suspension pivot points. the big problem with the older corvetts was not bump steer but aero lift in the front and that is why the C-2 and 3 were a hand full at hi speed. we just added a "snowplow" spoiler to the front to cure that problem.

 

 

i can go on all day since i am retired

 

Here is a technical excerpt from Longacre's website


Bump Steer

Bump steer is the toe-in or toe-out of the front wheels as the suspension goes from normal ride height through full bump (suspension system moves up) to full droop (suspension system moves down). Measurement is usually limited to 3" up and 3" down from ride height. It is specified either by a graph or measurements at 1", 2", and 3".

Bump steer affects handling much as setting toe-in does. All cars have a certain designed-in pattern of bump steer. Check with your chassis builder for his normal pattern. If you have a factory chassis, you'll probably want to try to minimize bump steer as a starting place.

Due to normal manufacturing tolerances, the actual bump steer can vary from the designed pattern and should be checked on a new car and occasionally during the life of the car to see if it has changed. Many professional racers even use bump steer as a chassis tuning tool. Again, check with your chassis builder.

Checking Bump Steer

First you must determine the position of the suspension system at ride height. This is a starting point as this is where normal toe-in is set. Later you are going to put the car on a ride height block and remove the front wheel and spring.

There are two easy ways to determine the front suspension position
Measure the length of the shock absorber.
Measure the angle of the upper A frame.
Choose one and take the measurement with the car at ride height. Also measure the frame-to-ground clearance at this time.
Make a ride height block from wood (or anything solid) the same as frame-to-ground to place under the frame when you take the front wheel off.
Put the ride height block under the frame and remove the wheel and spring. Also disconnect the sway bar. Place a hydraulic (or floor) jack under the A frame and raise the suspension to ride height by measuring the shock length or A frame angle as before.
Bolt the aluminum plate to the hub. If necessary you can drill other holes for your particular car. (After you're done, keep the bolts with the set for future use.) Rotate the plate so that the small level shows horizontal.
Lean the bump steer gauge (tubular frame with dial indicator) against the plate at a slight angle (approx. 15º) so that the upper tube is parallel with the plate and the dial indicator tip and roller bearing contact the plate. Loosen the knurled ***** adjust the height so the dial indicator tip and roller bearing are next to 0" on the plate scale. Rotate the dial on the dial indicator to 0".
Using your hydraulic jack move the suspension system until the dial indicator is at the 1" mark. Note which direction the dial indicator moves to see if the wheel toes in or out. The reading you get on the dial indicator is the actual amount of bump steer. It's that simple. Record this and go onto to 2" and 3". If you want to make a more detailed measurement, you can take readings every 1/4" or 1/2" and plot a graph.
Note: When you are taking measurements the steering must not move. If necessary, lock the steering in place. Also, the hub and plate must not rotate. If it does, turn it back to horizontal using the small level.
Now go back to 0" and take similar measurements as the suspension systems moves down. Repeat this procedure on the other side of the car. Keep the readings as part of your records.
To adjust bump steer refer to your setup sheet or manual, or there are several good books on the market that describe how to make adjustments. Because suspensions vary widely, it is not practical for us to go into detail on actual adjustment procedures.
When you are done with the adjustments, re-check as before.
________________________________________ _______

 

Matt,

I think there may be some decimal points missing here. You can do your own simple test if you like. Hit a driveway ramp at a near 90 degree angle, and put only one wheel up on the curb. Check the steering angle on that wheel, and compare it to the one still on the street.

"Fun to Drive" is subjective, of course. An old Vette may indeed be funner than a new one, but there are host of factors that feed into that. The hot cams and loud sidepipes would immediately jump this factor up quite a bit on their own, no matter how poorly someone thought they steered.

Michael