alignment specs for type one?

[Brave Salmon]

I'm going in to have my alignment checked on the hotrod. the specs in my manual call for 1/16 total toe in, -0.5-0.75camber and 6-7 caster. This is power steering car. Does anyone have ideas if these specs are still applicable or has a better setup been developed? My car seems a bit twitchy at speed so I thought I would ask. thanks

[FF33rod]

Have to agree. I haven't driven a lot on the highway but feels very light as I get to 50-60 mph. Would feel very uncomfortable trying to push it faster

[NAZ]

Tom, your specs seem reasonable and very close to what I'm running and my car handles fine even at 150 MPH on the track. Your tire manufacturer may have a camber suggestion but it will likely be close to what you stated above. I don't run power steering and still have no trouble with 6-deg caster & -0.4 camber. My toe-in is set to 1/16" using toe plates.

If the car feels twitchy it may just be the feeling you get from the power steering but you can also get that from bump steer and roll steer on a solid rear axle car if the lower control arms are at an angle. Remind me which rear end you're using.

[Brave Salmon]

Thanks NAZ. I'm running the 4link with QA1s in the rear. yeah, my lower control arms are at a slight angle because I have the rear raised a bit for better travel in the rear. Maybe I can try to switch the PS off and try that after the alignment. you may have something there. As always, thanks and take care,,,

[AJT '33]

This is a picture of the setup of mine on a drive on alignment machine when my son did the alignment. We used a base Mustang setup as you can see on the screen.

He wants to go back this spring to recheck it against the spec and possibly adjust the fronts as it can get squirrely at 60mph if I come across rods that have ruts (actually scary) to feel them less. Mine is all manual steering with a 2015 IRS in the rear.
137575 137576

Hope this helps.

[FF33rod]

Was able to dig up the alignment report for mine, also have IRS...

137580

Steve

[1932]

I have shelby- shelby R , turnin and corner holding is good. But car is twitchy and very touchy at high speed . On road with ruts i have to be on it, probably made with wide tires. IRS & power steering. Play in steering rack?

[NAZ]

I have shelby- shelby R , turnin and corner holding is good. But car is twitchy and very touchy at high speed . On road with ruts i have to be on it, probably made with wide tires. IRS & power steering. Play in steering rack?

"Twitchy" can mean different things to different people, so that's not much to go on. If you call a car that seems to veer left & right when driving straight ahead at high speed requiring you to constantly work the wheel "twitchy", then that may be un-commanded steering input from a suspension issue or an unconscious commanded steering input. The latter is easily explained and corrected. The former could be any number of causes and often is more than one cause.

[1932]

Un even road makes for veering and small input makes bigger movement of car at speed.

[NAZ]

Un even road makes for veering and small input makes bigger movement of car at speed.

Let’s address the unconscious steering inputs first as it’s more common than most realize and easy to fix. At high-speed (let’s say >100 MPH) the steering gets easier and needs a softer touch as every small input makes an instant and larger reaction than at highway speeds. Every small bump makes the car react noticeably and you will feel your body moving around in the seat more. Drivers new to high-speed driving will tend to grip the wheel harder and elevate their elbows to get more leverage as there is a sensation that you need to hold on tight so you don’t loose control. That tight grip and stiff arms transfers every little jostle your body gets from road seams and small bumps to the steering wheel. The steering, now more sensitive to driver inputs will make you feel like the car is darting back and forth. And you will saw on the wheel trying to catch it, but are always behind it. You will swear that it’s the car doing it not you the driver. But if you relax your grip on the wheel and tuck your elbows in at your sides the car will respond by running straight.

Now for the twitchy feeling over rough roads, here’s a few things to check. Tire pressures should be equal side to side. Any amount of toe out (front or rear) can cause a wondering feel at speed. Bump steer will cause a twitchy feel and upset the chassis (front or rear). If you haven’t adjusted out the bump steer you likely have some degree of it. And less likely but also will cause a twitchy car – loose or damaged suspension components.


For a larger list of things that can cause handling issues: http://racetrackdriving.com/car-setup/vehicle-dynamics-cause-effect-guide/