Does corner weighting effect alignment?? Change in rear tire effect corner weighting?

[Silver Bullet]

I believe the answer is yes to both of these but wanted to check.
Might go to shorter 315/35/17 in rear and feel that needs to be on there before I corner weight because of size difference. Reat combo will remain the same weight though.
Also will I need to realign car after cornerweighting??
Trying to get every last few tenths of a second per track lap here.
Is this worth tenths or more like hundreths??
Thanks.
DJ Worm i look forward to one of your awesome informative answers you always seem to have.

[DJWorm]

1. Yes, but indirectly re corner weight and alignmnet
2. Yes, but only slightly re 315x17

You can corner weight a car a number of ways and it is usually a combination of all of these.

Obviously one should take everything unnecessary and loose out of the car....making it as light as possible.
Corner WEIGH the car 1st with 1/2 tank WITHOUT the driver to set a base line.
Then ADD the driver to see what effect it has.
1. NEXT, (this is the first method) try to balance the car by shifting the weight of componants within the car. IE relocate the battery to the rear either center well or over the right rear axel centerline, which ever is better. I beleive the rear centerwell is best with a lighter sealed gel cell such as the Hawker Odessey batteries (but I degress). Moving the alternator and using a lighter alternator to the right side. Moving the hand held Fire Extinguisher to the right side, and if so equiped installing the fire suppression system bottle on the right side. Using a lighter carbon Fiber Hood and other body panels if allowed.
2. Adjust ride height to be equal side to side with at least a 1/4" to 1/2" rake in the front to rear ride height (REAR BEING HIGHER ALWAYS). You can now CORNER WEIGHT the car by adjusting each corner ride height. I do not like to use this method first and I do not use it exclusively. I think adjusting the individual corners to effect corner weights should only be used as a last method and only to fine tune the final readings in small increments. Many use this method first as it is the easiest.
3. A frequently overlooked method and probably the least understood is preloading the swaybars with adjustable end links. That is adding more preload to one side or corner to effect cornerweights in STATIC set up will have a positive effect when the car is DYNAMIC but may have to be adjusted for feel. For Example: If a rear weight is
L900-----------800R
looking from the rear of the car, you could preload the the left side by increasing the length of the left sway bar end link resulting in an equal STATIC corner weight, resulting in
L850^-----------850R.
This may be perfect in Static but when the car is DYNAMIC you may find that it sways to much to the right in a left hand turn. You may have to readjust the right end link to half of the original adjustment to achieve something like
L875^/2------------825R.
This may be the best compromise for DYNAMIC.
You could now use the other methods to enhance the compromise.
3. using differential Adjustable shock compression or bump settings
4. using and adjusting shock rebound to counter act any adverse corner weight setting
5. using different spring rates (assuming coil overs).
6. adding ballast
7. Adjust ride height differentially only as a last resort.

After you have lowered and cornerweighted the car, then align it

To see how a slight weight adjustment effects alignments when you are sitting in the car, move your hand from the steering wheel to the shifter and you can see the toe and camber settings change!. This is amazing and can be seen most readily on a laser alignment machine. That's why during the alignment the driver must sit perfectly still preferably with his hands on his knees for stability!

The object of lowering is to not only get the Center of Gravity lower but to get the Roll Center as low as possible. Roll Center is the key factor in handling.Sometimes the Roll Center of a car can actually be BELOW the pavement in a properly set up car!! (along with the Instant Centers of each corner). Of all the methods of corner weighting after lowering, adjusting ride height will effect the roll center more adversly than any other.

The 315x17's have a small differential in height from the stock 295x18, but not much. The actual ride height change is negligable, and just putting the 315's on will not necessitate an alignment check. However you should check ride height as to rake to make sure you still have the 1/4" - 1/2" rear to front rake (back being higher). If you do not you will have to raise the rear or lower the front further. Then you will have to recheck the alignment. Once the rake and alignment is set for the 315x17's you will not have to check anything if you switch back to the 295x18 F1-GS's

[Silver Bullet]

Great info.
Now the swaybar piece scared me.
Just mounted new T1 bars with helm end links and must admit having second thoughts.
Although a number of people have told me they are one of the biggest improvements possible for our cars.
Currently they make horrible noises (although maybe poly bushings) and the car is now stiff as a rock.

As for current ride height/rake issue.
Car measured by space at wheel wheels to a spot on tires is almost 1 inch difference side to side in front. Rear is about .3 inch.
That is my major concern and why I am having this done.
We lowered the car on stock bolts 3 turns per side so it should be even.
I will go pull on flat pavement and measure again.

[Subdriver]

Currently they make horrible noises (although maybe poly bushings) and the car is now stiff as a rock.

That's what mine sounded like and I didn't have poly bushings. Those helm end links are noisy.
But on the track, car felt great with those sway bars.
Tomorrow will be first day on track with full T1 suspension kit. Will report on feel early next week.

[DJWorm]

Squeaky Sway bar is usually from the inboard mounts.

Did you use a Silicon or Lithium based grease to lube the bushings?

If You used the stock mounts did you use 3-4 washers to shim them....otherwise they will be too tight.

Can you rotate the sway bar by hand in the bushings after torquing down the mounting bolts?

Are you measuring ride height with 1/2 tank and driver in the seat?

Which side is higher?

[Silver Bullet]

I assume the sway bars won't effect this and somehow they didn't lower properly but when measured side to side there is the following difference.
In the front the drivers side is a full inch lower at tire to wheel well opening top and at lower valance.
Rear is only about .4 inch.
Well just got beneath car and in front the top of bolt to spring is about and extra 1/4 inch on driver side at least.
I need to do a search now on lowering to see what I should see.
rear I could see 5 threads on passenger side and 4 on drivers side.
I don't want it fulley lowered bu if I recall you want about1.5 threads back from none showing for full lowering so I figure about 4 threads showing is about right. And they show on top of the spring correct??


I have stock shocks so really just trying to clean it up a little and avoid bump stop issue by not going fully lowered.

[Silver Bullet]

We greased swaybars and yes you could turn them slightly.
Car has 1/2 tank and nobody in it for my current evaluation and measurement.

[truckrookie]

you are checking ride height with the sway bars unhooked right? Setting the bar takes two people......the one sitting in the driver's seat and a buddy to adjust the heims untill the bolt falls through the control arm. This means the bar is neutral.....obviously, with you in the car. At rest with you out of the car the bar will tie the car down on the left side probably putting more LR/RF diagonal in the car. Once that is done don't put it back on scales with you out of the seat because it will scare you.