When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I cannot answer at your question... maybe different machines read different caster. I am sure mine was +9.5° stock, with wheel in the center. Now at +10.1° is pushed forward. Instead of checking the value I would check the wheel in the fender.
Increased Caster would have the opposite effect on what you are describing. It should make the steering effort higher and harder, not lighter as Caster value increases.
I noticed a light front-end when I did a test drive last week end at about 90 MPH.
I plan on going -2.5 F with Toe and -2 R with 1.5 toe in per side and rear toe end-links when I get mine.
I am hoping that by going to -2.5 in the front with shims it will give enough positive caster to give it a not so light feel.
Yours it is not centered, it's way back. I can really believe your caster is +8.7°.
When I said that my front side is light I don't mean the steering... I mean light weight or slight "floaty" (and then low grip).
I have no such sensation from the front of my Spyder, solid and planted was my description.
It would be helpful to know or have a reference point to determine what is centered. Perhaps not the best picture because of the shadows, but "it's way back". I am not so sure about that...
For reference I just measured the distance between the tire and the front edge and rear edge of the wheel well opening and they were identical at 12.7mm front and rear.
You have a very low caster at +8.7°, stock was +9.5° on mine and now is +10.1°... dunno what is better but they should behave very differently just for this reason.
At +8.7° your front wheels should be pushed back, mine are pushed forward from the center. Could you take a picture? This is mine at +10°
Originally Posted by Westcoast
Here is mine, just snapped this picture... remember we installed caster pucks to correct the wheel position and keep it centered.
To me the red top pic looks way more centered than the silver bottom pic.
@SpyderLegend referring to the picture below, measure the space at the locations I show, keep the ruler level to the ground... measure lower edge to the tread surface not the side of the tire, of course this should be with the steering wheel centered and on level ground.
8.7° caster vs 9.5° (stock car) vs 10.1°, in order (you can trace the same line with wheels and not tires, it doesn't change):
Do you have a citation that stock is 9.5 degrees, I see a different number on the Hunter Alignment rack chart? The range being shown as 7.8-8.8 degrees, which would put my front wheel inside the range.
The lines are not helping, did you actually measure it as I suggested?
Do you have a citation that stock is 9.5 degrees, I see a different number on the Hunter Alignment rack chart? The range being shown as 7.8-8.8 degrees, which would put my front wheel inside the range.
The lines are not helping, did you actually measure it as I suggested?
Since we went to different alignment shops, it's true that your car on my shop might be measured ~9.1 instead of 8.7 (and mine at your shop might be ~9.8° instead of 10.1)
I haven't yet measured as you suggested, I will do ASAP (remember, I can measure the current 10.1° setting, not default one), but I am sure there are differences between your current value and my default value. Optically it is so much different to my eyes they cannot be at the same caster.
PS: I think your 7.7/8.7 range is for standard Boxsters&Caymans, are you sure they selected the right car in the computer (981 GT4)?
Last edited by SpyderLegend; 03-01-2021 at 04:04 PM.
Working with John and his folks at BGB. I'm running 2.2/F and 2.0 rear. 7mm spacers up front, toe links rear. First AX= FTOD. First track day at Sebring this weekend. Working on an acceptable balance between Street/AX/Track. Plenty of room to adjust, and the BGB Team is a great resource!
Working with John and his folks at BGB. I'm running 2.2/F and 2.0 rear. 7mm spacers up front, toe links rear. First AX= FTOD. First track day at Sebring this weekend. Working on an acceptable balance between Street/AX/Track. Plenty of room to adjust, and the BGB Team is a great resource!
Is that small of a spread of F to R camber because of the spacers? Most recommend a .5 delta between the F and R for camber on the GT4.
Is that small of a spread of F to R camber because of the spacers? Most recommend a .5 delta between the F and R for camber on the GT4.
I plan to go -2.5 F & 2.0 R
I set the camber based on whichever end needs more grip. As you have seen since the beginning, Porsche has always wanted more camber in the rear of the Boxster solely because it has more weight...i.e. more body roll, i.e. more camber gain / loss so the rear might need more unless you have insufficient grip at one end or the other. KBS wanted more rear grip so I added grip to the *** end.
@SpyderLegend referring to the picture below, measure the space at the locations I show, keep the ruler level to the ground... measure lower edge to the tread surface not the side of the tire, of course this should be with the steering wheel centered and on level ground.
Those arrow measurements will not determine whether a tire is centered in the wheel well. I just took a measurement of the spoiler back edge to ground and the body front edge to ground and they differed by ~1/8" vertically; I used a regular measurement tape. Using trigonometry with a radius value of 13.37598" and taking the vertical difference of 1/8" into account the horizontal distance between both points to the tire radius differs by 0.10678". Its a small number but enough that it cannot be used to make a center determination.
02-26-2021 | 04:03 PM
