How low is too low?

[StlRomAniaN]

Hey guys,

I just recently lowered my Camaro SS on Pedders Xa Coilovers. My ride height, from the bottom of the rim to the fender, is 642 mm on the rears and 639 mm on the fronts.

My questions are, how low is too low? What are you guys running height-wise on your coilovers? Also, I'd like someone to explain the stress being put onto the rear axles at this height, or lower. Is there any upgrade to deal with axles at a lowered height like this?

[StlRomAniaN]

Bump for people with coilovers.

[Angrybird 12]

If you high center over a speed bump its definitely too low.

[R8E1D]

I'm at 655 front and 665 rear. There is some stress put on the axles when you lower. I read it on here somewhere. I've also seen where one of the vendors has an option of "smoothing" the cv joints. Sorry cant remember which one it was though. Ill post the link when I find it.

[JusticePete]

This is not what you want to hear. 642mm is too low. It screws up the IRS geometry. 660 is as low as you should go with 20s

[Rod Knock]

I was initially at 645 all four wheels and ended up raising it later to 653 on front and 658 on rears. I have about 4 1/2 inch clearance to bottom of front air dam and (very) slightly more to lowest part of the exhaust.

I didn't realizen there may an issue with the suspension geometry but hopefully 2mm won't hurt it that much

[JusticePete]

Originally Posted by Rod Knock

I was initially at 645 all four wheels and ended up raising it later to 653 on front and 658 on rears. I have about 4 1/2 inch clearance to bottom of front air dam and (very) slightly more to lowest part of the exhaust.

I didn't realizen there may an issue with the suspension geometry but hopefully 2mm won't hurt it that much

2mm won't matter.

[StlRomAniaN]

Hm, I would be interested in seeing exactly how the IRS geometry and axles are affected.

[JusticePete]

Allow me a bit of literary license to explain.

From a level position you have 3" of travel up and 3" of travel down in an arc. With 90 Degrees as the level line 0 degrees as maximum upward travel to 180 degrees and maximum downward travel.

Lower the car 2". 1" of travel up and 5" of travel down. The level line becomes 45 degrees. 45 degrees to 0 degrees up and 45 degrees to 180 degrees down.

Attach secondary arms to the main control arm. There are limits to the travel of these 'multiple' swing arcs before they go into a bind position.

The ideal lowered ride height allows the arms to operate within the constraints of the OEM geometry. This is achieved by controlling travel with higher spring and damping rates.

The half-shaft angle is more clear. Run the CV joints in anything other than a straight line and the amount of friction increases. Friction is heat. Heat liquifies the factory CV lube. The CV boot is designed to keep dust out, but liquified lube is thrown out the seal. The lower you go the more friction you'll have in your CV joints. Remember the illustrative explanation with 90 degrees being the OE center? Dropped 2" the half-shaft spends almost every operation minute between 0 and 90 degrees or is at a higher than OE angle almost constantly. This increases friction. Friction is heat. Liquified lube and heat are a prescription for increased wear.

Pedderised Camaros have been the fastest modern muscle cars at the OPTIMA Ultimate Street Car Invitational since 2009. We ran the first year with ride heights of 660mm and 19" wheels. With 20s we run 672mm. The harder you run the more important the IRS geometry becomes, especially when using all of the track. We found 680mm to be best for the most aggressive driver we put in one of our cars.

At the 2012 OUSCI the Lingenfelter-Pedders L/28 driven by Danny Popp posted the fastest modern muscle car hot lap, even though we broke the drive-shaft coupler. It was the 5th fastest time of the day. The four faster cars did it on their hot laps. We pulled our lap time from a standing start on our warmup lap and broke the drive-shaft coupler as we began or first hot lap.

[Driveshaftshop]

changing the ride height as far as axles (not handling and center lines) should only change the angle about 3-4 degrees, the axles are not straight to begin with and lowering them will put more of an angle but i believe its more of a boot problem than a CV issue. the factory axles have the hard durometer boots that are not very forgiving. we have done numerous road cars with a different style boot that will not only help this issue but we use a much better grease to ensure there is no issue.

[Nitroman28]

Anyone know what the factory height is from the fender to the ground? I'm at 28.5 F 29.25 R with lowering springs, Wondering what it will put be back at with stock springs.

[StlRomAniaN]

Originally Posted by Driveshaftshop

changing the ride height as far as axles (not handling and center lines) should only change the angle about 3-4 degrees, the axles are not straight to begin with and lowering them will put more of an angle but i believe its more of a boot problem than a CV issue. the factory axles have the hard durometer boots that are not very forgiving. we have done numerous road cars with a different style boot that will not only help this issue but we use a much better grease to ensure there is no issue.

This is very interesting!

[StlRomAniaN]

Originally Posted by Nitroman28

Anyone know what the factory height is from the fender to the ground? I'm at 28.5 F 29.25 R with lowering springs, Wondering what it will put be back at with stock springs.

I believe it's 690-700 mm from the bottom of the rim to the fender. You want to measure from the bottom of the rim so you can eliminate variables such as a tire with less air that would result in inconsistent measurements.

[JusticePete]

Originally Posted by StlRomAniaN

I believe it's 690-700 mm from the bottom of the rim to the fender. You want to measure from the bottom of the rim so you can eliminate variables such as a tire with less air that would result in inconsistent measurements.

Spot on.



Front 685 - 695
Rear 690 - 700