medamullet

I have been thinking of running the stock rear springs with 13mm pads and 10mm spacers in the rear and the H&R springs in the front with 12mm spacers. Running the stock 235 40R18 in the front and buying a taller 255 40R18 tire. I don't like the rear tires being taller in the front.


Has anyone done this?


What are the spring rates for our rear springs vs H&R?

kb24forlife24

Just do both front and rear H&R or OEM, don't mix it up. Not worth it and the ride will be weird.

Roswell

^^ I agree, different spring rates can be dangerous.

medamullet

Our stock springs are different rates....

Why would the ride be weird?

medamullet

FYI


I just called H&R they won't share their information on spring rates.

Roswell

H&R & OEM definitely have different spring rate. H&R is a bit stiffer cuz they are shorter, mixing both can make ur car unstable , not well balanced & ur handling might suffer.

Do at ur own risk, look vs function

medamullet

^^Iunderstand what you are saying and I am not disagreeing with you. The front of our cars weighs more than therear. The front spring rates and heights will be different than the rears withOEM and aftermarket springs.





Ihave run a number of coil-over suspensions for both my track and street cars andit’s very common to mix and match spring rates. 8k fronts 6k Rears, 10kfronts 8k rears. The preload at various percentages plays a huge differencein rate/performance. This isn’t even taking into consideration sway bars. There are lots of factors when setting up suspension. I am just looking fornumbers to do the actual math. This isn't going to be a track car. If it were I wouldn't even be messing with sport springs and OEM struts.

Roswell

I see ur point, if not tracking with it u prolly won't see much of a difference.

But I still didn't take a chance & went ahead with full H&R springs at all 4 corners & raised the rear a bit with the thicker 17mm spring pads.

medamullet

I like your cars look for sure. Yours is actually the car I was copying the numbers off ;-) I just want to run a taller tire in the back (maybe) I would rather the tire not completely tucket under the fender. If I could run H&R front and rear and find a 25mm spacer that would be perfect. I would have the engineered spring rate match plus the extra 25mm to make up for the tire difference.

Roswell

I don't understand the 25mm spacers? I run 10mm spacers in the rear with 255/30/19 (or equivalent to 255/35/18).. No way I could use a taller profile sidewalls of 255/35/19 (or 255/40/18) without rubbing let alone changing the 10mm spacers to a 25mm spacers, that would be a disaster for my fenders lol

But yes if u stay at stock height in the rear, u could upsize the sidewalls to 255/40/18 but i can't see u running a 25mm spacers even at stock height.

medamullet

Sorry the spacer I was referring was to lift the rear 25mm higher. The 255 40r18 and 255 35r18 is a 25mm difference. To keep the stock ride height and use the H&R springs front and rear I was talking about adding a 25mm spacer and the 17mm pad to NOT have to use the stock rear springs and have a crazy front and rear spring rate difference.

Roswell

Ok got you! I'm new to the suspension game so excuse my ignorance about using spacers to raise the car. I'm only used to spring pads.

Yeah though call for u & I doubt someone here has the answer for u, best bet is to give it a try by lowering the front first. Good luck

medamullet

Thanks. Maybe I will do just the fronts tomorrow and drive it for a few days before doing the rears. I'll post pics.

Roswell

Exactly, great idea & report on the handling. I hope the rake look won't be too pronounced

medamullet

Finally got around to taking pictures. Can't really tell the difference with the rear springs being stock. Took about 3 hours and definitely need spring compressor to install the new springs. Taking the stocks off no problem but on I'm definitely not strong enough to push the top hat down. :-)

Pictures coming shortly. I'm on my phone now.....

AMG3.2

HR Lowering springs are progressive and therefore do not have a spring rate as the rate is constantly changing based on how compressed the spring is.

medamullet

medamullet

Finally got around to finishing my rear springs. The H&R feel much better and stiffer. My rear end felt floaty and not connected with the stock springs. I did the 17mm pads in the back as well. Purchased some SL63 AMG 10 spokes in black. Tomorrow I will post some pictures. Looks good, and feels good. Rear diff needs work. I hate the 1 wheel spin.

malahhaor

i test drove C63 for the first time today and coming from a carrera i noticed that the ride is ok but felt a little bouncy at times. is that why youre looking to get H&R?

medamullet

Yes. the exact reason.


with H&R springs 17mm rear pads.


19x9.5 +45 offset rear 19x8.5 +45 front with 12mm spacers on the front, no spacers rear.

I don't like the skinny sidewall on the tires but oh well. Maybe next time I will try a taller tire.

Roswell

How did I missed these pictures? Looks really good with the OEM rear, not too much of a rake but maybe ur front didnt settled yet?

At the end it seems u went H&R all around. Good choice! Car is looking good.

medamullet

Front was settled. I liked the look too. I didn't like how soft the rear felt with the stock springs on there. The H&R springs front and rear handle much better.

tpliquid

i drove 400 miles with front hr and stock rears. no problems. didnt have time to finish installing the hr springs

medamullet

That's what I did. Except I drove for almost 5 months.... other that it was softer and felt floaty in the rear end no adverse affects. I liked the look, just with the stock springs were stiffer.

kjkidd21

Can you link to where you purchased the 17mm rear spring pads?