Lowering the rear end on a stock height 2010 SVT none PP

Did a lot of reading on this and other forums. Read that I could put the stock rear tire size on the front too without any issues so that will be done when I need to replace the front Pilot 4S that are wearing. Rims and tires are all stock size.

I want to lower the rear slightly around 1 inch max to decrease the slope of the rake but keep the front at the same height and keep the ride quality satisfactory.

Here is what I have come up with: (I don't track or dragstrip the car)

H&R Sport Springs 51655-500 I believe these are the OE Sport springs - (black color?)
Either Bilstein HD series shocks (2005-14) or Koni SRT.T series (non adjustable)
Ford Performance Jounce Bumper kit to replace the stock ones in the rear

Any suggestions or recommendations? Trying to keep the costs down and right now I have easy access with the exhaust out. Already have an adjustable BMR panhard bar on it.

If I'm reading this correctly all your wanting to do is lower the rear to get rid of the rack. If this is the case another option would be to buy some ride height adjusters. Steeda, revan racing, maximum motorsports, bps, and upr sells them. They are an adjustable perch similar to what you'll find on a coil over set up. You can choose your spring height and spring rate depending on how low or high you want to go. However, if you choose the upr setup you will have to weld. I know you can get a set of just rear springs for a bit cheaper it doesn't allow for the adjustability that these kits do. Another option is to just get both front and rear springs.

Sent from my SM-G960U using the svtperformance.com mobile app

The spring adjusters use 2.5" i.d. 10" length coil-over springs. Rear spring rate on a 2010 coupe is 180 lb/in springs.

Looked over the ride height adjusters... I think I like the UPR one the best (non-welding version one) since it still uses the factory isolator for dampening and I don't see any insulation with the Steeda unit. Also don't like the way the Steeda sits up on top of the mount instead of mounting over it.

Questions....
Since I want to lower about an inch

How do I know what spring length to get - seems like they all imply 10 inches but I don't know what stock is and I want to lower it so if stock is ten then I need less than 9 right off the bat (not even considering mount thichness)

If factory is 180 I am thinking I should probably go with 200 since I have reduced travel an inch. Options appear to be 175 or 200 or greater

Do I need to consider the stock shocks if they are being changed from their normal position by an inch?

Other thing that concerns me is what really keeps the adjusters and springs in place if axle ever dropped a lot....does shock travel limit still always keep some tension on the spring even after lowering it?

Just a little personal experience on the Koni non-adjustables. I have a set I bought 2 years ago. The drivers side rear shock blew a seal in about a month. Koni replaced it under warranty, no big deal, crap happens. I put caster/camber plates on the front 3 weeks ago and both front struts are leaking badly. I daily drive my car and the roads in Maryland are not great but 2 years? Come on...

I have a set of QA1 adjustables that need to be rebuilt that I am going to put on the rear and I am going to get a set of Strange 10 way adjustables.

I have to see if my Shelby stock shocks in the rear are oil based or gas based. I am not changing the front height so everything in the front should be okay.

With old oil shocks you could pull or push on the shock and the shock basically remained in that last position with no internal loading in the shock.

With gas shocks I once had they tend to return to their neutral position and the gas pressure inside is minimized. If my stock Shelby shocks are like those then I will have an issue probably because the shocks are designed knowing the normal position the piston will be at during normal resting. By lowering my rear I now changed the shocks piston and it is no longer at its normal rest spot. I think internally I will be creating additional gas pressures that are always pushing against the seals. In addition the piston may now travel more in one direction than it normally would creating even higher internal gas pressures than it normally would. I think this will cause premature wear and early seal failures. I see where some kits have you adjust their gas shocks at the new normal car height level to probably try and minimize the internal gas pressures at the new height. I am only guessing this is how they work and why they perform this step so I need to research it and probably order gas shocks that I can manually adjust. And by adjusting I am not referring to the hardness or firmness some have on the top of the shocks, I mean adjusting the shock so it is at rest with the car at its resting height.

XP900 said:

Any suggestions or recommendations? Trying to keep the costs down

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Don't lower it? That's cheap
If you do lower it, will your pinion angle be affected?
And FYI, there were no Performance Packs in 2010

For more info posted in this forum related to your spring and shock choices (with pics):

Search... H&R sport springs
Posted by member: SCGallo2

XP900 said:

How do I know what spring length to get - seems like they all imply 10 inches but I don't know what stock is and I want to lower it so if stock is ten then I need less than 9 right off the bat (not even considering mount thichness)

If factory is 180 I am thinking I should probably go with 200 since I have reduced travel an inch. Options appear to be 175 or 200 or greater

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Coil-over springs are not that easy to find in odd number lengths. 10" length covers most spring rates between 175# and 225#. Higher springs rates may warrant a 9" spring. QA1 has some 9" long coil-over springs. It's too short for anything less than 250#. Landrum makes an 11" spring if you go less than 175#. Ride Tech makes a 185# 10" spring. You need to cut your bump stop snubber so you have a bit of clearance at ride height. That's what really controls your down travel.

I find the problem with stock-type springs is it may be higher or lower than what you have in mind. Springs are usually matched as a set. I'd stay as close to the stock spring rate as you can if your not changing the fronts.

1Kona_Venom said:

Don't lower it? That's cheap
If you do lower it, will your pinion angle be affected?
And FYI, there were no Performance Packs in 2010

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The 2010 seems to sit really high in the back compared to the other years..just want the same wheel to body spacing the same between front and back.

Still on the fence.....yah the pinion angle would change a little and I would need to put in an adj UCA...also would probably replace the LCA with BMR polys...that also affects angle setting from what I read...supposed to be 1/2-1 degree less with poly bushings in the control arms...

Sort of a hassle once you start down the road. Already replaced pinion bearings and diff bearings at 30K and don't want to mess them up and do that work ever again.

Catmonkey said:

Coil-over springs are not that easy to find in odd number lengths. 10" length covers most spring rates between 175# and 225#. Higher springs rates may warrant a 9" spring. QA1 has some 9" long coil-over springs. It's too short for anything less than 250#. Landrum makes an 11" spring if you go less than 175#. Ride Tech makes a 185# 10" spring. You need to cut your bump stop snubber so you have a bit of clearance at ride height. That's what really controls your down travel.

I find the problem with stock-type springs is it may be higher or lower than what you have in mind. Springs are usually matched as a set. I'd stay as close to the stock spring rate as you can if your not changing the fronts.

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Thanks, I will look into the Ride Tech and ask them. I guess I need to know the height of the read stock springs to really figure out what length I need to see if the ride adjusters will give me the proper height. I was going to install the FR bumpstops and possibly cut them down if needed.

Is there any reason to put on adjustable LCAs from BMR versus the non adjustable ones? I can't see me installing new LCA mounts for any reason since and I usually stay with stock tires and wheels.

Its much easier to adjust pinion angle with the LCA's than the upper one.

If I'm not mistaken the adjustable LCA have rod ends on one end at a minimum. If you drive on velvet highways they may be okay, but on the roads in my hood, they were too violent for me. I have no problem adjusting my UCA for pinion angle.

I have 225# 10" long coil-overs on the car in this pic and using Maximum Motorsports' spring adjusters. The adjustment collar is all the way down. Rear tires are 325/30-20s which are said to be 27.7" overall diameter. I have since installed the 185# rear springs and it drops the rear by .58", but I have them adjusted up to roughly the same ride height. There's about 1.5" of total adjustment. Distance from the ground to the center of the fender lip is 28.5". I've had the car lower (sig pic), but with headers and resonators, it was too low for the crappy roads in these parts.

might I recommend a 1 piece driveshaft while your at it?
Its just the right thing to do

Catmonkey said:

I have 225# 10" long coil-overs on the car in this pic and using Maximum Motorsports' spring adjusters. The adjustment collar is all the way down. Rear tires are 325/30-20s which are said to be 27.7" overall diameter. I have since installed the 185# rear springs and it drops the rear by .58", but I have them adjusted up to roughly the same ride height. There's about 1.5" of total adjustment. Distance from the ground to the center of the fender lip is 28.5". I've had the car lower (sig pic), but with headers and resonators, it was too low for the crappy roads in these parts.

View attachment 1689701

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Thanks, That was what I needed to know. I live in NY and their are bad roads here so I cannot lower much at all if any. That's why I am only looking at .75 for the rear...which raise the splitter a hair at the same time. I also read about a lot of issues with NVH using poly bushings and that has me concerned. I'm inclined to install the Roush upper UCA to get rid of any wheel hop...but then I have limits on the pinion angle which I am measuring now. I don't want to use adjustable LCAs to prevent NVH issues nor LCA brackets if I can avoid it. Maybe solid BMR LCA bars only if I still have wheel hop after UCA change. Using Michelin 4S now so a better tire isn't really an option.

Trying to calculate how much my pinion angle changes if I drop just the rear .75 - 1 inch max.

1Kona_Venom said:

might I recommend a 1 piece driveshaft while your at it?
Its just the right thing to do

Click to expand...

I installed the Ford Performance one-piece last year with the BMR safety bracket (panhard bar too) when I had to replace my differential bearings. No noticeable NVH and no rubbing or hitting yet. Even the differential was still quiet after the new bearings and I kept the backlash exactly as it was before I started.

That's why I am concerned about changing parts on this car...no noises from rear yet...

Catmonkey:

Let me know what you think about this...

I am thinking I need 11 inch coils based on what you wrote. I suspect these are linear coils I would be getting.
I read that the stock 2010 is 30 inches from ground to the rear upper lip - can't measure mine right now.
Your car was at 28.5
Need to subtract .4 (half the tire difference between yours and mine 27.7 - 26.9 = .8)
Need to decrease another .58 for the drop using 185 lb springs which I will be using
Therefore my rear lip height with your 185 coils and adjusters would be about 28.5 - .4 -.58 = 27.52 inches with adjusters at their lowest level. Even at their full height it would only get to about 27.52 + 1.5 = 29.02 ( .98 inches lower than my current setting)
With an 11 inch coil my range would be 28.52 to 30.02 which would be perfect for my .75 drop. I'm sure these readings may be off a little but with 11" coils I may have more room to adjust.

With only a .75 drop in the rear are lower control arm relocation brackets even needed?

Bear in mind a lighter spring rate will compress more than a heavy spring rate given the same amount of weight carried, so you need to consider that as well. Landrum springs makes an 11" barrel spring and it is also available in a 185# spring (along with 175# and 200#). Each rear spring will be carrying roughly 600# of unsprung weight. Unsprung weight would be those components that are not supported by the spring. The entire rear axle, rotors, calipers, wheels and tires. In other words a 185# spring will compress 3.28" (600/185) vs. 3" for 200# spring (600/200). If you deduct those measurements from the unloaded spring length, that is your compressed spring length. The rolling radius of the tire is going to be something less than half the unloaded diameter of the tire, but comparing that measurement between two tire sized probably won't be that far off. I think you're reasoning above is sound. Let us know how it turns out.

I have a set of Vogtland Sport Springs I was getting ready to post for sale. Will drop you about 1-1.5 inches and still have a good ride. I had these on my 2007 with stock shocks and adj UCA. My pinion angle was not that far off and not out of spec. As a matter of fact, I used the UCA to get more bite for road courses (added angle). Hit me up and we can talk price and shipping if interested. The only reason I changed these out is I went with a complete coilover set up for road courses.