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Need To Lower Rear Only By 1" After New Rims


yell03
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I installed 19x8.5 front and 19x10 rear Black AMR rims with stock size tires on my 2011 GT500 Convertibleicon1.png. They look great, but the rear tire to Fender gap is 3" and the front is 2".
I want to lower the rear only by 1" max.
I think the 2" gap in front looks perfect.
After hours of research I have found I can buy Rear Only Lowering Springs.
It seems H&R Rear Sport Springs would drop it 0.75 inch, this would probably be great, maintaining some rake, but closing the wheel gap.
Roush also makes a Rear Only Spring, but some people say it will be lower in the back than the front.

Also, with a mild 0.75" drop, will I definitely need an adjustable panhard, or should I install them and then see if it is necessary afterwards?

Have any of you tried doing the rear only?

Here are pics of how it sits now...

 

GT500washedampsunnypics071_zps49e3d29b.j

 

GT500washedampsunnypics034_zps9b1ed06f.j

 

GT500washedampsunnypics033_zpsb0ead4ec.j

 

GT500washedampsunnypics107_zps0d0110af.j

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My $.02: Not worth only doing the rear springs and might create unwanted handling characteristics if the spring rates are not correct in comparison to the front of the car. I would replace all four. Adjustable panhard is OK, but many guys prefer the watts link.

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Good point on the handling. I am more of a cruiser and drag racer than a corner carver, so as long as it is safe I would be OK.

Many of the aftermarket springs have the same specs as stock, I really don't want to drop the front any lower if I don't have to.

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Doing just the rear springs to take out the rake is fine - use the Roush rear only ( Maximum Motorsports sells em') but remember to cut the jounce stops down to save your rear suspension travel and put in an adjustable PH bar ( yes watts is preferred but some don't want to spend the money ). They drive and handle nice for cruising/daily driving.

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Doing just the rear springs to take out the rake is fine - use the Roush rear only ( Maximum Motorsports sells em') but remember to cut the jounce stops down to save your rear suspension travel and put in an adjustable PH bar ( yes watts is preferred but some don't want to spend the money ). They drive and handle nice for cruising/daily driving.

I would do either the Roush or H&R.

Maybe I should throw 100lbs in my trunk, I could use the traction anyway, lol

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i used H&R sport lowering springs in the picture you see of my car they lowered the front a little more than a inch ,the rear 2 inches , since that picture i have lowered it more even more,i like it low , but i have to install relocation brackets, i think the H&R might be good for you because i don't think 1 inch drop will be that noticeable

Edited by BLUE 2010 SHELBY GT 500
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i used H&R sport lowering springs in the picture you see of my car they lowered the front a little more than a inch ,the rear 2 inches , since that picture i have lowered it more even more,i like it low , but i have to install relocation brackets, i think the H&R might be good for you because i don't the 1 inch drop will be that noticeable

Are they the Sport or Super Sport version?

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Are they the Sport or Super Sport version?

i just sold them , now that you say that i think they where super sport, the H&R web site will tell you the drop, i think they where the super sport,,yello i also have the adjustable panhard bar ,dont be afraid of the drop,my ride did't change that much ,i just looked them up they where super sport,and the drop in the rear is more then 2 inches ,but with the space in the rear of our cars you could fit your head in between the tire and quarter panel the drop would look good

Edited by BLUE 2010 SHELBY GT 500
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The challenge is finding shorter rear springs with the same rates, or you risk a very unpredictable car, not that anybody buys a GT500 Convertible for its handling prowess.

 

What rear tire profile did you use? Did you retain the OE diameter of 27 or 28 inches (depending on year and trim)? I'd recommend plus-sizing your rear tires by an extra 5% which will re-fill the gap, give you far better hook and a MUCH improved ride without messing with the suspension geometry.

 

I don't know what you went FROM, but I suspect you will also restore the rake back to much closer to what it was.

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i just sold them , now that you say that i think they where super sport, the H&R web site will tell you the drop, i think they where the super sport,,yello i also have the adjustable panhard bar ,dont be afraid of the drop,my ride did't change that much ,i just looked them up they where super sport,and the drop in the rear is more then 2 inches ,but with the space in the rear of our cars you could fit your head in between the tire and quarter panel the drop would look good

my son dropped his 2" and my back can't handle it in his car

 

The challenge is finding shorter rear springs with the same rates, or you risk a very unpredictable car, not that anybody buys a GT500 Convertible for its handling prowess.

 

What rear tire profile did you use? Did you retain the OE diameter of 27 or 28 inches (depending on year and trim)? I'd recommend plus-sizing your rear tires by an extra 5% which will re-fill the gap, give you far better hook and a MUCH improved ride without messing with the suspension geometry.

 

I don't know what you went FROM, but I suspect you will also restore the rake back to much closer to what it was.

I kept the same size 285/35/19 rear tires, but the rim went from a 9.5 to a 10" wide which might have shortened it a small amount.

I thought about going with a 295/35/19, but it is not worth the cash at the moment.

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yello, i can't say the ride got softer with the lower springs , but its all personal choices, my is a 2010 , i have it for 4 years this past july and just turned 6000 miles so i understand not everyone likes the stiffer ride but lower a inch or a little more my be good try the sport H&R i think the drop said 1inch , good luck with your choice, what ever it is , show us the results with some pics when you decide , the car looks great anyway with those blk rims

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yello, i can't say the ride got softer with the lower springs , but its all personal choices, my is a 2010 , i have it for 4 years this past july and just turned 6000 miles so i understand not everyone likes the stiffer ride but lower a inch or a little more my be good try the sport H&R i think the drop said 1inch , good luck with your choice, what ever it is , show us the results with some pics when you decide , the car looks great anyway with those blk rims

spoke to H&R yesterday.

They said the drop on the sport spring out back is 0.75, it will not settle much more after that maybe to a full 1" drop.

The front spring is a full 1" drop.

 

Your car looks perfect at your drop level.

 

I drive mine every day unless it is snowing, I've put 8000 on since last April.

Edited by yell03
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yello, thanks, for a daily driver mine is way to low, i have to come out of garage to the driveway and go across my other 2 driveway spots sideway to get it off the curb so i don't hit the front splitter, as far as the H&R springs i also had them in my 04 terninator and just like this car a little stiffer of a ride but .7.5 drop i think will not be to bad for back , after it settles it will closer to 1 inch , with the takicos i have in the car now i can just about get 1 finger in betwwen the tires and wheel wells

Edited by BLUE 2010 SHELBY GT 500
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yello, thanks, for a daily driver mine is way to low, i have to come out of garage to the driveway and go across my other 2 driveway spots sideway to get it off the curb so i don't hit the front splitter, as far as the H&R springs i also had them in my 04 terninator and just like this car a little stiffer of a ride but .7.5 drop i think will not be to bad for back , after it settles it will closer to 1 inch , with the takicos i have in the car now i can just about get 1 finger in betwwen the tires and wheel wells , i love it now i can wax it without standing on box lol

I can't go through that every time I want to leave for work

 

I lowered the rear on my 2009 GT500 with a set of roush springs(forgot the part#). Got the perfect ride height(for my taste), with zero handling issues...

I sent an e-mail to Roush and to H&R, it will be between those two most likely

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I spoke to a rep at Roush and a Rep at Maximum Motorsports (H&R distributor).

Roush said if I use their rear springs that nothing else is needed, no adjustable panhard bar or anything else. Drop should be 1", no more.

The Rep at MM said the H&R drop is 0.75", maybe settle a little more than that, but not more than an 1". He said the adjustable panhard bar is not needed, but he recommended shorter rear bumpstops or the suspension will bottom out frequently.

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When it comes to lowering, Ford will state nothing further is required up to about 1.5" drop. But because of the Panhard bar and geometry, ANY lowering will shift the rear axle assembly to the left. It may be minute, but you can detect it if you look for it. Such a small shift into itself doesn't appreciably alter handing, but given the endless variety of modifications people make, an adjustable bar makes re-centering the rear possible regardless of spring height.

 

That said, the body will always shift to the left relative to the rear axle whenever the suspension expands no matter how adjustable a Panhard bar may be. Nobody has yet invented a dynamic Panhard bar, making a Watts Linkage about the only way to constantly keep the rear as close to centered as possible.

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When it comes to lowering, Ford will state nothing further is required up to about 1.5" drop. But because of the Panhard bar and geometry, ANY lowering will shift the rear axle assembly to the left. It may be minute, but you can detect it if you look for it. Such a small shift into itself doesn't appreciably alter handing, but given the endless variety of modifications people make, an adjustable bar makes re-centering the rear possible regardless of spring height.

 

That said, the body will always shift to the left relative to the rear axle whenever the suspension expands no matter how adjustable a Panhard bar may be. Nobody has yet invented a dynamic Panhard bar, making a Watts Linkage about the only way to constantly keep the rear as close to centered as possible.

thanks

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  • 2 weeks later...

Finally made up my mind....

I ordered the H&R Sport Rear Springs for a 0.75" drop and Maximum Motorsport Rear Bump Stops.

I like the H&Rs, they are rated specifically for a 2011 GT500 Convertible for a 0.75" drop, on a 2010 GT500 it is rated at a 1" drop.

This should maintain a slight rake as the front end will be lower by 0.25" than the rear.

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  • 1 month later...

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