Uneven drop on springs - why? - Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community

JDM4E · 08-21-2015, 10:38 AM

Why manufactures, such as Eibach and others, make springs that drop the car uneven front and rear? For example EU Eibach pro kit is listed as -25mm front, -20 rear. Why?

My average joe brain would say, that you want the car even with the road as OEM (is it?).

Racecomp Engineering · 08-21-2015, 10:52 AM

Most of the time it's for looks....but you can use rake to your advantage if you know what you're doing. IMO for lowering springs the main reason for doing it is just looks (the wheel arch is bigger in the front).

- Andrew

JDM4E · 08-21-2015, 10:58 AM

Thanks, I had the same thought. So if I don't know what I am doing then finding springs that are even (or set coilovers evenly) is preferable, right?

Racecomp Engineering · 08-21-2015, 11:04 AM

Quote:

Originally Posted by JDM4E

Thanks, I had the same thought. So if I don't know what I am doing then finding springs that are even (or set coilovers evenly) is preferable, right?

That's usually a good place to start and it will help you focus on other more important things (like alignment and tire pressures).

A good suspension tuner can help you out when it comes to looking at the full system.

- Andrew

Tcoat · 08-21-2015, 11:05 AM

Quote:

Originally Posted by JDM4E

Thanks, I had the same thought. So if I don't know what I am doing then finding springs that are even (or set coilovers evenly) is preferable, right?

Doesn't hurt if you "don't know what you are doing" either it is just you won't see the handling advantage. It is marginal even for the guys that do know how to use it.

If doing for looks then the larger drop in front does have a bigger effect. As RCE said the wheel arch in the front is bigger so by dropping the front that tiny bit more it evens things out.

Tcoat · 08-21-2015, 11:10 AM

Quote:

Originally Posted by Racecomp Engineering

That's usually a good place to start and it will help you focus on other more important things (like alignment and tire pressures).

A good suspension tuner can help you out when it comes to looking at the full system.

- Andrew

This^^^ if it is performance and not looks that is your priority.

Nigelr32 · 08-21-2015, 04:41 PM

It could also be the fact that the rear shocks are shorter so limiting the drop on them is less likely to cause them bump stopping all the time,( I think you call them jounce rubbers in the good ol USA)??

soulreapersteve · 08-21-2015, 05:31 PM

Quote:

Originally Posted by Nigelr32

It could also be the fact that the rear shocks are shorter so limiting the drop on them is less likely to cause them bump stopping all the time,( I think you call them jounce rubbers in the good ol USA)??

Bump stops also here in 'Murica. Never seen jounce rubbers being mentioned before, at least during my short time researching all things suspension.

DAEMANO · 08-21-2015, 05:37 PM

Quote:

Originally Posted by soulreapersteve

Bump stops also here in 'Murica. Never seen jounce rubbers being mentioned before, at least during my short time researching all things suspension.

Sometimes also referred to as Jounce Bumpers. Which actually may be a more accurate term depending on the usage.

Nigelr32 · 08-21-2015, 06:24 PM

Sorry guys. I used to own a 2008 Mustang GT, I bought shorter bump stops from Roush. They were called Jounce rubbers or bumpers.

JDM4E · 09-10-2015, 08:24 PM

Well it seems harder than I thought to find 1" evenly dropped springs.
Thinking about Pro Kit and live with the 25/20mm drop, but my OCD would love to know what effect the "rake" has on a car? I tried google it but without much success.

why? · 09-12-2015, 09:20 AM

It has no real effect besides look.

Racecomp Engineering · 09-12-2015, 01:14 PM

There is an effect, but 5mm isn't a lot of rake. Generally, a rear higher than the front will promote a little more oversteer...however too low in the front will result in riding on the bumpstops which causes understeer. Depending on how much rear travel you have and how ride height is adjusted, a taller rear (with more bump travel) will help you put power down exiting a corner.

Our RCE Yellow springs are an even 20mm drop.

- Andrew

wparsons · 09-12-2015, 01:33 PM

Quote:

Originally Posted by Nigelr32

It could also be the fact that the rear shocks are shorter so limiting the drop on them is less likely to cause them bump stopping all the time,( I think you call them jounce rubbers in the good ol USA)??

They also use less shock travel for the same wheel travel than the fronts.

08-21-2015, 10:38 AM	#1
JDM4E Senior Member Join Date: Dec 2014 Drives: Honda Accord Euro Location: Europe Posts: 204 Thanks: 251 Thanked 54 Times in 38 Posts Mentioned: 1 Post(s) Tagged: 0 Thread(s)	Uneven drop on springs - why? Why manufactures, such as Eibach and others, make springs that drop the car uneven front and rear? For example EU Eibach pro kit is listed as -25mm front, -20 rear. Why? My average joe brain would say, that you want the car even with the road as OEM (is it?).

08-21-2015, 04:41 PM	#7
Nigelr32 Senior Member Join Date: Oct 2014 Drives: '14 GT86 project, '13 GT86 DD Location: UK Posts: 249 Thanks: 99 Thanked 263 Times in 100 Posts Mentioned: 4 Post(s) Tagged: 0 Thread(s)	It could also be the fact that the rear shocks are shorter so limiting the drop on them is less likely to cause them bump stopping all the time,( I think you call them jounce rubbers in the good ol USA)?? __________________ Nige '14 GT86, '13 GT86 Build :http://www.ft86club.com/forums/showthread.php?t=75794

08-21-2015, 06:24 PM	#10
Nigelr32 Senior Member Join Date: Oct 2014 Drives: '14 GT86 project, '13 GT86 DD Location: UK Posts: 249 Thanks: 99 Thanked 263 Times in 100 Posts Mentioned: 4 Post(s) Tagged: 0 Thread(s)	Sorry guys. I used to own a 2008 Mustang GT, I bought shorter bump stops from Roush. They were called Jounce rubbers or bumpers. __________________ Nige '14 GT86, '13 GT86 Build :http://www.ft86club.com/forums/showthread.php?t=75794

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08-21-2015, 10:52 AM	#2
Racecomp Engineering Join Date: Nov 2011 Drives: 2016 BRZ, 2012 Paris Di2 & 2018 STI Location: Severn, MD Posts: 5,517 Thanks: 3,541 Thanked 7,412 Times in 3,032 Posts Mentioned: 310 Post(s) Tagged: 9 Thread(s)	Most of the time it's for looks....but you can use rake to your advantage if you know what you're doing. IMO for lowering springs the main reason for doing it is just looks (the wheel arch is bigger in the front). - Andrew

08-21-2015, 10:58 AM	#3
JDM4E Senior Member Join Date: Dec 2014 Drives: Honda Accord Euro Location: Europe Posts: 204 Thanks: 251 Thanked 54 Times in 38 Posts Mentioned: 1 Post(s) Tagged: 0 Thread(s)	Thanks, I had the same thought. So if I don't know what I am doing then finding springs that are even (or set coilovers evenly) is preferable, right?

09-10-2015, 08:24 PM	#11
JDM4E Senior Member Join Date: Dec 2014 Drives: Honda Accord Euro Location: Europe Posts: 204 Thanks: 251 Thanked 54 Times in 38 Posts Mentioned: 1 Post(s) Tagged: 0 Thread(s)	Well it seems harder than I thought to find 1" evenly dropped springs. Thinking about Pro Kit and live with the 25/20mm drop, but my OCD would love to know what effect the "rake" has on a car? I tried google it but without much success.

09-12-2015, 09:20 AM	#12
why? Only happy when it rains. Join Date: Feb 2013 Drives: series.blue Location: Harnett county NC Posts: 1,995 Thanks: 5,698 Thanked 1,265 Times in 750 Posts Mentioned: 26 Post(s) Tagged: 0 Thread(s)	It has no real effect besides look.

09-12-2015, 01:14 PM	#13
Racecomp Engineering Join Date: Nov 2011 Drives: 2016 BRZ, 2012 Paris Di2 & 2018 STI Location: Severn, MD Posts: 5,517 Thanks: 3,541 Thanked 7,412 Times in 3,032 Posts Mentioned: 310 Post(s) Tagged: 9 Thread(s)	There is an effect, but 5mm isn't a lot of rake. Generally, a rear higher than the front will promote a little more oversteer...however too low in the front will result in riding on the bumpstops which causes understeer. Depending on how much rear travel you have and how ride height is adjusted, a taller rear (with more bump travel) will help you put power down exiting a corner. Our RCE Yellow springs are an even 20mm drop. - Andrew

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