[euro]

This whole thread is related to the fronts... Can we talk about the rears?

can someone post a pic of the rear spring with the car on the ground?

[Greg]

Originally Posted by euro

Can we talk about the rears?

There's no problem with the rears. Lots O room back there. The RCE replacement springs for the v1 owners are the fronts only.

[stretch]

Yeah, but there's waaaay more available travel back there too. There has to be for the days that you have rear passengers and junk in the trunk. It's quite easy to add 500lbs over the rear axle which will cause quite a bit of sag back there in addition to a lowering of the spring frequency.

If bind is possible in the rear, it will happen less frequently in practice compared to the front. I wouldn't expect to see paint chipping on the springs- just two rear passengers complaining (but let's be honest, the back seat is always worth complaining about).

However, looking at how many extra winds of coils the rear springs have (due to extreme progression), I wouldn't rule bind out for most springs. Just like the front, the stock springs and struts compress to a very short distance. I think the magic number is going to be a solid length of four inches.

The stock springs have exactly 6 winds but with no ground ends. No ground ends means there is air between the first and last coils and their perches. The coils are .54 inches thick and I'd estimate a solid length of 3.78. Add the rubber insulators on the coil and the stock springs basically have a solid length of four inches. As you can see, just like the front, there may not be room for an extra coil in aftermarket springs... but in the rear, sometimes many extra coils are used to achieve a strong progression of spring rate. Here's an example:



At a cursory glance it looks like most aftermarket springs use 7 winds of coil instead of the stock 6, including Prodrive, Cobb, and others. The original copper RCE springs (pictured above) and Tein springs had 8 winds of coil (if I'm counting correctly).

The Swift springs are the only springs I can find that stick to the stock 6 full coil winds in the rear (and 4.5 up front). Swift springs seem to offer the most travel of aftermarket springs while still offering rates that match the stock struts. Ohlins owners, are you listening? If you must lower the car on the stock struts (not something I'd recommend, but people do it), those are the springs to use. Turn-In Concepts has been pushing these, perhaps for good reason.

I'll leave it to the owners to do their own measurements since apparently my doing so, for whatever reason, just lights fires under everyone's asses... some companies just love to shoot the messenger.

[euro]

edit: nevermind

[RaceComp Engineering]

Originally Posted by stretch

Yeah, but there's waaaay more available travel back there too. There has to be for the days that you have rear passengers and junk in the trunk. It's quite easy to add 500lbs over the rear axle which will cause quite a bit of sag back there in addition to a lowering of the spring frequency.

If bind is possible in the rear, it will happen less frequently in practice compared to the front. I wouldn't expect to see paint chipping on the springs- just two rear passengers complaining (but let's be honest, the back seat is always worth complaining about).

However, looking at how many extra winds of coils the rear springs have (due to extreme progression), I wouldn't rule bind out for most springs. Just like the front, the stock springs and struts compress to a very short distance. I think the magic number is going to be a solid length of four inches.

The stock springs have exactly 6 winds but with no ground ends. No ground ends means there is air between the first and last coils and their perches. The coils are .54 inches thick and I'd estimate a solid length of 3.78. Add the rubber insulators on the coil and the stock springs basically have a solid length of four inches. As you can see, just like the front, there may not be room for an extra coil in aftermarket springs... but in the rear, sometimes many extra coils are used to achieve a strong progression of spring rate. Here's an example:



At a cursory glance it looks like most aftermarket springs use 7 winds of coil instead of the stock 6, including Prodrive, Cobb, and others. The original copper RCE springs (pictured above) and Tein springs had 8 winds of coil (if I'm counting correctly).

The Swift springs are the only springs I can find that stick to the stock 6 full coil winds in the rear (and 4.5 up front). Swift springs seem to offer the most travel of aftermarket springs while still offering rates that match the stock struts. Ohlins owners, are you listening? If you must lower the car on the stock struts (not something I'd recommend, but people do it), those are the springs to use. Turn-In Concepts has been pushing these, perhaps for good reason.

I'll leave it to the owners to do their own measurements since apparently my doing so, for whatever reason, just lights fires under everyone's asses... some companies just love to shoot the messenger.

The rears will obviously always have partial bind due to the necessary dead coils but I have never seen or felt evidence of full bind on a rear with any spring. The Swifts do offer a good amount of travel in terms of solid length but the main thing that worries me with them is the amount that they lower the car. They are advertised at 30mm lowering but I have found they are even a bit lower than that. Even with shortened bump stops, you are losing a fair amount of strut travel.

-Dan

[Turninconcepts.com]

Originally Posted by RaceComp Engineering

The rears will obviously always have partial bind due to the necessary dead coils but I have never seen or felt evidence of full bind on a rear with any spring. The Swifts do offer a good amount of travel in terms of solid length but the main thing that worries me with them is the amount that they lower the car. They are advertised at 30mm lowering but I have found they are even a bit lower than that. Even with shortened bump stops, you are losing a fair amount of strut travel.

-Dan

The new ones will have less of a drop by 10mm.

[RaceComp Engineering]

Originally Posted by Turninconcepts.com

The new ones will have less of a drop by 10mm.

Is Swift making a version 2 of their standard sport springs or are you talking about your springs?

-Dan

[Turninconcepts.com]

Originally Posted by RaceComp Engineering

Is Swift making a version 2 of their standard sport springs or are you talking about your springs?

-Dan

This is a new product. The sport springs are not changing. These new ones are less of a drop and higher rates. They're the ones we've had the prototypes of on Rob's car for a couple of months now. They aren't going to be TiC branded, but instead will continue to carry the Swift name.

[RaceComp Engineering]

Oh I see, so you have been testing a prototype for Swift but they will be labeled as Swift springs. Cool deal, I was a little confused there for a second.

-Dan

[stretch]

Originally Posted by RaceComp Engineering

The rears will obviously always have partial bind due to the necessary dead coils but I have never seen or felt evidence of full bind on a rear with any spring. The Swifts do offer a good amount of travel in terms of solid length but the main thing that worries me with them is the amount that they lower the car. They are advertised at 30mm lowering but I have found they are even a bit lower than that. Even with shortened bump stops, you are losing a fair amount of strut travel.

-Dan

Aye, well you know my stance on that- less is more with regards to lowering springs. It just looks to me that for people who absolutely want to ignore suspension travel issues and slam the car (which people tend to do), the Swifts (with the short solid lengths) are probably the best way to do that- especially when mated with longer-travel struts.

I do agree that because there's a lot of travel in the rear, feeling coil bind in the rear would be extremely rare. Heck, Whiteline says they use 7" long, 224lb/in springs back there in their coilovers, and that's waaaaaay less travel than any lowering springs discussed here. Even on that nobody seemed to notice coil bind.

So, not a big deal. Or at least, I wouldn't expect it to be. But the guy asked, and yes, I think some springs could bind in the rear when the car is loaded down- particularly the few floating around with 8 winds of coil.

[lackskill]

I ran across another occurance of coil bind this weekend. It is in a non-STi application though.

My brother bought a Sentra Spec-V and it was lowered on eibach springs. He was given the stock springs when he bought the car and he was getting rubbing in the front on full lock. So this weekend we threw the stockers back on there (which imo looks better). When we pulled the eibachs off there were definite signs of coilbind. The directions for those springs said to cut a significant portion of the jounce bumpers. Whats more, they were EXTREMELY progressive. Their rates are listed as 25% stiffer than stock, but we were able to compress them a good deal just by leaning on them, while the stockers we were unable to compress at all.

[snorky]

I installed the RCE replacements if anyone cares, the pics,etc are in my journal.

[Carciprete]

I've installed the version 2 RCE front springs as well. The version 1 springs were banged up pretty bad on the underside. Pics to follow.

The ride seems much more compliant over rough surfaces and bumps with no decrease in handling from the version 1 set. I want to wait a week to let them settle in before making a final comment.

One other note is that I lubricated both the front and rear struts with Mobile 1 Synthetic grease. I used a generous amout of lubrication just to be on the safe side. The "clunk" from the rear struts has disappeared, so I am very happy about that.

[chaos311clarity]

im going to check my springs today... they are on Ohlins fixed perches... what do i need to do if there are indications of bind? racecomp/gtworx guys chime in?

[RaceComp Engineering]

Give us a call and we'll take care of it

-Dan