What coil over spring rates do you use for street or track, front and back?

[rnoswal]

I have another thread here about a good compromise for mostly street driving and some track. I will be getting adjustable shocks but spring rates are all over when you look at whats for sale. Plus none say that the buyer can get different rates if wanted. Most of the springs seem common in diameter and length for coil overs. There probably is a build it yourself coil over someplace but nice to have a good starting place.

So, I wanted to know what spring rates coil over drivers are using here front and rear. How they drive on the streets and then on the track, mostly street though. I know air suspensions are very popular but lets just stick with coil overs for this. I know sway bars come into play too but there aren't that many choices so that is easier to make.

Mine is a 2015 gt and just taking steps to make it a better car for my driving pleasure.

Thanks
Russ

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[NightmareMoon]

For street, probably between 190-275 front is fine. For track we’re talking 500-650.

Streetability of your spring rate is also determined by your ride height.

 

[Biggsy]

I think its also a preference thing. To me, the BMR handling springs 250/980 has been great between street/track but to another, it may too harsh.

 

[rnoswal]

I understand the different spring placements with real rear coil overs as opposed to the ones that just replace the rear spring and have a separate shock. The latter is what I am looking at for my car. I guess I should have been more descriptive of that system I am looking for. So when I hear numbers like you guys have mentioned, which type coil over are you referring to? Seems like the 950 is for a type I am looing at and not a true coil over but still, 950 seems really strong! But I understand the need for that for racing.

I am still seeing 450 to 550 lbs/in up front and close to 550 to 650 lbs/in for the rears. I understand the different placements of the springs as far as why the bigger numbers out back. Again, I wish sellers would offer different coils front or rear for those "kits". I guess there are those who know what they need after trying out different coils so that is why I ask here, taking advantage of that knowledge.

Russ

 

[Bluemustang]

I understand the different spring placements with real rear coil overs as opposed to the ones that just replace the rear spring and have a separate shock. The latter is what I am looking at for my car. I guess I should have been more descriptive of that system I am looking for. So when I hear numbers like you guys have mentioned, which type coil over are you referring to? Seems like the 950 is for a type I am looing at and not a true coil over but still, 950 seems really strong! But I understand the need for that for racing.

I am still seeing 450 to 550 lbs/in up front and close to 550 to 650 lbs/in for the rears. I understand the different placements of the springs as far as why the bigger numbers out back. Again, I wish sellers would offer different coils front or rear for those "kits". I guess there are those who know what they need after trying out different coils so that is why I ask here, taking advantage of that knowledge.

Russ

950 is really not high for a divorced rear spring location. It would be for a true coilover rear yes. What @Biggsy is talking about is just a sporty street spring rate and not a true track or race car level.

 

[rnoswal]

I appriciate that explanation. In dirt track racing we built up a big supply of springs. I was hoping to narrow it down to something between 550 and 900, which of course would be 725. Yes, it is a personal choice as far as each drivers ride and stability goes. Now have to see which companies offer choices of springs. Thanks

 

[Bluemustang]

I appriciate that explanation. In dirt track racing we built up a big supply of springs. I was hoping to narrow it down to something between 550 and 900, which of course would be 725. Yes, it is a personal choice as far as each drivers ride and stability goes. Now have to see which companies offer choices of springs. Thanks

Hyperco and Swift I think offer a lot of springs for the common coilover units. Which coilover unit are you buying? You could try reaching out to Vorshlag. They know a lot about tracking the S550 Mustangs and they offer a number of coilover units and spring choices. They would have some good advice for you too.

 

[bnightstar]

Ok so first of all you need to decide on the coilovers you will use because spring rates are determined by two factors:

1. Location of the spring: divorced(OEM Location) MR:047 or on the shock: MR based on discussion is around 0.75 or so.
2. Is the valving of the shocks and can they handle the springs you are looking for.

The rear springs don't matter really in general you want them as soft as humanly possible to help with corner exit but not soft enough that the car adds wheel hop or unsettle over bumps.

With that in mind your sole focus is on the front for few reasons:

1. Front is heavier in stock form 53%/47% of the weight.
2. Front reaches the corner first and is doing more in corners.
3. Whatever you chose for front will help with rear rate.

So when I was going through that I chose Ohlins for a few reasons:

1. The front shocks are inverted with moves the weight higher and is better for traction.
2. The front rate out of the factory was 515 lbs which is enough to have the car on 200TW tires and manage it maybe 650 lbs will be better though but wanted street capabilities.
3. It has dual flow technology which help for the street.
4. It's valved very good to support different spring rates much higher than the off the shelf stuff.

So I'm currently on the factory Ohlins rates of 515/800 lbs and it's doing grate on both track and street though it's mostly a track car.

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