Ohlins R&T Spring/Sway Choice

[Grke46m3]

At that rate I would not go to 7.8. You will struggle to lower the car. To put it in context I used 8in but at 250, and I could not lower the car bellow stock. At 300+ you will make the car sit high. You need to calculate your weight per corner and then you will know how much you will compress the spring and choose height from there.

Got it! So at 7.1 the bottom strut spacer is still needed right?


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[maupineda]

At that rate I would not go to 7.8. You will struggle to lower the car. To put it in context I used 8in but at 250, and I could not lower the car bellow stock. At 300+ you will make the car sit high. You need to calculate your weight per corner and then you will know how much you will compress the spring and choose height from there.

[Grke46m3]

The shorter 7.1” spring will be slightly lighter than the longer 7.8” ohlins spring, but only by a few percent. The only real way to make a substantially lighter spring given a fixed mounting diameter is a material change like titanium. I wouldn't sweat the weight, but the shorter spring might help tire clearance so I'd agree with the final recommendation since it appears that you can still get ride height to the right place. Might want to double check coil bind though.

The length of the spring at the same rate is purely for tire clearance? Ohlins makes a 7.1 and a 7.8 in a 60n/mm? If im looking to keep the ohlins recommended front ride height with the beehive spring just wanted to lower the rate to a 60n/mm with a 2.5id spring should I go with a 7.8 spring? Weight isn't a factor. Tire clearance not being an issue.


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[Tbonem3]

I didn't say it being shorter made it lighter, just listing the particulars. It's lighter because it's less metal (diameter and height).

Coil bind is not an issue at that rate.

[Bry5on]

That linear ohlins 60n/mm spring looks heavy. I went with light weight H&R 60n/mm (343lb) 7.08" which is plenty of height at that rate. I would recommend swift in 65mm or hyperco/eibach 2.5" over the ohlins springs.

The shorter 7.1” spring will be slightly lighter than the longer 7.8” ohlins spring, but only by a few percent. The only real way to make a substantially lighter spring given a fixed mounting diameter is a material change like titanium. I wouldn’t sweat the weight, but the shorter spring might help tire clearance so I’d agree with the final recommendation since it appears that you can still get ride height to the right place. Might want to double check coil bind though.

[Tbonem3]

That linear ohlins 60n/mm spring looks heavy. I went with light weight H&R 60n/mm (343lb) 7.08" which is plenty of height at that rate. I would recommend swift in 65mm or hyperco/eibach 2.5" over the ohlins springs.

[Slideways]

Any updates on this? Have you bit the bullet and ordered these springs?


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All the parts are sitting in a box . Had to help out on two other car projects recently and put my stuff on hold. Should be able to get to it this weekend.

[Grke46m3]

Any updates from those that have swapped the stock 400 Ohlins springs to a softer 340ish spring such as this - https://3dmmotorsport.com/collection...32802582298729 ?

I'm trying to add as much comfort as possible to the R&Ts and want to change as few parts as possible. Parts list so far: 2.5in spring perches will be needed for the Turner Street plates, 340 Ohlins 7.87 springs, Ohlins front strut spacers and an aftermarket front sway bar.

Any updates on this? Have you bit the bullet and ordered these springs?


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[cobra]

Ah, this is a good question. Having adjusted the rear shocks a great number of times (I know, the adjustment relates primarily to rebound), I learned the following with 504lb rear springs: (1) at 15+ clicks, the rear moves around almost constantly, often times out of sync with the front, and weight transfer becomes noticeable under even moderate acceleration; and (2) at <10 clicks, the rear loses compliance, nvh is noticeably increased, and feel begins to degrade.

I am no expert, but I do have a broad and extensive experience behind the wheel of the “benchmark” cars currently on offer. If nothing else, I know what feels right to me. YMMV, of course.

Yeah it's a tricky thing to dial in especially if you don't have the ability to independently adjust compression and rebound.
How's the grip/handling balance at the limit. More understeer or oversteer?

[LSB4Me]

How do you know the rear springs are too soft and you aren't just lacking compression damping?

Ah, this is a good question. Having adjusted the rear shocks a great number of times (I know, the adjustment relates primarily to rebound), I learned the following with 504lb rear springs: (1) at 15+ clicks, the rear moves around almost constantly, often times out of sync with the front, and weight transfer becomes noticeable under even moderate acceleration; and (2) at <10 clicks, the rear loses compliance, nvh is noticeably increased, and feel begins to degrade.

I am no expert, but I do have a broad and extensive experience behind the wheel of the “benchmark” cars currently on offer. If nothing else, I know what feels right to me. YMMV, of course.

[LSB4Me]

Thanks for the update. Are you going with a stiffer front sway bar or keeping it stock?

I’m going to keep the bars stock until I settle on the springs, pun intended. Need less variables.

[cobra]

I actually have an update for you guys.

Having played with the dials more and driven the car a bit, I can now confirm that my 504lb rear springs are too soft. You were absolutely right, TBone. I plan to revert to the stock Ohlins 628lb rear springs next month as they will place me into the flat ride zone—albeit, just barely.

Additionally, my shop set the ride height for looks … without asking for my OK. The car looks great, but I am bottoming out on bumpy streets at slow speed. I’m going up in height at least 0.25”.

With all this said, even with the softer-than-ideal rear springs, I was able to dial the car in for that lovely rotation feeling and achieved better ride comfort. I am still much happier with the car now than when the stock 400lb Ohlins springs were up front. Those were VERY stiff and really upset the ride in Los Angeles.

How do you know the rear springs are too soft and you aren't just lacking compression damping?

[Slideways]

I actually have an update for you guys.

Having played with the dials more and driven the car a bit, I can now confirm that my 504lb rear springs are too soft. You were absolutely right, TBone. I plan to revert to the stock Ohlins 628lb rear springs next month as they will place me into the flat ride zone—albeit, just barely.

Additionally, my shop set the ride height for looks … without asking for my OK. The car looks great, but I am bottoming out on bumpy streets at slow speed. I’m going up in height at least 0.25”.

With all this said, even with the softer-than-ideal rear springs, I was able to dial the car in for that lovely rotation feeling and achieved better ride comfort. I am still much happier with the car now than when the stock 400lb Ohlins springs were up front. Those were VERY stiff and really upset the ride in Los Angeles.

Thanks for the update. Are you going with a stiffer front sway bar or keeping it stock?

[LSB4Me]

Any updates from those that have swapped the stock 400 Ohlins springs to a softer 340ish spring such as this - https://3dmmotorsport.com/collection...32802582298729 ?

I'm trying to add as much comfort as possible to the R&Ts and want to change as few parts as possible. Parts list so far: 2.5in spring perches will be needed for the Turner Street plates, 340 Ohlins 7.87 springs, Ohlins front strut spacers and an aftermarket front sway bar.

I actually have an update for you guys.

Having played with the dials more and driven the car a bit, I can now confirm that my 504lb rear springs are too soft. You were absolutely right, TBone. I plan to revert to the stock Ohlins 628lb rear springs next month as they will place me into the flat ride zone—albeit, just barely.

Additionally, my shop set the ride height for looks … without asking for my OK. The car looks great, but I am bottoming out on bumpy streets at slow speed. I’m going up in height at least 0.25”.

With all this said, even with the softer-than-ideal rear springs, I was able to dial the car in for that lovely rotation feeling and achieved better ride comfort. I am still much happier with the car now than when the stock 400lb Ohlins springs were up front. Those were VERY stiff and really upset the ride in Los Angeles.

[fattycharged]

Boots for top and bottom of spherical to keep grime out.
Spherical is sandwiched in poly to minimize NVH, easily replaceable.
Worst thing I've noticed is the cheap 3 bolt mounting hardware sprayed with a rhino liner, all the bolts slightly corroded…


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