Ohlins R&T Coilovers with Swift Springs!

[tm1v2]

I have the RT kit for my Model Y and am trying to decide if softer springs would be worth it. My main gripe is that my tires sometimes leave the ground on bumps on the highway. I've tried all different damper settings with no avail.

@nadkoolio Is it front or rear wheels that happens to? What kind of highway surface does that happen over? Describe and/or provide pictures as best you can.

Either the compression damping is too strong and won't let the spring compress in time, or the spring is so stiff that it simply won't compress sufficiently. Or both!

I think R&T compression damping being too strong for this use case is most likely. Maybe softer springs will mask it. A revalve or switching to a street-focused damper is probably the more holistic solution. Or drive faster.

 

[nadkoolio]

@nadkoolio Is it front or rear wheels that happens to? What kind of highway surface does that happen over? Describe and/or provide pictures as best you can.

Either the compression damping is too strong and won't let the spring compress in time, or the spring is so stiff that it simply won't compress sufficiently. Or both!

I think R&T compression damping being too strong for this use case is most likely. Maybe softer springs will mask it. A revalve or switching to a street-focused damper is probably the more holistic solution. Or drive faster.

@tm1v2 Best I could describe is that if I'm going between 50 to 80 mph on the highway, I experience 2 different behaviors with encountering a bump. Either the car goes over the bump and I barely feel it, which is great, or, it if it's a larger bump, then I get the feeling of the tired get knocked into the air. It's significantly worse in the rear. My wife and cargo will get airborne like you'd experience in the back of a school bus!

It's hard for me to predict which bumps will cause this to happen. Which sucks because this is really reducing my confidence while driving in the highway.

I think you're right that the combination of the strength of the compression damping and the stiffness of the spring isn't allowing the spring to compress enough to absorb the impact.

I'm considering switching to a softer spring (I might just through the OEM spring on there and see how it feels), but my fear is also what you suspect that the main culprit is an excessive amount of compression damping.

 

[canasion35]

I have the RT kit for my Model Y and am trying to decide if softer springs would be worth it. My main gripe is that my tires sometimes leave the ground on bumps on the highway. I've tried all different damper settings with no avail.

Did you guys have this issue with the stiffer springs before switching? How is ride comfort now? Comparable to OEM but with better handling? What damper settings re you guys running with the softer springs?

Have you tried increasing your rebound? That’ll get the shock to force the tire to stick to the ground much better.

 

[tm1v2]

@tm1v2 Best I could describe is that if I'm going between 50 to 80 mph on the highway, I experience 2 different behaviors with encountering a bump. Either the car goes over the bump and I barely feel it, which is great, or, it if it's a larger bump, then I get the feeling of the tired get knocked into the air. It's significantly worse in the rear. My wife and cargo will get airborne like you'd experience in the back of a school bus!

It's hard for me to predict which bumps will cause this to happen. Which sucks because this is really reducing my confidence while driving in the highway.

@nadkoolio I'm now thinking it's both the spring rate and compression damping, but more the damping.

For a comparison point, I haven't felt that on my Model 3. I have 11kg rear springs, vs 12kg for your R&T, but my M3P should be about 500 lbs lighter than a dual motor Model Y. Assuming 250 lbs lighter in the rear (could be wrong), and assuming motion ratio is very similar between 3 and Y, my ratio of rear spring rate to rear vehicle weight should be very similar.

So what's actually softer on my car? I think it's the damping / valving.

Now to be clear if it's a big bump you can certainly feel it in my car, I don't have the soft GT kit, but I've never felt like my wheels left the pavement over any bump. In fact quite the opposite, I feel like the suspension on my car does a supreme job of keeping the wheels planted and the car's weight settled. Any time I've tried to describe how this suspension feels, "planted" and "settled" are pretty much the first words that come to mind.

Only going fast over a crest have I felt it go light and struggle to maintain contact with the road. But doing jumps in the family car is bad mmmkay?

I still really want to see pictures of these bumps though, or a detailed written description. Many of the roads where I am are in pretty poor condition, but it's possible yours are even worse and that's the real difference. Can you pull up pictures of some bumps where the rear got light in Street View (in Google Maps)?

I think you're right that the combination of the strength of the compression damping and the stiffness of the spring isn't allowing the spring to compress enough to absorb the impact.

I'm considering switching to a softer spring (I might just through the OEM spring on there and see how it feels), but my fear is also what you suspect that the main culprit is an excessive amount of compression damping.

Swapping in the OEM rear springs would be a nice experiment. If you do that let us know how it feels! I'm really curious now if a softer spring alone would solve this issue.

Btw it sounds like some sandbags in the trunk might be the easiest solution.

 

[Leafable]

Yes you can raise the rear spring perch if it's too low now

It's that the preload setting? I would prefer not to add more preload cause we don't want to make it harder for the rear

 

[nadkoolio]

Have you tried increasing your rebound? That’ll get the shock to force the tire to stick to the ground much better.

Yes, I've tried decreasing damping as much as possible to increase the rebound. This does help make it less sharp, but doesn't keep the tires on the ground.

 

[nadkoolio]

It's that the preload setting? I would prefer not to add more preload cause we don't want to make it harder for the rear

You could call it the preload setting, but changing preload doesn't change the ride quality. The spring doesn't get stiffer as it's compressed as long as it isn't in coil bind.

Changing ride height by changing preload does change your relative amount of compression and droop travel. Currently with your lower ride height you have less compression travel available, which does increase chance of hitting your bump stop, especially when also coupled with a softer spring.

 

[tm1v2]

It's that the preload setting? I would prefer not to add more preload cause we don't want to make it harder for the rear

Preload shouldn't change your suspension firmness with linear rate springs. They're "linear" because their rate doesn't change as they compress.

I'm also not sure that adjusting the rear spring perch would really count as preload. I think that term applies more to coilover suspension, like in the front of our cars.

 

[nadkoolio]

So what's actually softer on my car? I think it's the damping / valving.

You have the Redwood performance kit? If so, I think your damping is 30-40% than it is on my RT kit, which is definitely a bigger difference than the 8.3% difference in our rear spring rate.

In fact quite the opposite, I feel like the suspension on my car does a supreme job of keeping the wheels planted and the car's weight settled. Any time I've tried to describe how this suspension feels, "planted" and "settled" are pretty much the first words that come to mind.

I bought the RT kit hoping this would be my experience. Sadly I'd have to describe it as jumpy currently, which is the exact opposite of what I was hoping for.

Many of the roads where I am are in pretty poor condition, but it's possible yours are even worse and that's the real difference. Can you pull up pictures of some bumps where the rear got light in Street View (in Google Maps)?

I'm experiencing this mostly on bumps on I-95 around Philadelphia. I'll try to make note of a specific instance I can look up later in Street View, but might be hard. Happens more on weekends trips than my daily commute.

Swapping in the OEM rear springs would be a nice experiment. If you do that let us know how it feels! I'm really curious now if a softer spring alone would solve this issue.

Will definitely let you know. I'm going to try and do this in the next day or two.

Btw it sounds like some sandbags in the trunk might be the easiest solution.

 

[tm1v2]

@nadkoolio One more anecdote...

I did my rear suspension install a week after my front, because life reasons. So for a week I had the firmness of the Redwood Performance Sport up front (with dampers set on the stiffer side!), and the bounciness of the OEM suspension in the back. It wasn't awful, but it was definitely a worse ride than either full Performance Sport or full OEM. Of course nobody ever claimed a chimera suspension would be any good!

(No comment on the handling, I didn't push the car hard in that state.)

Your experience swapping back in the OEM rear springs should be completely different since you're keeping the R&T dampers all around. I just figure you might find this anecdote interesting.

 

[Mash]

Don't forget that aside of spring rates and compression/rebound adjustments you also have tire pressure, ride height and anti-sway bars. If anti-sway bar is too stiff - bumps easily bringing opposite wheel in the air. If tire pressure is too high it tends to be bouncy especially if it's a high side-wall tire. Also don't eliminate possibility of valve failure - it happens, ohlins or not.

 

[Berylg2019@gma]

I would 100% suggest softer Springs if you are looking for a comfy ride. I Lowered my car by 25mm from stock and right now I am using softest settings which is 20 clicks. On 11/12k springs I had rattle/squeak sound all over my interior when driving on road pits. Now with 8/9k Swift Springs I can barely hear anything.

 

[Jigglypuff]

With highly stiff settings on the rear, I get a bit of a jump on some stiff bumps. Backing off on the rear stiffness helps, but then the car wallows a bit more than I want (though less than stock). Just gotta find the happy medium, I suppose. Remember, this is a track kit, not a cuddle kit.

 

[nadkoolio]

I did my rear suspension install a week after my front, because life reasons. So for a week I had the firmness of the Redwood Performance Sport up front (with dampers set on the stiffer side!), and the bounciness of the OEM suspension in the back. It wasn't awful, but it was definitely a worse ride than either full Performance Sport or full OEM. Of course nobody ever claimed a chimera suspension would be any good!

I actually had a similar situation. Installed the rear first so was running OEM front and RT rear. It actually was a pretty good combo, improved handling and at least at that time I didn't notice as much adverse behavior as I do know.

I've had a lot of corresponce with Ohlins USA over the past few weeks and given the issues I'm having they're actually sending me a pair of test springs (90 N/mm) to try, so will wait to receive those rather than trying the OEM springs.

With highly stiff settings on the rear, I get a bit of a jump on some stiff bumps. Backing off on the rear stiffness helps, but then the car wallows a bit more than I want (though less than stock). Just gotta find the happy medium, I suppose. Remember, this is a track kit, not a cuddle kit.

It's somewhat reassuring to hear another Model Y owner having this issue, as doesn't sound like anyone with a Model 3 has had this issue. However mine is jumpy even at the softest settings, and it just gets worse at the stiffer settings.

It is a dual purpose kit though. And my complaint isn't about comfort, it's about the tires not staying on the ground, which is the most fundamental function of suspension.

 

[tm1v2]

It is a dual purpose kit though. And my complaint isn't about comfort, it's about the tires not staying on the ground, which is the most fundamental function of suspension.

@nadkoolio Yes that! R&T feeling quite firm is expected, but trouble keeping the wheels planted? That is surprising to me. Not what I expect from any Ohlins DFV suspension, based on my experiences (across two cars) or those of a trusted friend (a third car).

I am wondering if @Mash might be right, that something is out of spec with your dampers. More likely an assembly mistake than failure or wear, since they're brand new.

 

[Motion122]

@nadkoolio Yes that! R&T feeling quite firm is expected, but trouble keeping the wheels planted? That is surprising to me. Not what I expect from any Ohlins DFV suspension, based on my experiences (across two cars) or those of a trusted friend (a third car).

I am wondering if @Mash might be right, that something is out of spec with your dampers. More likely an assembly mistake than failure or wear, since they're brand new.

Are the tires really coming off the ground or just felt like they are? Check to make sure the rear isn't riding or bottoming on the bumpstops.

 

[Jigglypuff]

It's somewhat reassuring to hear another Model Y owner having this issue, as doesn't sound like anyone with a Model 3 has had this issue. However mine is jumpy even at the softest settings, and it just gets worse at the stiffer settings.

It is a dual purpose kit though. And my complaint isn't about comfort, it's about the tires not staying on the ground, which is the most fundamental function of suspension.

Nasty bumps at high speed on at or near full stiff, I get a bit of a jump, yeah. It's just too much damping, I think. If you're getting it at full soft, you might be experiencing something else.

 

[dsgerbc]

Are the tires really coming off the ground or just felt like they are? Check to make sure the rear isn't riding or bottoming on the bumpstops.

That's what I thought too. Maybe the rear shock length is set too long for the ride height.

 

[Motion122]

Do you know how to do a zip-tie test for compression travel?

 

[Occhis]

Does anyone know what the spring rates are for M3 AWD Redwood GT kit?