5100's @ .85 causing imbalance in spring rate

I have an issue that I am trying to solve.


I have had Bilstien 5100's installed for about 3 weeks. I am using the stock linear springs (sr5). After having enough time behind the wheel I feel that the front springs @ .85 are preloaded enough to cause an imbalance in the suspension. For example when on the freeway and taking the interchange the rear end skips while going over bumps while going around the bend (it never did this stock). I can feel the rear is not as tight as the front when this happens. Right now I am thinking of simply putting it at Zero and throwing in a 1" corn-fed spacer as this should get me where I need to be. I come from driving sports cars so i notice everything.


I really do not want to get into the suspension game playing around with parts as i have done in the past with my 350z a total of 7 times.


I liked how the Sr5 rode stock as I was able to remove the floaty boaty by inflating all tires to 37psi.


I was thinking of OME springs but i cannot stand progressive springs. I would really prefer linear and this is why i really am Leary about replacing the springs.


Has anyone dealt with this problem on an Sr5 specifically? TRD off road has progressive springs i believe so that model cannot be compared with the Sr5.


Thanks!

 

The springs are not pre-loaded with 5100's. They are not compressed any more than if you were sitting stock. It's just the lower spring perch is sitting higher, which is lifting your truck.

I suspect you're just feeling the difference between the front end being firmer with the stiff valving of the 5100 vs the softer stock valving of the rear end.

A spacer won't help because you're still dealing with the 5100 valving.

I know you don't want to chase suspension issues, but I think you're going to have to a bit. I see a couple of potential solutions:

1) Replace the stock rear shocks with some Bilsteins. This will make the overall ride firmer than stock, but the front end shock valving will be a closer match to the rear

2) Get rid of the 5100s and put Eibach adjustable shocks on the front instead. These have a softer valving that pairs well with the stock rear shocks. It will still give you a sporty feel to the ride, but it won't be stiff like the 5100s.

 

Oops.

I forgot to mention. I replaced all 4 shocks with 5100's

 

Well Shit.

Now it looks like a slightly stiffer spring in the rear if this is the case.

I am going to email Bilstien and see what they say. Hopefully someone replies.

 

I feel like there are only a few things that can make the rear end wash out like that. Rear shocks being too soft, rear shocks being too firm, inadequate tires, or you're going too fast for what the vehicle can handle.

Does the rear end feel too soft or too stiff? Do you think it could be skipping out for one of these reasons?

What kind of tires? How worn are they?

How fast are you going around these corners?

Keep in mind it's not a sports car so it wont corner like one. Just want to keep your expectations realistic.

 

I have brand new tires. 265's Bridgestone Revo 3's. This is a nice sticky tire that grips the road very well.

I am going the same speed I usually go around that bend which is 50mph and recommended sign says 55.

FYI I emailed Bilstien to see what they say and listed part numbers for them. Ill post a response if they email me back just so that the information is available to everyone.

 

What about the rear shocks themselves......do they feel too soft, too stiff, or do they feel good?

 

as far as the rear end feeling pretty stiff I initially thought it felt about the same.

 

Everything feels good. Fronts feel stiffer but in no way am i saying they are very or overly stiff.

 

Hmmm, I'm stumped then.

I would wait to see what Bilstein says and let us know.

Maybe someone else on here has some input.

 

Does the rear end feel too soft or too stiff?

To answer this question i would have to say softer around the corner according to the butt dyno and it feels slightly delayed compared to the front.

 

I agree. I even checked the tire pressures to make sure Toyota didn't change them when performing the alignment

 

Yeah, I'm wondering if Bilstein recommends a stiffer spring with their shocks then.

I've never heard this before, but maybe they do.

See what they say.

 

Prior to me putting the Eibach adjustable shocks on my 2017 I had the opportunity to test drive a 2015 with the 5100’s (.85) on the highway and some very rough roads at significant speeds. I noticed none of the things you stated OP but like nimby stated they are much stiffer than stock and Eibach. Maybe they are defective? I thought they rode nice even with the Nitto TGs on it.

And I could be wrong but I thought the SR5 and Off-roads share the same coil springs? I know the Tacoma’s don’t share the same...

But if it does have progressive coils I would dump those as well. I always felt the SR5’s Rode the best. 4Runners and Tacoma’s

 

Bilstein wrote back. He did have some interesting information. He said that the trd offroad shocks are the same as the shocks installed at the factory in regards to valving.

I did ask the rep some additional questions about "stronger" valving compared to stock, if the front springs on a trd offroad are linear or progressive, and also asked about the Rear springs that they offer and the difference in rate compared to stock. I'll post that response when it arrives.





On Jun 24, 2019, at 12:57 PM, <Michael.Ritchie@thyssenkrupp.com> <Michael.Ritchie@thyssenkrupp.com> wrote:

Hello,

Changing the front ride height by .85” and using the 5100 rear should not cause any such condition. The front/rear shocks are the same shocks installed at the factory on the Toyota TRD models.

Did you have the vehicle aligned?

We recommend you have a certified auto technician inspect the vehicle for possible install errors and proper alignment.

Kind Regards,
Michael Ritchie
Technical Sales & Warranty Support Expert
thyssenkrupp Bilstein of America, Inc


T: +1 858 386-5909, michael.ritchie@thyssenkrupp.com
thyssenkrupp Bilstein of America, Inc, 14102 Stowe Drive, Poway, CA 92064, USA, www.bilsteinus.com


Sent: Monday, June 24, 2019 1:12 PM
To: Ritchie, Michael <Michael.Ritchie@thyssenkrupp.com>
Cc: Trexler, John <John.Trexler@thyssenkrupp.com>
Subject: Re: Contact Box BILSTEIN - Request


Hello


Yes I did have it aligned at the dealership.


These are not the same as the trd model. The red model comes with 6112/5160


I have 5100 all the way around. Is it the same deal with this setup?


Thanks!

Sent from my iPhone


From: <Michael.Ritchie@thyssenkrupp.com>
Date: June 24, 2019 at 1:20:25 PM PDT
To: <daniel@jdandrews.net>
Cc: <John.Trexler@thyssenkrupp.com>
Subject: RE: Contact Box BILSTEIN - Request

Hello,

The rear 5100 are the same as OEM TRD (non-pro) and OEM Toyota they should not cause any ride issues. Please have a certified technician check over your vehicle for possible install errors and proper alignment.


Kind Regards,
Michael Ritchie
Technical Sales & Warranty Support Expert
thyssenkrupp Bilstein of America, Inc


T: +1 858 386-5909, michael.ritchie@thyssenkrupp.com
thyssenkrupp Bilstein of America, Inc, 14102 Stowe Drive, Poway, CA 92064, USA, www.bilsteinus.com

 

Sounds like they responded via script. I would ask an off road shop

 

I know this isn’t you OP but the “same valving”...I call BS on that. My step father has a completely stock TRD off-road and it feels very different from the one I got to test drive with the Bilsteins. I would be in utter shock because of the amount of money I lost betting on different valving. My Eibachs significantly changed the ride so even if I haven’t used Bilsteins before I could not imagine them not changing the ride. Now I am no suspension expert but I understand that valving has a lot to do with ride quality. This reminds me of a few heated conversations I had over on Tacomaworld. There are many people that believe the TRD shocks are the same as the Bilstein 4600...the valving was again much different.

 

Just for clarity, SR5's and TRD Offroad 4runners come with the exact same springs and Tokiko shocks..........not Bilsteins.

The only 4runners that come with Bilsteins are the Pros.

If Bilstein valves all of their 4Runner shocks the same as what they put on the Pro, then I know what the difference is. The spring rate on the Pro's are slightly softer than the stock SR5 or Offroad. Not exactly sure about the rear end of the Pro's, but I've hear it's the same spring as the SR5 and Offroad, but with a Bilstein shock. This is why the suspension on a Pro feels a little softer than putting 5100s on an SR5 or an Offroad.

Not to say this is causing your issue.......just trying to get the facts straight.

 

Also, I believe all springs on all 4Runners are linear......even the Pro's.

I don't think Toyota offers a progressive spring on any 4Runner.

 

That makes more sense. FYI i can confirm Tokico shocks on a factory sr5

 

Sent: Monday, June 24, 2019 4:39 PM
To: Ritchie, Michael <Michael.Ritchie@thyssenkrupp.com>
Subject: Re: Contact Box BILSTEIN - Request


Hi Michael,


One last question. Does Bilstein make front coils for the 5100s?


If not are they designed for stock coils or can aftermarket coils be used?


Thanks!

Sent from my iPhone

From: <Michael.Ritchie@thyssenkrupp.com>
Date: June 25, 2019 at 7:13:49 AM PDT
To: <daniel@jdandrews.net>
Cc: <Junior.Africa@thyssenkrupp.com>
Subject: RE: Contact Box BILSTEIN - Request

Hello,

No the 5100 are designed to use only the factory OEM springs.


Kind Regards,
Michael Ritchie
Technical Sales & Warranty Support Expert
thyssenkrupp Bilstein of America, Inc


T: +1 858 386-5909, michael.ritchie@thyssenkrupp.com
thyssenkrupp Bilstein of America, Inc, 14102 Stowe Drive, Poway, CA 92064, USA, www.bilsteinus.com

 

I just wanted to see what this guys response was......

 

I think I read that thread. So silly people will argue that when all they have to do is get under the truck and LOOK at the stamping that clearly says "Tokico"

I agree the shocks are not the same as the trd offroad. If that were the case people would be installing spacers or replacing with high end.

 

I have read multiple threads of those who went from 5100's in front to 6112's and they say the same thing that they are a softer spring but that it handles really well. Its a 2.5 shock with more oil in it with a 600lb spring.

I believe the 4runner front coil is 10-20lbs below that number yet the valving is slightly more aggressive in front compared to the rear. I'm sure there is a rear spring that will solve this problem. I'm curious if some of the FJ guys have dealt with this issue

 

The front coils are something close to 580lbs on the SR5 and Offroads. Pro's have 550lb coils up front. I think all 4runners have a 180lb rear spring.

If you think the rear spring will solve it, try looking at Dobinsons, Eibach, or OME. All make good rear springs for the 4Runner.

This one is stock height with a 10% increase over the stock spring rate. Might be close to what you want, but I would ask the vendor just to be sure what you're after is achievable with a stiffer rear spring.

https://www.dobinsonsdirect.com/pro...-height-rear-coil-springs-for-toyota-4runner/

 

Oh wow. So the pros have a 550 lb spring in front but the 6112's have a 600lb spring. I did not know that.

 

They did when the Pros came with Bilsteins. Not sure if its the same spring rate on the newer Pros with Fox shocks (2019s), but likely the same.

 

I have an update.

I went to the dealer who now installs suspensions in house. The mechanic who installs these suspensions drove my 4runner. He said it feels like the tires are causing the squishyness in the back but also said he feels it a little in the front. Recommended i bump up the tire pressure. I went from 36-40psi

I removed the shit I had in the hatch. About 100lbs of recovery equipment etc.

The ride is back to normal. putting the weight back it the ride it improved.

Here is what I learned. The mechanic told me that the springs in the back of the 4runner are very sensitive to weight and my situation is exaggerated because of the tires.

they had an sr5 with bilstein 5100 all the way around with the fronts maxxed out (2.5) on stock coils and a daystar 1.5 inch spacer in the rear. He explained that they put LT tires on their trucks and that the sidewalls are much stiffer and ride better.

I have dealt with this before in a 350z where i went away from bridgestones with a stiff sidewall for a week and hated it so bad i broke down and bought another set of bridgestones.

To me it sounds like my tires (p rated 265 bridgestone revo 3's) are the single factor here. I can live with the tire pressure bumped up. Not sure how this will affect tire wear but at least I know what i need to do when swapping out tires again--> Go LT rated.....and this is if i go 275's or 285's as there will be more sidewall and stiffening it up with an LT tire will help tremendously. My current p rated 265's will be fine. It feels slightly bumpy at 40psi. I am going to drop the tires from 40-39 until i find a compromise of the improved handling and a smooth ride.

When I had my Tacoma that truck had an on road sweet spot tire pressure of 38psi.

As far as I am concerned I feel the stock rear springs are fine.....I mean these are the same springs that come on the pro's

 

Glad you figured it out!

Thanks for the update.

 

Reporting back. I settled at 38Psi all the way around which is the sweet spot for the best handling. Any higher = darty handling as reported by the wife going to work on 40psi. Funny how 2psi makes a huge difference. (for those who did not read the entire thread these are p265/70/17 bridge-stone Revo 3's... most are running LT's so be aware there is a difference in handling between p and LT tires ).
After a recent road trip this last weekend to Scottsdale AZ (I totally missed both earthquakes here in California ) and some fun in saguaro national park on the dirt roads. I feel like the suspension settled in a really good way. I really was not expecting the suspension to settle at all. No complaints from the wife which is a BIG DEAL! Such a shame that the Apache trail was closed.

Until I screw with the suspension again in the future I am good for now!

Future mods will simply be bfg K02's or Firestone Destination AT's in 275/70/17 and either 1/4 inch spacer up front with ome 0.4 inch trim packers in the rear or eibach springs 1.6 with 1/4 inch spacer in front and 1" rear matching spring.

Tires will be first with Psi tuning and then suspension spring upgrades just to make sure everything is done right with the least amount of troubleshooting.

The goal is to keep the 4 runner looking as stock as possible just like the Tacoma I posted above so I will retain the stock wheels.

after that all I really want is a bug deflector to stop chips on the hood, some nfab nerf bars, and a low profile rola rack mount kit with a Cabela's roof basket with extension. (the Cabela's roof basket is just a re branded Curt model but is hella cheaper in price) to put my 3 XL sportsman trunks and pelican case up top and out of the way.