Mostly stock, ride bouncy like a bobble head?

[kohai]

Stock 2019 LC 200 with OEM size KO2 tires (46psi) and only 25,000 miles on the vehicle. Tires only have about 5,000 miles on them now.

I went on about a 2,000 mile road trip with freeway speeds upwards of 80-85 mph (speed limit is 80, so nobody flame me). The LC seemed to bounce like a bobble head on bumps like crossing overpasses or on sharper curves. I'm not sure what the right vocabulary is for describing this. I don't know if this is the stock suspension or the K02 tires or what exactly the issue might be.

The bounciness plus a bit of wind plus the bit of play in the steering wheel made for a tiring drive trying to keep it in the center of the lane. I wasn't comfortable letting others take a shift driving on the higher speed roads with all of the semis.

Any insights on what this could be, if it could be addressed, or if it is just the nature of the beast?

 

[jwmNC]

Without knowing the year of your 200, I’d blame the KO2s. They are heavy tires which means more unsprung weight for your shocks to manage. But if the vehicle is older, despite low mileage, maybe a suspension refresh would help quiet it down. I had KO2s on mine for a while and felt the same way about them, and I don’t miss them now they’re gone.

 

[gaijin]

Stock 200 with OEM size KO2 tires and only 25,000 miles on the vehicle. Tires only have about 5,000 miles on them now.

I went on about a 2,000 mile road trip with freeway speeds upwards of 80-85 mph (speed limit is 80, so nobody flame me). The LC seemed to bounce like a bobble head on bumps like crossing overpasses or on sharper curves. I'm not sure what the right vocabulary is for describing this. I don't know if this is the stock suspension or the K02 tires or what exactly the issue might be.

The bounciness plus a bit of wind plus the bit of play in the steering wheel made for a tiring drive trying to keep it in the center of the lane. I wasn't comfortable letting others take a shift driving on the higher speed roads with all of the semis.

Any insights on what this could be, if it could be addressed, or if it is just the nature of the beast?

If by "OEM size KO2 tires" you mean the LT285/60R18 118/115S Load Range D tires, then your RCTIP (Recommended Cold Tire Inflation Pressure) is 46psi Front/Rear.

If, and I truly hope not, by any chance you are running the stock tire pressure of 33psi, then you would certainly observe the "bobble head" phenomenon you describe - as well as putting yourself and others in danger with dangerously underinflated tires.

Increase your cold tire pressure to 46psi and see if your problems persist.

Senpai says do it now!

HTH

 

[KDAWG97m3]

Isn’t there a site that helps calculate that? I need to research air pressure in my 80 and 60. Thanks

 

[kohai]

If by "OEM size KO2 tires" you mean the LT285/60R18 118/115S Load Range D tires, then your RCTIP (Recommended Cold Tire Inflation Pressure) is 46psi Front/Rear.

If, and I truly hope not, by any chance you are running the stock tire pressure of 33psi, then you would certainly observe the "bobble head" phenomenon you describe - as well as putting yourself and others in danger with dangerously underinflated tires.

Increase your cold tire pressure to 46psi and see if your problems persist.

Senpai says do it now!

HTH

Yes I should have mentioned, I am running at about 46 PSI (thanks to this forum). While driving the console was saying it was about 48 PSI (give or take).

 

[gaijin]

Yes I should have mentioned, I am running at about 46 PSI (thanks to this forum). While driving the console was saying it was about 48 PSI (give or take).

I am very relieved to hear that.

My only thought after that is a KDSS system that is not fully charged. Have you had any suspension work done?

 

[gaijin]

Isn’t there a site that helps calculate that? I need to research air pressure in my 80 and 60. Thanks

Yes, there are several. Here's one I have found mostly reliable: TireSize.com

But remember, the results are only as good as the data you input, so be sure you are fully and properly describing your OEM tires.

HTH

 

[kohai]

I am very relieved to hear that.

My only thought after that is a KDSS system that is not fully charged. Have you had any suspension work done?

No, it is all stock. I am having the oil changed this week -- I could ask the dealer to check.

 

[gaijin]

No, it is all stock. I am having the oil changed this week -- I could ask the dealer to check.

Did you buy your 2019 LC200 new or used? And has it been a "bobblehead" for the entire time you have owned it, or just recently?

 

[bloc]

I’m betting your problem is the KO2s, both the mass and the higher required pressure, neither of which stock dampers can effectively control. I had this exact same issue with KO2s.

Many will say they prefer the ride, but it’s highly subjective. Those tires at that pressure added a harmonic shuddering type feel to the suspension that was really distracting and uncomfortable.

You can try lowering the pressure for some distance on surface streets (being careful to avoid highway, lest the tires get damaged from too little pressure and therefore too much heat) to see if you find the ride better.

 

[kohai]

Did you buy your 2019 LC200 new or used? And has it been a "bobblehead" for the entire time you have owned it, or just recently?

I bought it in October 2019 with 600 miles on it from the dealer. I don't remember this issue with the OEM tires on previous road trips. I got these K02s 18 months ago -- I don't put a lot of miles on this vehicle so I am only just now getting to my first tire rotation on these K02s.

 

[kohai]

I’m betting your problem is the KO2s, both the mass and the higher required pressure, neither of which stock dampers can effectively control. I had this exact same issue with KO2s.

Many will say they prefer the ride, but it’s highly subjective. Those tires at that pressure added a harmonic shuddering type feel to the suspension that was really distracting and uncomfortable.

You can try lowering the pressure for some distance on surface streets (being careful to avoid highway, lest the tires get damaged from too little pressure and therefore too much heat) to see if you find the ride better.

Did you change tires or make a different change to address it? e.g. does switching to Emu BP-51 or similar address the issue?

 

[TeCKis300]

Yes I should have mentioned, I am running at about 46 PSI (thanks to this forum). While driving the console was saying it was about 48 PSI (give or take).

You've been bamboozled by the biggest lie on this forum and 46 PSI is the reason for the brittle ride. This has been going on for years, with many experiencing what you have, due to the limited and often false narrative a certain individual insists on. When there has been an abundance of data that says his methodology creates too high pressures in certain tire sizes, and dangerous underinflation for others. I mean, would you follow and RCTIP methodology that tells someone to run 25 PSI? When has any modern car run 25PSI? Yes, that's what he insists on, and putting people in danger, when there's clearly evidence it can be misleading.

In engineering, blindly following a single model or approximation is a dangerous strategy and that's what we have here with RCTIP. Tire pressure is established considering a balance of factors.

The easy button is to use the LX570 load rating (same axle, heavier vehicle) for a more sane first approximation, ~42 PSI. There is room to go lower too if you're not actively loaded to the rear Gross Axle Weight Rating (GAWR) of 4300lbs.

If you cross check pressure, look at tire wear, or another approach which is to chalk test. It is very likely to show more wear in the center of the tread.

 

[bloc]

Did you change tires or make a different change to address it? e.g. does switching to Emu BP-51 or similar address the issue?

Dampers designed to work with heavier tires at higher pressures can help a lot. I’ve been through a few sets of tires but when I set my rig up properly for LT tires (and more serious use) such as your KO2 I went with king shocks. Plenty of others would do a good job with those tires though.. and as Teckis said there is room to play with pressures to help some of the negative attributes. But I wouldn’t go too far..

If you aren’t aware the reason these tires need more pressure than stock is they are much more robust construction, which means more internal friction and therefore heat. Excess heat kills tires. So they recommend more pressure, which reduces the tire flexing, and the tire stays safe.

What gaijin recommends is technically the industry standard method to derive pressures when you change size or construction or load rating. But also as teckis points out, other factors matter.

The industry method calculates out to 27psi when you switch to a P-metric P285/70R17, and I can say from experience that while they wouldn’t overheat or anything, they are flat out dangerous when cornering or doing something like an emergency maneuver. But, the ride is the opposite of bobble-head. Like floating on a cloud.

So there is gray area. Subjectivity.

Mechanically, Toyota says 33psi on a stock-size tire can support the vehicle during cornering, stopping, etc. and your KO2 would even be a bit stiffer than stock. But 33 could very well lead to tire problems at high speeds. So you’ll have to make a decision about what you’re comfortable with.

The full story is I eventually went back to stock suspension and tire size/construction.. and am very happy with it for my use case.

 

[kohai]

I switched to the KO2 after the OEM tires got chewed up a bit on a trail with volcanic rock. I opted for something tougher hoping to avoid changing tires due to sidewall damage. I use the 200 on desert roads, forest roads, bumpy trails, etc. I don't do a lot of freeway driving as the mpg is poor. Yet, this vehicle is more comfortable than my other cars for longer driving and has space for luggage. I appreciate everyone's input. I'll look into doing a chalk test too.

 

[Sandroad]

No, it is all stock. I am having the oil changed this week -- I could ask the dealer to check.

The “bit of play in the steering” is not normal and could be caused by alignment being off. When you do the oil change I’d have that checked. I’m pretty sure the others above are right and it’s the tires causing the instability. Unless you need the BFG tires, I’d sell those and get an OEM size set of Michelin Defender LTX M/S2 and run them at 33 psi. You’ll be back to a nice stable ride.

 

[bloc]

and get an OEM size set of Michelin Defender LTX M/S2 and run them at 33 psi. You’ll be back to a nice stable ride.

That’s what I did minus the M/S2 detail and am super happy with the change.

 

[987R]

I dumped the KO2s for the same reason. A bouncy-ish ride with too much shudder going over bumps/road imperfections. It's noticeable better with the LTXs, but still there somewhat. Not sure if I need new shocks or an AHC bleed, or if that's just what you get driving a truck.

 

[kohai]

I'm glad to hear others chiming in. I read so many threads about the K02 prior to purchasing, I'm surprised I didn't come across this issue mentioned. If I believe I have need for the K02 robustness, is there an aspect to this that is suspension related that is addressed by swapping to another suspension like BP-51? I'm trying to wrap my head around the variables.

 

[stonepa]

What did you drive before the LC? If you came from a german sedan or SUV you’ll notice a bit of a difference with the 200.