Stiff Ride After New Leaf Springs - Looking to Soften the Ride

Fronts are brandy new Bilsteins out of a 2017 TRD Sport. Rears (as I stated) are Rancho RS5000's with less than 5,000 miles on them. Said another way, it ain't the shocks.

 

40psi? What tires are you running that hold 40psi safely. 30-35psi is safe for stock and most aftermarket tires.

 

I was asking the OP [JoeSchmuck]...but OK. Enjoy your Ranchos.

 

40 PSI ride like this:


And 32-36 PSI be like this:

 

My tires say 80 psi on the sidewall. 40 is the sweet spot for my truck. My passengers frequently comment on how smooth my truck rides.

 

Any load range C tire has a max pressure well above 40psi.

 

Damn that’s good to know. Whether it was a car or a truck, all my vehicles have been between 30-40psi, and if it was above 40, it was a commercial vehicle, ie tractor, skid steer, etc. What tires do you run @Pigpen ?

 

Load E 255/85/16. I have to sets on wheels. One is Toyo M55s the other Dean Backcountry MTs.

 

The manufacturer makes the vehicle and determines what type, size, & pressure it should have. Look in your operator's manual or on the inside driver side door for air pressure.

 

Ummm... Okay. Thanks for playing.

 

The door panel guide is for the tires that come with the truck originally. If you change the the type of tire from the original, then that sticker is no longer valid for the current tire you are running. You’re not gonna run a load E tire at 29 psi on the highway. And yes, my panel sticker says 29 psi for front and rear tires.

 

Pigpen, have you checked your operator's manual?

Apparently this guy hasn't seen the list of crap you carry around!

 

The load curve for the tire - which does depend on the tire size and whether P or LT - is what tells you the required pressure for a given load. These load curves DO NOT depend on whether the tire is load C, D or E in fact - which is counter intuitive but true. The load letter only tells you the maximum pressure and thus maximum load a tire can take.

As to the "optimal" pressure to run the tire at that depends on more than just the load and the *vehicle* manufacturer determines that. Identically loaded tires of identical size on different vehicles will in fact have different recommended inflations. Those inflations will be *at least* as high as the minimum pressure from the tire load curve at maximum gross axle weight but generally are higher. How much higher depends on the suspension and other aspects of the vehicle.

For instance the stock OR lists 29/32 for P265/70R16 which is for a load of 2015 lbs per front tire or 2115 lbs per rear tire. That's way above the actual maximum GAWR.

For the TRD Pro the door panel says 46/46 for LT265/70R16 which is for a load of 2200 lbs per tire. Again way above the GAWR but the PSI is way below the 80 PSI on the sidewalls of those tires. Swap those stock load Es for a load C and the recommended pressure is exactly the same despite the sidewall pressure being a lot lower. Note the Pro has different stocks than the OR so not surprising the point chosen on the load curve is a bit different.

Different size tires have different load curves so recommended to the tire installer is to set the inflation that matches the same load value as the door panel recommendation for the stock size. But again, the load curve for a given tire size is identical for all tire manufacturers for a given size regardless of load rating. Remember though that P and LT are different "sizes".

Of course many of us also drastically change the suspensions and also load the vehicle well past the very low "soccer dad" load that Toyota optimized for. So a mixture of ride quality and chalk test is how most folks get to their chosen pressure.

Key point though is that the load curves for LT and P are drastically different so LT will almost always run at a higher PSI than the stock P tires. Also usually larger tires will run at a lower PSI than smaller tires but this is not universally true. Sometimes seemingly closely sized tires have rather different load curves.

My LT235/85R16 being small and LT run nicely around 46 PSI with a GVWR around 5500 lbs.

 

Sorry reading too many threads here. If he has different type tires than OEM, look at the tread is it wearing in the center more than the sides? Then he has too much air in the tires!

 

I just read a guy refer to the TSB springs as a 'screw up'...

 

I can't believe no one has thought to ask op what he is running for air pressure in his tires.

 

Let me think! He went to the dealer cause of a recall of the rear springs and he got stiffer ones. Now his ride is too stiff! I would go back and tell them to make it right or reinstall the original ones. If there's any further issues I'd get a Air suspension kit!

 

I'd imagine Toyota legally could not reinstall the old ones as they have been deemed unsafe for use after many reports of them breaking. The leaf pack he received is the enhanced pack to remedy the defective pack that was originally equipped. As I'm sure most people like to have recalls performed on their vehicles to ensure they are safe, they are voluntary. Only solution I see is for him to source the old pack from someone who had them replaced before the recall and has them laying around. Toyota definitely won't install them as that would muddle things from a legal stand point for them. Or give them more time to break in.

 

If it were me I'd take it back tell them to make it right. If that doesn't work, take a leaf spring out, detemper a leaf, or cut it short. If he needs more rear support then get a Air suspension kit.