Help Reducing Road Vibrations on New TRD OR

Interesting, it list's the same shock for all...and no mention of A.C., D.C., Short or Long bed. Guessing they list "Fitment as all" since, they're the same length, size and bolt the same ?
2020 Toyota Tacoma Limited, SR, SR5, TRD Off-Road, TRD Pro, TRD Sport 2.7L L4 - Gas, 3.5L V6 - Gas
2019 Toyota Tacoma Limited, SR, SR5, TRD Off-Road, TRD Pro, TRD Sport 2.7L L4 - Gas, 3.5L V6 - Gas
2018 Toyota Tacoma Limited, SR, SR5, TRD Off-Road, TRD Pro, TRD Sport 2.7L L4 - Gas, 3.5L V6 - Gas
2017 Toyota Tacoma Limited, SR, SR5, TRD Off-Road, TRD Pro, TRD Sport 2.7L L4 - Gas, 3.5L V6 - Gas
2016 Toyota Tacoma Limited, SR, SR5, TRD Off-Road, TRD Sport 2.7L L4 - Gas, 3.5L V6 - Gas

 

I know you said you tried different pressures in your tires and it didn't make a difference. That is surprising to me because in my Sport it makes a big difference.

 

If you have already tried the following disregard.

1. Check all 4 shock bodies to see if one or more is leaking. This should not be happening on a new truck, but you never know. When I got my dodge ram new, within 3 months I had a failed shock. I didn't have vibrations. But this is a place where you could get that.

2. I would take it into the dealer for vibration issue under warranty and ask them to figure it out and point to maybe one or more unbalanced wheels. Could be the wheels are off balance, but why pay for it when the dealer can check it out for you.

 

It would definitely be worth a trip to the dealer as l recall several people on here with complaints of vibrations ending up with warped drums or axles, think there possibly might have even been a TSB for that.

 

Yes, I asked about that to make sure and the parts guy I spoke with said all the OEM shocks say that on their website because they technically fit all the different trims. But I confirmed with him that the shocks in the link I gave are the (black) Hitachis that come on the Limited. The Limited also uses the same shocks for all submodels... 2wd/4wd, long bed/short bed, etc...

 

For this particualr vibration over the expansion joints in the freeways, it didn’t. I’m sure if I go low enough it would make a difference (like in the 20s), but I on all the vehicles I’ve ever owned, I have to keep my tires above ~32 PSI min because I drive curvy mountain roads for work and lower than that would kill the lifespan of my tires.

 

This is likely a combination of things.

First, your tires are too hard. These act like springs. Drop them down to 29-30 psi at the low elevation, reset the TPMS and ignore the warning light at high elevation. You won't loose any traction. In fact, likely put more tread on the road, thereby increasing traction.
2nd, the shocks dampen wheel rebound.
3rd, the springs may be a bit stiff. These will set up a harmonic with the hard tire.

A "softer" shock will soften (slow) the rebound. A "stiffer" shock will harden (quicken) the rebound.

Have you tried different speeds on the "jack hammer" road? The bumps in the road can set up a harmonic vibration as the excitation source in the suspension.

The tire pressure gauge is reading the pressure in the tire referenced to the atmosphere as 0 psi. When you increase elevation, the reference pressure will decrease, meaning your pressure gauge will indicate a higher tire pressure. This is why balloons expand as they gain elevation. You can search the internet for detailed explanation of Gage pressure vs Absolute pressure.

Suggest to try the following before you load the parts cannon.
1. Inflate the tires to the 29-30 psi at your low elevation.
2. Reset the TPMS system. I doubt, the TPMS warning will illuminate at your high elevation.
3. Drive it for a week, try different speeds on the "jack hammer" road.
4. If after a week, the vibrations remain unsatisfactory, then look for springs with a lower spring rate. Careful, this will reduce the load capacity.

 

Coming out of a F250 4x4 with 65PSI in the tires, my Tacoma TRD OR rides like a "cloud".......

 

I tried these freeways with 30 PSI, it wasn’t enough to help much with these particular vibes. While the higher elevation does increase the tire pressure, the colder temps counteract that and then some. This time of year the temp will often go from say 60* at 1000 ft. to 30* at 6000 ft., and the tire pressure will drop sometimes by 7 or 8 PSI even with the higher altitude. After driving these same mountain roads for over 25 years, I’ve found that 35 PSI is the sweet spot for a balance of good tread wear, and good cornering. I can feel a difference in handling and stability around the fast curves at 30 PSI compared to 35 PSI. To the point that I have to go slower than I want to drive. I’d rather deal with the jackhammering on the freeways, that go that low on my pressure in the mtns... and If I set my PSI at 30 at home, it would be in the low-mid 20s up there on the colder evenings. Hopefully the shocks will make a difference, the issue isn’t big enough for me to start swapping out leafs. Thanks, I appreciate your (and everyone’s) input.

 

UPDATE: I installed the rear Limited shocks a few days ago (easiest shock swap ever BTW... took <5 min per side). They dampen the vibrations a lot better than the stock OR Bilsteins and it was worthwhile for me to do the swap. I’m not feeling the extreme “jackhammer” effect anymore in those certain parts of the freeway that were really bad before with the stock OR shocks - Now I just feel normal road vibrations that I’d feel in any other car or truck. The Limited shocks got rid of the unreasonable shake/bounce I was feeling before. These Limited shocks have larger diameter shock bodies than the stock OR Billies too, and feel more heavy duty.