285 70 17 ko2 with 49 psi

Am I running too high of a PSI I only drive 42 miles a day on my way to work and back

Would my PSI at 40 smoother on the road

 

Those things are going to wear like the blade on a pizza cutter at that PSI.... lmao

 

Lmfao went down to 45 just now and already feel a difference

 

Well just brought them down to 40 and it feels like a dream.

 

First Post! (TRDSport 4x4 DCSB 6MT on order)

Just thought I could add in some constructive feedback here. OP, lowering to 40psi is pretty much exactly where you should be. This has everything to do with load capacity of your tires. Stock tires on the TRD Sport are 265/65 r17 P-metric. These tires are rated to hold x lbs of load at the recommended PSI (I believe it's 32psi in the door card, but since I don't have my taco yet, we'll just assume and run with it). In order to determine what load the tires are rated to bear at that pressure, you would use your manufacturer's load inflation table. Many tire companies withhold this data for installers only, but Toyo tires are kind enough to leave that data out there (keep in mind this data will be very similar across manufacturers assuming similar metrics - P, LT, M+S - and similar load ratings - C, D, E). Using Toyo's load inflation table we see that the factory is spec'ing a load around 2337 lbs:


If we look at the load inflation table for your LT285/70 r17 KO2s (in this case an LT285/70/17 Toyo Tire) we see:

So in order to get pretty close to that 2337lbs number from the factory you need to be right near 40psi; which in this case gives you 2315lbs. Coming from the 4Runner world, modded rigs get heavy quick, so keep your added weight in mind as you check your pressures. Running low psi at speed at heat and severely shortens the life of tires.

Hope this helps!

OA

 

Yes that is very useful information. Thank you so much for the feedback. I feel confident and comfort in my new 40psi

 

That's one hell of a first post. Cheers!

 

Tires usually show max psi only no

 

You forgot the adjustment factor.
2,337÷1.1=2,124
Also, tire placard is based on GVWR not actual ride weight.
As an example, my adjusted PSI is 37; my current optimum is 35/31; or 5,100 lbs, 500 lbs below GVWR and 800lbs above curb weight. Which makes since; my actual ride weight is about 600 lbs over curb weight. What I lose in payload potential is worth it for ride comfort; nothing an air compressor can't fix.

 

Ah skipped that entirely! Thanks for covering the gaps.

OA

 

I'm confused now. So what psi should my 275/70/17 KO2 be at?

 

Depends...
What was your original tire?
What's your Vehicle Placard Recommended PSI?
How much do you weigh and how much sprung weight have you added front and rear?
Do you want optimum or max payload potential?

 

Chalk test them at 35

I run my 275/70/17 ATms @ 40

 

i have the same exact tire and it feels amazing at 40 psi, right now they are at 37 bc i went offroading but i will probably put them back to 40

 

Factory door sticker from the Baja version wearing T/A KOs in LT265/70R16 (Load D) calls for 46 psi front and rear. Used that as a guide for my KO2s in LT265/75R16 (Load E) with excellent results. These tires need higher pressures to carry the same load as P tires of equivalent size.

 

Maybe you can borrow his chalk.

 

Thanks guys. I'll give 40 psi cold a try. Currently at 32 from tire shop. Hopefully this will also improve mpg.

 

Chalking is closer to current optimum.
Knowing the math allows you to adjust pressure to allow for added payload without rechalking; like if someone put a shit-ton of lumber in their bed.

 

I don't adjust my pressues for lumber