11Series

I have had my 2014 STX SCAB 4WD for about a year now, and like many others, I am wanting to swap out my wheels/tires for something more aggressive.

I am looking at going with something like the Boss Ultimate lift, and 34” (or so) Duratracs on 17” rims.

I currently have P rated 275/55/20 that came stock with the truck.
So my question is how much I am going to degrade my ride quality from stock with this setup. I know there are a ton of threads on this, and I think I have probably read all of them, but one thing that hasn’t been clear to me is this:

The move from P to LT tires will obviously stiffen things up. However, I will also be increasing sidewall height at the same time in my move to taller tires and smaller rims. Will this have some compensating effect at all? Also, I understand the Boss kit to provide a better ride than stock, so any thoughts on how a setup like this would compare to my stock ride?

I probably do 15% of my driving on dirt roads, 50% on paved backroads and 35% highway. We get some snow here in Jersey. I don’t do any offroading these days, but if I get a chance to move in the next couple of years, that would certainly be on the table.

Would appreciate any thoughts on this matter.

-Tim

winchested

Yes it will... it will feel like a truck.

But you can run stock air pressure for a softer ride, but less tire life.

RedAggie03

I've had P, D, and E tires on my truck already - and to be honest I could only tell *slightly* that the E's rode harsh, but they were also aired up more I think. To be honest, there isn't a big difference I found. I've tried the following:


275/55R20 Stock Pirelli's
275/60R20 D load BFG KO2s
275/65R20 E load BFG KO2s


I ended up settling on the D load tires and they ride pretty nice I think. Overall, it's a firm ride but it's not bad.

BCSquare

^this is a good assessment.

I went from the stock STX 18" wheels to some 17" wheels with E rated 285/70 LT tires. The tire pressure in there is higher than stock but it's not as stiff or harsh as some people say. To me the truck drove and rode smoother. You'll just notice the additional weight and track width depending on the offset more than anything else.

uzikaduzi

if you're going with higher volume tires like you mention... you will be running a LOWER pressure in them than the recommended tire pressures on the door sticker (and significantly less than the tire's max pressure)... unless you need additional payload capabilities (which your truck isn't rated for), you don't run them higher because you will wear out the center of your tread quicker and you will have less grip on the road... Duratracs look pretty aggressive but actually feel similar to a non aggressive at as far as how smooth they roll on the pavement... i don't think you will overly feel the stiffness increase unless you air up too much. i can't comment on the lift but going from a ~32 inch tire to a ~34 inch tire, you're gonna feel the power loss (and the lift will make it slightly worse on the highway)... whether that's acceptable or not is up to you.... if it's not acceptable, you 'can' chase some of that back with a tune/tuner but you've still lessened the mechanical advantage your engine had regardless of what you get back so your transmission will have to work harder. many people report long lives out of their transmission after larger tires, so the additional strain maybe negligible but if you tow much, i promise you can see it in the temps. personally i think a substantial tire size change requires re-gearing which is 2 x's the cost for a 4x4.

tomtom52

I'm running 18 inch 33s LT street tires at the recommended 50psi. I regreat it but at over a k in tires I'm just going to have to wear them out. Ive seen a loss in power and with no weight in the bed it can be bouncy on bad roads but if I want to hook it to a trailer I don't have to worry about the tires and it feels SO much more stable at 70+ mph. On the flip side my 2 year newer xl work truck that has a few hundred pounds in the back with p tires rides great but has a lot of sidewall flex at 70+.

uzikaduzi

I don't mean to be rude... what do you mean by recommended 50psi? where is that recommended? it's not on your door jam, there certainly isn't a recommendation on the tire itself... are you looking at the tables for recommended psi for load from the tire manufacturer? if so, i can't imagine many LT tires calling for 50 psi for a load your truck can handle unless it's the HD payload.

winchested

I don't know where you get your magic information but you must run more air pressure in an LT tire to match the stock P rated load capacity.

Check the Toyo PSI chart table. Always Higher on an LT tire!

uzikaduzi

you should re-read this

http://toyotires.com/sites/default/f...-LT_102913.pdf

compare tires of different sizes and see the amount of pressure you need for the same load... to increase load, you 'may' need more pressure in them, but the p rated load capacity is at your max payload anyways. so going beyond that will cause you to have a bad contact patch and you'll wear out the center of your tread. (as well as decrease you traction and decrease ride comfort)

specific to your example, a toyo 33x13x18 tire at 50 psi can hold 3000 pds, i don't know what you had stock but 260/60r18's are a stock option... p rated they can carry 2271 pds at 35 psi a 33x13x18 can carry 2335 pds at 35 pds. at 50 psi, you are saying that you need to inflate them to carry 6k pds per axle with is way way way past your gross per axle... hell it's about ~1500 short of gross vehicle weight.

when you increase tire size, you have more surface area of the tire touching the ground (more sq inches), but your truck did not increase in weight so it takes less pounds per square inch (psi) to hold your truck.

winchested

It looks to me that by that chart you are at equal pressures when stepping up from a 32" to a 35" tire.

From 32- 33.5" tire 40 PSI.

32 to 32" 45-50 PSI.

This is only to carry the same load, has nothing to do with tread life which you did state.

But at 35 Psi on the P rated tires you do not get the best tread life either. As most do know that the outer edges round off real quick at 35 PSI on P rated tires.