I am running the ko2 in that size on the same rim. I tow a 3500 lbs trailer. The end game is to do the exact kind of trips you are doing. The only thing I will do when it is time to replace tires is go up to 285/75.
LX 570 with EVO Corse wheels? (1 Viewer)
- Thread starter Bhebert449
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Whatever AT tire you all land on, I'd encourage you to go bigger and wider. No need to stay with these mild sizes as the LX can run bigger than the common LC200 sizes.
KO2s offer an interesting 295/70R17 that spec to 33.3" x 11.8". I'd go with that if you're doing KO2s.
KO2s offer an interesting 295/70R17 that spec to 33.3" x 11.8". I'd go with that if you're doing KO2s.
Steveray450
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That would put us at about 33.9" O.D...how much trimming if any you think?
Steveray450
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I will definitely look at that...thank you!
One of the deliverables on the EVO 17" wheels is they are approx 10lbs lighter than the stock 20's. ...which offsets a bit of the additional weight of bigger tires.
I know you have been running (I thought I read) 305's....but showed interest in going to the 295's ...did you pull the trigger?
I actually went bigger still, now running 35x12.5s.
Regarding towing, I would give some consideration how a taller tire is going to affect gearing, braking, and also engine braking. IMO a small 33" tire is going to be about what you want without re-gearing or BBK. A tall 33" or 34" tire is going to work better with re-gearing (<2016 models), particularly with larger and heavier trailers.
More info in my build thread in my sig if you want to explore bigger tire enabling mods.
EverywhereBear
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I have done Toronto to Tuktoyaktuk and back on KO2s with zero issues - not towing anything. I have also done a couple of Toronto to Florida trips with KO2s. No issues there either.
Steveray450
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I will probably just hang tight at the 285/70/17 mark. I am pretty weight conscious on trips...in fact I remove middle and rear seats etc.
I also have to add and extended fuel tank (for Alaska trip)...so...MO MONEY!
By the way...you have unselfishly added a tremendous amount of quality content and information to this forum. I have and continue to benefit from it. THANK YOU!
Steveray450
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Do you have an extend fuel tank? I had to look that place up
...there really is a "Tuktoyaktuk". That is a big haul!!!What size wheels/tires...just curious?
Steveray450
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By the way is that the Dalton Hwy in your Avatar?
EverywhereBear
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Do you have an extend fuel tank? I had to look that place up
What size wheels/tires...just curious?
No extended fuel tank, I carried 20L on a roof basket, but did not need it.
I did that trip in my 08LX, I now have a 2018. Tire size was 285/55/20 LT on stock LX rims.
Avatar is from the Dempster Highway - heading south.
bloc
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I was going to say this if you didn’t.
I’m probably doing gears and brakes with no intent to tow.. and still on 285/70/17. Partly to plan for 285/75, but also because even the 285/70 triggers enough torque converter unlocking at interstate speeds with higher altitudes like northern NM I40 or when dealing with north Texas wind.
Can you elaborate on this? Are you saying that due to the weight of the wheel/tire combo the truck is downshifting to maintain speed?
I'll have 285/65/18 on a set of Evocourse installed on Monday... and do a lot of highway driving....
Steveray450
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Steveray450
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Lexus recommends towing in S mode NOT D (gear 5 or lower) on my 2015 LX. I tow around 5000-5,500 lbs...on and off road. I utilize the vehicles S mode ability to maintain an efficient and relative rpm etc on hills, flat highway, off-road up hills etc. The truck doesn't seem to have any issues with towing this weight what so ever and with stock set up.
Now adding 10-15 additional lbs of unsprung weight and/or 2 more inches in diameter, I have yet to experience that. Maybe TeCKis300 can help us out ...as it looks like he has experience pulling a pretty good size Airstream. Though Airstream are a pretty nice & friendly tow.
If I have to change gearing and brakes just because I want better looking (larger) tires...I will probably not go there.
Now adding 10-15 additional lbs of unsprung weight and/or 2 more inches in diameter, I have yet to experience that. Maybe TeCKis300 can help us out ...as it looks like he has experience pulling a pretty good size Airstream. Though Airstream are a pretty nice & friendly tow.
If I have to change gearing and brakes just because I want better looking (larger) tires...I will probably not go there.
I haven't towed anything of note. I did gears (4.88 on a 2009 - 6 speed) preemptively at the start of my build so I wouldn't be constrained by aero, tire, and weight choices I might make in the future.
I don't regret the gears at all, they get used every second I drive, and increase the agility of the truck immensely.
However, without gears, I think the tipping point is around 34" tires. the 8 speed in the 2016+ will do better on larger tires for sure, and probably could run 35s, it has a super low 1st. Many will run 34" on no gears and be fine with it, the engine in these trucks is really strong.
The big impact is the gearing loss due to increased overall diameter of the larger tires. Correct that generally at speed, one can downshift to find more gearing for conditions. Most of us towing on the upper end trailer weights that have large frontal area cruise in 4th gear.
The challenge is the lower gears and braking.
1st is only so low (on pre-2016s) and when you compromise gearing on that, there's no more gearing to reach for. The 5.7L is a brute and handles larger tires well. 34s on rigs not towing or built especially heavy can work. But when combining gearing loss, with high overall rig weights, maybe throw in some grade, and high elevation, it's a lot to ask.
I've done a 33.2" diameter tire with a 15k gross combined vehicle weight on stock gears. And while she did the dead, there were situations especially pulling out on grade and elevation in the Sierra Nevada's, where there is not enough gear to access the 5.7s powerband. Putting lots of load on the torque converter. Then not being able to power out of 3500 rpm in second without more acceleration.
Brake torque is also compromised. Will need more physical pressure on the brake pedal. Engine braking especially on super steep grades where even in second, the rig won't be able to maintain slower speeds and can start to feel a bit like a runaway train, so judicious brake use becomes very critical. The computer won't always allow first gear access unless well under 15mph, in some situations as it's likely trying to prevent the huge lurch.
I'm on the high end of rigs with ~15k combined rig weight, so take it with a grain of salt. Lighter rigs will generally do okay.
There's solutions for all this as I'm now on 35s. If re-gear and bigger tundra brakes interest you, look in my sig. Note this is applicable only to pre-2016s as post 2016s has gearing galore (1st gear on par with the 6-speed and 4.88s) and the larger brakes.
bloc
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For freeway driving the weight of the tire package is a negligible factor. What does matter is tire diameter, which impacts final gearing, and drag. Drag will partly be the large open tread blocks and thicker rubber of AT tires causing more rolling resistance, but for many of us a bigger factor is our aero profile. Even with stock bumpers and nothing on my roof, the 2”+ lift shielding less of the front tires, the A-arms hanging down more into the flow of air around the vehicle.. all that adds up to needing more horsepower to push my cruiser down the road at a given speed.
The stock gearing (meaning transmission and axle ratios) are designed with stock diameter tires to put the engine in an rpm range where it can produce a bit more horsepower than is needed to push a stock vehicle across the road and through the air at that speed, while not reviving too high, to save fuel.
Hypothetically let’s say we need 60hp to do that on a flat road at 70mph, and our engine can make 60hp at 1800rpm. Generally they won’t gear the truck so it cruises exactly on that fine line.. otherwise as soon as there were a slight incline or a head wind, the truck would have to downshift to maintain speed. They’ll typically gear the vehicle so the tallest transmission ratio can make, say, 70hp at our 70mph cruising rpm. This way the vehicle can respond to hills or winds or hauling light loads without impacting the driving experience too much.
So what happens when we lift the vehicle and add taller, higher rolling resistance tires?
The larger diameter deep lug tires both increase rolling and wind resistance, and effectively changes our gearing for the worse. Suddenly we need 70hp to push the vehicle down the road at 70mph.. and there is no overhead. The overhead is needed to prevent the TC unlocking when I get on the rolling hills along I40, or face a stiff headwind in the Texas panhandle.
So my plan for 4.3s will change the cruising rpm and as a result the horsepower available in 6th when cruising on the interstate.. plus get back the little bit of acceleration I lost going to a taller tire.
For a stock tire 3.90 geared US 2008-2015 we turn 1895rpm at 75mph. We only need 1817rpm to have the same ground speed with typical 285/70R17, and the engine naturally makes a bit less power at this lower rpm, taking away some of that overhead I mentioned. In my case going to 4.30s will require 2004rpm at 75mph, effectively making it easier for the engine to produce the required horsepower plus a little when needed, at that cruising speed. It should drive much closer to stock.
All of this is in the context of a stock body rig with a lift and larger ATs. Anything we do to further change aero or rolling drag changes things dramatically. Like a steel front bumper that uncovers much of our front tires and wheel wells. Or a RTT and traction boards on the roof. Or towing a large air stream.. which no one would really try to do in 6th anyway. But even in 4th, as Teckis tows his, there are benefits to “bringing back” some of the stock characteristics and balance. And his point about restoring torque and engine braking in the lower gears is a great example of that.
To be clear I’m not trying to tell anyone they have to regear to run 285/70R17s. I’m saying if you like the way the truck drives stock, and you really pay attention to things like the TC unlocking on the freeway (which is a sign that the drivetrain is just barely getting the job done at that speed), you’d probably appreciate a mild bump in gears to maintain those driving dynamics. Let alone if you go to 285/75 as I plan to.
Steveray450
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Steveray450
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Given what you just shared (which was extremely helpful...thank you!!) and assuming one would prefer to stay away from changing stock gearing... it seems that for folks that are towing on and off-road (gravel/dirt corrugated and bumpy)...a 265/70/17 tire for example...like say the Michelin LTX A/T2 or Defender LTX M/S (31.52 OD) both with low rolling resistance...durable, with some room to air down might be the smart money?
Not the best looking choice for sure...but most practical/functional choice?
Not the best looking choice for sure...but most practical/functional choice?
Everything is a balance and has trades. I wouldn't hesitate to run up to a 32 to small 33" spec diameter tire on stock gearing and brakes. Even towing as I've towed over 10k miles on a similar setup.
I personally would suggest not to run a 265. There's other trades like cornering and braking performance. The 200-series is a really heavy vehicle and needs tires larger than what 4Runners run. Unless using a narrow 7" wheel, I would have reservations about bead retention, especially when aired down.
At one point in time, Toyota had a recommended factory upsized tire fitment with Rock Warrior wheels - 285/70R17 that specs to 32.7" diameter. That would be a fine choice all parameters considered.
