The 8-Speed Transmission was Designed for Bigger Tires

[Somebody]

I know, that's a bold statement. But let's talk about this.

Along with other members, I have lodged my complaints with the 8-speed transmission. It shifts abruptly; first gear is too low; it hunts between 1st and 2nd after coasting, etc. All of these complaints were based on a completely stock setup.

I recently upgraded my 2016 LC to 285/65R18 KO2s. Above all else, the most dramatic thing I have noticed is that the 8-speed transmission seems substantially more at home with larger (and heavier) tires.

With stock tires, I would be shifting to second before I cleared the intersection of a 4-way stop. The acceleration was touchy and the shift to second was too hard. Now, the transmission feels completely at home. First gear has a purpose; it seems perfectly geared for the larger tires. Acceleration is smooth but not jerky. The truck also shifts at a slightly higher speed, which seems to reduce the punch when shifting to 2nd. The heavier tires may also mitigate some of the shift harshness. Candidly, I still get a little hunt between 1st and 2nd after coasting, but it seems less common now.

On a related (but off-topic) note, I enjoy the brakes better with larger tires, too. On stock tires, they were just too grabby--especially as you approached a full stop. With the larger tires, the brakes seem much more balanced.

I recall from reading elsewhere on this forum that the LC is shipped with larger tires on 17" wheels in other countries. But I also recall reading that the 8-speed was only introduced in the U.S. market. So while it may be pure coincidence, I'm going to go out on a limb and suggest the 2016+ LC was actually designed for a larger-diameter tire than stock. I'll even speculate that the ever-present quest for better fuel economy may have dictated smaller stock tires but that the engineers knew many buyers would opt for larger tires later.

Maybe it's all in my head, but I'm interested if others agree.

 

[allan man]

I doubt it...im sure the LC being toyotas flagship the engineers have tested it over and over in different countries in the harshes condition and looked at every aspect.

Just my 2 cents. Btw congrats on the new shoes.

 

[Andreas P]

I know, that's a bold statement. But let's talk about this.

Along with other members, I have lodged my complaints with the 8-speed transmission. It shifts abruptly; first gear is too low; it hunts between 1st and 2nd after coasting, etc. All of these complaints were based on a completely stock setup.

I recently upgraded my 2016 LC to 285/65R18 KO2s. Above all else, the most dramatic thing I have noticed is that the 8-speed transmission seems substantially more at home with larger (and heavier) tires.

With stock tires, I would be shifting to second before I cleared the intersection of a 4-way stop. The acceleration was touchy and the shift to second was too hard. Now, the transmission feels completely at home. First gear has a purpose; it seems perfectly geared for the larger tires. Acceleration is smooth but not jerky. The truck also shifts at a slightly higher speed, which seems to reduce the punch when shifting to 2nd. The heavier tires may also mitigate some of the shift harshness. Candidly, I still get a little hunt between 1st and 2nd after coasting, but it seems less common now.

On a related (but off-topic) note, I enjoy the brakes better with larger tires, too. On stock tires, they were just too grabby--especially as you approached a full stop. With the larger tires, the brakes seem much more balanced.

I recall from reading elsewhere on this forum that the LC is shipped with larger tires on 17" wheels in other countries. But I also recall reading that the 8-speed was only introduced in the U.S. market. So while it may be pure coincidence, I'm going to go out on a limb and suggest the 2016+ LC was actually designed for a larger-diameter tire than stock. I'll even speculate that the ever-present quest for better fuel economy may have dictated smaller stock tires but that the engineers knew many buyers would opt for larger tires later.

Maybe it's all in my head, but I'm interested if others agree.

Totally agree with you. I even noticed a dramatic improvement in my 2016 LX behavior especially in first and second gears once I changed to 33" tires. Even highway manners improved. For some reason, Toyota/Lexus decided not to change to bigger tires. The stocks look too small for the size of the body.
I believe the 8-speed has been introduced everywhere, except Australia.

 

[TeCKis300]

Nice! The gearing of the lower gears of the 8-speed are definitely in the aggressive part of the spectrum. To the tune of 20% lower gearing than the 6-speed. Or said another way, equivalent of stock 6-speed gearing with 4.88s, on stock wheels! The 5.7L doesn't really need this low of gears for unloaded work. So it's incredibly hard to not translate even the slightest of shifts, shocks, and transitions into something the passenger can feel. Some load is good! And you'll still have great gearing for larger tires and bigger loads! Glad it smoothed out things for you.

 

[danielb]

I recently upgraded my 2016 LC to 285/65R18 KO2s.

You mentioned better shifting, better braking. How about ride quality and road noise? I know it's subjective but what is your impression of the KO2s vs stock in that regard?

 

[OregonLC]

Not to be too technical here, but don't confuse braking feel with braking performance. That the brakes feel over boosted with stock sized tires is different than better braking performance with larger tires. The tire radius is the leverage arm acting on the brakes. The longer this radius, the less effective the brake is on slowing the vehicle. Also potentially affected is VSC and ATRAC performance.

Link

 

[Somebody]

You mentioned better shifting, better braking. How about ride quality and road noise? I know it's subjective but what is your impression of the KO2s vs stock in that regard?

I really enjoy the KO2s, and this is coming from someone that drives 95%+ in the city. Tire noise increase is present but negligible. I'm a stickler for fixing rattles and other noises, and I have no concerns with these tires. The ride is firmer, but the truck wallows less on uneven roads. It's tough to describe, but the stock tires have a tendency to feel squishy which translates to a sway feeling when you drive on poor streets. The stiffer KO2s don't give that sensation. The truck feels more planted--like a sportier suspension.

 

[Somebody]

Not to be too technical here, but don't confuse braking feel with braking performance. That the brakes feel over boosted with stock sized tires is different than better braking performance with larger tires. The tire radius is the leverage arm acting on the brakes. The longer this radius, the less effective the brake is on slowing the vehicle. Also potentially affected is VSC and ATRAC performance.

Link

View attachment 1638148

Sorry if that was misleading. To rephrase, it felt like 100% of the braking performance occurred with 50% of available pedal travel with stock tires. The result was that the brakes felt overly sensitive or grabby. With the larger tires, braking performance undoubtedly decreases. But the overall pedal feel seems more balanced. I suspect the brakes are more than capable of reaching maximum brake performance with either set of tires.

 

[OregonLC]

With 35s on my 100, it is hard to achieve ABS activation at highways speeds due to the lack of mechanical leverage. This is not the case with our stock LX 470. I've not run 35s on a 200 so I can't comment on whether the system can achieve maximum performance at that diameter. At some point you run out of available pedal travel, available force... or available road.

 

[linuxgod]

@OregonLC I can't speak to 35s but I can confirm it's not that hard to engage ABS on 34s on dry pavement. I did perform the VSC reset procedure after adding my lift though it knows nothing of tire size.

 

[Dan Higgins]

I really enjoy the KO2s, and this is coming from someone that drives 95%+ in the city. Tire noise increase is present but negligible. I'm a stickler for fixing rattles and other noises, and I have no concerns with these tires. The ride is firmer, but the truck wallows less on uneven roads. It's tough to describe, but the stock tires have a tendency to feel squishy which translates to a sway feeling when you drive on poor streets. The stiffer KO2s don't give that sensation. The truck feels more planted--like a sportier suspension.

As for the feel of the KO2s (285/65R18), I love mine. Mine have seen ~35K miles now and the tread still looks great. Lots of highway driving. In fact I'm in the midst of a road trip from Denver to SD. Now in Palm Springs and heading to Sedona next week. And I was thinking to myself how comfortable this tires are at freeway speeds. (Also nice to jump off the highway for a little exploring with confidence.)

I can also echo what @Somebody said - that in comparison the stock tires feel "squishy" or less planted. It was especially noticeable this year when I put the stock-size snow tires on. The fact that my truck now has a minor suspension upgrade/lift and weighs ~6500# probably contributes to this feel when the snow tires are on. The KO2s (E-rated) feel much better.

 

[baldilocks]

I'm an 80 series owner who usually stays in the 80 section. I wish I had problems like too much torque down low and brakes that feel too powerful. These issues are what my dreams are made of.

 

[Chrisleduc1]

I'll chime in now that I have swapped out the stock 21s on my '18 for a set of LT285 60R20s.

I drove the stock setup for about 1400 miles, over a period of about 10 weeks. A good combination of neighborhood storage and go, as well as 70-80 on the highways.

I have two immediate observations after about 30 miles today.

1. These Defenders have vastly improved the ride. The feel of small imperfections in the road has been greatly reduced.

2. Shifting has greatly improved at 1st/2nd gear rolling speeds. I hadn't checked the speedo, but I had noticed that after accelerating from a stop in a parking lot, and taking my foot off of the gas to cruise at a relatively slow speed through the parking lot, I would then have a hard and delayed shift once I gave it some gas again. The feel was a lot like a transmission slipping. I had learned how to manipulate the throttle to reduce the effect, but it was always there. After installing these new, larger tires, that issue seems to be gone. I'll need to do some additional driving over the coming days, but it seems that the OP's hypothesis is correct.

 

[alsation]

I'll chime in now that I have swapped out the stock 21s on my '18 for a set of LT285 60R20s.

I drove the stock setup for about 1400 miles, over a period of about 10 weeks. A good combination of neighborhood storage and go, as well as 70-80 on the highways.

I have two immediate observations after about 30 miles today.

1. These Defenders have vastly improved the ride. The feel of small imperfections in the road has been greatly reduced.

2. Shifting has greatly improved at 1st/2nd gear rolling speeds. I hadn't checked the speedo, but I had noticed that after accelerating from a stop in a parking lot, and taking my foot off of the gas to cruise at a relatively slow speed through the parking lot, I would then have a hard and delayed shift once I gave it some gas again. The feel was a lot like a transmission slipping. I had learned how to manipulate the throttle to reduce the effect, but it was always there. After installing these new, larger tires, that issue seems to be gone. I'll need to do some additional driving over the coming days, but it seems that the OP's hypothesis is correct.

Pics if you have them. We’re you able to use the oem wheels?

 

[Willy beamin]

I crested a hill on the interstate a few weeks ago and had to immediately mash my brake pedal. ABS did its job and allowed me to maneuver off the pavement into the median to avoid a collision. Im running 6 speed tranny, stock rotors, TRD pads and 35's. No negative impact on ABS with this particular set up.

 

[Moose545]

@Willy beamin what year did the 200 series switch up, 16'? I'd be looking at an early 200 anyhow but I'm just curious, this entire conversation has bits of info I never thought of and make sense.

 

[krice118]

@Moose545 yes the 8speed was introduced in 2016.

 

[Willy beamin]

I’m not sure

 

[Chrisleduc1]

Pics if you have them. We’re you able to use the oem wheels?

See the 200 Picture Thread, or Black Onyx PVD stock 20s and Defender LT285/60R20s - ClubLexus - Lexus Forum Discussion

 

[Rodwilsonsr]

I know, that's a bold statement. But let's talk about this.

Along with other members, I have lodged my complaints with the 8-speed transmission. It shifts abruptly; first gear is too low; it hunts between 1st and 2nd after coasting, etc. All of these complaints were based on a completely stock setup.

I recently upgraded my 2016 LC to 285/65R18 KO2s. Above all else, the most dramatic thing I have noticed is that the 8-speed transmission seems substantially more at home with larger (and heavier) tires.

With stock tires, I would be shifting to second before I cleared the intersection of a 4-way stop. The acceleration was touchy and the shift to second was too hard. Now, the transmission feels completely at home. First gear has a purpose; it seems perfectly geared for the larger tires. Acceleration is smooth but not jerky. The truck also shifts at a slightly higher speed, which seems to reduce the punch when shifting to 2nd. The heavier tires may also mitigate some of the shift harshness. Candidly, I still get a little hunt between 1st and 2nd after coasting, but it seems less common now.

On a related (but off-topic) note, I enjoy the brakes better with larger tires, too. On stock tires, they were just too grabby--especially as you approached a full stop. With the larger tires, the brakes seem much more balanced.

I recall from reading elsewhere on this forum that the LC is shipped with larger tires on 17" wheels in other countries. But I also recall reading that the 8-speed was only introduced in the U.S. market. So while it may be pure coincidence, I'm going to go out on a limb and suggest the 2016+ LC was actually designed for a larger-diameter tire than stock. I'll even speculate that the ever-present quest for better fuel economy may have dictated smaller stock tires but that the engineers knew many buyers would opt for larger tires later.

Maybe it's all in my head, but I'm interested if others agree.

I know it's been a while since this post...
I traded in my 2011 6 speed for a 2016 8 speed. The shifting from 1 to 2 is driving me bananas. it's like a hesitation kinda skipping feeling. I had 2 dealers look at it and the latest software update. Nothing has changed. both dealers say everything is fine.
All the other gears feel just fine.

Are you still finding going with the larger tire resolved the 1 to 2 shifting debacle?
My stock tires are 285/60/R18. It looks like the 285/65R18 KO2's are about an inch larger in diameter compared to the stock tires?

Thanks
Rod