2ND Gen 285/75/17 Fitment & Gears

After checking out the 285/75/17 3rd Gen thread and various other tire fitment threads I'm still not clear on how this size tire fits on a 2nd gen, specifically 2012 crew cab 4.0 liter.

I'm in the SE so ground clearance in sandy/muddy/rutted roads and trails is the priority over crawling capabilities. I'm currently running 255/80/17 Cooper ST Maxx on SCS Stealth 6 wheels with a Toytec 2.5" lift, SPC upper control arms and am looking at going with Toyo ATIII in either a 285/70/17 or 285/75/17. No cab mount chop yet but that's not a problem to address.

Who out there is running 285/75/17s on a 2nd gen and what did you have to do to get them to fit?

Gears are also going to happen as I tow a boat and camper as well. What gears are you running with 285s in either size?

 

ran 33’s. Now 35. 35 is more work.
Don’t know about something in the middle.

I think gearing differs dramatically between auto and manual.
It’s great finding posts on reviews that most of the time leave out what transmission the truck is, being misleading.

At 35” 6MT 4.88 I may be slightly overgeared. I don’t know if gearing to crawl is smarter than using a crawlbox for that. Most travel on any Tacoma is highway regardless if it wheels. Trails are over an hour away not 5 minutes.

to me, 3.73 is dumb. Audi B6 S4, A4 1.8T, B7 RS4 is around 4.10. 4.11 to be exact.
So why would one use 3.73. Old cop cars are said to be 4.10. And diesel trucks. Probably more.
But that also interacts with individual trans gears.
Some old Toyotas came with 4.10. So does Jeep Rubicon. So why run 3.73.

33 felt small. 35 feels like it wheels better. 33 was still capable. Too late to go back.

FJ is 4.30. Don’t know if they sell kits. 4.10 is findable.
Then you have 4.56 and 4.88. 5.29 is not available in beefed up axle from ECGS I believe.
Also depends what motor and motor setup you plan to run later.

only pain I have to deal with 35 right now is figuring out slight contact to tub at compression.

I think gears should help tow.
The lower the gears the less pinion teeth strength they say. 4.56 pinion I think has one more tooth than 4.88.

it seems every place recommends something different. One place says 4.56. Another 4.88. Another 5.29.
Potentially without knowing differences in vehicle. 2nd gen vs 3rd gen, 5AT, 6AT, 6MT is not the same.

had one place insist on 5.29. Vehemently against anything else. Meanwhile truck feels somewhat overgeared on 4.88, speed limited, and why folks report better city MPG than highway with it. Which normally is not the case. Sounds odd they would recommend that just because it’s what’s done on automatic 3rd gen’s which is completely different.
I may be wrong but 4.56 seems like a logical choice I haven’t heard large complaints of, based on tire size. Given it is shorter than what was available stock.

folks with FJ 4.30’s modded may regear after anyway as well.

you can always get spare diffs and take an incremental approach. There is pros and cons to that.
Pros? You have spare units to work on. Bench builds is cheaper than dropping a whole truck.
Cons? Each master kit is at least $1000 regardless of how you go about putting it in.

again may be different trans ratios. Co worker had 3rd gen 4runner TRD OR with factory 4.10 on 33’s said he liked it.
That is one of the only things that sketches me out about certain older Toyotas and potentially losing things by going back in time. 1st gen Tacoma for example is supposedly only 4spd in the Auto and 5spd manual instead of 6.

33 and 35 is common. Don’t know many folks running in between sizes.

cab mount you can start with a chop and see what it works with. That’s cheaper than a relocate. Relocate is if you’re for sure going to run big tires at some point and want the most clearance possible. It can always be done later.
At this point my CMR is behind the tub so it could’ve been overkill. Oh well too late.

 

Good point on the tranny info. Mine is an auto in a crew cab, short bed TRD Sport. Not sure what the factory ratio is though. While it'll pull a 20' boat and camper, I don't think a little lower gear would hurt. Especially when there're hills involved. I'm leaning towards 4.56, but that's based on little other than internet perusing.

 

I don’t know if shorter gears has an engine braking effect to reduce MPG

grimjeeper has calculator

auto you might be able to get away with taller gearing

don’t know if there’s a way to know for sure. Like experiments recording and calculating what highway speed and RPM is ideal for MPG.

highway 65-70 I’m around 2700RPM in 6th which probably could be lower. Given it’s a torquey low end motor and more RPM usually means higher fuel fuse.

edit: drove on the highway. Felt like it lost power at 2500rpm and needed more gas. That tells me above 2500rpm would be the sweet spot. And that’s not including things like wind, rain, loaded with more gear, more armor, or towing.
So maybe above 2500rpm is the sweet spot and 4.88s fine. FJ 6th might drop 6th by 150rpm. So might manual trans from 3rd or 4th gen.
Grimmjeeper calculator shows from 4.88 to 4.56, RA60F, 70mph RPM would drop approximately 150rpm which could be good, bad, or indifferent.

however it shows switch to RC62F on 4.88 would result in 400rpm drop in 6th @70 down to 2328rpm which sounds like too low of an RPM. Even more on 4.56.

maybe that’s why 5.29 seems more popular on 3rd gen. 5.29 35” 70mph RC62F says about 2500rpm.

most MPG I’ve had was stock. Modded may need more RPM to keep it moving.
Can always borrow a stock truck from dealer to test and see what RPM at what speed like what it turns at 70.

 

I’ve always used the method of grabbing one lower gear for every +1 in tire size. Examines le. Stock is 30.5 and you got 285.(32.7) your choice would be 430 or 456 , 488s if you really want a big change.

 

Running 285/75/17 33.9 with a 3.5 toytec lift jba UCAS, and 1.25 spidertrax spacers. I do rub when off roading, need to do cmc and fender chop. I get pretty decent gas milage with no regear. I dont tow or have any excessive weight.

 

My 2015 Tacoma TRD Sport (2WD) DCSB daily driver.

Suspension:
Front: Bilstein 5100 Shocks, OME Lift Springs (Old Man EMU), SPC UCA
Rear: Bilstein 5100 Shocks, Add-A-Leaf

Wheels & Tires:
Method Racing MR305 NV l17x8.5 +0 offset, Toyo Open Country AT 3 285/70/17

Revolution 4.56 gears and Eaton eLocker to be installed in June.

 

Sounds like solid logic. Thanks

Great data point. What wheels are you running?

That's a very sharp setup. How do you like the Toyos?

 

Toyo open country at3

 

2007 4x4 4.0
285\75\17 Wrangler Duratrac RT
FJ wheels (15mm offset) .75" Bora spacers, cab mount chopped as well as some plastic fender, pinch Weld was beat back also.
Total Chaos UCA, Toytec 3" lift up front & Wheelers add-a-leaf HD leaf pack 2.0 Icon shocks.
Stock 3.73 gears currently avg 14.5 mpg.

Flexed at home, no rubbing issues. I'm not certain I won't find some rubbing once I get it off-road, minor if any I suspect.

 

That's what I've been looking for. Nice setup.

 

I have afe throttle body spacer, drop in k&n, flowmaster outlaw exhaust. No regear that I know of got really nice low torque.