This!
We are doing quite a few 16+ 3.90 regears as of late. We keep the complete diffs in stock, open or ARB locked.
To re-gear or not to re-gear?
- Thread starter BetoLC
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This!
We are doing quite a few 16+ 3.90 regears as of late. We keep the complete diffs in stock, open or ARB locked.
CharlieS
GOLD Star
I have a set of 3.9 factory gears from a '13 and a rear pumpkin off my '16 if anyone needs them (I have a front clamshell too, but not sure if it is useful for someone regearing). Still headed back from lcdc, but will be home this weekend. Drop me a line.
Agree on the gears. Supercharger is fantasy land for us, we’re really reluctant to modify the engine as we want it for every single possible mile it can take us.
kcjaz
SILVER Star
I came out of LCDC this year convincing myself I want re-gear/lockers sooner than latter. I have always thought I'd go up one more tire size when my current tires need to be replaced (next set will be 285/75/R17, don't want to mess with 35s or larger) and ultimately add drawers and LRA (12 or 24 gallon), then lockers/gears. After reading this thread and talking to folks at LCDC, I was thinking 4.88s (2013 LC, 6 speed). I called Slee today to get an idea of cost and logistics. I mentioned 4.88s and the guy I was speaking to said they have never done 4.88s in a 200 and he wouldn't recommend it, or rather said he didn't think 4.88s were necessary and may adversely impact highway performance at higher speeds. I don't really tow on the high way very much and at my current weight, the only time I feel I want lower gearing is steep offroad descents. Really, the situation was most often when 4LO 1st was too low but 2nd was too high. I often would go 1st gear with a little gas going down hill. The 200 ahead of me with 4.88s would be in second with no gas.
I get that with 285/75/R17's 4.3's would really be all I need to get me back to stock ratio (actually, if I did the math right, about 2% lower) and that is probably really all the guy was saying, but 4.88s still seem like the way to go given that I know I will be pushing 8000lbs and would still like to tow occasionally. I'm surprised Slee is saying they don't have 200 owners asking for that.
I get that with 285/75/R17's 4.3's would really be all I need to get me back to stock ratio (actually, if I did the math right, about 2% lower) and that is probably really all the guy was saying, but 4.88s still seem like the way to go given that I know I will be pushing 8000lbs and would still like to tow occasionally. I'm surprised Slee is saying they don't have 200 owners asking for that.
It's driver's preference.
I've never felt 'held up' by the 4.88s on the freeway, and they are absolute gravy on the slow speed maneuvers you describe. I don't tow (though I hope to play around with a rental trailer next year).
I figured with aero losses, tire losses, and a built truck, I wanted more effective gear than stock. I'm not optimizing for whatever tradeoffs Mr T was after with the initial ratios anyhow.
bloc
SILVER Star
4.56.
And find someone’s truck to drive.
When you look at the actual numbers 4.88 is going pretty far, and turning a lot of revs on the freeway. I do understand feeling 4.3 returning to stock-ish ratios isn’t quite enough, but .56 puts you in a good mid range between the two. OTOH it would suck to feel you didn’t go far enough after all that cost… personally after 20 years of online car tech discussion I’ve seen a whole lot of “bigger is better” mentality. Way less here than many boards but still, I feel that is a factor in .88s on our rigs, unless we are talking a vehicle that lives in Africa.
Speaking for myself, definitely didn’t do it for the braggies.
4.56 might be a good choice, not sure that there’s a set to be had in that ratio, but it wouldn’t hurt to consider.
4.56 might be a good choice, not sure that there’s a set to be had in that ratio, but it wouldn’t hurt to consider.
bloc
SILVER Star
Yeah I didn’t mean bragging rights.. just that it’s easy to get wrapped up in bigger numbers being better. I’ve done that my fair share of times with many other projects.
I just assumed the big gear companies offered them.. pretty sure it’s available in genuine toyota from other markets. @bjowett could probably spit out some part numbers from memory..
I see more clearly what you’re saying.
For me it was having a canvas big enough for whatever amount of paint I was going to need to add, plus spillage. And allow for plans to change or grow without it being an issue.
Doing the gears early in the build allowed for all options to be considered, and provide benefit ever rpm on the journey.
I didn’t want to get on the slippery slope where all the incremental changes suddenly added up to a built truck that was no fun to drive.
Of all the mods, gears = grins.
I’ve been seriously debating this as well after returning from a 3 week trip towing a 4500 pound camper. I have the 8 speed and 285/70/18 tires, practically the same size you’re looking at plus all the other heavy gear and mods, truck weighs 8200 when fully laden including 400 pound tongue weight. Mine maintains highway speeds fine but any incline and I’m feeling the weight, steep stuff like mountain passes are terrible… prolonged RPMs in the 4-5k range to maintain 45 mph in 2nd gear, 3rd will slowly drop mph until you’re back in 2nd winding out the tach. I can also relate to your comment about steep descents.
All this to say, I don’t know how aggressive I want to go but I can tell you it will get more noticeable as you gain weight and lose aero. For me, contemplating this is not easy because If you’re adding a front locker this will likely be the most expensive single modification you do while also dramatically changing the driving characteristics.
My gut says go big on 4.88s but for some reason I’m really reluctant for no discernible reason.
Is there a way to calculate what my rpm’s would be at different speeds with different gearing?
You may be better off doing some of your mods first, especially if you aren’t doing bumpers and losing the aero, you may find that less gear is more to your liking. I don’t daily mine and I will tow a lot with it so my max highway speed will rarely exceed 65-70, if i routinely was running 75+ this would factor into my decision bigly.
Thread 'Definitive 200-series Gearing Reference'
Definitive 200-series Gearing Reference - https://forum.ih8mud.com/threads/definitive-200-series-gearing-reference.1043543/
kcjaz
SILVER Star
The math is fairly easy. An online tire size calculator will give you the wheel revs per mile for your tire size. At 60 mph this is equivalent to wheel RPM. Take wheel RPM times differential gear ratio times transfer case gear ratio times transmission gear ratio to get engine RPM. Transfer case gear ratio is 1.0 in high range. Google will tell you the gear ratios for your transmission and stock differentials by model year.
kcjaz
SILVER Star
Link isn’t working for me.
A few points that might help you make some trades.
- Climbing is a HP game. There's no real way to avoid RPMs to make power, because by definition HP is the product of RPM and torque, and is what does the work to pull you up a hill. Dyno provided to show where the 5.7L makes its power.
- Gearing does not make HP. It only optimizes access to the powerband. Critical points to consider is maximizing bottom end gearing to get off the line, while balancing top end gearing for efficiency. Also considering often used speeds and load points for things like cruise or towing. Worthwhile to note that the 8-speed you have, already has an overall 1st gear ratio that's equivalent to a 6-speed modded with 4.88s!
- That said, 3.9s to support the 285/70R18 tires would make for a nicely tuned combo. With gearing that 6-speed owners would be envious of.
Relevant tables copied from the thread @lx200inAR linked.
This is very helpful, thanks a ton!
While I understand gears don’t equal HP your comment about ‘access to the power band’ is a far better way to sum up my issue. This is precisely why I can’t maintain speed while climbing, once hitting 5k in second shifting into 3rd is 2.5k’ish which is short of the power band.
I believe the 3.9 are Toyota gears so that’s another selling point for them for me.
If you have a light-ish trailer and aren’t going 35s or larger I’d get 4.30 gears. It puts you back to stock and won’t compromise MPG
I have 4.88s and on 34s they are overkill. Fun, sure. I definitely feel more drag coming to a stop light and I turn more RPMs on the highway. MPG is about 13 on the highway and around town, if I’m east on the throttle. 4.30 would be a better highway gear
When towing, I have found I can often (but not always) maintain 5th gear now with 4.88s. And that helped MPG by a few % but nothing huge. But when I’m on a slight incline I have to go down into 4th and now I’m turning 3700 RPMs or more. In those cases I wish I had 4.30 gears… but then I probably couldn’t hold 5th with them so it’s a trade off.
4.88s does make it easy to pull a 6000# trailer and 8000# rig over an 11k mountain pass doing 55 mph in 3rd gear. And with the ECT PWR button and no trailer it’s like a go kart from a stop light. So there is that
FWIW I’ve found my fluid temps run hotter now when towing… A/T and engine oil will run around 212 whereas they used to sit closer to 200 on 3.90 gears.
If all you want is improved 4Lo craw ratio is look around to see if anyone has a way to change out the transfer case gears. That would give you the best of all worlds
Also… you don’t need lockers, but if you do decide to add them the rear is more important than the front. There are better ways to spend the $1500 per locker TBH but I know it’s a “while I’m in there” thing.
I have 4.88s and on 34s they are overkill. Fun, sure. I definitely feel more drag coming to a stop light and I turn more RPMs on the highway. MPG is about 13 on the highway and around town, if I’m east on the throttle. 4.30 would be a better highway gear
When towing, I have found I can often (but not always) maintain 5th gear now with 4.88s. And that helped MPG by a few % but nothing huge. But when I’m on a slight incline I have to go down into 4th and now I’m turning 3700 RPMs or more. In those cases I wish I had 4.30 gears… but then I probably couldn’t hold 5th with them so it’s a trade off.
4.88s does make it easy to pull a 6000# trailer and 8000# rig over an 11k mountain pass doing 55 mph in 3rd gear. And with the ECT PWR button and no trailer it’s like a go kart from a stop light. So there is that
FWIW I’ve found my fluid temps run hotter now when towing… A/T and engine oil will run around 212 whereas they used to sit closer to 200 on 3.90 gears.
If all you want is improved 4Lo craw ratio is look around to see if anyone has a way to change out the transfer case gears. That would give you the best of all worlds
Also… you don’t need lockers, but if you do decide to add them the rear is more important than the front. There are better ways to spend the $1500 per locker TBH but I know it’s a “while I’m in there” thing.
kcjaz
SILVER Star
For those who have regeared, are there any horror stories out there as far as gear failures or other mechanical issues associated with the regearing?
you won't save back the gears investment in fuel savings. Quelle horror!
kcjaz
SILVER Star
wait what????
nwfl4runner
GOLD Star
2010 with 4.88s and no issues whatsoever.
