Low Gears

Trailabite

Well-Known Member
Messages
266
Anyone running gears lower than 5.38's and driving on the street? Do you love it or regret it?
 

TBItoy

Well-Known Member
Messages
10,176
I ran 5.71s and 5.29s in Toyotas with 38-39" tires.

one had a TBI v8 with a 700r4 swapped in.

I think gearing to your tire size to get it close to "stock" makes a huge difference in how street-driveable a vehicle is.

Also, the gear reduction in the axles takes away some of the effect of torque on the drivetrain/chassis/suspension

ie the rig with 5.71s didn't have as much torque lean vs when it had 4.10 gears. (it was linked f/r on soft coils with no sway bars)
 

ridered3

Not Rigless
Messages
4,959
How much/often do you plan on driving?

Also what types of roadway (highway vs interstate vs stop & go) will you be driving?
 

Trailabite

Well-Known Member
Messages
266
This is for my Jeep/Truck project. It's mostly going to be for rock crawling but I will occasionally drive it to work on a Friday or to take the wife to Cold Stone for some ice cream lol. Maybe, get on 400 for one or 2 exits. I'm looking at running 6.17's maybe 7.17's with 42" tires. With the over drive gearing of the 700r4 running at 55mph doesn't seem to be too bad according to the calculators.
 

84mallcrawl

Well-Known Member
Messages
209
I have ran d60s and 5.13 with 38's powered by a 22r. 55mph on flat ground in 4th was all it would do. I would think that any v8 auto would push far better than that
 

nvrenuf

Well-Known Member
Messages
76
I run 5.86's and 43's (no o/d) in my Blazer but it's not a daily driver. I do street drive it occasionally and it's no big deal. Don't get psych'd out by the numbers, with a 40"+ tire you need a lot of gear to be proportionate again. @tvguy used to have a truck with 6.17's and 35" Boggers, he drove it all the time locally and it felt perfectly normal riding around.

For those that may argue about pinion size, you can always do a D70 gear conversion in a D60 - even when it's small it's still big.

One thing to seriously consider is high quality synthetic oil to combat break down from "high speed" use. I say high speed because realistically Dana, etc never intended for gears like this to be run in anything being driven normally.
 

CHASMAN9

Hardline OG Administrator
Staff member
Messages
7,700
This is for my Jeep/Truck project. It's mostly going to be for rock crawling but I will occasionally drive it to work on a Friday or to take the wife to Cold Stone for some ice cream or San Diego for some seafood. lol. Maybe, get on 400 for one or 2 exits. I'm looking at running 6.17's maybe 7.17's with 42" tires. With the over drive gearing of the 700r4 running at 55mph doesn't seem to be too bad according to the calculators.

Fixed
 

Trailabite

Well-Known Member
Messages
266
I ran 617 with a 350/205 with 44’s in my Jeep . For the mountain but I did drive it on the road some :dblthumb:
How hard did you drive it on the trails? After more research it sounds like the pinion is small, as in less contact with ring gear and people seem to break a lot. I may just stick with the 5.38 gears, that seems to be a common setup.
 
Last edited:

tallnate

Well-Known Member
Messages
486
How hard did you drive it on the trails? After more research it sounds like the pinion is small, as in less contact with ring gear and people seem to break a lot. I may just stick with the 5.38 gears, that seems to be a common setup.
Yeah for gear strength, I wouldn't run anything lower than a 5.38. There's still 8 pinion teeth and 43 ring gear teeth on a 5.38 where as a 6.17 pinion only has 6 teeth and 37 ring gear teeth. So obviously, the lesser amount of teeth on the pinion puts a larger amount of stress on the ring gear during load.
 

nvrenuf

Well-Known Member
Messages
76
The 5.86 tooth count is 7 & 41, probably never feel the difference between these and 6.17's
 

extremetownie

Well-Known Member
Messages
427
I am pretty sure i would break a 6.17 coming up my drive way. I personally think a 5.38 would be a much more reasonably option.
 

Moto85

Bham, AL
Messages
176
I drove mine to and from the trails for a few years with 5.86 gears, before I got sticky tires. I have no real HP though, The pinions are small with that deep of gears and it would probably eat them up if I had more power. I beat the snot out of it every time and always made it home. Some trips would be 2-3 hours one way...
I drove all back roads, and stayed off the interstate.
 

crawler 129

Roll Tide
Messages
624
How hard did you drive it on the trails? After more research it sounds like the pinion is small, as in less contact with ring gear and people seem to break a lot. I may just stick with the 5.38 gears, that seems to be a common setup.
It’s no bouncer but It was beat on it plenty hard . Jeep was built around 06 most people I knew then ran 617. With that being said what I’ve learned now and that I make more money now an atlas and higher gears would be the way I would do it.
 

ttocsshit

New Member
Messages
3
Anyone running gears lower than 5.38's and driving on the street? Do you love it or regret it?
Ive run 6.17s 39 krawler with a 4.0 AW4 trans combo in a Cherokee 75mph on the freeway no problem roughly 26-2700rpm the OD ratios are very close between a 700r4 and aw4
 

ttocsshit

New Member
Messages
3
Yeah for gear strength, I wouldn't run anything lower than a 5.38. There's still 8 pinion teeth and 43 ring gear teeth on a 5.38 where as a 6.17 pinion only has 6 teeth and 37 ring gear teeth. So obviously, the lesser amount of teeth on the pinion puts a larger amount of stress on the ring gear during load.
the tooth count is not as big of a deal At any given point you only have"x" amount of contact A 9 nine 6.20 pinion is like 6 tooth but the teeth are fat compared to a higher count pinion i have smashed my 400 plus HP moonbuggy into backdoor smoking sticky trep 42s full of water with Dana Spicer 6:17s ive shattered spidertrax units {old ones} 300M rcv 35 spline inners but no R&Ps
 

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