jonb1032

Living in Flat Florida, in a 2 door Rubicon with 315/70/17, is 4.10 always better. will low range be to low with no crawl trails? but will mostly be used as daily driver with occasional trail rides. currently have a 3.73 jku and it seems to work just fine...

Desert Fox

If you are only using your JKR as a daily driver with occasional light duty trail rides I think you will find that your 3.73 gearing will meet your expectations. DF

karls10jk

If you run into mud on your light trails where you'd need more spin to your tires then the 4.10 would be a better option. In theory, the 3.73 would be better for a DD in regards to highway mileage. If you plan on adding ridiculous weight then the higher gear may be a better option.


So to answer your question- it depends on environmental factors beyond what the internet can predict.

1996cc

Huh? 4.10's would spin your tires slower than 3.73's with everything else being the same (tire size, gear ratio, and RPMs)

silverbullet88

You'd have more power to spin the tire's with the 4.10's rather than the 3.73's. Once it starts to bog in the mud/ snow/steep hill it won't want to spin the tire's. The 4.10's and 'higher' or up will spin the tire's better.

With my 4.10's and 315/70r17 the only way I can spin the tire's once I'm stuck is using 4low(making the ratio numerically lower 4:1). Just don't have the grunt!

ReadyToMount

The tire would spin the same with either gear ratio. Rolling distance does not change unless you change tire size. Gearing will increase or decrease driveline speed depending on which way you are going. 4.10 will cause around a 10% increase in rpm's of the drive shaft in relation to the axle shaft. Engine speed goes up with higher number gearing. Typically you want to increase gearing 1/10th for each inch of tire. So if stock was 32" and you go to 35" to keep your engine in the sweet spot you would go from 3.73 to 4.10 gearing. If you have the Pentastar then leaving it at 3.73 on 35's is usually fine. The extra gearing is better for city driving, off-roading, towing etc. But as others mentioned may not be necessary for your situation given the cost involved.
I'll stop the rambling now.

silverbullet88

I wouldn't say the sweet spot for 35's is 4.10's with the 3.8L! Unless you like going 60mph up hills on the freeway lol

ReadyToMount

I did not see what the OP had. That is why I referenced the Pentastar. The 3.6L is a much better option for the JK. Given the example I provided it would be essentially the same for any engine. 3.6 or 3.8 That is why the 3.6L JK's have different gearing options than the 3.8's. The Rubicon 3.8 came with 4.10 gearing and when the 3.6 was released it had enough power to offer an option of 4.10 and defaulted to 3.73 as standard.

jonb1032

I was referring to the 3.6.. Looking at a 2 door rubicon, the 4.10's are a little harder to find. was thinking that if didn't need the super low crawl speed, i.e. No rocks that maybe a 3.73 would actually be better. But with 90% street and highway the 4.10 with 35" would be the better option

zstairlessone

I have to say the difference between a 4:10 and 3:73 is minor compared to the 4:0 and 2:72 low range difference. When not in 4-low (where you need to be to lock 'em up) in flat no rock climbing Florida the 3:73 may be the best choice of the two with tires that aren't too tall.