Tires VS Engine

[Henrix123]

2019 Sahara 2.0 & I've read through lots of threads regarding regearing when going to 35s. Not much talk on the additional torque of the 2.0 over the V6 as a factor of weather to re-gear or not. Has anyone driven both engines with 35s & stock gearing?

Not concerned with it being underpowered when wheeling since it's mainly a DD.

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[AnnDee4444]

2019 Sahara 2.0 & I've read through lots of threads regarding regearing when going to 35s. Not much talk on the additional torque of the 2.0 over the V6 as a factor of weather to re-gear or not. Has anyone driven both engines with 35s & stock gearing?

Not concerned with it being underpowered when wheeling since it's mainly a DD.

I haven't driven both engines with 35s, but I can graph out the road force for each scenario. I think that because of the 2.0's lower redline and higher torque, there isn't as much of a need to re-gear (at least in Rubicons). The biggest issue seems to be the loss of a usable 8th gear (or 6th for the manual). For a good comparison, I calculated that the 3.6 Rubicon auto has about 382 pounds of road force at 75MPH. Both scenarios you have described are about 290-300 pounds at 75 MPH, which may not be enough to use 8th gear.

This graph below is with 35.0" tall tires with 1.1" of tire sag, 3.45 differential ratio, & 17% drivetrain loss.

Solid = 2.0
Dashed = 3.6
​

 

[Henrix123]

I haven't driven both engines with 35s, but I can graph out the road force for each scenario. I think that because of the 2.0's lower redline and higher torque, there isn't as much of a need to re-gear (at least in Rubicons). The biggest issue seems to be the loss of a usable 8th gear (or 6th for the manual). For a good comparison, I calculated that the 3.6 Rubicon auto has about 382 pounds of road force at 75MPH. Both scenarios you have described are about 290-300 pounds at 75 MPH, which may not be enough to use 8th gear.

This graph below is with 35.0" tall tires with 1.1" of tire sag, 3.45 differential ratio, & 17% drivetrain loss.

Solid = 2.0
Dashed = 3.6
​

Not being familiar with the road force you referenced is the loss of 8th because of available power? Drivetrain rotating slower because of the larger tire?

Anyone personally experience the 2.0 spending more time in 6-7 on the HWY opposed to 7-8 as it would stock?

 

[AnnDee4444]

Not being familiar with the road force you referenced is the loss of 8th because of available power? Drivetrain rotating slower because of the larger tire?

The road force is can be thought of as the amount the tires are pushing against the roadway. It is a similar concept to axle torque, but with the tire height also taken into account.

The loss of 8th gear would be because with 3.45 gearing the torque in 8th gear at 75 mph would not be enough to overcome wind resistance, drive-train loss, etc. Going to a numerically higher gear ratio is one way to solve this, weather that means using 7th gear or a different axle ratio.

 

[OnlyOne]

I’ve owned both on 37s. I didn’t even feel the loss to be honest with you. With either motor and the auto. The Turbo just makes the drive more enjoyable and effortless on the highway. This is obviously on a Rubicon so your results with a Sahara will vary.

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