17x9.5 vs 17x8

[grimmjeeper]

Grimmjeeper
Some of that engineer OCD would be much appreciated on the below:

Factory Set-up:

Firestone Destination XT 255/70R17: ~50lb
Factory Jeep wheel 17x7.5: 21lb
Full set up with sensor is about 73lbs total.

Possible new set-up:

Toyo Open Country AT III 35/12.50R17LT: 59lbs
*I have found various 17x8 and 17x8.5 with average weight of ~26lbs.
Full new set up with sensors: ~ 87lbs

So I’m looking at a gain of about 12lbs per wheel/tire, and an overall net gain of 48lb (60lbs if including spare mounted on back)

Thoughts?

You're going up over 10% more in tire diameter. That puts you in a place where you want to consider swapping out axle gears for 4.10, 4.56, or 4.88, regardless of weight.

It depends on what gears you have now. Also, what engine and transmission you have. Where and how you drive influences the decision as well.

You may want a small lift (possibly with bump stop extensions) to accommodate the bigger tires. If you use wheels with a lot of backspacing, you may want to install spacers to move them out a little.

Sponsored

 

[Mifsuud]

I have Toyo 315/70r17 RT Trails on 17x9 wheels on my '21 4xe Rubicon. You can see them in the pics on my signature link. I think the weight increase over stock is 15lbs per corner. 37s would have increased the increase, likely pushing the need to re-gear as well. Which is why I did not buy 37s. Also, I run with max regen on all the time. This really helps with slowing and braking especially with heavier tire/wheel combo.

Once the tire size was reprogrammed I noticed no issues when driving, In town electric range maybe down 2 miles. I never run straight electric at highway speeds as that's useless. Transmission gets into 8th gear on the highway. The RT Trails are more aggressive than the AT3 for sure. Have been very happy with them on and off road.

Rubicons do have 4.10 gearing which helps. You'll have more than enough torque to get rolling. Passing will still be easy in hybrid mode, a bit slower in electric. That's seat of the pants over the last year testing only. My wrangler also has a drawer and gear in back 100% of the time adding around 100lbs of cargo.

 

[Rkobel]

You're going up over 10% more in tire diameter. That puts you in a place where you want to consider swapping out axle gears for 4.10, 4.56, or 4.88, regardless of weight.

It depends on what gears you have now. Also, what engine and transmission you have. Where and how you drive influences the decision as well.

You may want a small lift (possibly with bump stop extensions) to accommodate the bigger tires. If you use wheels with a lot of backspacing, you may want to install spacers to move them out a little.

You're going up over 10% more in tire diameter. That puts you in a place where you want to consider swapping out axle gears for 4.10, 4.56, or 4.88, regardless of weight.

It depends on what gears you have now. Also, what engine and transmission you have. Where and how you drive influences the decision as well.

You may want a small lift (possibly with bump stop extensions) to accommodate the bigger tires. If you use wheels with a lot of backspacing, you may want to install spacers to move them out a little.

The Willy’s 4xe comes with 3.45 gearing. It has a 2.0-liter turbocharged 4 cylinder engine and is paired with 2 electric motors and a 400-volt 17-kWh battery pack to supposedly put out 375 hp and 470 lb-ft of torque. Narrow track axles w/dana 44’s. 2.72:1 full time 4WD.

I have a Metalcloak True Dual Rate 2.5 inch lift w/redrock shocks. https://metalcloak.com/4xe-jl-wrangler-dual-rate-lift-kit-2-5in.html

I’m currently running the stock wheels with 1.75” spacers. Looking at 17x8 w/-6mm offset for new set.

With my daily driving being 95%+ street and highway, would the transmission/gearing be enough to accommodate the newer larger set up?

 

[Rkobel]

That’s light for 35’s, and no gate reinforcement needed. I wish the AT3’s were a couple pounds heavier with the rubber on the sidewall, oh well, they are a terrific tire. Do you have a Tazer or other to Lower the TPMS warning ? 30-32 psi is good but in the warm day,cold night time of year frequent 28 lb morning low tire warnings, not when set down to 25 lbs. I would try 28 psi if not for the TPMS, but I don’t want to shut it off.

I don’t have the device to adjust the TPMS warning. I was actually wondering if I should consider new sensors or swap the factory ones to the new setup. The shop I get my work done at can adjust the TPMS warning to a lower PSI, I think they’re set fairly high for the stock wheels and tire set up.

 

[Rkobel]

I have Toyo 315/70r17 RT Trails on 17x9 wheels on my '21 4xe Rubicon. You can see them in the pics on my signature link. I think the weight increase over stock is 15lbs per corner. 37s would have increased the increase, likely pushing the need to re-gear as well. Which is why I did not buy 37s. Also, I run with max regen on all the time. This really helps with slowing and braking especially with heavier tire/wheel combo.

Once the tire size was reprogrammed I noticed no issues when driving, In town electric range maybe down 2 miles. I never run straight electric at highway speeds as that's useless. Transmission gets into 8th gear on the highway. The RT Trails are more aggressive than the AT3 for sure. Have been very happy with them on and off road.

Rubicons do have 4.10 gearing which helps. You'll have more than enough torque to get rolling. Passing will still be easy in hybrid mode, a bit slower in electric. That's seat of the pants over the last year testing only. My wrangler also has a drawer and gear in back 100% of the time adding around 100lbs of cargo.

Here’s my current setup:

3.45 gearing. 2.0-liter turbocharged 4 cylinder engine and is paired with 2 electric motors and a 400-volt 17-kWh battery pack to supposedly put out 375 hp and 470 lb-ft of torque. Narrow track axles w/dana 44’s. 2.72:1 full time 4WD.

Metalcloak True Dual Rate 2.5 inch lift w/redrock shocks. https://metalcloak.com/4xe-jl-wrangler-dual-rate-lift-kit-2-5in.html

I’m currently running the stock wheels with 1.75” spacers. Looking at 17x8 w/-6mm offset for new set.

With my daily driving being 95%+ street and highway, would the transmission/gearing be enough to accommodate the newer larger set up? Also need to consider new TPMS sensors (or can I swap out factory ones and reprogram tire size and pressure)

 

[2nd 392]

I don’t have the device to adjust the TPMS warning. I was actually wondering if I should consider new sensors or swap the factory ones to the new setup. The shop I get my work done at can adjust the TPMS warning to a lower PSI, I think they’re set fairly high for the stock wheels and tire set up.

Sensors changed June of 21 , either swap existing or make sure to get the right ones. The lowest warning the computer will accept is 25psi, if they can great. Tazer, j-scan, likely others will adjust. If you don’t adjust run 32psi to minimize the warning PITA, it gets annoying. My OCD wouldn’t let me ignore the light, maybe you can.

 

[Rkobel]

You're going up over 10% more in tire diameter. That puts you in a place where you want to consider swapping out axle gears for 4.10, 4.56, or 4.88, regardless of weight.

It depends on what gears you have now. Also, what engine and transmission you have. Where and how you drive influences the decision as well.

You may want a small lift (possibly with bump stop extensions) to accommodate the bigger tires. If you use wheels with a lot of backspacing, you may want to install spacers to move them out a little.

The Willy’s 4xe comes with 3.45 gearing. It has a 2.0-liter turbocharged 4 cylinder engine and is paired with 2 electric motors and a 400-volt 17-kWh battery pack to supposedly put out 375 hp and 470 lb-ft of torque. Narrow track axles w/dana 44’s. 2.72:1 full time 4WD.

I have a Metalcloak True Dual Rate 2.5 inch lift w/redrock shocks. https://metalcloak.com/4xe-jl-wrangler-dual-rate-lift-kit-2-5in.html

I’m currently running the stock wheels with 1.75” spacers. Looking at 17x8 w/-6mm offset for new set.

With my daily driving being 95%+ street and highway, would the transmission/gearing be enough to accommodate the newer larger set up?

 

[grimmjeeper]

The Willy’s 4xe comes with 3.45 gearing. It has a 2.0-liter turbocharged 4 cylinder engine and is paired with 2 electric motors and a 400-volt 17-kWh battery pack to supposedly put out 375 hp and 470 lb-ft of torque. Narrow track axles w/dana 44’s. 2.72:1 full time 4WD.

I have a Metalcloak True Dual Rate 2.5 inch lift w/redrock shocks. https://metalcloak.com/4xe-jl-wrangler-dual-rate-lift-kit-2-5in.html

I’m currently running the stock wheels with 1.75” spacers. Looking at 17x8 w/-6mm offset for new set.

With my daily driving being 95%+ street and highway, would the transmission/gearing be enough to accommodate the newer larger set up?

Short answer, no. The transmission won't accommodate the tire size change. Not entirely.

It may be "Good enough" for some people to tolerate. But the top gear or two will be all but unusable.

The 3.45 gears were designed for optimizing the EPA test loop to get the highest possible mileage. You really want 3.73s or better for real world driving with stock size tires. As you go up in tire size, it keeps getting worse without matching the tire size change with an axle gear change.

The bigger tires rotate slower at speed than smaller tires. That means the driveshaft is spinning slower, so the transmission has to downshift to compensate. Shorter gears (higher number) cause the driveshaft to turn faster and get you back where you need to be. Tire size and gear ratio are tied together and should match.

The 8 speed transmission tends to mask the symptoms of mismatched gears and tires a lot better than transmissions did way back when. But it's still a good idea to match tires with the right axle gears.

 

[Rkobel]

Short answer, no. The transmission won't accommodate the tire size change. Not entirely.

It may be "Good enough" for some people to tolerate. But the top gear or two will be all but unusable.

The 3.45 gears were designed for optimizing the EPA test loop to get the highest possible mileage. You really want 3.73s or better for real world driving with stock size tires. As you go up in tire size, it keeps getting worse without matching the tire size change with an axle gear change.

The bigger tires rotate slower at speed than smaller tires. That means the driveshaft is spinning slower, so the transmission has to downshift to compensate. Shorter gears (higher number) cause the driveshaft to turn faster and get you back where you need to be. Tire size and gear ratio are tied together and should match.

The 8 speed transmission tends to mask the symptoms of mismatched gears and tires a lot better than transmissions did way back when. But it's still a good idea to match tires with the right axle gears.

Understood. I will most likely hold off on re-gearing for now as well as larger 35”.

What would be the safest larger tire size in your opinion? Would 285/70R17 still cause issues? Basically going from a 32” to 33”.
or even a 285/75R17, basically 34”s.

Im just wanting something larger sitting under the 2.5” lift, but of course will wait until I can afford ALL the work that has to go into the investment of a larger wheel/tire setup.

 

[grimmjeeper]

Understood. I will most likely hold off on re-gearing for now as well as larger 35”.

What would be the safest larger tire size in your opinion? Would 285/70R17 still cause issues? Basically going from a 32” to 33”.
or even a 285/75R17, basically 34”s.

Im just wanting something larger sitting under the 2.5” lift, but of course will wait until I can afford ALL the work that has to go into the investment of a larger wheel/tire setup.

Thing is, it will probably be acceptable with any of those tires in the short term. Good enough to drive it for a while. The electric motor in the 4xe does help a lot.

Long term goal should be to regear but it may be "good enough" without.

 

[Rkobel]

Thing is, it will probably be acceptable with any of those tires in the short term. Good enough to drive it for a while. The electric motor in the 4xe does help a lot.

Long term goal should be to regear but it may be "good enough" without.

I really appreciate your knowledge. “Good enough” has never been good enough for me, I prefer to run all things At or near optimal.
That being said, I think it wiser to turn this new setup into a longer-term build.

I will probably start by upgrading my wheels to a 17x8 with appropriate offset/BS, around -6 to -10. This can still accommodate my stock 255/75R17’s and I can get rid of the 1.75” spacers.

Then I will save up for a re-gear to 4.56 and a set of 35/12.50R17 around the same time.
(Would getting the regear to 4.56 first and having the stock 32” tires for a while be an issue?) just trying to configure the costs and saving at once or spread out over time.

Also, 4.56 or 4.88? I would assume 4.56 would be optimal to pull 35”s given the transmission I have.

 

[grimmjeeper]

I really appreciate your knowledge. “Good enough” has never been good enough for me, I prefer to run all things At or near optimal.
That being said, I think it wiser to turn this new setup into a longer-term build.

I will probably start by upgrading my wheels to a 17x8 with appropriate offset/BS, around -6 to -10. This can still accommodate my stock 255/75R17’s and I can get rid of the 1.75” spacers.

Then I will save up for a re-gear to 4.56 and a set of 35/12.50R17 around the same time.
(Would getting the regear to 4.56 first and having the stock 32” tires for a while be an issue?) just trying to configure the costs and saving at once or spread out over time.

Also, 4.56 or 4.88? I would assume 4.56 would be optimal to pull 35”s given the transmission I have.

The 2.0 is fine with 4.56.

 

[Blckdog]

Roy, does the same apply for the 3.6 w/ESS?

Sponsored