Sponsored

40s on narrow track axles?

BlueScapegoat

Well-Known Member
First Name
Trevor
Joined
Dec 2, 2018
Threads
14
Messages
1,126
Reaction score
2,732
Location
MN
Vehicle(s)
91 ST185, 04 Ram SRT10, 04 Forester XT, SC'd 05 Rubi, 22 JTRD
Occupation
Air Traffic Controller
Vehicle Showcase
4
Not a helpful reply. If you aren’t here for the conversation then why be here at all?
( ::editing for clarity in the backspacing area)

Fair response. You're borderline sounding like you don't want a conversation and you want an affirmation on the purchase you've already made.

So adding spacers doesn't change the WMS. (wheel mount surface.) Not geometrically. Sure your wheel mounts on the outside of the spacers, that doesn't mean anything. It's the same as highly offset wheels. You are still at the same WMS and adding bandaids to it. Visualize your clearances as your tires pivoting around your ball joints. That pivot point doesn't change with spacers or offset wheels. I'm speaking to you from a place of 20 years of pounding this through my own head and stubbornly trying to find ways around it on my other older Jeeps and other builds.

What are you trying to do with it? That's the question. I don't think I need to deep dive into all the cons if you just want to look cool on the road. You can run the Core4x4 arms I previously mentioned on the street and you probably won't rub metal at ride height.

This is maybe 3/4 steering lock on 40s on 68" WMS Rubicon axles with 17x8.5 wheels at 5.72" backspacing with 1.5" spacers. This IS a narrow setup, I tried to keep it as narrow as I could.

Jeep Gladiator 40s on narrow track axles? PXL_20250928_211854606


So in your mind just take that image and move the tire inward perpendicularly to the wheel face and see what it looks like. ( ::edit:: or out. my point is the same, the clearances work on an arc but you need to visualize that arc then being further towards the frame rail :: ) Then shift it again inward towards the frame and that's your narrower axle. That's with gutted fenders and 2" bump stops. This is with the axle positioned front-to-rear to accomplish the same clearance in the back.

My Savvy inner liners after a week in Moab. These are as far as I can tell the highest clearance liners on the market:

Jeep Gladiator 40s on narrow track axles? PXL_20251025_234028529
 
Last edited:
OP
OP
Trail_Limo_Tim

Trail_Limo_Tim

Well-Known Member
First Name
Tim
Joined
Sep 25, 2025
Threads
31
Messages
293
Reaction score
208
Location
Vancouver, WA
Vehicle(s)
2021 Gladiator Willys Diesel
( ::editing for clarity in the backspacing area)

Fair response. You're borderline sounding like you don't want a conversation and you want an affirmation on the purchase you've already made.

So adding spacers doesn't change the WMS. (wheel mount surface.) Not geometrically. Sure your wheel mounts on the outside of the spacers, that doesn't mean anything. It's the same as highly offset wheels. You are still at the same WMS and adding bandaids to it. Visualize your clearances as your tires pivoting around your ball joints. That pivot point doesn't change with spacers or offset wheels. I'm speaking to you from a place of 20 years of pounding this through my own head and stubbornly trying to find ways around it on my other older Jeeps and other builds.

What are you trying to do with it? That's the question. I don't think I need to deep dive into all the cons if you just want to look cool on the road. You can run the Core4x4 arms I previously mentioned on the street and you probably won't rub metal at ride height.

This is maybe 3/4 steering lock on 40s on 68" WMS Rubicon axles with 17x8.5 wheels at 5.72" backspacing with 1.5" spacers. This IS a narrow setup, I tried to keep it as narrow as I could.

PXL_20250928_211854606.webp


So in your mind just take that image and move the tire inward perpendicularly to the wheel face and see what it looks like. ( ::edit:: or out. my point is the same, the clearances work on an arc but you need to visualize that arc then being further towards the frame rail :: ) Then shift it again inward towards the frame and that's your narrower axle. That's with gutted fenders and 2" bump stops. This is with the axle positioned front-to-rear to accomplish the same clearance in the back.

My Savvy inner liners after a week in Moab. These are as far as I can tell the highest clearance liners on the market:

PXL_20251025_234028529.webp
I don't want any affirmations. I only want to hear about people's personal experiences. Just trying to know what to expect and avoid as many mistakes as I can. You just shared a more detailed personal experience so I appreciate that. Sometimes things get lost in the internet, when you can't look a person in the eyes and just talk. I'll have to think more about what you said. The way I think I understand the end position of the tire may not be the reality of it. And if I'm wrong that's ok. I like learning new things and often times it means being wrong before you are right.
 

BlueScapegoat

Well-Known Member
First Name
Trevor
Joined
Dec 2, 2018
Threads
14
Messages
1,126
Reaction score
2,732
Location
MN
Vehicle(s)
91 ST185, 04 Ram SRT10, 04 Forester XT, SC'd 05 Rubi, 22 JTRD
Occupation
Air Traffic Controller
Vehicle Showcase
4
I don't want any affirmations. I only want to hear about people's personal experiences. Just trying to know what to expect and avoid as many mistakes as I can. You just shared a more detailed personal experience so I appreciate that. Sometimes things get lost in the internet, when you can't look a person in the eyes and just talk. I'll have to think more about what you said. The way I think I understand the end position of the tire may not be the reality of it. And if I'm wrong that's ok. I like learning new things and often times it means being wrong before you are right.
Run the shit you already bought and see what issues come up. Adjust to your needs. I'm not even very old (by old Jeep Guru standards) but old enough to remember figuring it out yourself and adjusting. That figure-it-out process birthed most of our leading parts manufacturers today, internet wasn't always here. Keep fresh eyes. You might find some new solution to something nobody has seen before.

Figuring it out myself is most of what keeps me in this hobby.
 
OP
OP
Trail_Limo_Tim

Trail_Limo_Tim

Well-Known Member
First Name
Tim
Joined
Sep 25, 2025
Threads
31
Messages
293
Reaction score
208
Location
Vancouver, WA
Vehicle(s)
2021 Gladiator Willys Diesel
Run the shit you already bought and see what issues come up. Adjust to your needs. I'm not even very old (by old Jeep Guru standards) but old enough to remember figuring it out yourself and adjusting. That figure-it-out process birthed most of our leading parts manufacturers today, internet wasn't always here. Keep fresh eyes. You might find some new solution to something nobody has seen before.

Figuring it out myself is most of what keeps me in this hobby.
I hear you. If all my parts were here I would be installing them already 😂 Instead I’m on here rambling and waiting on Black Friday to purchase some lift components.
 

Sponsored

JeepDaddyJT

Well-Known Member
First Name
Jason
Joined
Mar 31, 2024
Threads
6
Messages
64
Reaction score
365
Location
Massillon Ohio
Vehicle(s)
2020 JT , 2021 Mojave , 2012 jk , 2006 LJ , 2004 L
Occupation
PipeFitter
Imo Rubicon axles are still a smidge too narrow for 40s properly. Real 39x12.5s would be the max, if anybody made them.

Narrow axles you're going to be making even more sacrifices. Can it be made to work? Sure. But not well. Lots of steering stop and bump stop.
Wrong
 

JeepDaddyJT

Well-Known Member
First Name
Jason
Joined
Mar 31, 2024
Threads
6
Messages
64
Reaction score
365
Location
Massillon Ohio
Vehicle(s)
2020 JT , 2021 Mojave , 2012 jk , 2006 LJ , 2004 L
Occupation
PipeFitter

nbennettksu

Well-Known Member
Joined
Sep 1, 2023
Threads
4
Messages
132
Reaction score
162
Location
Fort Lauderdale
Vehicle(s)
Gladiator
My original setup (narrow):
-tereflex 4.5" off the shelf, oem upper and lower control arms (angled)
-vision wheels 17x10", 4.5" backspacing, -25 offset
-40x13.5x17 atlas paraller (wouldnt wish those ass of tires on my biggest enemy)
-no spacer until i put spacers
-factory bumps

**no rub, no scrape. would it have with rubbed with straight control arms? I dont know

setup now (narrow and now wide):
-tereflex 4.5" off the shelf, straight adjustable upper and lower control arms
-kmc grenade 17x9", 3.5" backspacing, -38 offset
-40x13.5x17 trail grappler
-1.75" spacer (i didnt need this because I was rubbing, i wanted the wheels wider)
-factory bumps

**still no rubbing or scraping on fill lock in any direction
 
OP
OP
Trail_Limo_Tim

Trail_Limo_Tim

Well-Known Member
First Name
Tim
Joined
Sep 25, 2025
Threads
31
Messages
293
Reaction score
208
Location
Vancouver, WA
Vehicle(s)
2021 Gladiator Willys Diesel
My original setup (narrow):
-tereflex 4.5" off the shelf, oem upper and lower control arms (angled)
-vision wheels 17x10", 4.5" backspacing, -25 offset
-40x13.5x17 atlas paraller (wouldnt wish those ass of tires on my biggest enemy)
-no spacer until i put spacers
-factory bumps

**no rub, no scrape. would it have with rubbed with straight control arms? I dont know

setup now (narrow and now wide):
-tereflex 4.5" off the shelf, straight adjustable upper and lower control arms
-kmc grenade 17x9", 3.5" backspacing, -38 offset
-40x13.5x17 trail grappler
-1.75" spacer (i didnt need this because I was rubbing, i wanted the wheels wider)
-factory bumps

**still no rubbing or scraping on fill lock in any direction
If the wheel company will ever ship my wheels I can fk around and find out. 🙃
 

BlueScapegoat

Well-Known Member
First Name
Trevor
Joined
Dec 2, 2018
Threads
14
Messages
1,126
Reaction score
2,732
Location
MN
Vehicle(s)
91 ST185, 04 Ram SRT10, 04 Forester XT, SC'd 05 Rubi, 22 JTRD
Occupation
Air Traffic Controller
Vehicle Showcase
4
I'd love to see one of your rigs that don't rub at all with the wheels cut to the stops and the suspension flexed out.
 

Sponsored

BlueScapegoat

Well-Known Member
First Name
Trevor
Joined
Dec 2, 2018
Threads
14
Messages
1,126
Reaction score
2,732
Location
MN
Vehicle(s)
91 ST185, 04 Ram SRT10, 04 Forester XT, SC'd 05 Rubi, 22 JTRD
Occupation
Air Traffic Controller
Vehicle Showcase
4
Bump stops for my 3 1/2 inch lift of course no one would run factory bump stops with 3.5” lift - no changes to the steering stops
How big are your bump stops? Maybe that's where we're differing here. I hit the core grille support with the wheels cut and flexed out. If I pushed the wheels out like 3" further and trimmed the bumper (and removed the AAL turn signals) then it might fix the front issue but I'd be eating the rear of the fender, which is already trimmed back. And it would drive atrociously. There's core structure in the way.
 
OP
OP
Trail_Limo_Tim

Trail_Limo_Tim

Well-Known Member
First Name
Tim
Joined
Sep 25, 2025
Threads
31
Messages
293
Reaction score
208
Location
Vancouver, WA
Vehicle(s)
2021 Gladiator Willys Diesel
How big are your bump stops? Maybe that's where we're differing here. I hit the core grille support with the wheels cut and flexed out. If I pushed the wheels out like 3" further and trimmed the bumper (and removed the AAL turn signals) then it might fix the front issue but I'd be eating the rear of the fender, which is already trimmed back. And it would drive atrociously. There's core structure in the way.
Curious which control arms you’re using. Factory length or long arms?
 

BlueScapegoat

Well-Known Member
First Name
Trevor
Joined
Dec 2, 2018
Threads
14
Messages
1,126
Reaction score
2,732
Location
MN
Vehicle(s)
91 ST185, 04 Ram SRT10, 04 Forester XT, SC'd 05 Rubi, 22 JTRD
Occupation
Air Traffic Controller
Vehicle Showcase
4
Curious which control arms you’re using. Factory length or long arms?
Factory mounting points in the front, they're adjustable Core4x4 arms with JJs.
 
 







Top