Tested 35" tires on the R1T - for offroading / overlanding

[Rexbo]

Hey all -
I've seen lots of experimentation by lots of people (including myself) on trying to stuff as much tire onto these trucks as possible for offroad/overland purposes. So, I wanted to consolidate what I've found into one place, and will try to cite sources where possible. I'm going to exclude (for now) people that are willing to take a sawzall and do fiberglass work to get bigger tires onto these trucks. Also tire diameters may vary slightly by tire manufacturer despite being same size

Objective: To achieve the largest contact patch that fits on the truck without tearing up the fender liners.
Method: Minimize rim diameter & maximize tire width and sidewall
Observation #1: The front outboard fender plastic is the width constraint on tire compression.
Observation #2: The front forward fender is the offset constraint at wheel lock

Findings: So far it seems that 35" diameter is the largest that will reasonably fit without really hurting things.

Wheels	Tires	Rub?	Sauce
OEM: 20x8.5" +58 (7.03" backspace)	OEM: 275/65R20 (34.1" dia)	None	OEM
OEM: 20x8.5" +48 (6.65" backspace)	OEM: 275/65R20 (34.1" dia)	None	OEM
OEM: 20x8.5" +48 (6.65" backspace)	285/65R20	Tire-dependent	@oybed tested!
OEM: 20x8.5" +48 (6.65" backspace)	35x11.5R20	None	@twvette tested!
20x8.5" +40 (6.32" backspace)	275/65R20	Need testing	1EV RMaxx R800 https://evsportline.com/ Recommended tire size from 1EV
20x8.5" +35	275/65R20	Low: Minor rubbing on bumps	Black Rhino Voltaic wheels BFGoodrich K03 tires @0_r1t_0 tested! Thread
20x9" +38 (6.5" backspace)	275/65R20	Need testing	1EV RMaxx R500 https://evsportline.com/ Recommended tire size from 1EV
20x9" +38 (6.5" backspace)	285/60R20	Need testing	Need testing, this might be the goldilocks zone
20x9" +38 (6.5" backspace)	285/65R20	Need testing	Need testing, this might be the goldilocks zone
20x9" +38 (6.5" backspace)	295/65R20	Need Testing In the attached video presenter states too much rubbing (~4min)	1EV RMaxx R500 https://evsportline.com/
20x9" +25 (5.98" backspace)	275/65R20	Lowest: minor rub on turning Low: OK	@OffRoad987Tested!
20x9" +25 (5.98" backspace)	285/60R20	Low: Minor rubbing on bumps Standard: OK	@dp351 tested!
20x9 +18 (5.71" backspace)	275/65R20	Need testing	Need testing
20x9 +18 (5.71" backspace)	285/60R20	Need testing	Need testing, probable rub at low ride height
20x9 +18 (5.71" backspace)	285/65R20 (34.6" dia)	Low: Bumps & Steering rubbing Standard: OK High: OK Highest: OK	@Rexbo Tested! Raceline 950B Gauge wheels BFG A/T K02 tires
20x10 +50?	295 or 305 width	Need Testing	There might be a way to do this with super high offset, but nobody makes this sizing

*Note: Why TF have we normalized mixing imperial/metric units?!?

For reference, here are some photos of my truck with the Racelines installed and sitting at standard ride height, to be determined how much rubbing there is while offroading but assuming there will be some.

If you guys have tested other combinations for offroading, please post and I'll update the matrix above!

Sponsored

 

[chandlerr85]

that looks awesome, do you plan on contacting the service center to get your speedometer adjusted/ do you know if they can/will adjust for non stock tire sizes at this time?

I was actually just recently casually looking at what would need to be done with swapping tires; I recently updated my configuration for the road tires to get msrp under 80k for tax rebate, and I was thinking I would just swap tires at a later time.

 

[mikehmb]

Thank you for consolidating!

While I recognize it’s not the intent of your analysis, have you recorded efficiency data for the KO2s? That’s the tire i also intend to switch to when i prep the truck for over-landing next summer. It will be useful for trip / charger planning as we’ll be highway bay area -> utah.

 

[Rexbo]

that looks awesome, do you plan on contacting the service center to get your speedometer adjusted/ do you know if they can/will adjust for non stock tire sizes at this time?

I don't really care for now, will just go speed of traffic, there are no TPMS sensors in them either, since I figured I may not have these rims for too long now that those sexy beadlocks are out!

have you recorded efficiency data for the KO2s?

From my experience on my other trucks, its safe to assume a 10-15% range hit with the heavier K02s, for planning purposes just assume 20% range loss between the tires and offroading.

 

[COdogman]

Wow, great research. Looks amazing too!

 

[dp351]

Wow! Thanks for sharing this great research. The truck looks awesome with those wheels & tires!

Just so I’m clear - would you please define “backspace”?

 

[R1Sky Business]

So KO 2 range hit about same as 20 AT OEMs......

 

[windblowlc]

I don't really care for now, will just go speed of traffic, there are no TPMS sensors in them either, since I figured I may not have these rims for too long now that those sexy beadlocks are out!



From my experience on my other trucks, its safe to assume a 10-15% range hit with the heavier K02s, for planning purposes just assume 20% range loss between the tires and offroading.

OEM wheels have ET +48, not +38.

 

[Rexbo]

OEM wheels have ET +48, not +38.

Sharp eyes, thanks! Fixed

 

[dp351]

Someone shared this in another thread. It shows stock offsets are 48mm or 58mm, depending on the wheel.

 

[Rexbo]

Someone shared this in another thread. It shows stock offsets are 48mm or 58mm, depending on the wheel.

Ooo this is fantastic! I'm gonna do some math and I think now that we have a known maximum backspacing (inner limit) and a maximum outer limit... This should get interesting!

 

[OffRoad987]

I tested 275/65/20 on 20x9 +25

No steering rub on Lowest.
Just did a static test today with a front tire for brake caliper clearance. Need to relocate wheel balance weights before doing rolling tests.

Will drive the car next week on this rim/tire combo to check bump rubbing on low and lowest.

 

[Dark-Fx]

Hard compressions on lowest with my stock 22's at steering lock would cause rubbing in the passenger side liner. That side does sit lower in my truck even after Rivian said they were fixing it.

 

[chandlerr85]

Wow! Thanks for sharing this great research. The truck looks awesome with those wheels & tires!

Just so I’m clear - would you please define “backspace”?

 

[pnwr1s]

Watching

Sponsored