What can you do with a monster GDP 8" Portal Gear Lift on a Polaris RZR XP Turbo S? Pretty much anything. Eight inches of lift at the hubs plus a 45% or 60% gear reduction gives you room for 40-inch and larger tires and the torque to turn them, so the machine pushes through deeper mud and climbs bigger rocks. GDP is the most widely used portal system on the trail, so you're buying proven hardware, not an experiment.
Highlights
- 8" of lift at the hubs
- 45% or 60% gear reduction
- Cast or USA-made billet aluminum housings
- Precision-ground 9310 alloy billet steel gears
- 1.5" diameter 4340 hardened steel driveshaft
- Increases width by 4" per side (8" total)
- 1.5" forward and rear offset
- 5/16" advanced steel alloy backing plates
- Universal hubs for 4/156, 4/137, 4/115 and 4/110 bolt patterns
- Frame stiffener available and highly recommended
- Limited lifetime warranty from the manufacturer
Made for Mud
Bounty holes favor machines that go big. Eight inches of clearance on top of tall mud tires keeps you from sinking neck deep, and the extra torque keeps the tires turning and the machine moving forward. The 4-inch-per-side width increase also adds stability with the extra height.
Gear Reduction Protects the Drivetrain
The reduction happens right in the hub, at the very end of the drivetrain. That means the axles, differential, prop shaft and transmission all benefit, carrying less stress than stock. The result is more torque at the tire and a machine that holds up better under huge tires.
| Reduction | Best for |
|---|---|
| 45% | Big tires with a balance of torque and top speed |
| 60% | The largest tires and the deepest mud, maximum torque |
The manufacturer's recommendations aim to maximize torque while keeping factory top speed; a larger reduction than needed adds torque and lowers top speed.
Better Gear Material
The gears are precision-ground from 9310 alloy steel, which makes them quiet, smooth and strong. They're built for the abuse of oversized tires.
Housings and Backing Plates
- Choose cast or USA-made billet aluminum; tens of thousands of these housings are in use every week
- Housings reinforced in the right places and designed for oil flow and gear forces
- No vents; testing showed vents do more harm than good
- 5/16" backing plates in an advanced steel alloy stronger than chromoly
Seals and Bearings
Both housing types use advanced gaskets with excellent oil resistance and a lower deterioration rate than Kevlar gaskets, a sealed input gear, a double-lipped output seal and full sealing coverage, so oil leaks aren't a worry. Output bearings are double-angular contact units that resist breaking and premature wear over hard bumps.
Universal Hubs and Slotted Rotors
Precision-ground stainless steel slotted rotors run cool for strong braking. The hubs come with lugs and work with 4/156, 4/137, 4/115 and 4/110 bolt patterns, so almost any UTV wheel that meets the size requirements will fit. The hubs mount on a tapered output shaft, a GDP design that locks securely without wobbling or wearing over time.
Frame Stiffener Strongly Recommended
The stock Turbo S frame is tough, but not tough enough for this much lift and tire. A frame stiffener gives you peace of mind that the machine will hold together when the pedal's down. Add it at checkout or choose "No" if you already have one.
Is 8 Inches Too Much?
The 8-inch portal is for builds where clearance and tire size come first. It's the tallest GDP option for the Turbo S, and with the 4-inch-per-side width increase and 1.5-inch forward and rear offset it creates a very different machine from stock: taller, wider, longer and able to turn enormous tires. That makes it ideal for mud bogs, deep ruts and big rocks. If you ride a lot of fast, off-camber trail, the 4-inch or 6-inch portals keep the center of gravity lower and may suit you better.
Because the reduction choices start at 45%, this kit is geared for torque from the start. Choose 60% if you're running the largest tires or spend most of your time in deep mud.
Wheel and Tire Planning
The 8-inch kit needs wheels of 22 inches or larger with no more than 5 inches of backspacing, and a center bore of at least 3.25 inches or a 1-inch spacer. Since the wheel and tire package is a big part of the investment, plan it alongside the portals so they arrive together and fit correctly the first time.
Supporting Upgrades
Huge tires multiply the load on everything they're attached to. Plan for strong power steering assist, since steering effort rises sharply with tire size, along with the frame stiffener. Keep an eye on tie rods, ball joints and the steering rack as well. These parts work much harder on a machine of this size.
Living With an 8-Inch Build
The speedometer will read differently after the change in tire size and gearing. Check the portal boxes for oil level and seepage during regular service, especially after mud and water, and re-torque the hub and backing plate hardware after the first rides. Getting in and out is a bigger step, so a set of nerf bars or steps can help passengers.
Cast or Billet?
Both housing types are built on the same proven design and use the same gaskets, seals and bearings. Cast housings are the value choice and are the most common on the trail. Billet housings are machined from solid aluminum in the USA and cost more; riders often choose them for the premium construction and finish on high-end builds. Whichever you pick, the gears, shafts, backing plates and hubs are the same, so the choice comes down to budget and preference rather than which one will survive. Both carry the same limited lifetime warranty from the manufacturer.
Let Us Help You Spec It
An 8-inch portal build is a big investment, and the wheel, tire, gearing and stiffener choices all work together. Tell us your tire size, wheel plans and where you ride, and we'll help you put together the right package before you order, so nothing has to be swapped after it arrives.
Fitment Notes
- 22" or larger wheel required
- Wheels cannot exceed 5" backspacing
- Wheels need a center hole of at least 3.25" (82.55 mm), or a 1" wheel spacer is required
What's in the Box
- (4) Assembled portal hub boxes with 9310 gears, seals, output shaft, gaskets and thrust bearings
- (4) Universal hubs and stainless steel slotted rotors with lugs
- (4) Steel alloy backing plates
- Caliper mounting plates and adapters
- (2) Steel steering arms
- Extended brake lines
- All required hardware, including a recessed castle nut socket
- Frame stiffener, if selected
Who It's For and What Pairs Well
For all-out mud and rock builds running 40-inch and larger tires. Add the most steering assist available from RZR Turbo S steering parts, consider RZR Turbo S A-arms and RZR Turbo S lift kits for the very largest tires, and compare heights in RZR Turbo S portal gear lifts.
Fitment
| Year | Make | Model |
|---|---|---|
| 2018-2021 | Polaris | RZR XP Turbo S |
| 2019-2021 | Polaris | RZR XP Turbo S Velocity |
| 2019-2021 | Polaris | RZR XP Turbo S 4 |
Wheel Requirements
- 22" or larger wheel required
- Wheels cannot exceed 5" backspacing
- Wheels need to have a center hole of at least 3.25" (82.55mm) or require a 1” wheel spacer
Installation Notes
This is an advanced install that replaces all four hub assemblies, brake mounts and steering arms. Fill the boxes with gear oil, bleed the brakes and align the machine before riding. Instructions for each version are linked below.
- source:
- superatv
- satv_url:
- https://www.superatv.com/polaris-rzr-xp-turbo-s-8-inch-portal-gear-lift
- fitment_raw:
- Polaris RZR XP Turbo S 2018-2021; Polaris RZR XP Turbo S Velocity 2019-2021; Polaris RZR XP Turbo S 4 2019-2021
- install_pdf:
- https://madmin.superatv.com/amfile/file/download/file/3876/product/14165/
- desc_status:
- rewritten_2026-10-26
- sub_brand:
- GDP
