GDP Portal Gear Lifts give you a lift and a gear reduction in one package, and they let you choose between a 15%, 30%, and 45% gear reduction. That’s a lot of choices! And you might have some misconceptions about what a gear reduction really does or why you’d want a small gear reduction instead of a huge gear reduction.
Never fear! We’re here to answer some common questions about this mystical force that lets your cousin ride like a pro, but leaves you getting winched out of the mud. We’ll help you understand why gear reduction is important, why you might need it, and how you can get it. Spend some time reading now, and you will be talking ratios and torque with the best of them later.
You should care about gear reduction because it helps to create more torque.
Ah, torque.
Here’s another word most of us claim to understand, but just in case you don’t—allow us to explain it. Torque is the amount of power that your engine produces to turn your tires. Simply put, the more torque your UTV can produce, the easier your engine can turn your wheels (which leads to faster acceleration). Less torque leads to higher top speed, but slower acceleration and less power.
More than likely the answer is yes, especially if you’re considering getting lifted with a set of portals. Even more simply put, if you’re going to put larger than stock tires on your machine, you definitely need more torque. How much torque you want depends on how you ride. A side-by-side that rolls off the showroom floor usually has a clutch and transmission set up for a balance of speed and power based on stock equipment. Your average ATV/UTV rider might find this completely adequate, but if you are all about hitting the trails and getting the blood pumping, you’ve probably already upgraded your machine. The list of upgrades that can potentially affect the performance of your ride is long, but we are going to focus on one of the biggest culprits: tire size.
The biggest torque killer with larger tires is the distance around the tire, or the circumference. When most riders say bigger tires, they are talking about their height from the ground. This is how tires are sold. The size of a tire = the height of the tire from the ground. But by increasing the height of a tire, you also increase the distance around the tire. If we think about the tire as a gear, it takes more force to roll a bigger tire one revolution because it needs to travel a further distance.
You can skip reading this next part and use this gear reduction calculator, or you can keep reading and learn something new. We suggest you keep reading.
If you marked two tires, one 25″ and one 32,” and rolled them both together for a total of one complete revolution (or the distance it takes for that mark to travel from the ground all the way around and back again), the 25″ tire would travel about 78.5 inches while the 32″ tire would roll about 100.5 inches. Trust us on this one—it’s math. (If you want to know more about the math, check out this article on determining gear ratios.) To roll that bigger tire the extra distance, your engine has to work harder because it needs to spin it more to achieve one revolution. In this example, if we figure the percent increase from 78.5 inches of travel to 100.5 inches, we find that you are losing 28% of your torque. This translates into a loss of acceleration and power.
And now, my friends, we have come full circle. If you want to make up for that loss caused by your bigger tires, you need more power. You need a gear reduction! How much reduction do you need? The simple answer—enough to replace what you lost by increasing your tire size. If you go from a 25″ tire to a 32″ tire, you would need a reduction of about 28%.
We list the recommended gear reductions for each tire size (and the lift you’d need in addition to the portals to achieve those tire sizes) at the bottom of each of our 4″ and 6″ portal pages. These recommendations are specific to each machine and they tell you which gear reduction you’d want to choose to get back to (roughly) stock max speed.
It’s a very basic way to optimize your speed and your power/acceleration with bigger tires. But you don’t have to follow it. For example, most mud guys aren’t worried about hitting their max speed through a mud hole—they stick it in low and crawl through crazy deep mud on monster tires. They want the biggest gear reduction they can get, not the most balanced one for bigger tires. That super-high torque lets them plow through mud like it’s nothing.
The same holds true for rock crawlers. More torque is more preferable than power balanced with speed. Getting up and over huge boulders is more about pure power than speed.
With trails and dunes, a smaller, more balanced gear reduction might do just fine. With tires that are just a little bit larger than stock, the smaller gear reduction can get your power back and keep you moving as fast as possible.
One of the best ways to reduce your gear ratio (and get a bigger gear reduction) on your UTV or ATV is to install a portal gear lift kit. Odds are if you’re thinking about bigger tires, you’re already thinking about a lift and now you should be thinking about a gear reduction—a GDP Portal Gear Lift gives you both and more.
Unlike a transmission kit, there isn’t a need to replace your factory gears. Instead, a portal gear lift is attached to the end of an axle at the wheel hub. The reduction and increased power come from the gears that are built into the box that operates at the wheel. This makes installation much less time consuming and accessible to all riders.
Portals transfer the force of the engine more closely to the object being turned (the tire), so there is less stress on the axles, differential, drive shaft, and the transmission—even less than a stock machine. A transmission gear reduction, on the other hand, can cause more stress on your drivetrain components since they’re subject to even more torque than stock.
You probably need more torque because you added bigger tires or a lift. Remember? That means you also probably put your axles to work at an angle that they aren’t used to because they are now connected to your wheel hubs from a different height than factory. This can cause a lot of stress and wear. An advantage of going with a GDP Portal Lift is that it relocates the axle centerline so you retain much of the factory steering geometry.
Not only are you going to get more ground clearance from your bigger tires, but if you use a portal lift gear reduction, you will also get an increased height of 4, 6, or 8 inches (depending on which lift you choose). This is a big advantage that you won’t get by simply putting in a transmission gear reduction kit.
Finally, SuperATV GDP Portals allow a greater reduction than any transmission kit. This is really important if you have extra heavy tires or need additional torque for heavy rock crawling or climbing. The GDP 4″ Portal Gear Lift provides a 15 or 30% gear reduction, the 6″ GDP Portal Gear Lift gives a 30 or 45% gear reduction, and the 8″ GDP Portal Gear Lift comes with a 45% gear reduction. If you need a lot of torque, the only way to easily achieve it is with SuperATV portals.
Updated by Kavan Wright on 1/30/2020.
56 Comments
I have your 4 inch gen 3 portals at 30% reduction tires are your 32x14x10 intimadators original tires where 27x14x10..how far off will my speedometer be off now say at 60mph reading.
Hey Richard, unfortunately, there are a lot of factors that can play into this. There are a lot of apps nowadays that can tell you your speed. We would recommend downloading this and compare that to your speedometer. Thanks for the support!
Can they be used for the street for everyday use and can a locking hub be installed
Hey Richard, thanks for tuning in! Yes, with proper maintenance, they can be used on the road as well. A locking hub cannot be installed; however, a locking differential can.
I have your 4″ portals and a set of your warrior 35″ tires. Portals are 30% and also IGR of 25% the latter compensates for the increased tire diameter and the portals give the torque to go through mud and a bit of rock crawling. I am using Honda Talon 1000X OEM wheels with 1.5″ spacers in the front and 2″ spacers in the rear to allow enough clearance between the portal plate and the wheel. If move to the 6″ or * GDP portals will it increase the width? Thanks and the current combination is killer just looking for a bit more height and considering a little bump in torque going to 45% on the taller portals. This would also leave room for even larger tires in the future.
Hi George! First off, it sounds like you’re making some pretty great aftermarket choices. 🙂 As far as your question goes, going to 6″ portals will not increase the width. Our 6″ portals have the same width as our 4″ portals installed. You would keep the same width, gain 2″ of height, and would need 18″ wheels or larger to clear the portals. Thanks for the support!
Question; I have a 2020 Polaris S 1000 and I’m considering putting on 4 ” portals . If I also install 1.5 ” wheel spacers will that give me enough room without changing my stock 12″ wheels ?
Hey Ron, unfortunately it will not work. 14″ minimum wheel size is required for the 4″ portals. Thanks for reading!
I have a 2019 Polaris Ranger 1000 XP Crew High Lifter Edition, we installed your 6” big lift last year. We are running 38” Outlaw 3’s on 22” rims. We are continually breaking stuff, so obviously we need to add portals. I am just trying to figure out which portals we need? The Ranger HL edition comes with 15% gear reduction so i’m not sure if i need 30% more or if i need to go with 45%? Can you help??
Hey Dana, with your setup and tires, I’d suggest 45% gear reduction. We do have a dedicated portal technical support team in office if you’d like to reach out for more advice: 855-743-3427. Thanks for the support!
I have can am defender max hd8 can I run 6″ portals with 40 inch tires and be ok or do I need to stay with 37’s
Hey Jason, thanks for reaching out! The 37’s will not rub if you install the 6″ lift with the 6″ portals. However, if you only add forward offset A-arms instead of the lift, you could only run up to a 34. Unfortunately, there isn’t a combination that we currently offer where we could recommend running a 40″ tire without rubbing. We appreciate the support!
Hi, I have a 2018 Polaris XPT 4 with 4” portals / 30% reduction. Trans clutch and motor are stock. What I am noticing is that I am not putting any load on my turbo at all. The problem with that is I’m building heat in the engine and turbo. The machine will tackle any obstacle in Moab without going over 4000 rpms. The machine will reach higher rpms and when I do hit the gas harder my engine temps drop.
What can I do to mitigate this?
Clutch kit – Add weight to the primary, lighter primary spring?
Hey Shawn, thanks for tuning in! I’d recommend a Rev1 ECU Tuner that will kick the fan on at a lower temperature. Check out our tuners here: https://www.superatv.com/polaris-rzr-xp-turbo-hand-held-ecu-tuner Feel free to give our customer service team a call if you have more questions, 855-743-3427!
I have a 2017 can am mav turbo ds, 72″ with 33″ tires on 15″ rims, will 15% reduction work on these rims and set up, will I need a lift and will I remain at 72″? Thanks, Mike.
Hey Mike, if you’re talking about adding portals with 15% gear reduction, it will depend on the wheel offset and will add about 9″ to the width. Feel free to give us a call at 855-743-3427 for any portal tech support!
I have Krx trail edition w/ outer bead lock 15″ stock wheels, will i need spacers for 4″ portals
Nope, you won’t need the spacers. Thanks for the support!
Hello i currently have a 2014 rzr800s with 4″ gen 1 15% reduction portals and runing 35″ motohavoks would like to go with 6″ portals for the extra 2″ and also bigger and stronger than gen1 but idk what size reduction i should get 30% or 45% im also runing a muddrr clutch kit from epi idk if that makes a difference but reving about 4,000 rpm going 5 to 15mph my average speed
Hey Tony! It’s a personal preference, really. If you want a little more speed out of the gate, go with more reduction. If you’d rather have a little higher top end speed, less reduction. But it will also pull better with less reduction, and the clutch kit SHOULD help offset some of that top end loss. Check out our portal calculator to get estimated speeds: https://www.superatv.com/portal-calculator Thanks for the support!
I just purchased some 6” portals for my 2010 rzr 800 and wondering if wheels off of a can am will fit the portals
Hey Victor! You can make it the correct bolt pattern for sure. However, the wheel size will more than likely not work because the 6″ portals require an 18″ wheel or larger with no more than 5″ back spacing. Feel free to reach out to us at 855-743-3427 for anymore technical help!
I have a 2000 2020 want razor XP pro ultimate was wondering if I put 4″ portals on would it be OK to run them in 30 fives in the dunes and what is guessing top speed with the foreign portals with 35XT Warrior tires
Hey Mitchel, yes – you should be able to run 35s. Check out our portal calculator to get estimated speeds: https://www.superatv.com/portal-calculator Thanks for tuning in!
I have a Honda Pioneer with 3” lift and 1.5 A-arms. I’m currently running a 30” BKT. I’m going to purchase the 6” portals and run a 35” tire.
I’m looking for a good all around ride. Mud, trail and top speed. What gear reduction do you recommend? The 30 or 45?
Hey Zach! Sounds like a great setup! I would probably recommend 30%; however, we have a portal calculator to help with this because it does really depend on your personal preference. Check it out: https://www.superatv.com/portal-calculator Thank you for the continued support!
I have a 2012 canam commander 1000 with a super ATV 6 inch lift and I want to add 6inch portals and already have 18 s for my rim size I think the tires are 33 can I use the 6 inch portals with this set up
Thanks for tuning in! Unfortunately, the GDP portal gear lifts are not directly compatible with the SATV Commander 6″ suspension lift kits. We have seen customers fabricate kits to make the combination work, but it’s not something that we offer or recommend due to the added stress to the Commander frames.
I have 2016 terxy4 800 im running 35’s on 20’s with a 6″ lift but not sure if a 4″ portal will be enough !! Should id go 4″ or 6″ portals ?
Hello! Thanks for tuning in. Both the 4″ and 6″ portals would give you enough clearance for those tires. If you’re wanting to know if it’s enough as far as gear reduction goes, that comes down more to personal preference and ride type. If you’re sticking with the 35’s, I would go with the 30%. If you’re wanting to go to a bigger tire or if your main riding is crawling, then you could consider the 6″ with a 45% reduction. If you need any more help, give us a call at 855-743-3427 and our portal support team will get you figured out!
I have a 2020 can am x3 xmr turbo. I ordered 6” portals with the 30% reduction. I plan on running 40x24x8.5 BKTs. Will i have any issue as far as reduction wise? Should i go to a lower reduction?
Thanks for reaching out! To answer your question, it will depend on what you’re wanting out of the machine and where you ride the most. Typically, with that size of tire, you’d want more reduction. Check out this link to get an idea of where you would be speed wise. https://www.superatv.com/portal-calculator Thank you for the support!
if i buy 4″ portals 15% reduction can i buy gears to change to 30%
Hey Ronney, thanks for checking in! Unfortunately, this is not an option since they are different boxes. Feel free to give our portal support team a call at 855-743-3427 for any questions!
What is the estimated time on putting 4″ portal kit on a teryx4?? Thanks..
Depending on the mechanic ability, it could take anywhere from 3-5 hours. Thanks for tuning in!
I have a 2018 Maverick X3 XMR Turbo R (72″ model). The engine, clutch and suspension are stock. I have flashed the ECU to lower the fan temp with the Dynojet PV3. Since then I have added GDP portals at 30% reduction and 35″ Motohavoks. I’m not sure what the stock gear ratio is on the XMR’s but I’ve now added 30% more reduction so I’m sure it’s due to the higher RPMS it is now running but now it is running a bit hotter than I would like. When in the mud (mostly clay) it’s not unusual to see 210-215°F. I was wondering if I should make adjustments or upgrade the stock clutch or maybe add a second radiator to help with this. With the added dear reduction I operate in Hi most of the time as well since Lo is extremely Lo
Hey George, we appreciate you reaching out! Your question is a hard one. There could be any combination of issues. You could have air in the system, dirt or mud in the radiator, or you could even just have a plugged-up air filter. Unfortunately, we do not currently offer clutches or radiators for this machine, so it’s hard for us to pinpoint the exact issue.
I have a Polaris sportsman 850 with 31” out laws and im thinking of install portals on it i do a combination of trail riding and mud riding and was wondering which gear reduction i should go with the 15% or the 30% i rarely get the bike above speeds of 30 mph since I enjoy just cruising
Hi Dylan! You really can’t go wrong either way. Something that might help you make the decision is our portal calculator. It’ll give you an idea of where you’ll be speed wise. Check it out: https://www.superatv.com/portal-calculator Thanks for the support!
I have a Polaris General with a 24% gear reduction in the transmission. I currently have 32″s and looking at 4 inch portals. Since the transmission is done, what gear reduction do you recommend, 15% or 30%? Would never go larger than a 35 inch tires. Also, how far does the portals push the tires out per side. Thank you
Hey Rick! For gear reduction recommendations, it really depends on what kind of riding you’re going to be doing the most. Check out our portal calculator to help you make the decision: https://www.superatv.com/portal-calculator. Lastly, the portals will push out 4″ per side. We appreciate the support, and thanks for checking in with us!
I have a 2018 Polaris Ranger Crew 900 with an 8″ lift, 15″ rim, and 35″ tires and im looking to go with the 6″ portal gears. Can I run spacers in order to keep the 15″ wheels I have on now? Also, what would my ideal tire size be for a total of 14″ lift?
Thanks for checking in! Unfortunately, we wouldn’t recommend the number of spacers you would need for clearance. With our 6″ suspension lift and 6″ portal gear lift, you would be able to clear a 38″ tire with no contact.
I have a 2018 ranger xp 1000 looking to install 2 inch forward A arms 6^ portals on 33 what gear ratio would I use
Then if you wanted to use 35s will the gear ratio be the same
Hey Andy! What gear ratio you use is all going to depend on what kind of riding you do the most. Or are you more interested in figuring out what tire size would get you back close to stock? Check out our portal calculator as it may be helpful in figuring out what you’re after: https://www.superatv.com/portal-calculator
I have a 2016 Rzr 1000 Turbo, I have two sets of wheels/tires. The stocks and an aftermarket mud set ( 35 inch tire and 20 inch wheel) I love the way it runs and the speed it produces. I like to trail ride and the occasional mud hole along the way. I don”t plan on mud Bogging but I do like to hit a hole here and there so my question is. With a 6inch portal and my mud set… 35 inch tire with a 20 inch wheel, am i going to loose my top end speed?
Hey Darius! If you choose to go with the 30% gear reduction on our 6″ GDP portal gear lift, you should balance out your top end speed by running 35″ tires at a decent amount, while increasing your acceleration speed. You can also help improve top end with a clutch kit and/or ECU tuning. Here is a link to our portal calculator that should give you a better idea of where you would be at speed wise with each gear reduction option as well as tire size. https://www.superatv.com/portal-calculator Thanks for the support!
I have a 2021 Polaris general XP four deluxe will a 4 inch portal keep my 33” tires from rubbing the bike
Hey Jimmy! We have to be careful about recommendations like this because each machine will be a little different due to shock/spring wear. So if there is any type of contact at full shock compression or turn, we have to say it doesn’t fit. I will say that we’ve got some offset arms that are in the works that should help with this, but we’re still a couple months out ETA wise. Feel free to check back in with us!
Have 4 inch portals with 32 inch juggernauts on my maverick xmr. Speedo says 82 mph but GPS said 51mph. What’s the gear ratio?
Hey Alex, thanks for checking in! It’s hard to say for sure without more information, but based off what you’ve said, it sounds like you’ve got a 30% portal. Feel free to call in at 855-743-3427 to confirm.
Tyler first I’d like to start by saying what an incredibly well written article. Your advice to other riders above has completely convinced me that these portals are the only way to go. Ok, so here’s my situation: Tomorrow I’m buying a 2019 RZR XP 4 1000 HighLifter. Currently sits on 29.5” tires on a 14” rim. Based on height restrictions in my garage, I think the max height I’ll be able to go with, will be the 4” portal with a new set of 18 or 20” rims on 35” mud tires. My question, is how much gear reduction should I go with? Also, do you think the dual idlers are substantiated for a novice trail rider like myself? Or is the added strength more suited for hardcore muddies and rock crawlers? Appreciate your help!
Hey there, Steve! With 35″ tires, we recommend a 30% gear reduction. You’ll need the extra torque to turn those big ol’ tires! And when it comes to the dual idler option, we absolutely recommend it! Dual idlers are a no-brainer in almost any situation, and well worth the investment. It sounds like you’re going to have a pretty sweet setup! Thank you for reading!
im ordering 18″ STI HD Beadlock wheels for 17 x3 on 6″ portals. will a 6+1 rim work
Hey Nick! The wheel requirements for this are: 1) 18″ or larger wheel, 2) 18″ wheels cannot exceed 4-1/2 backspacing, and 3) 20″ and larger wheels cannot exceed 5″ backspacing. Thanks for checking in with us!