SKAT-TRAK WARLOCK BY EXTREME TIRE 30X11X14
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sand shark
Well-Known Member
That looks like a big tire. Put it up next to the 28" Blaster so we can see the size difference.
sand shark
Well-Known Member
cool
August 23rd, 2011, 02:44 PM #1
Waszak1977
First Name: ╠══MIKELANGELO══╣
My RZR: ╠═o8 FULLBORE TURBO═╣
Member #18310
Join Date: Sep 2010
Location: ╠══════HAARP═════╣
Posts: 3,685
Garage
(1)
Tire/Wheel Weight & Rotational Mass VS. HP!
OK, I finally got digging into how much Horsepower (HP) one loses for the weight of adding bigger tires &/or just changing out tires & Wheels. This does not just go for "Duner's".....
At first I didn't know if this was rated as Crank HP numbers or RWHP numbers, UPDATE, It is RWHP Numbers!
Also at the end I'm going to address some questions of my own as not everything "adds up". Read on, you'll see what I mean..
A huge thanks to Dave Kuskie of Fullerton Sand Sports - Distributer of Performance Tires & Wheels
I was careful to take everything word for word on the accounts & testimony from the SXS Mania DVD Produced by Greg Painter.I know that the numbers are not exact & scientific but do get us close..
So here we go, I knew that the weight of your wheels & tires combined had an effect on the amount of HP & performance of our RZR's but just not as much as this! Now this is geared for "Duners" (but only at the beginning), but I will close this with adding in accounts of my own RZR running semi-heavy Kenda Executioners (Medium Mud Tires) rated a step(Class) below Silverbacks, Terminators ect.. I'll even talk about the Silverbacks.
Performance: Wheel weight alone is huge, Often it gets overlooked as most worry about the weight of the tires. This should change your thinking. Be it your wheels are Stock & Steel, Aluminum Milled, Spun Aluminum, or Cast.. This difference is staggering! I could do a whole thread on just wheel weights, let alone tires.
The following is info, ratio's, ect.. From SXS Mania
Rotational mass on a UTV is huge for every 1 pound that you add to the back of a tire over another set your basically losing 1 HP then you multiply that X 4 so you can imagine how much advantage there would be running a lighter tire & wheel set.
For you Duners'
If you're in virgin pure sand all the time & you don't have to worry about sticks, stones, or junk that will be in the sand, you can run a thinner treaded tire. Which reduces the weight, the rotational mass & improves your performance of your UTV or ATV. Anything that's on a tire from the Mohawk(Picture's Below) to a paddle is all rolling resistance the more paddle's & the more lugs you have on the Mohawk (or any tire for that matter) that's rolling resistance which pulls the power of the vehicle down, the more paddles you put on there the slower it will run Mile a Hour(MPH). The wider the tire is the more rolling resistance it has because it flattens the paddle out & puts more square inches of paddle in the sand. It also slows the vehicle down, but you have to figure out where that happy medium is for the right amount of hook-up, right amount of climb, right amount of performance, & still pull the right performance MPH for you. The guys that are wanting to get the fastest tire possible want to run the least amount of paddles as they can to get the car to leave on & the least amount of rolling resistance & a narrower tire. The narrower the tire the less rolling resistance there is because it crowns the paddle and it lifts the paddle out of the sand the smoothies on the front have no rolling resistance they run faster MPH in a straight line. Handling in the sand that's moist, the smoothies actually still turn pretty decent even in 2wd when it get lighter & fluffier the smoothies will push a lot (in 2wd). You run it in 4wd & you got it turning & actually helps pull the cars around.
Skat Trak Smoothies, Skat Trak MoHawks, & Skat Traks Paddle's
So taking this information from Dave Kuskie @ Fullerton Sand Sports & Applying it to the everyday rider it can help us make better decisions as to what we want. Some just want big heavy mud tires & don't really care, After all, How can we make it through the Mud w/o the big huge bulky tires.... Well I'm sure about 90% of you have been to Monster Truck races & seen the tractor pulls.. I'd safely say 99.9% of them where more worried about how much horse power was spinning them wheels then how they "dug in".. Also most had the same tires anyways, Kinda like Silverbacks at Mud-Nats.. HP Wins..
Now my Kenda Executioners (Considered Medium Class Mud Tires) are sized & weighed at: Not counting Wheels
27x10-12 @ 31 Lbs. ea. X2
27X12-12 @36 Lbs. ea. X2
Total weight 134Lbs. Total @ 72 Lbs just rear.
If I decide to Purchase the Maxxis Bighorn 2.0's Lets see the difference.. **Now If I do, This time I'm getting all 4 tires the same size so its easy if I need to use my spare.
Maxxis Bighorn 2.0's
26X9-12 @ 21.2 Lbs ea. X4
Total weight 84.8 Lbs. Total @ 42.4 Lbs. Just rear.
Total savings of all 4 tires is 49.2 Lbs. (Or according to the above statements just short of 50HP) Now, More practically lets look at just rear wheel drive. Total savings of just the rear tires is 29.6 Lbs. (Or according to the above statements just short of 30HP)
OK, Going one step further... The Gorilla Silverback
32x10-14 @ 52 Lbs. ea. X4
Total weight 208 Lbs. Total @ 104 Lbs. just rear.
Ok now if I took the same comparison to the Maxxis Bighorn 2.0's then the Total (savings) weight differance on all 4 tires is 123.2 Lbs., If I go off the equation/ratio that "basically" every pound added to a tire/wheel setup costs you 1HP then we have a mathematical issue as the RZR doesn't have 208 Hp let alone should be able to run them if all of this was that "Simple".
The best I can come up with is that there is a range in the RZR's (doesn't matter which RZR or UTV for that matter), but there's a range that is actually effected by the weight of these tires/wheels that can be calculated. Dave @ Fullerton Sand Sports gave us a baseline to work with sand tires. The weights on those setups he puts together with spun Aluminum DWT Wheels might actually be dead on for that category.Remember he said "Basically" a loss or gain of 1 HP per pound..
I decided to start this thread as I'm sure not everyone has seen the DVD & we as members & a community can add to it. If you have tried different setups on a Dyno & know what different weights the wheel/tire combo's has made on the actual HP be it RWHP or at the crank it welcome here.
Lastly, I've tried to remember but my memory is a bit on the lacking side but I did see at one time a way that you could mount a wheel & tire to a machine, even a home-made "meter" to gauge just how much force and/or energy it takes to spin that wheel. Just looking at it that way it's obvious the improvements over using lightweight wheels & tires far out weight the benefits of adding bolt on engine improvements with outrageous claims. When you can spend $900 bucks on a Dual exhaust thinking you are getting 5-HP in gains, Turns out a lighter set of tires might just get you much more than that....
Waszak1977
First Name: ╠══MIKELANGELO══╣
My RZR: ╠═o8 FULLBORE TURBO═╣
Member #18310
Join Date: Sep 2010
Location: ╠══════HAARP═════╣
Posts: 3,685
Garage
(1)Tire/Wheel Weight & Rotational Mass VS. HP!
OK, I finally got digging into how much Horsepower (HP) one loses for the weight of adding bigger tires &/or just changing out tires & Wheels. This does not just go for "Duner's".....
A huge thanks to Dave Kuskie of Fullerton Sand Sports - Distributer of Performance Tires & Wheels
I was careful to take everything word for word on the accounts & testimony from the SXS Mania DVD Produced by Greg Painter.I know that the numbers are not exact & scientific but do get us close..
So here we go, I knew that the weight of your wheels & tires combined had an effect on the amount of HP & performance of our RZR's but just not as much as this! Now this is geared for "Duners" (but only at the beginning), but I will close this with adding in accounts of my own RZR running semi-heavy Kenda Executioners (Medium Mud Tires) rated a step(Class) below Silverbacks, Terminators ect.. I'll even talk about the Silverbacks.
Performance: Wheel weight alone is huge, Often it gets overlooked as most worry about the weight of the tires. This should change your thinking. Be it your wheels are Stock & Steel, Aluminum Milled, Spun Aluminum, or Cast.. This difference is staggering! I could do a whole thread on just wheel weights, let alone tires.
The following is info, ratio's, ect.. From SXS Mania
Rotational mass on a UTV is huge for every 1 pound that you add to the back of a tire over another set your basically losing 1 HP then you multiply that X 4 so you can imagine how much advantage there would be running a lighter tire & wheel set.
For you Duners'
If you're in virgin pure sand all the time & you don't have to worry about sticks, stones, or junk that will be in the sand, you can run a thinner treaded tire. Which reduces the weight, the rotational mass & improves your performance of your UTV or ATV. Anything that's on a tire from the Mohawk(Picture's Below) to a paddle is all rolling resistance the more paddle's & the more lugs you have on the Mohawk (or any tire for that matter) that's rolling resistance which pulls the power of the vehicle down, the more paddles you put on there the slower it will run Mile a Hour(MPH). The wider the tire is the more rolling resistance it has because it flattens the paddle out & puts more square inches of paddle in the sand. It also slows the vehicle down, but you have to figure out where that happy medium is for the right amount of hook-up, right amount of climb, right amount of performance, & still pull the right performance MPH for you. The guys that are wanting to get the fastest tire possible want to run the least amount of paddles as they can to get the car to leave on & the least amount of rolling resistance & a narrower tire. The narrower the tire the less rolling resistance there is because it crowns the paddle and it lifts the paddle out of the sand the smoothies on the front have no rolling resistance they run faster MPH in a straight line. Handling in the sand that's moist, the smoothies actually still turn pretty decent even in 2wd when it get lighter & fluffier the smoothies will push a lot (in 2wd). You run it in 4wd & you got it turning & actually helps pull the cars around.
Skat Trak Smoothies, Skat Trak MoHawks, & Skat Traks Paddle's
So taking this information from Dave Kuskie @ Fullerton Sand Sports & Applying it to the everyday rider it can help us make better decisions as to what we want. Some just want big heavy mud tires & don't really care, After all, How can we make it through the Mud w/o the big huge bulky tires.... Well I'm sure about 90% of you have been to Monster Truck races & seen the tractor pulls.. I'd safely say 99.9% of them where more worried about how much horse power was spinning them wheels then how they "dug in".. Also most had the same tires anyways, Kinda like Silverbacks at Mud-Nats.. HP Wins..
Now my Kenda Executioners (Considered Medium Class Mud Tires) are sized & weighed at: Not counting Wheels
27x10-12 @ 31 Lbs. ea. X2
27X12-12 @36 Lbs. ea. X2
Total weight 134Lbs. Total @ 72 Lbs just rear.
If I decide to Purchase the Maxxis Bighorn 2.0's Lets see the difference.. **Now If I do, This time I'm getting all 4 tires the same size so its easy if I need to use my spare.
Maxxis Bighorn 2.0's
26X9-12 @ 21.2 Lbs ea. X4
Total weight 84.8 Lbs. Total @ 42.4 Lbs. Just rear.
Total savings of all 4 tires is 49.2 Lbs. (Or according to the above statements just short of 50HP) Now, More practically lets look at just rear wheel drive. Total savings of just the rear tires is 29.6 Lbs. (Or according to the above statements just short of 30HP)
OK, Going one step further... The Gorilla Silverback
32x10-14 @ 52 Lbs. ea. X4
Total weight 208 Lbs. Total @ 104 Lbs. just rear.
Ok now if I took the same comparison to the Maxxis Bighorn 2.0's then the Total (savings) weight differance on all 4 tires is 123.2 Lbs., If I go off the equation/ratio that "basically" every pound added to a tire/wheel setup costs you 1HP then we have a mathematical issue as the RZR doesn't have 208 Hp let alone should be able to run them if all of this was that "Simple".
The best I can come up with is that there is a range in the RZR's (doesn't matter which RZR or UTV for that matter), but there's a range that is actually effected by the weight of these tires/wheels that can be calculated. Dave @ Fullerton Sand Sports gave us a baseline to work with sand tires. The weights on those setups he puts together with spun Aluminum DWT Wheels might actually be dead on for that category.Remember he said "Basically" a loss or gain of 1 HP per pound..
I decided to start this thread as I'm sure not everyone has seen the DVD & we as members & a community can add to it. If you have tried different setups on a Dyno & know what different weights the wheel/tire combo's has made on the actual HP be it RWHP or at the crank it welcome here.
Lastly, I've tried to remember but my memory is a bit on the lacking side but I did see at one time a way that you could mount a wheel & tire to a machine, even a home-made "meter" to gauge just how much force and/or energy it takes to spin that wheel. Just looking at it that way it's obvious the improvements over using lightweight wheels & tires far out weight the benefits of adding bolt on engine improvements with outrageous claims. When you can spend $900 bucks on a Dual exhaust thinking you are getting 5-HP in gains, Turns out a lighter set of tires might just get you much more than that....
I posted up that old post from RZR forums and its from 2011 now nobody really talks about weight and Rotating mass weight and how hard it is on the performance of these cars but same is true for all motor sports. He'll look at the drive shafts in your truck there aluminum most of the time.
Sent from my SM-N915T using Tapatalk
Sent from my SM-N915T using Tapatalk
sand shark
Well-Known Member
It was certainly an important topic when a SXS had 28 to maybe 50hp.
. Your kidding right. Lmao. These things only put down about 90 hp now.on average. Weight and especially Rotating mass is huge and it is even more important on these under powered cars. Every bit counts. Look at ford's new F150 all aluminum and that Eco boost makes good power. So you might want to re think your position on that comment. I'm worried now lol. Common sense tells ya weight savings is the best way to go when you want more out of your machine and it doesn't matter if it's a Nascar or SXS
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sand shark
Well-Known Member
No I get it. My point is on the under powered stock Rhino, Teyrx, and RZR800 any weight savings made a huge difference. On my rhino I replaced the stock bed with an aluminum one to save weight.
With the 100+hp SXS a 28 pound overall difference in your paddle tire set up compared to another set up is not going to be as dramatic of an effect. It becomes more the paddle set up and flotation that make a big difference. Now start adding every accessory, bumpers and other stuff to your SXS making it a big fat pig and then yes the weight of the paddle tire set up will play a huge role.
If you paddle set up weighs less than your stock tire set up you are already ahead of the game, correct?. So then paddle set up and flotation become your concern.
There is that fine line between too much bite and too much spin and finding the happy medium is where you want to be.
By the way Ford went with the new design to decrease weight to up the payload and towing capacity. There is not fuel savings with the claimed 700lb lighter design. The Ecoboost has a ton of power and torque.
megadesertdiesel
Well-Known Member
My lightweight setup.
26x12.5x12 7 paddle skats 85" roll out, 13.5#
12x8 .50Caliber beadlocks 11.5#
25# total
work great for my XRS, but i do bottom out on hard G-outs.
26x12.5x12 7 paddle skats 85" roll out, 13.5#
12x8 .50Caliber beadlocks 11.5#
25# total
work great for my XRS, but i do bottom out on hard G-outs.
Well your really missing the point that Rotating mass is a huge deal and if you can get the Rotating mass down as best as possible that will be a huge gain. Say for example you have a set of 4 tires and rims, mud tires, dirt tires, what ever it is and another set of 4 tires and rims that are a total of 54 lbs heavier. On a small engine making a whopping 88 hp do you think 54 lbs less Rotating mass is gonna be substantially noticed when Accelerating and also braking to. Common sense alone will tell you yes the motor will like to spin up easier. I also believe in over weight savings like what ford does to as my example. But my big point of focus is the Rotating mass that the engine deals with. We're gonna do a dyno run soon to show what happens when you have identical roll out but weight is significantly different and how the motor reacts to the difference in Rotating mass. It's obviously a big enough deal that motor builders like to lighten cranks and other Rotating assemblies. Also aluminum drive shafts. My buddies boy races them motocross bikes and there is a super light bolt kit for the bike that shaves of something like 7lbs and that titanium bolt kit costs 11k. So it is a huge deal all the way around. If we can get light weight wheels and tires it's huge. He'll to go overboard you could build some aluminum drive shafts to. Axles obviously would not survive but it would help if it was possible.
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My lightweight setup.
26x12.5x12 7 paddle skats 85" roll out, 13.5#
12x8 .50Caliber beadlocks 11.5#
25# total
work great for my XRS, but i do bottom out on hard G-outs.
View attachment 11693
Hey Mega what would you like to run on your car, a 25lb rear tire or a tire &wheel combo of 43lbs each rear. for a difference of 36 pounds of Rotating mass on the rear alone then lets say your fronts weigh in at 23lbs each vs a front that weighs in at 33 lbs. so 20 lbs of rotating mass up front so 56lbs of total rotating mass. how well would your car like that weather you have 80hp or 180 hp.
Attachments
Hey Sandy Blaster STU. Skat-Trak on a 10" wide rim at 15 psi , STU on a 10" Rim at 15 psi also.
Skat-Trak 30 x 13 x 14 (94" Rollout) weighs in at 27 lbs on rim.
STU 28" (88" Rollout) Blaster on Method Beadlock weighs 43. lbs.
Also weighed the Skats 30 on the GMZ Venomous 10" wide wheels weighed 30.75 lbs
Attachments
sand shark
Well-Known Member
That is a big light ass tire! Now throw them on the method rims and weigh them.
The 94" rollout should do well in the sand. Can't wait to check them out at the sand show.
The 94" rollout should do well in the sand. Can't wait to check them out at the sand show.
sand shark
Well-Known Member
Now back to your rotating mass - shouldn't we all be looking at the lightest rim possible? Seems the popular beadlock rims weigh a lot.
So to be fair - mount those blaster on the rim you use on the skats and lets see the weight difference. I am sure the skats are still much lighter, but I am guessing it won't be a 16lb difference..
So to be fair - mount those blaster on the rim you use on the skats and lets see the weight difference. I am sure the skats are still much lighter, but I am guessing it won't be a 16lb difference..
Thats a great idea sandy but for anything other than straight forward running on the STU they have to pretty much have to run a Beadlock wheel. Many many moons ago Sand tire was sued by a family whose son had a bent rim and stuffed a rag in it to help get the tires bead to seat up and as he was airing it up the rim came apart and killed the poor guy.
So afterwards Sand Tire runs there beads a little bit looser so they seat up at a lower air pressure. Well when the tires seat up at about 7 to 8 psi which is low it then means the same for coming off the beads which sand tire is known for. Skats seat up over 15psi and they are very tough to get back off the beads. That's why STU tires run the bead lock rings cause they come off easily. So yes it would be nice if a guy could run a light weight rim on the STU but most guys run them under inflated like 8 psi range. Running a paddle tire of any make under 15psi is not good because these cars are in the 2000 lbs range and with the G-Forces involved bottoms the rim. Out as it crushes down with low air pressure. People air paddles down thinking it runs better because the tire slips more. Airing a paddle tire up makes the paddles more ridged and bites harder and if you have to many paddles it will feel slower.
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So afterwards Sand Tire runs there beads a little bit looser so they seat up at a lower air pressure. Well when the tires seat up at about 7 to 8 psi which is low it then means the same for coming off the beads which sand tire is known for. Skats seat up over 15psi and they are very tough to get back off the beads. That's why STU tires run the bead lock rings cause they come off easily. So yes it would be nice if a guy could run a light weight rim on the STU but most guys run them under inflated like 8 psi range. Running a paddle tire of any make under 15psi is not good because these cars are in the 2000 lbs range and with the G-Forces involved bottoms the rim. Out as it crushes down with low air pressure. People air paddles down thinking it runs better because the tire slips more. Airing a paddle tire up makes the paddles more ridged and bites harder and if you have to many paddles it will feel slower.
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