- Don't you just wish there was a car out there
that could conquer the dirt, the dunes, the track,
even a freaking frozen lake,
but still be able to legally drive it on the street?
If you look at the history of do-it-all vehicles,
they often tend towards making design compromises,
rather than achieving the best of multiple worlds.
But, there's one company out there making cars
that don't only do it all,
they do it all very, very well.
If you took your childhood go-kart
and it made sweet love to a trophy truck,
and then that creation then made sweet love to a motorcycle,
you'd have this.
(motor revving)
And today, we're gonna figure out
how the engineers over at Sierra built one of the coolest
and most versatile vehicles of all time.
They did a sub 10 minute Pikes Peak run in this thing.
Then they gotta swapped out the wheels
and freaking jump this (beep) in the dirt.
If that doesn't tingle your freaking car loving bones,
then you must be a jellyfish.
Don't be jelly.
Get boney.
Let's go.
(upbeat music playing)
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- Trying to drive on different terrains
can make wildly different demands
on both the car and the driver.
You need a totally different set
of tools to drive on asphalt, dirt, or ice.
So how does Sierra Car in their RX3,
dominate each of these surfaces?
Well the answered lies in the sum of its parts,
as well as the very lightweight of all those parts.
Power to weight ratio is a big part
of what makes this car so versatile.
Let's start with the weight,
which is largely dictated by the frame.
The RX3 is super lightweight,
because of a tube frame chassis.
Now road cars are gonna be a lot heavier
because of their frame.
Even the lightest cars out there,
made with a an aluminum alloy frame
will weigh more than anything on a tube frame chassis.
The total weight of a super light car,
like a Lotus Elise is gonna come in in about 2000 pounds.
The overall weight of the RX3 is a mere 950 pounds.
That is super impressive and a major part
of the overall agility of the vehicle.
Now weight was kept to a minimum
by utilizing finite element analysis or FEA,
oh, that brings me back to the days of college.
Oh, you gotta do an FEA analysis on this frigging pin.
We had to design pins in school.
The Sierra team was able to run stress simulations
on 3D modeled components,
by simply applying computerized forces to certain surfaces.
The geometry and overall design of the RX3's parts
are such that the car stays as light as possible,
while still retaining the necessary strength needed
to resist strain or deformation.
You don't know about strain and deformation?
Cool, those are two big words you're gonna learn
in college, maybe.
Strain is the ratio between deformation
and the original length.
Deformation, is a measure of how much an object is stressed.
That being said, this frame makes
for an incredibly sturdy and responsive environment
to cradle the driver.
The frame is rigid and maintains its ability
to transfer vibrations to your butt.
Now that obviously doesn't make
for the most comfortable every day driving,
but those vibrations, being able
to feel what's going on underneath you,
is what allows you to make the right decisions
at the right moment.
Like not hitting this Prairie dog crossing the street,
while you're doing a Pike's Peak run.
And whether you're on dirt or asphalt,
being able to feel and respond to your environment is key.
Adding to the lightness of the car, they ditched the doors.
Other than being a mechanically fun aspect of the car,
not having doors, having to slide through the window,
it also serves a purpose.
If your goal is to shed pounds,
one way to do that is by removing not only the doors
but all the hardware and hinges associated with it.
They save 10 pounds per door by doing that.
And that might not seem like a lot,
but on a 950 pound car, that's 2% of the weight.
So finding 2% throughout the car,
helped make this a sub 1000 pound vehicle.
But the next part of that weight to power to ratio,
is the power part.
That's the fun, okay?
You guys know me, I'm a power bottom.
So I like talking about low end grunty power.
So when you're looking for an engine,
to power your lightweight Swiss army knife
of a car, where do you go?
Well, you need an engine that also is lightweight,
makes a lot of power, and as a bonus,
I don't know, can rev up to 11,000 RPM.
How do they go about doing that?
Well, luckily, Suzuki already makes said engine.
Sierra uses none other than the four banger
from the Hayabusa, the peregrine falcon itself
to power its cross cards.
Peregrine falcon!
Pew. Pew. Pew.
(mimicking bird sounds)
Hayabusa in Japanese, literally means Peregrine falcon.
A 1.3 liter, 16 valve, inline four,
capable of 200 horsepower.
By pairing that engine with its lightweight frame,
it gives the RX3 a power to weight ratio
of 4.6 pounds per horsey.
The lower the number, the better.
So for example, the GT3 RS, wild regarded as having one
of the better power to weight ratios out there,
comes in at 5.99.
That's a $200,000 car.
The RX3, it costs 30 grand and it smokes it.
Freaking heck yeah, man.
And really, I don't wanna distract too much from this,
but the Pontiac 6,000 LE comes in at a crazy 3.21.
If you wanna know more about power to weight ratios
and why decreasing weight is important,
click this right here.
We did a whole episode on it.
I promise you, you'll learn something.
Maybe even cry.
Now there's no question that the RX3 engine
is capable of putting out a lot of power,
but that means it needs a transmission strong enough
to withstand the abuse from the Hayabusa engine.
And solution was found in a bulletproof racing transmission.
A six speed sequential was implemented
to send power to the wheels.
This transmission is a bit different,
than ones you'll find in most road going cars.
The gears in this guy are straight cut,
meaning that the gear box is less prone
to self-destruct and the overall assembly
is lighter than that of road cars with helical gears.
The straight cut gears makes their gear stronger
than their everyday driving helical counterparts.
Additionally, the carburization process
makes the gears harder at the teeth surface,
while maintaining strength throughout the part.
Both the mechanical and material design choices,
make for gears that can withstand shifting
at 11,000 RPM without snapping teeth off.
And the transmission, it's not just tough,
it's also smart.
It's got a flat shift sensor, which acts as shift assist
so you don't have to cut as much throttle,
when you go to shift gears.
A sensor reads tension on the shift knob
and then cuts ignition for gear change.
So the driver can stay at high throttle,
slam through the gears and worry less about grinding.
This makes it possible to drive more aggressively
and shift harder, which is perfect
for doing things like this.
(motor revving)
But having a good power to weight ratio
is all well and good,
but you to be able to get that power to the ground.
So what do they put in this sucker?
A limited slip differential or LSD.
Freaking groovy man.
An LSD distributes power to the wheel with the most grip,
maximizing traction in any scenario.
So at the track, an LSD improves corner inability
by allowing the inside wheel
to rotate faster than the outer wheel.
Helpful, since your outer wheels have to travel
a longer path than the inner wheels during a turn.
If your wheels rotate at the same speed,
you're gonna get slippage,
which will have you sliding all over the place,
might be fun for drift, but not for going up Pikes Peak.
And when you take the RX3 off-road,
an LSD helps improve handling as well.
The LSD allocates power to the wheels,
which reduces wheel spin
to an unloaded or less loaded tire.
So even if the two drive wheels
are traveling over different surfaces,
each will stay at the limit of grip,
optimizing the vehicle's ability to accelerate and handle.
We actually talked about this more
in an episode we released a couple weeks ago,
check it out here.
You got a whole catalog videos.
You can just learn, learn, learn.
Learn, and laugh.
Learn and laugh.
(upbeat music plays)
A part of what makes this car so unique
is that the tires were designed to play
an active role in the suspension setup.
You can take this car anywhere
in large part because you can put nearly any tire on it,
thanks to it having an open wheel suspension.
Normally, if you wanna put big nobby tires on your mudder,
you need to install lift,
and rip out the fender flares to fit them.
But you don't need to do that with an open wheel design.
If you know how to turn a wrench,
you can completely transform the vehicle's performance.
With just three different tires
you can go from track, to dunes, to ice.
Now on the track you want wide tires
that maximize the tires footprint,
for sand, bigger tires with aggressive treads
will do the trick,
and studded tires will get you across
a slippery ice surface.
Now another benefit of an open wheel suspension
is that it gives the vehicle excellent balance.
The driver in a single seat, the center of mass
of the vehicle is pretty similar
to that of a mid engine car.
Most of the weight of the vehicle comes from the frame,
the power train and the driver,
all which exist in a centralized location.
The control arms, the wheels, the brakes,
those are the only systems contributing weight
to the periphery of the vehicle.
But you might be thinking,
Hey, okay you can put different wheels on there,
but what about the suspension components themselves?
Now, how is it possible that changing only the tires
can effectively turn the RX3 into three different cars?
Well, the answer is, compromise in your suspension.
The designers of the Sierra RX3 didn't set out
to build a suspension that was perfect
for every environment.
They set out to create the best suspension
that could transition between environments
and transition with minimal effort.
But it can get to about 80% of what either can do
and most importantly,
can go between either setting with very little effort.
Now, while you don't technically have
to change anything to go between track and dirt in the RX3,
other than your tires,
you can still make small changes
to your suspension setup to maximize your performance
and you only need one tool to do it.
So what makes the RX3 so good on and off the road
is that it has a lot of adjustability.
For instance, we have this rear sub frame right here,
it's made out of billet aluminum
and these arms right here are adjustable,
so that you can control your camber on the rear wheels.
Now inside right here, we have a toe adjustment.
We have a sway bar right here, which is really, really cool.
Now this sway bar, is a torsion bar inside this sleeve.
And a torsion bar is you might have seen
on Porsche's, if you're a Porsche guy,
that's the main weightbearing spring
in the suspension system.
But what they have here, is they use that as the sway bar.
So they have two arms right here that also can be adjusted.
You can then adjust this bar
by taking it out and replacing it
with a completely different spring rate torsion bar.
So another way to change the stiffness
of this sway bar is this slotted arm right here.
So you can undo this linkage
and shift it into each of these holes.
This is in it's softest setting,
right here is in its stiff setting and it's on both sides.
Right here, we have trailing arms.
So there's two adjustments for this trailing arms too.
One is the vertical setting,
which will change the pitch of the rear end of the car.
And the second is this threaded rod right here,
which can actually lengthen the wheel base of the car.
Pretty cool.
Now upfront, we have some adjustability as well.
We got this same sway bar system,
with the torsion bar, same exact principle.
We can change that torsion bar and change the slot here.
And we have adjustable A-arms.
We did a whole episode where we talked
about adjustable A-arms on the catfish.
If you want more info, you should freaking click right here,
get your cat catfish on man.
This thing's like a catfish baby.
So all that adjustability allows this car
to be really good on asphalt and dirt.
Hmm.
And we're about to get dirty.
(upbeat music plays)
(motor revving)
The RX3 runs spring rates that are soft enough
for dirt and it has sway bars
that are stiff enough for the track.
The upper A-arms are adjustable with threaded castor
and camber adjusters within,
and roll center adjustment in the upper control arm.
You can detach the sway bar completely
for off-road performance using just a single wrench.
Having sway bars on, gives you better performance
on the track, taking them off,
better performance on the dirt.
Beyond being able to just take them on and off,
the sway bars run a spline bar with adjustable ratio.
There's six different sway bar settings
going from soft to stiff,
all controlled by the same single bolt you change,
if you were to disconnect it.
So if you wanna go from 30 inch off-road tires
to 13-inch slicks and get the max result from either,
all you need to do is just adjust the sway bar.
Now let's say you want to tune the car even more,
get even more out of the Swiss army knife of cars.
Well, you get to keep all the same suspension components
between environments.
You don't have to change your shocks or your springs,
however, by detaching one bolt off the front shocks
you can toggle between stiff and soft.
The shocks were designed in tandem with Zebroz,
who are the best known for making snowmobile suspension.
They modified their existing suspension,
perfect for dirt and made some small tweaks
that enhanced the suspension's asphalt performance.
The RX3 has the potential for 12 inches
of wheel travel, baby, from rear to front.
12 inches, oh, no big deal.
It has adjustable motion ratio, which means the rate
in which the spring gets compressed can be changed.
This allows you to change the effectiveness
of your springs without actually having
to change the springs themselves.
Pretty freaking cool.
Three points of motion ratio take the RX3
from eight to 10 to 12 inches of travel.
Then, you've got a two way adjustable shock
with both compression and rebound adjustment.
You've got a two and a half-
(fly buzzing)
You got a two and a half inch shock in the rear
and a two inch shock in front.
All four are which equipped
with external nitrogen filled reservoirs.
So the goal of the RX3's designers was
to keep the same suspension kinematics,
how that suspension behaves in its range of motion,
across any surface that it might be traveling on.
This means that the core components behind movement
don't change, but the ratio
at which the spring can change does.
The RX3 is able to conquer essentially any arena
because it was designed to be able to conquer any arena.
Add in a surplus of power and customizable suspension
and it's a combination that's hard to beat.
So this answer makes sense on paper,
but here at B2B we thought,
that it would be necessary to confirm this
by doing a bit of field testing.
So we took a few RX3's out for a spin
and we ran a couple tests, you know, for science and all.
(motor revving)
(upbeat music plays)
(upbeat music continues)
- [Camera Man] You good?
- I blew the tire off.
I don't wanna say I'm proud of that, but it's pretty cool.
I don't know when I lost it though.
- [Cole] Hello?
- Is this Cole?
- [Cole] Yeah.
- Hey Cole, this is Jeremiah.
I'm sorry, man.
(whimsical music plays)
- [Cole] I got a spare here. - Okay.
- [Cole] Bring the 4Runner back.
- Okay.
- [Cole] Floor jack it and a spare tire
and we'll jack up and put a new tire on.
- Okay, cool. Sounds good. We'll be right there.
- [Camera Man] I'm running outta gas.
I'm on empty.
- Really? - [Camera Man] Yeah.
- In your 4Runner?
- [Camera Man] Yeah.
- Oh great.
(whimsical music plays)
Beautiful.
Thanks so much for watching this episode of B2B.
If you wanna see more content like this,
leave a comment down below.
Hit that like button, subscribe button
that really helps us out.
We appreciate you guys.
If you want your own RX3 from Sierra Cars,
hit the link in the description below.
And if you don't happen to have 50K
just burning a hole in your pocket,
Cole does rides in these,
so you can pay 75 bucks or something and rip a couple laps,
which I can guarantee you will be the most fun
that you've ever had on four wheels.
This is definitely one of the highlights
of my auto driving career.
So go check him out, support Cole.
He's a good dude.
Follow us on Instagram at Donut media.
Follow me @jeremiahburton.
And until next week.
Bye for now.