- It's probably the easiest way
to change the way your car looks and the way it handles.
Today I'm gonna show you how to pick the right wheels
for your car, including size, material,
offset calculation, all that jazz,
and then I'll show you how to pick the right tire
for whatever it is you're doing,
drifting or carving the canyons or whatever.
I'll show you how to understand tires.
Then, we'll cover how to install them
and have you off rip and nasty turns in the canyons
in no time.
I'm Zach and this is Money Pit.
Let's do it.
(aggressive upbeat music)
Let's talk tires.
This is a stock wheel and tire from the Miata,
and first I wanna go over all the different numbers
that are stamped into the side of the tire
so we can understand all the things
that the tire is trying to tell us.
So we'll start with the size, that big batch of numbers.
The 185, 60, 14, what do these numbers mean?
The first number, the 185 that's the width in millimeters,
so that's 185 millimeters wide.
The second number, the 60 that is the sidewall profile.
It's called an aspect ratio
and it's completely dependent on the width of the tire.
60 means that the sidewall is 60% of the width of the tire.
So a 60 sidewall isn't the same on every tire.
It's always dependent on the width.
Remember that.
Then, you've got the last number 14,
that's the size of the whole tire,
so you know what size wheel to put in it.
That's pretty simple, the sizing.
You get a nice combination of metric
and imperial measuring systems, which is always fun.
But then after that there is a couple of numbers
and a letter.
We've got 82 here.
What does that?
That is your load rating.
Basically, it's a system that operates on numbers.
The higher the number, the higher the load rating.
You can look up the chart
to see specifically what the load rating is,
but most tires say it somewhere,
1,047 pounds is the max load rating on these tires.
Also most tires will say on the tire
specifically what the load rating is in pounds.
So next to our load rating on the tire, 1,047 pounds.
We've also got our maximum inflation says 51 PSI.
Listen, that is not what you're supposed to drive on.
That's just the max pressure that the tire can handle.
You need to check your driver's door jam,
or the owner's manual for the actual pressure
that you're supposed to run on the tires
while you're driving.
For cars, it's usually somewhere in the ballpark
of like 30 to 35 PSI.
Trucks, large trucks often closer to 60 to 80 PSI.
But if you drive on your tires max pressure,
you're gonna get very bad tire wear and tire life.
So, anyway, back to where we were,
the letter on the end here, what does that?
That is another rating.
It's your speed rating.
If you wanna go fast,
you gotta have tires that can handle it.
If you spend time at a speed above your tires rating,
the tire can start to delaminate and basically come apart.
It mostly goes from A to Z,
with Z being the fastest rating at 186 plus miles per.
But if the tire is rated to over 149,
they'll add a Z into the size
and instead of this just being an R, it'll say ZR.
But to get your specific speed rating,
you look just pass the load rating.
This tire an H which means this tire is good
to 130 miles an hour.
All right, so that's a big one down.
Now we know how to read the size of a tire,
it's load rating and its speed rating,
but we are not done yet.
We've got some more DOT's standardized specs.
The US Department of Transportation that is
and their highway arm,
the NHTSA put forth a set of standards
to measure critical functions of tires for consumers
to make better, more informed decisions on buying new tires.
Those standards are called the Uniform Tire Quality Grade
standards, or UTQG.
They've standardized three measurements:
treadwear, traction and temperature.
Let's start with treadwear.
It's a bit of a convoluted one, but let's talk it out.
The treadwear rating is intended to be a comparative rating
of the wear rate of a tire or how fast
and easily the rubber will wear down.
This means that the treadwear rating assigned to a tire
means nothing in and of itself because it's comparative.
It means that in theory, a 200 tread wear rating tire
will last twice as long as the 100 treadwear tire.
So that's all pretty simple,
but it's important to note
that the Department of Transportation
is not the one conducting any of these tests.
They leave it up to each tire manufacturer
to conduct testing on their own tires
against the standardized course-monitoring tire.
The treadwear rating is often,
honestly closer to a marketing tool
than an actual consumer information tool.
You'll get a good idea of the longevity of tires
relative to other tires made by the same manufacturer,
but don't expect a 400 treadwear Bridgestone tire
to necessarily last as long as a 400 treadwear Goodyear
or something else.
As a general rule though, the lower the number,
the grippier and stickier the tire will be,
and some high performance tires will even rock
like a zero treadwear rating
because we don't care about treadwear.
Anyway, the next UTQG standard is traction.
And this test is a lot less fudgeable and much more sciency.
The goal with this test is to measure tires,
straight line, wet traction.
The way they perform this test is they stick some tires
to be tested on an unpowered axle
that has all sorts of sciency instruments on it,
and then they pull that test axle behind a truck
at a constant 40 miles an hour on wet asphalt
and wet concrete.
The brakes on the axle are then yanked
and as the tire skids along, the instruments on the axle
measure the tires coefficient of friction
or them breaking g-forces baby.
So this test is mostly about how sticky a rubber compound
a given tire is made out of.
There are four tracks and grades: C, B, A and AA.
Each grade correlates to a threshold g-force,
but I'm not gonna sit here and tell you those numbers
'cause (beeping).
Anyway on to the last UTQG standard which is temperature,
and it's pretty simple.
Although it would probably be more accurate
to call it a temperature-resistance rating,
as it measures the tires resistance to the buildup of heat
or its ability to dissipate heat at speed.
When tires blow apart in chunks
like in drifting for example,
it's usually 'cause it got too hot doing all of them skids.
There are three grades of temp: A, B and C.
A means that the tire can maintain a speed
of 115 plus miles per hour without generating too much heat.
B means a 100 to 115 miles per hour.
C means 85 to 100.
Anything below that cannot be sold here in the USA,
but pretty much every real tire being sold these days
has a high temp rating.
(upbeat music)
Okay, moving right along here is something
that you won't see on every tire.
You can see here it says outside
'cause this is the outside of the tire.
Sometimes it'll say rotation with an arrow.
And that's because these tires are asymmetric.
It doesn't mean they're not round,
it just means that the tread is not symmetric side to side.
And that's done for a number of reasons.
Sometimes water evacuation or handling characteristics.
And so these tires are just an inside-outside,
so it really only matters
for the person installing the tires onto the wheels,
but then this can go on either side of the car.
Can't really go wrong, but for rotation specific tires
you need to pay attention to which side of the car
you put them on, and how they're mounted on the wheel.
Bonus points if both of those people are you,
the guy installing them and mounting them.
So let's talk DOT code.
What is that?
Well, kind of like your car has a VIN,
your tire kind of has a TIN,
Tire Identification Number of sorts.
At the beginning of the DOT code
has a bunch of seemingly random numbers and letters,
which denote where the tire was made, it's size
and some other manufacturer's specific info
but what we really care about are the last four numbers
attached to the DOT code.
And they're only gonna be on one side of the tire
so keep that in mind.
The last four digits are how we can determine
when the tires were made.
37 the first two digits are the week that the tire was made
in a given year, the given years, the last two digits.
So here, 3710 means that these tires were made
the 37th week of 2010.
It also means they're 10 years old,
which means they're way too old.
General rule of thumb is that after six years,
tires should kind of be retired.
Overtime tires dry out and they lose their flexibility
and they start to crack and they become dangerous.
So, you can check your DOT code
whenever you're looking at a car.
It's an easy way to check how old your tires are.
Okay.
Now we understand all of the basics about tires
and what they're trying to tell us,
but that's only half of the equation.
The other half is, the wheels.
They're equally important in my opinion.
You gotta get them right,
especially if you want good fitment.
So, there's kinda a lot to talk about with wheels.
So let's.
(upbeat music)
Okay, so, we'll start with the basics.
Size because that matters.
This is a 14 by I think five and a half inch wheel.
Which means that this is a 14 inches in diameter
by five and a half inches in width.
The wheel, pretty simple, right?
But, there's another parameter that we give a (beep) about.
Offset, what is it?
I know it can be scary, but let me break it down.
And a little bit later I'll show you how to calculate
and measure your offset and what you can fit for a new wheel
so you can get that fitment
that you've all been lusting after.
So offset, it's the measurement of the offset from center.
Remember that, offset from center,
of the mounting face of the wheel.
The outside or the face of the wheel is the positive side
and the empty barrel, the negative space,
is the negative side.
So imagine an imaginary line
through the center of the wheel that is zero.
Now insert your offset.
These are a plus 45.
So from the center of the wheel plus 45 millimeters,
which means towards the positive side or the face
and that's where our wheels mounting face will be.
The further you move this mounting face
towards the face of the wheel
and the more of the wheel gets tucked or sucked
into the car, and the more weak your fitment is, obviously.
The more negative you go, the more the wheel pokes out
because you move that mounting face
towards the inside of the wheel.
And so the more the wheel pokes out
and the more gangster fitment you can get.
All right, how about the bolt pattern?
That is the pattern of the bolts.
The Miata has a four by 100 bolt pattern.
That means that there are four lugs spread evenly
across an imaginary 100 millimeter diameter circle.
So, this means if you have a set of wheels
with an even lug pattern, you can effectively measure
from hole to hole to find out what size they are.
But, if you have a five lug vehicle, you have to do math
because no two holes actually oppose each other.
So, yeah, I guess is my interesting thing
about bolt patterns.
Moving on, the last thing that we care about sizing-wise
is the old hub hole here.
And it's important because your wheel
should be the right size to just slip onto the hub.
That's what we in the industry call being hub-centric.
It means your wheel is centered by your hub.
If your wheel hole is too big,
the wheel will then only be centered by the lugs
and that's what we call being lug-centric.
If you have too big of a hole,
you can get hub centering rings
in like a million different sizes to perfectly take up
that gap and center your slabs up
which unfortunately I think we're gonna have to do.
I thought I had hub-centric rings
for our new wheels, and I don't.
So we're gonna be lug-centric for the next week or so
until I order some rings, whatever.
All right, now how about different types of wheels?
Let's briefly touch on all the types of wheels
in order from cheapest to expensivest.
Generally speaking, starting with steelies.
You know they are, they're made out of steel.
They go behind hubcaps, and they can look cool.
Next, cast wheels.
It's just when you pour molten aluminum into a wheel mold
and you get a wheel.
Then we've got roll formed wheels,
which are basically a cast blank
and then they put a roller system onto that blank
and they draw out the barrel,
which means that they can get it pretty light,
pretty strong, a little bit more than just the cast wheel.
It's also a little more expensive.
Now we've got forged wheels,
which is basically when you take a billet of aluminum,
put it into a forging dye and squeeze the hell out of it
to get a really strong, really dense, really light
but expensive aluminum.
All right, and then we've got the gangster class
of wheels, multi-piece.
You've got two piece and three piece.
The face is separated from the barrel
and sometimes the barrel is made out of two pieces.
And all those different pieces can be made
using various forms of the stuff that we just talked about.
You can spend as much money as you want,
and you can get whatever fitment you want,
and they look pretty sick, but they're also very expensive.
All right, now that you're up to speed on wheels and tires,
it's time to talk about we bought for the Miata and why.
That's right folks.
We got RPF1s.
Can you believe it?
Very unique.
I know I said of Enkei, RPF1s.
But listen, they're one piece, they're light,
they're very strong, they're made
with that roll-forming process that we talked about earlier
and they're basically just a great crossroads
of all the things that we care about in a wheel.
So, these are a 15 by eight inch,
positive 28 millimeter offset.
So as I break down how I got to this wheel,
I'm gonna install them 'cause the sun's going down.
Ooh, starting to get excited.
All right, so first let's talk about the diameter.
Stock wheels are 14 inches, these are 15.
Did that for a few reasons.
One, some day we're going to put bigger breaks on this car
and bigger breaks need more room.
So we went with a an inch larger in diameter.
Beyond that tires, you have a lot more options
for 15 inch tires like these.
Fourteens you don't have nearly as many options.
Another thing with the tires is that the larger the wheel,
the smaller your sidewall ends up being
so, you'll get a little bit less flex
with a shorter sidewall.
So these will be a little bit more performance-oriented
and beyond that, I guess really the most important thing
of all is that they look better.
They look a little bit bigger, look a little more sporty,
and that's kind of what we're going for, right?
So these are eight inches wide
and the stock ones were six inches wide.
And the reason for that, the reason I wanted wider wheels
is so I could have wider tires,
which means I can have a wider contact patch on the asphalt,
which means I'll have more grip.
But the question is,
how did I know that eight inches would fit?
And the answer here, honestly, is mostly from the forums.
I did a lot of research, and read what other people
had done and I knew that these would fit.
But, if you can't do that, you can measure.
You can have your stock wheels on the car
and measure inwards to the nearest thing
that you would run into.
Remembering that every inch you go wider
will make it stick further in half an inch and further out
half an inch, as long as you're not changing offset.
So you can measure or you can do a bunch of research
on the forums, which is what I did, and they fit.
So for tires, we went with a Toyo RAAAR,
which is gonna be super sticky.
It's a 205/50 15.
How did I decide that size?
Well, the wheels, like we said, are eight inches wide,
which translates to I think 203.2 millimeters.
And you guys, we know how to read a tire size now.
We know that 205 means that it's 205 millimeters wide.
So, it's pretty much the perfect fitment for our wheel.
We could've gone with a 225 on this
and it would look a little bulgy,
and that's kind of a cool look too
but I went with this
because I didn't wanna have to modify the body yet.
As far as the sidewall goes, the 50-series profile,
we did that because it leaves us with a very similar
to stock rolling diameter.
The overall diameter of the tire.
And the reason that you pay attention to that
is because if you change that very much,
then your speedometer won't read correctly
because now the wheel being a different diameter
will spin a different amount of times for a given distance.
Okay, and then the 15 part of the tire was pretty obvious
because that's the size of our wheels.
And these tires are W speed rated,
which is good for 168 miles an hour.
So if we can make this thing do that speed,
we'll be prepared.
(upbeat music)
All right, that is four on the floor,
but there's something we haven't talked about yet
and that is our offset.
These are a plus 28 millimeter offset.
How do we get to that?
Well, again, the forums were super-helpful
because so many people have Miatas.
It's very easy to find fitments that other people have done.
So I knew this would work,
but, if you don't, you can measure
and figure out how much offset you can handle.
All right, so imagine use your imagination
and imagine this is a stock wheel
and imagine that we remembered to film this part
two hours ago when we had the stock wheels on.
And basically what you wanna do at ride, height like this,
is get a straight edge and go from edge to edge
through the center of your wheel
and then you'll measure in millimeters how much gap you have
from your wheel to the inside of your fender.
Now obviously, we're a little bit past flush
because our straight edge goes the outside of our fender.
But if that's where the stock wheel,
we'd be far inside of the fender and we'd be able to measure
from our straight edge to the inner lip of the fender
and then you can see how many millimeters
you can move outwards.
Now that's only if you're not changing width
at the same time.
If you are, you have to take that into account as well.
But it's very simple, straight edge measure
and then you know.
Okay, so there's another thing that we haven't talked about
which we have been using and you're gonna need
and that's lug nuts.
So you could in some cases get away
with reusing your stock lug nuts.
We could have done that here, but it wouldn't look as cool
and that's a problem for us.
But what do you need to know to choose some lug nuts?
Not really that much.
You need to know the diameter and thread pitch
of your lug nuts or your bolt holes.
These on the Miata are a 12,
which means 12 millimeter diameter
and 1.5 millimeter thread pitch,
which means a millimeter and a half between each thread.
And then the other thing you need to know is your seat,
the seat of your lugs.
In this case it's a cone because the shape here,
which really is important about the wheel.
You need to match your lug nuts to your wheels.
Most are gonna be cones but you need to make sure
that you're getting the right stuff for your car.
Then you put them on, torque them down
to whatever your torque spec is, and that's it.
(upbeat music)
(laughs out loud)
That's it.
That's our first official modification
on the Money Pit, Miata and I couldn't be more excited.
We've got a nice set of wheels and some sticky tires.
This thing is gonna be so much better than it was already,
but, if you look at the car,
you will notice that it sits way too high.
So we have to address that next.
So that'll be next week.
We're gonna do some coil overs
and get this thing sitting just right.
So, I appreciate you guys watching.
I hope you're having fun.
I hope you learned a thing or two.
So we'll see you guys next week.
In the meantime, follow me on Instagram at Zachjobe
and follow my boys that helped me make this show
at Eddie_Esparza and at Tendoroni.
My guys.
Love you guys.
See you next week.