bforbrian

iTrader: (11)

After having gone through so many sets of wheels, I have been bombarded with questions about fitment, what offset means, hub-bore, etc. To help minimize the number of threads regarding wheels (width, offset, backspacing, hub size, bolt pattern, etc.) and tires, I decided to create this thread in hopes that it would get stickied so community novices will find a wealth of information before asking already covered topics.

I will first discuss wheels and everything you need to know about them..

Wheels

• Diameter

Diameter is pretty self explanatory; it is the distance in inches from one point of the wheel passing through the center to the other directly across. If one measures the wheel diameter with a measuring tape, he will find that it is not the full specified diameter, but shorter. This is because the diameter does not include the rim flange. Technically speaking, it is the distance between the bead seats (for the tire), as measured in the plane of the rim and through the axis of the hub which is or will be attached, or which is integral with the rim.

• Width

Width is the separation distance across rim flanges. So this does not include the outer most part of the rim.



In summation, none of the measurements are taken with the rim flange included. For novices, the rim flange can be said to be "the part where curb rash usually occurs."

• Offset (ET)

Offset can get confusing to some individuals not familiar with wheel technicalities. Simply put, it is the distance between center line of the wheel to the mounting surface on the backside of the wheel, in millimeters (mm).



A positive (+) offset is when the mounting surface is shifted from the centerline toward the front or outside of the wheel.

A negative (-) offset is when the mounting surface is toward the back or brake side of the wheel's centerline.

A zero offset is when the mounting surface is in the plane of the centerline.



Negative offsets are considered aggressive, since the mounting surface of the wheel will "hit the hub of your car much quicker, hence the wheel will stick out more."

The TL's stock wheels are 17x8 +45.

There are two ways the outer rim comes closer to the fender, or even pokes outward. Wider wheel width and lower offset.

There are 25.4 mm in an inch. So if we were to increase the stock TL wheel's width to 17x9 +45, this means that both the inner and outer rim are widened. So with respect to the outer rim, it has moved out 25.4/2 mm, or about 13mm.

Recap: Increasing wheel width by one inch moves the outer rim out by 13mm. But the inner rim also is widened, so you actually have 13mm less clearance on the inner rim, totalling 25.4mm. In other words, it moves closer to the your suspension strut.

• Bolt Pattern/Pitch Circle Diameter (PCD)

The PCD has to do with the sizing of the diameter of a circle that the lug holes create. The center of every bolt/lug lies on the circumference of a circle that they create. PCD is usually measured in millimeters (mm).

For example, the 5x114.3 (or 5x4.5 in inches) PCD that our 3G TLs use means that there are 5 lug holes, with a pitch circle diameter of 114.3mm or 4.5in.

• Center bore/Vehicle Hub-Bore size

The wheel's center-bore is the size in millimeters (mm) of the diameter of the circle, behind the wheel. See picture below:



The vehicle's axle hub is the part of the axle/rotor that the wheel "sits" on when the wheel is mounted. Why was this created? To reduce stress on the wheel studs. Obviously, the lug nut holes on wheels are a HAIR larger than the wheel studs themselves because of ease of mounting. Without identical hub-bore and wheel centerbore sizes, when the wheel is mounted onto the lug nuts and left to hang, the weight of the wheels will lie on the lug nuts, creating stress.



Thus, if the car's hub-bore size is identical to the wheel center-bore size, the wheel will mount right up to the hub, and the weight of the wheel will rest on the hub, rather than on the lug nuts.

Obviously, if the wheel's center-bore size is BIGGER than the vehicle's hub size, it can technically still mount up, but the weight of the wheel will rest on the lug nuts--not good. Thus, hubcentric rings are used so that the wheel's centerbore size is decreased so as to equal the vehicle's hub-bore size.

See picture below:



Thus, the inner diameter is the wheel's center-bore size and the outer diameter is the vehicle's hub-bore size. Hubcentric rings take the load off of lug nuts to decrease vibrations.



The 3G TL's hub bore size is 64.1 mm. So, it makes sense that our stock wheels (made specifically for our cars) have a centerbore size of 64.1 mm as well so that there is no load on the lugs and that there are no vibrations.

• Wheel Manufacturing

Via TireRack:

If we were to construct a rough list of wheel durability, it would look something like this, with the most durable at the top.

• Forged (Volk, HRE, IForged, etc.)
• Flow forming (Enkei, Forgestar, etc.)
• High pressure cast: roughly the same as flow forming (Vossen)
• Low pressure cast (Avant Garde, Miro, etc.)
• Gravity cast (Varrstoen, Rota, etc.)

Gravity cast: Gravity casting is the most basic process of pouring molten aluminum into a mold utilizing the earth's gravity to fill the mold. Since the process relies on gravity to fill the mold, the aluminum is not as densely packed in the mold as some other casting processes. Often gravity cast wheels will have a higher weight to achieve the required strength.

Low Pressure cast: Low pressure casting uses positive pressure to move the molten aluminum into the mold quicker and achieve a finished product that has improved mechanical properties (more dense) over a gravity cast wheel.

Forged: The ultimate in one-piece wheels. Forging is the process of forcing a solid billet of aluminum between the forging dies under an extreme amount of pressure. This creates a finished product that is very dense, very strong and therefore can be very light. The costs of tooling, development, equipment, etc., make this type of wheel very exclusive and usually demand a high price in the aftermarket.


Tires

Tires are a bit more easier to understand; a lot of it is just knowing what symbols represent. Here is an example:

235/35R19 91S.

235 represents the section width, or cross-section in millimeters (mm).

35 represents the sidewall aspect ratio, or the thickness in millimeters (mm)

19 represents the diameter in inches (in).

R represents internal construction.
-R represents radial.
-D represents diagonal.
-B represents belted.

91S represents the service description. 91 is the load index, and the letter S is the speed rating. Speed ratings go up to Z, or the highest speed rating.

rptls08

iTrader: (1)

awesome info!

Steven Bell

iTrader: (2)

Well done Brian!

07tlsWDP

Great info!

I was wondering yesterday as I was shopping for some winter tires. How low can I go on the load index and still be considered safe? You mentioned 91 in your post. Have you used as low as 91 tires before without problems?

Yeah sure load index of 91 would still cover the weight of the car plus 5 passengers, so am I safe to assume a minimum of 91 is ok to go with?

swoosh

iTrader: (5)

great info....sticky ?

justen

I have some 16" lexus wheels with snows, but they are 5x114 with a center bore of 60.1
The TL is 5.114 with a 64.1 center bore so they don't sit on the hub flange correctly.
Does anyone know how thick a spacer would need to be to clear the certer hub?
basically, how far does the center hub stick out past where the wheel should sit flat?
is this even possible? hopefully someone knows.

murph145

nicely done sir!!! I hope this helps out a lot of people and saves some threads from being constantly replicated

myron

iTrader: (4)

you can take the wheel off and measure.

justen

Obviously, But i guess a better question would be. is this ok to do?
will it cause issues?
has anyone ever installed a wheel with a smaller center bore in the past?
If noone has, I will pull a wheel tomorrow morning and measure it and post back here to add to the thread.

Elegant TYPE S

iTrader: (2)

This info is GREAT and should be stickied.. but still won't stop the ideots who don't bother to look... from starting new threads...

So in short... adding an 1 inch to the diameter of your wheels is like adding a 13mm spacer or .5 inch to the wheel is to a 6.5mm spacer.

BTW ne one know what casting method the RJ INSPYRES are manufactured from? I know they are not forged.

Turbonut

iTrader: (1)

Without a hub adapter you'll be looking at keeping the wheel centered by the lug nuts only, but can probably get by with this for the winter. To make it work properly, you'll need spacers the depth of the flange, and then to get the center bore centered, you can purchase 60.1" hub bore spacers with lugs to place over the spacers. Less cost and less aggrevasion just get the correct wheels.

Turbonut

iTrader: (1)

Probably mean to say 1" to wheel width, not diameter, and will add .5" to each side (inner/outer) providing the offset is 45mm.

Aman

Well done, just one thing:

In your tire size, I think the 35 is the height of the sidewall as a percentage of your width. So if you have 235/35 tires, your side wall is 35% of 235mm tall, or 82.25mm.

renedcruz

iTrader: (8)

Bravo Brian! Well done. Awesome info here...

Elegant TYPE S

iTrader: (2)

Yup ... wrong word...

So in short... adding an 1 inch to the width of your wheels is like adding a 13mm spacer or .5 inch to the width is to a 6.5mm spacer.

anykey

Great info, very helpful for a wheel noob. Thank you for taking the time to put it all down.

So, if I get wheels on my TL that are 18x7.5 with a +55 offset, I would actually be losing the 1/2 inch from the wheel width itself, and the +10 MM of the offset because the higher the + offset, the more it brings the mounting surface towards the center line, correct? So, it would effectively make my wheels look even slimmer than they actually are?

is this where spacers are applied, and possibly a different (wider) tire to compensate for the add'l offset? The tire to wheel relationship still confuses me a little.

gatoferoz25

iTrader: (13)

Brian this info is very helpful for those who r running on there new set of wheels an for those who wants to get more info on how to work on theirs new set up it worked for me lol +1

bforbrian

iTrader: (11)

That's a good question. I would imagine the wheel will not even mount up to the hub, since you're putting a smaller circle onto a bigger one. Usually it is the reverse, hence the convenience of hub-centric rings.

Adding 1" is "like adding a 13mm spacer", and adding 0.5" is like adding "13/2 or 6.5mm". Yes, but that isn't the full story. Remember, by increasing width by 1", you're increasing the outer width by 13mm AND the inner width by 13mm. Therefore, the wheel will actually come closer to the suspension strut, while sticking out further.

Adding a spacer moves the entire wheel AWAY from the suspension strut.

I know for a fact that RJs wheels are not gravity cast, because they are pretty strong wheels. I can narrow them down to low or high pressure cast.

18x7.5 +55. With respect to width, you lose 0.5", or about 13mm total. With respect to outer clearance, you lose about 6.5mm. In other words, from the outside the wheel will sink in about 6.5mm. The inner rim will actually move AWAY from the suspension strut, as you are decreasing wheel width, not increasing. So you have about 6.5mm MORE clearance on the inner rim. BUT, you're increasing offset by 10mm. Explained in next paragraph..

With respect to offset, you lose 10mm, which means overall you lose the whole 10mm since offset changes the fitment of the entire wheel. In summation, the outer rim moves IN 16mm. With respect to the inner rim, it moves 4mm closer to the suspension strut (6.5mm more clearance, but the 10mm increase in offset effectively makes it a difference of 3.5mm, or 4mm closer to the suspension strut).

Winter wheels are supposed to be narrow but if you have a MT or type-s, those specs will most likely NOT clear the brakes.

dwb993

iTrader: (13)

Brian,
What about care & feeding instructions? Whats the safest way to clean wheels? How do I prep my new wheels for use (wax, sealant,etc)? Best way to store summer/winter wheels in the off-season? That kind of stuff.

TheDingo

Excellent post.. this should be "sticky" to prevent redundant threads.

Jesstzn

I'll chime in on this one.

1) Cleaning wheels ... while wheel cleaners are convenient the best thing for the wheels is car wash soap. Most of the wheels are clear coated just like your fender. Treat them as such. Wheel cleaners will strip any wax/sealant on the wheels and are harsh on the clear. Wheel cleaners will also badly stain wheels that aren't clear coated. Best thing .. wash them regualarly. If you bought or have nice wheels protect your investment by regualar washing. I have never had to use wheel cleaners on my own cars.

2) For new wheels ... Here is what I recommend .. before you install them with or without tires ( just for convenience ) clean the wheel and wipe them down with a 50/50 mix if IPA/water then apply a sealant to them. A very good low $$ sealant is NuFinish "liquid" . Its also layerable so if you wait 12/24 hours after the first coat you can put on a second/third etc..

3) Storing wheels ... see 2 above .. always apply a protective coating prior to storing. Never store alloy wheels dirty. Store in a dry place and off the floor, eg. laid on 2x4s. Some auto stores sell a tower that hold 4 tires/rims and they keep everything separated. Store out of sunlight.

vipTL

iTrader: (2)

awesome write up!

dwb993

iTrader: (13)

Thanks, Jess. A few more questions for you:
Please define "IPA".
My wheels came with instructions to use only a mild soap and water solution for cleaning---they specifically say to stay away from car wash soap. I'm thinking a Woolite/water solution would be good. I use the same on my interior. This should work, right?
When you say "off the floor, eg. laid on 2x4s", are they parallel or perpendicular to the floor? Can they be stacked? If so, should I use some kind of separator between them---heavy cardboard or similar?

SharksBreath

iTrader: (33)

dave, IPA = isopropyl alcohol

good info jesstzn...i'm taking off my summer wheels very soon and it's nice to know how to store them properly.

Jesstzn

Are these wheels clear coated? I have never seen any mfg say stay away from car wash soap unless they might be meaning the touch free which can be harsh.

Woolite & water is going to be harsher than any otc brand car wash soap.

They can be stacked and I use a cardboard between them.

Either way I just lay them on 2x4 to keep them off the cement .. dirt.

IPA = Rubbing Alcohol.

This is the stand I use .. was $20 up here and comes with a nylon cover.

dwb993

iTrader: (13)

Not sure about clearcoat. They are XXR527 in Chromium Black.

Jesstzn

Can't find anything on them .. but regular car wash soap is as mild as it gets and has never been a bother to any wheels I have had be they cleared or raw aluminum.

dwb993

iTrader: (13)

Thanks again, Jess.

dwb993

iTrader: (13)

So I'm looking at hubcentric rings and I see plastic and aluminum. Which are better for mostly high speed highway driving? 18X8.75 XXR527 225/40 Eagle GT

Jesstzn

Plastic ( penolic) is the better .. both work just fine but the aluminum ones have a tendency to corrode and bond to the wheel or hub making them a bitch to get off.

SharksBreath

iTrader: (33)

^dave, i have plastic ones and they seem to be fine.

dwb993

iTrader: (13)

Thanks, guys!

Skunkworks

iTrader: (6)

Great post with good information.

michaelw21

iTrader: (1)

Great write up!

JD TL-S

iTrader: (1)

Kool. Plastic are better.

Morrissey25

iTrader: (4)

Great post

serbj

iTrader: (1)

The reaction to this wonderfully informative post is not zealous enough. This is bad. We must appreciate this kind of posts.

serbj

iTrader: (1)

Here is some information you need to know about hubcentric rings. We prefer aluminium rings to plastics ones because aluminium ones last longer under moisture and heat:

Hub Centric Rings, Aluminium vs. Polycarbonate
http://forums.evolutionm.net/evo-tir...carbonate.html

Hubcentric Rings Who Uses Them??
http://forums.evolutionm.net/evo-tir...uses-them.html

Jesstzn

I have run Polycarbonate rings for years and never broke one or melted one but I have been stranded on the side of the road with an aluminum ring that was corroded onto the hub.

As for the ring carrying the weight .... that is incorrect ... a hubcentric wheel uses a center hole machined to exactly match the hub so the wheels are precisely positioned as the lug hardware is torqued down. The lugs still carry the weight.

Some wheels are non-hub centric by design. These are known as lug centric wheels. With these wheels it is critical to torque the lug hardware with the vehicle on jack stands, off the ground. This allows the nuts or bolts to center the wheel and torque down without the weight of the vehicle pushing them off center.

serbj

iTrader: (1)

I'm planning to buy some aluminium hub centric rings from Rays Engineering:
http://www.rays-msc.com/html/option_parts.html

Are these rings good?