[JTS2005]

Thanks To DiscountTireDirect:

The below offset specs are "conservative" We have acheived max fitments well beyond these specs, but below is for those of you who play it safe. When going to the edge...be sure to call to discuss it more throughly.

ALLIGNMENT PIN ON FRONT HUB CAN BE REMOVED, PIN IS
TRACK MODEL IS EQUIPPED WITH BREMBO BRAKES WHICH
LIMITS THE AMMOUNT OF WHEELS THAT WILL FIT!!!!
WIDTH OFFSET WIDTH OF TIRE
7.0 +5/+50 215/225
7.5 +11/+50 215/225/235
8.0 +18/+47 225/235/245
8.5 +20/+40 235/245
9.0 +22/+35 245
Rear Only
8.0 +7/+50 225/235
8.5 +13/+50 235/245/255
9.0 +19/+47 245/255/265
9.5 +20/+40 255/265/275
10.0 +22/+35 265/275

18 INCH WHEELS COME WITH A TIRE PRESSURE MONITOR TIRE SIZE CONNECTED TO O.E. VALVE STEM. NO LESS THAN 1/2 INCH AND NO MORE THAN 3/4 OF AN INCH HEIGHT DIFFERANCE BETWEEN FRONT AND REAR TIRE SIZE FOR ABS BRAKE SYSTEM/TRACTION CONTROL. 350Z'S WITH 18-INCH WHEELS HAVE A AIR MONITORING SYSTEM. THE SENSOR IS MOUNTED AT THE BASE OF THE VALVE STEM AIR PRESSURE SENSORS ARE A ONE PIECE UNIT AND CANNOT BE USED WITH REVERSE BARREL WHEELS


Wheel Offsets

The offset of a wheel is what locates the tire and wheel assembly in relation to the suspension. More specifically, it is the measured distance between the hub mounting surface and the center line of the rim. Below is an explanation of the various types of offsets which are pictured in the above graphic.

Positive Offset
A positive offset occurs when the hub mounting surface is on the street side (the side you see) of the center line of the rim. Most factory rims will have this type of offset.

Zero Offset
When the hub mounting surface is centered within the rim, it is known as a zero offset.

Negative Offset
If the hub mounting surface is on the brake side of the center line of the rim, it is considered a negative offset or deep dish.

Note that extensive negative offset can potentially cause increased steering wheel kick-back and place additional stresses on the vehicle's entire suspension.

 

[thrlskr]

So far this is one great site! I enjoy the fact that this site is more than a Z enthusiast get together but, also a first rate reference tool.

I believe in giving back so here is an awesome Tire Size Calculator, courtesy of Miata.net. This is very useful for...**** what are you waiting for??

Check it out!

Enjoy

 

[smoothz]

Can someone go into greater detail about the aftermarket offsets? As much reading as I have done, I still don't understand the 'plus' factor on offsets. It seems the smaller the number, the farther out your wheels sit? :dunno:

 

[sloe truk]

Can someone go into greater detail about the aftermarket offsets? As much reading as I have done, I still don't understand the 'plus' factor on offsets. It seems the smaller the number, the farther out your wheels sit? :dunno:

Dave you are correct. If you have a zero offset wheel, the inner and outer lips will be the same, ie a 9" wheel with 0 offset will have ~ 4.5" lip on both sides of the hub. for every mm of positive offset you move the outer lip of the wheel closer to the car, for every mm of negative offset you will move it away from the car.

ALmost all FWD cars today have very high postive offset wheels, while most of you 4X4 truck wheels have a little negative offset. the offset is the 'offset' from center. postitive offset brings the wheel towards to the differential while negative moves it away.

Hope that helps
Bryan

 

[Renovatio]

Dave you are correct. If you have a zero offset wheel, the inner and outer lips will be the same, ie a 9" wheel with 0 offset will have ~ 4.5" lip on both sides of the hub. for every mm of positive offset you move the outer lip of the wheel closer to the car, for every mm of negative offset you will move it away from the car.

ALmost all FWD cars today have very high postive offset wheels, while most of you 4X4 truck wheels have a little negative offset. the offset is the 'offset' from center. postitive offset brings the wheel towards to the differential while negative moves it away.

Hope that helps
Bryan

That helps but im still not quite figuring the offset numbers for the rims when it says +24/+40 on the 8.5 rims?
and what about the reusability of the tire pressure sensors didnt quite understand that one.

 

[bluedragonz]

Researching and trying to understand this subject matter.

 

[yoshi]

Is there such a calculator that involves the wheel width in the equation?

Correct me if I'm backwards, but doesnt the wheel width make a big deal on actual final diameter? I'd like to be able to be 100% sure of the diameter change so I can not upset the VDC, speedometer, etc.

For instance, I know I'll end up with say the 9.5" or 10.0" rear wheel. With a 275/40/18 tire put on each, the 10" will stretch it more than the 9.5" wheel would, right? Hence the calculators are lacking :\

 

[toykilla]

Is there such a calculator that involves the wheel width in the equation?

Correct me if I'm backwards, but doesnt the wheel width make a big deal on actual final diameter? I'd like to be able to be 100% sure of the diameter change so I can not upset the VDC, speedometer, etc.

For instance, I know I'll end up with say the 9.5" or 10.0" rear wheel. With a 275/40/18 tire put on each, the 10" will stretch it more than the 9.5" wheel would, right? Hence the calculators are lacking :\

I see what you are saying, but I dont think going from 9.5" to 10" would stretch the tire diameter.

 

[yoshi]

Yeah good point I realize that now, but this does stand:

If I chose a 10" rear, thas going from using the 245/45/18 stock tire with 8.5" wheel to the 10" with ???/40/18 . Thats a whole 1.5" jump in wheel width :\


Edit: Meant to add in: So how can I be sure what I am picking out will be truly the right diameter change with that 1-1.5" jump in mind? Thats all I was seeking, was assurance that the tire/wheel combo I get will be the same or close enough diameter.

 

[toykilla]

use the tire calculator:

245/45/18 is exactly the same as 275/40/18

http://www.miata.net/garage/tirecalc.html

 

[i8acobra]

Does anyone have a list of the offsets for the various OEM 350Z rims? Specifically, I'm looking for offsets for the '06 18x8" and 18x8.5" rims as well as the 18" and 19" Track rims.

 

[ablindbaby]

So if I wanted to push the wheels out farther from the center of the car, it would be a negative offset?

 

[toykilla]

Does anyone have a list of the offsets for the various OEM 350Z rims? Specifically, I'm looking for offsets for the '06 18x8" and 18x8.5" rims as well as the 18" and 19" Track rims.

Wheel specs

http://www.350z-tech.com/zwiki/Wheels

 

[toykilla]

So if I wanted to push the wheels out farther from the center of the car, it would be a negative offset?

no, just a smaller positive offset. If you go negative the tires will stick outside the fenders.

 

[i8acobra]

Wheel specs

http://www.350z-tech.com/zwiki/Wheels

Thanks. I looked there first but must have missed it.

 

[bamaboy]

wheel width has absolutely nothing to do with the diameter of your tires.

 

[Groover]

It seems that from the posts here, many people struggle to understand this subject. For those who are having trouble, the image (3 x sectional views of wheel) posted at the top of the first page of this thread are not overly enlightening until we understand that the right edge should be labelled outer edge and the left edge should be labelled inner edge. That may help.

Basically "offset" refers to the distance measured between the mounting face of the wheel (the surface that mates with your hub) and the actual centre of the wheel (for a 8" wide rim, this would be an imaginary line which is 4" (8/2) in from either edge). A positive offset means that the mounting surface is further out (towards the outer edge or fender) than the centre line of the wheel. The images which were posted at the start of this thread illustrate this.

So "+30/+35" refers to wheels which have an offset that is between 30mm and 35mm as described above.

The higher the number for a positive offset, the more the wheel sits under the fender. The lower the number (when referring to positive offset), the more the wheel sits towards the outter edge of your fender. Generally, on a Z, you will need between +15 - +40 depending on how wide your wheels are.

There is a direct relationship between wheel width, offset and the positioning of the wheel inside the fender. If we take the stock rear wheel on a track model Z (18x8.5 +33). 18" in diameter, 8.5" wide, a positive offset of 33mm. Say we replace this with a wheel which is 10.5" wide and uses the same exact offset (+33mm). This wheel will be 25.4mm closer to the outer edge (lip) of the fender. This is because we have basically added 1" (25.4mm) each side of centre without changing the relationship between the mounting face and the centre of the wheel (offset). If we had chosen the same wheel (10.5") but with a positive offset of 58.4mm (25.4 + 33) then in theory all of the additional width of this wheel over the stock wheel (2") would be accommodated towards the inside placing the outer edge of the wheel in exactly the same position as the stock wheel's outter edge.

Of course we can't really do that because that scenario whould result in the inner face of the tire fowling on the shock absorber (on a Z). Also you would never use a negative offset on a car like the Z unless you had rediculous flared fenders.

Hope this helps someone.

PS: Isn't it interesting that when we talk about wheel specifications (no matter which country you live in) we use the old imperial measurement for diameter and width and yet we use metric for offset and stud pattern.

 

[nic]

Thx Groover now all my confusions are gone!

 

[3FiftyZ.ST]

HELP PLEASE, from you expert out there.

I've fitted a set of 19" wheels to the car and now feel that the car handles little s..t, can't say really, but I'm sure you know what I mean. Name of the wheels are Antera 343. Size of wheels are, fronts 8.5x19 offset 25 tyre size 245/35 and the rears are 9.5x19 offset 30 tyre size 275/35. My original wheels were Rays 18" wiith 225 fronts and 245 rears. I have had the car lowered by 25-30mm using TEIN super sport coil overs and the dampers are set to postion 8 all round. Standard 350Z I believe would be in postion 4. There are 16 position with the TEIN so I 'm set on half way and my tyre pressures are around 32psi.

My problem I have is tram lining, I guess thats the technical name for it. I don't think the car is directional enough when approaching bends fasts. This situation does not make for comfortable driving the faster I go. I've spent good money on this wheels, surely it can't be the wheels could it?

I understand my chamber is a bit negative but thats to be expected if the car is lower 25-30mm. Or is this my problem the car has too much negative chamber.

Lots of you guys are fitting 19/20" has anyone had this problem and was able to correct it.. I have heard that the 350Z does not handle well with 19" wide wheels...?

HELP SOMEONE OUT THERE :banghead:

John

 

[toykilla]

Sounds more like suspension setup than a wheel problem.