offset question
09-14-11, 11:15 AM
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offset question
I have a lexus ls 400 1999 and am looking at 20" venaci mesh step lip wheels and don't know what offset to run. How do i determine offset? I dont know where to start.
09-14-11, 12:29 PM
#2
Offset is the measurement between the wheel's center line and the mounting surface to the hub. You can have three different types of offsets, "positive", "zero" and " negative".
Example: You have an 10 inch wheel. There center line will be at the 5 inch mark.
In this case a "zero" offset will split the wheel down the middle giving you a 5 inch frontspace (outer lip) and 5 inch backspace (rear lip, the one you can't see when mounted to car).
Positive, let's use 25mm, it's easier to calculate. If you have a +25et, this means the mounting flange sits 25mm (roughly 1 inch) closer to the outer lip, therefore creating a 4 inch frontspace and 6 inch backspace. Your wheel will sit 25mm (1 inch) closer to suspension components when compared to a "zero" offset 10 inch wheel. Generally, these fitments are usually the least aggressive and most believe clears big brakes the best; which is not true. Spoke design plays the primary role when clearing brakes.
Negative, again we will use 25mm. A -25et is the opposite of the positive. The flange will sit 25mm (1 inch) closer to the inner lip, giving you a 6 inch frontspace and 4 inch backspace. This wheel will sit 1 inch away from the suspension when compared to the "zero" offset and sit 2 inches away when it's a +25et. Generally, negative offsets are considered aggressive fitments with the most lip; again, it's not the case 100% of the time, spoke design also plays a role.
You need to check out the LS sub-forum, there's a fitment thread in there that will help you find your wheels.
Example: You have an 10 inch wheel. There center line will be at the 5 inch mark.
In this case a "zero" offset will split the wheel down the middle giving you a 5 inch frontspace (outer lip) and 5 inch backspace (rear lip, the one you can't see when mounted to car).
Positive, let's use 25mm, it's easier to calculate. If you have a +25et, this means the mounting flange sits 25mm (roughly 1 inch) closer to the outer lip, therefore creating a 4 inch frontspace and 6 inch backspace. Your wheel will sit 25mm (1 inch) closer to suspension components when compared to a "zero" offset 10 inch wheel. Generally, these fitments are usually the least aggressive and most believe clears big brakes the best; which is not true. Spoke design plays the primary role when clearing brakes.
Negative, again we will use 25mm. A -25et is the opposite of the positive. The flange will sit 25mm (1 inch) closer to the inner lip, giving you a 6 inch frontspace and 4 inch backspace. This wheel will sit 1 inch away from the suspension when compared to the "zero" offset and sit 2 inches away when it's a +25et. Generally, negative offsets are considered aggressive fitments with the most lip; again, it's not the case 100% of the time, spoke design also plays a role.
You need to check out the LS sub-forum, there's a fitment thread in there that will help you find your wheels.
Last edited by SChema; 09-14-11 at 12:33 PM.
09-15-11, 06:03 AM
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When verifying a wheel fitment you must also consider:
Bolt Pattern - Not as simple as 4-lug vs. 5-lug. There are currently 17 different 4- to 5-lug bolt lug patterns as well as 6- to 8- lug for light truck/SUV.
Centerbore - The wheel must, in most cases, fit the hub of the vehicle precisely, either as a direct fit or with the use of a centering ring.
Hub Interference - Many vehicles have additional items on the mounting surface area that must be considered for wheel applications, these include locating pins and rotor mounting hardware.
Load Capacity - The wheel must have enough load capacity when compared to the gross axle weight rating of the vehicle.
Lug Hardware - The lug hardware is not only specific to the vehicle but each wheel will require certain lug lengths and seat shapes
Suspension Components - The wheel must clear and not interfere with any of the suspension components and their operation on the vehicle.
Helpful Wheel Tech - Link
Bolt Pattern - Not as simple as 4-lug vs. 5-lug. There are currently 17 different 4- to 5-lug bolt lug patterns as well as 6- to 8- lug for light truck/SUV.
Centerbore - The wheel must, in most cases, fit the hub of the vehicle precisely, either as a direct fit or with the use of a centering ring.
Hub Interference - Many vehicles have additional items on the mounting surface area that must be considered for wheel applications, these include locating pins and rotor mounting hardware.
Load Capacity - The wheel must have enough load capacity when compared to the gross axle weight rating of the vehicle.
Lug Hardware - The lug hardware is not only specific to the vehicle but each wheel will require certain lug lengths and seat shapes
Suspension Components - The wheel must clear and not interfere with any of the suspension components and their operation on the vehicle.
Helpful Wheel Tech - Link
Last edited by zig@tr; 09-15-11 at 06:11 AM.
09-19-11, 08:49 AM
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Wow, thank you so much guys. This is the most information I've received. This was very helpful. I have a much better idea instead of just being lost.
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