Hi, this is my very first post but have been enjoying myself on this forum for few days now, just was not getting enough time to post something. Anyhow I am owner of a 03 Sedan with everything except Nav and Sat..anyhow I didnt care much about the 2 since I know my way around and not much into travelling outside my area with the car...

Thats that..to get to the point of this post, I am trying to get an 04 Coupe and wanted to look out for alloys for that, i found one site which tells me if the alloys would fit, and somehow the ones I was liking were not fitting, so now my question is

1. What is it that fits G35s..
2. What is Bolt Pattern (some numbers like 5/120 etc)
3. What is Offset? cant I put alloys by brabus on my G, as the website put then as strictly mercedes only, whats so special about then that cant be fitted on my G
4. And what the difference between cast and forged, also 1 piece and multi piece alloys?

I know these are too many question, but I hope I get some answers to clear my doubts..

I would also like to know about tires, I was thinking of 245s and 275s again, i am very unfamiliar with the other number that come along tires and alloys like

like alloys are marked 18x8.5 or 18x9 what is the 8.5 and 9?? In tires they have 245/50R16, I guess 16 is the diameter which would fit on 16" alloys, but what is 50?? the thinkness which distinguishes normal tires from low profile..

Can someone explain me what are the diff types of tires that there are, and how they affect ride and handling?

What type of alloys and tires do you have on?

I am so sorry for having to suck the information out like this, but I am new to this and would love to do catch up and be at speed...slowly slowly on things, tom probably I will post asking about performance parts

Please dont mind me, I am just a very proud G35 owner and would like to join the gang, but before that would like to learn...

Cheers

 

1. Depends. There are a lot. You just need to choose the bolt pattern, offset, diameter and width limitations well.. In the case of the 6MT, you need to make sure there is sufficient backspacing as well.

2. It should be 5 x 114.3mm.

3. Offset is dependent on width. Offset is measured from the center of the wheel so if you use a different wdth of wheel the offset will change how the wheel sits in the wheelwell(further out or further in.) Brabus is Mercedes only because Mercedes do not use standard lug patterns. In fact Porsche, Mercedes and BMW all use different lug patterns.

4. Cast wheels are basically liquid metal poured into a mold. Most if not all probably use vacuum forgings to keep the consistency and purity of the metal better. There are different ways of forging metal, but for the most part the metal is manipulated usually during the casting process by applying extreme pressure to the metal. This creates a denser and more uniform casting and for a given weight is much stronger. 1 piece wheels use a single cast of metal. 2 piece wheels are usually a center section attached to the outer part of the wheel. 3-piece uses a center section and 2 outer sections all attached together. There's no real significant advantages to either in terms of function. 1 piece forged are probably lightest and strongest overall as the whole thing is forged. Multi-piece wheels usually have a forged center section at best. The outer parts are usually spun cast and relatively weak and heavier for their weight. So why multi-piece? It can help keep production costs down over a large variety of wheel sizes. Particularly in width and offset. They can mix and match sections to creat different widths, offsets and even backspacing. This means the variety of sizes are more available so it can be better matched to the application. 1 piece wheels require different molds for most of the different sizes. Usually the offset will be the only thing that can be adjusted after the casting process. Multi-piece wheels can also be repaired by replacing individual damaged parts, but will probably not be a significant savings over replacing a wheel.

As far as sizes:

245/45-18.
245 would be the width in millimeters. 45 is the sidewall height, but it is measured as a percentage of the treadwidth. In this case 45% of 245. 18 is the diameter of the wheel the tire is designed for.

Wheel sizes:

18x8, 35 offset
18 is the diameter. 8 is the width. 35 is the offset of where the hub mounts to the wheel in relation to the centerline of the width of the wheel.

This is easier seen with a diagram:

http://www.tirerack.com/wheels/tech/offset.htm

 

Thanks a ton, wow! that was really helpful, I understand a lot more now than I did before.

So I am assuming the offset would be 35 for the coupe?

The only thing I didnt get was backspacing and how can I choose the right one, or let me put that in the correct form, what would be the appropriate backspacing for the 6mt.

But thanks a lot, it was really helpful.

Cheers

 

Again, the offset is dependent on the wheel's width. A 35 mm offset on a 7 inch wheel will sit much differently than a 35 mm offset on a 9 inch wheel. At least as far as the outer edge is concerned. It is a good idea to keep offsets close to the same as changing it will change the orientation of the centerline of the tire in relation to the vehicle, but with wider tires it can affect fitment and the look. Many will choose offset based on how the wheel will align with the outer fender edge to give a "flush" look. Depending on the overall width of the wheel, it can affect handling. The further out the centerline of the tire is, the more the tire is rotating around the steering axis as opposed to rotating at the steering axis when turning. This can cause the wheels to pull the car in one direction or another during braking if there are uneven traction conditions or bumps in the road and such. The G35 does use a dual lower control arm set-up that places the actual lower steering axis further outboard than cars without this set-up so you can get away with this with a lesser or no effect. If you are going to get a wheel based on how it sits in the wheelwell, a wider wheel will usually keep the centerline closer to the steering axis. For the record, I am not sure what the offset for the G35 stock wheels are so I can't really make a recommendation at this point.

Backspacing is the distance from the back of the spoke to the plane where the hib mounts to the wheel. It's not a measurement most wheel manufacturers provide. However, most Japanses wheel manufacturers will make wheels designed to clear calipers that have outboard pistons. While I haven't seen any published numbers many list or note these wheels as a high caliper wheel or go as far as to list what cars it will fit on.