I've been doing a bit of reading and what I have gathered is that if i'm buying new wheels I should be looking for an offset of between +40 and +30 what starts to happen that affects the handling once I start getting into +25 and +20?

If I'm wrong about the above forgive me.

I ask because there are some wheels that I like that seem to be in the +25's and +20 offset.

 

The smaller the offset, the further the rims will push out from the fender/quarter panel, and your tires won't clear and it's not legal.

For stock fender +30 or +40 is fine, but that also depends on the width of the rims.

Here is a reference guide for you: FC3S Pro v2.0: Mods - Rims

Also there is a big thread regarding FC fitment, spend some time and read through that before deciding on the rims.

 

Wow thank link was a gold mind for offset. But besides clearance with the fenders I thought I had read that off-set would affect the handling or is it relative to the wheel width?

Or is this all explained in the giant FC fitment thread.. I'll go look now.

 

Basically with wider tires or wider rims, handling will be affected because of larger contact space with the road surface, change in center of gravity, changes to inertia while cornering... there are a lot of things.

It would really depend on the setup of your car to somewhat figure out how much handling will be affected, and whether it will be positive or negative. We can't determine based on the info you provided.

 

the thing offset effects is the relationship between the center line of the tire, and the line defined by the steering axis.

usually in a stock car the, if you drew a line thru the pivot points of the steering (upper mount to ball joint?) and a line thru the center of the tire, they would be very close to intersecting at the ground.

changing the offset of the wheel/tire changes this relationship, which is either scrub radius and or the dave point... Sport Compact Car: Technobabble: September 1999

small changes are not noticeable, 5-10mm, but the further out you go, the more the car is going to be unstable

 

Wow that's awesome, I thought I was the only person that new about the Dave point lol. That use to be my favorite mag mostly for technobable.

Well I have an fc and I want to keep the front and rear with pretty much the same amount of tire. I was think of doing 17 X 9 or 18 X 9 and wanted to put 275's in the rear and keep the fronts pretty close to it maybe 265 or 255. My suspension is stock for now but I'm going to upgrade that very soon on this fc.

If fenders are the only issue my friend has a body shop here in Atlanta so I'm not to worried about that but I don't want my handling to get jacked up just because I 'm going of r greater contact patch.

 

+35 is about perfect for a 9" wide wheel. here's a pic of my old FC sitting on 17x8 and 9, +35. The tires are 235/40F and 255/40R. No rolling, no rubbing.

 

wheel fitment is going to greatly depend on front camber.

I run between -3 and -3.5* in the front and run 17x8 +30 w/ 245 hoosiers.


I just tested fitted these the other day: 17x9 +25 w/ 255 toyos:


they're a bit close... I'm going to have to play with my spring length and camber to see if I can run a smaller spacer.

you should read Blue TII's 255/275 fitment thread:
https://www.rx7club.com/suspension-w...7-rear-772831/

 

eage8 what are you running in the rear? 275's?

I really love these rota p45 wheels ROTA Wheel P45F 18x8.5 (5x114.3+25mm, 67.1 Hub)|Rota Racing Wheel

With so many fitment issues im starting to think maybe I should just go with 18x8.5 (5x114.3+25mm, 67.1 Hub)

I can't find a good wheel width vs tire chart. Id like to go wide but not to where the side walls start passing the rim but id rather not stretch ether.

 

Yeah, the rear is a 17x10 +30 or +35 (not sure if the spacer was on in that picture) with a 275/40/17 Hoosier.

Keep in mind that Hoosiers are much wider than normal street tires. Since that picture was taken I've had to massage my rear fenders quite a bit and they still rub.

 

Wow that is one awesome picture!

I it seems like everyone is running 17's is there a reason for that?

 

tire are more common to find, relatively cheaper, well rounded performance size, etc.

and 17's fit FCs well IMHO.