Offsets

[Twenty7]

Hey all, I know this has been talked about, and I have searched ... I'm just looking for some clarification.

I recently ordered some 20x9 wheels with a +30 offset - wanted square setup for AWD. (and, yes, I know people run the staggered as long as the circumference is the same and what not...)

And, a couple weeks later, the rims show up - they are 20x9 with +35 offset, and 20x10 with +40 offset lol Why? I have no idea.

Anyways, so I can ship them back and get the proper 20x9 with +30 ... but I remember seeing on here people ran 20x9 with +35. When I put them on as a test, the caliper with sitting flush with the wheel backing. It would definitely rub/scrape if I ran them. The 20x10 +40 was perfect in the rear.

Is there a reason some of you can run the +35 front without issue? Or, are all wheel companies different in this regard?

Thanks in advance.

2016 Gen 2 3.8 AWD

 

[Huddleston]

Tires can make a huge difference. Not all manufacturers are the same.

I think I'm 20x9 with 35 up front but I can't remember. Search my thread and you'll see

 

[Rloyola0426]

I think I read somewhere that the stock wheels are 8" +40. The smaller the offset, the more pushed out towards the fender the wheel becomes. So those guys running +35 are actually running less chance of rubbing vs those guys running +30, as those wheels would be closer to the fender edge vs the car's midline.

Correct me if I'm wrong, as I get confused with this concept myself.

 

[TEF]

The offset of your 8"x18" OEM wheel is 36 mm. I am using 8"x18" 350z rims with an offset of 30 mm with my snow tires. Effectively, that moved my tire/wheel combination out (from the cars midline) by just 6 mm. However, that small amount (about 1/4 of inch), puts the tire sidewall very close to the top of the fender arch. Should you choose a 9" rim with the same 30 mm offset, there is a good chance that the outside sidewall might rub. When making your decision, you might want to put your intended wheel/tire parameters into the calculator on this website. It provides a very clear comparison of the new setup against the stock one:

http://www.willtheyfit.com/

 

[Twenty7]

Yes, correct. The oem wheel for the 3.8AWD is 18x8 with +36.

So, I received a 20x9 with +35 offset which rubs on the actual caliper (fronts only). I was just wondering how some people have the exact same setup (i.e., 20x9 with +35) and it works fine.

I will be sending them back for 20x9 with +30 offset. I think the additional 5mm will be sufficient.

 

[TEF]

Interference with front caliper on the G2 Genesis seems to be a problem even with the correct offset. I suspect that OEM wheels are manufactured with another parameter (extra brake clearance) that some after market wheels lack. Since most cars come with floating calipers, most after-market wheels with the correct offset work fine. In the case of fixed-caliper cars (used on all G2 Genesis), many after market wheels rub the front calipers. My 350z came with Brembos, so those wheels fit on the Genesis with plenty of clearance (1/2 inch between caliper and cast wheel spokes). I am guessing that OEM Genesis wheels are machined with extra caliper clearance too. That might explain the rubbing problem with your setup and not for other aftermarket wheels with the same 35 mm offset.

 

[Kp117]

Interference with front caliper on the G2 Genesis seems to be a problem even with the correct offset. I suspect that OEM wheels are manufactured with another parameter (extra brake clearance) that some after market wheels lack. Since most cars come with floating calipers, most after-market wheels with the correct offset work fine. In the case of fixed-caliper cars (used on all G2 Genesis), many after market wheels rub the front calipers. My 350z came with Brembos, so those wheels fit on the Genesis with plenty of clearance (1/2 inch between caliper and cast wheel spokes). I am guessing that OEM Genesis wheels are machined with extra caliper clearance too. That might explain the rubbing problem with your setup and not for other aftermarket wheels with the same 35 mm offset.

I have been following your wheel milestones. How did you manage to increase the center bore on the 350 z Wheels?

 

[TEF]

Nissan uses a 1 mm (66.1) smaller center bore than Hyundai (67.1 mm). To enlarge it, I used a router with a straight-cut carbide bit and guide bearing. Fortunately, these wheels were manufactured so that just after the actual center bore, the hole flares out (in a slight taper) to a larger bore (where the decorative center cap fits). By slowly adjusting the depth of the guide bearing to the right spot on the taper, I was able to mill out the bore to fit the Genesis center hubs. Since carbide is much harder than an alloy wheel, it only took only seconds/wheel to enlarge the bore wall by only a 1/2 mm. BTW, the flat surface on the inside of the wheel's hub served as the rest for the router's base plate. I searched local machine shops for a large lathe, but setup and machining would have been very expensive.

 

[Kp117]

Nissan uses a 1 mm (66.1) smaller center bore than Hyundai (67.1 mm). To enlarge it, I used a router with a straight-cut carbide bit and guide bearing. Fortunately, these wheels were manufactured so that just after the actual center bore, the hole flares out (in a slight taper) to a larger bore (where the decorative center cap fits). By slowly adjusting the depth of the guide bearing to the right spot on the taper, I was able to mill out the bore to fit the Genesis center hubs. Since carbide is much harder than an alloy wheel, it only took only seconds/wheel to enlarge the bore wall by only a 1/2 mm. BTW, the flat surface on the inside of the wheel's hub served as the rest for the router's base plate. I searched local machine shops for a large lathe, but setup and machining would have been very expensive.

Sounds cool. I was looking to enlarge the center bore of 60.1 mm wheel. I hope I don't mess up. Any tips?

 

[TEF]

I appears that the center bore of your wheels must be enlarged more than mine. Short of going to a machine shop, enlarging the bore by 7 mm must be concentric with the wheels existing center and that's difficult. Assuming you make a plate with a 67.1 mm hole (to use as a guide for the router's pilot bearing), it must be centered perfectly with the existing bore or you'll destroy the wheel.

Depending on how your wheels are constructed, you might want to check youtube as there are several videos on the subject. In some cases, guys are using routers to to cut larger center bores in Chevy truck wheels(?), I think. In these videos, the object appears to be to enlarge a wheel's center bore to clear the wheel hubs, but there seems no attempt to create an exact 67.1 mm hole or whatever. Presumably, they assume that the wheel studs will center the wheel once mounted vice a hub centric fit.

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[patrick49]

https://www.rimsntires.com/specspro.jsp - this is a good way to get a comparison between various setups.