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View Full Version : The Rim Offset Question again....



XxSlowpokexX
03-17-2011, 12:21 AM
Now I know whats offered. I know what people have been running. I know reccomended offsets ranges.....

But what is the IDEAL offset for

an 18 *10 rear and 18*9 front rim.

This would be with running a 255 tire in front and a 288 tire in the rear.

Concerns for rear of course are the inside clearence. Just how far can we tuck it in. I'm concerned about wheel well interference however Im more concerned with clearence inside. People are running this size but are generally sbjected to what offsets are out there.

Fronts I'm concerned again with inside clearence but I would also not like it to rub my fender lip.

I guess when we deal with sn95 offset they stick out a bit...And with s197 they stick in a lil bit....

So Id like to know what ofest we could hav ethat would prevent tire to lip rub and still clear inside. In my case I have rolled rear lips

Thanks.....Just thinking here

ricardoa1
03-17-2011, 11:08 AM
+ 35-38mm Fronts
+ 39-42mm Rears.


You can go to 30+ on the fronts but then you cannot go too big on tires. Fender rub will likely happen on large dips. Rear you can go to 34MM+ but again you are just pushings wheels outward more and the larger the tire the more rub you will get.

XxSlowpokexX
03-17-2011, 03:24 PM
Is 45 to much for the rears? Would it be tucked in too much? I understand where the rim will be going I just figured maybe someone has figured out the ideal offset and not a range.

I think I currently have a 30 mm on the 99 cobra rims however they are only 17*8

Dahoopd
03-17-2011, 03:41 PM
Not sure if it helps you any, I have 18x9 with a 40mm offset all the way around buy they are SN95 lug.

ricardoa1
03-17-2011, 03:57 PM
Unless you are getting custom rims done. Then what are you looking at? Let me know and Ill let you know if it fits. Most aftermarket wheels have set settings so I gave you a range, that works.

45+mm for the rear is too much and will rub the inner fender near the shock mount on, You are fitting big tires and There is no perfect. Specially if you and Doug did not nail the centering. For example my car with 285s rubs when loaded for a trip, the inside on the left and the outside on the right.
42+ is what I had on the rears 18x10
I now have 36+ on the fronts on 18x9s I have not driven the car yet with the new 265 fronts, I think it looks much better then the 38+ fronts I had last year, so 36+ to me is about perfect for the diameter and width.
On the rears I am at at 40+ now though they claim 42+mm on the website and I have a feeling I will get more outer rubbing from the right side this time around but I dont think I will rub inside anymore.
My rubbing is nothing like you had and I dont chew up tires at all. And with the stiff springs and now higher level on the rear I dont think it will happen very often unless I move to san fransisco and start jumping hills.

ricardoa1
03-17-2011, 04:07 PM
Not sure if it helps you any, I have 18x9 with a 40mm offset all the way around buy they are SN95 lug.


Wow you must be cutting close to that spindle, the 38mm I had were pretty close already

XxSlowpokexX
03-17-2011, 04:27 PM
Rico after rolling my rear fenders I get none of that cutting.

It appears no offset is perfect but I have aplace by me that will make custon hubcentric billet spacers at any mm size. So that was one option. The other was custon rims.

Chris V has a 315 on his modified 17*10 99 cobra rims.

I figure if I go with an aftermarket rim with a slightly off offset lets say 45 instead of 42 I can get a small spacer to fix the issue... Im just throwing ideas out there..I may just get custom rims. If I do that Im looking at a 8.5 " rim up front and a 10 out back

Regardless tire size will be 255 up front and 285 out back.

Doug made a special tool to align K member..But the car itself may be off!
Once good thingh though is I dont have my k member or control arms wiggling around

ricardoa1
03-17-2011, 05:01 PM
I am aware of Chis tire size I think those cobra wheels started out at around 30mm You would know better then me. If you ride behind Chris's car you will see them sticking out past the fenders, but I think with his weight mods and springs that dont slam the car, I dont feel he will rub all that often.

45+ could work with 3-5mm spacers. But hubcetricity starts to become an issue and you might end up with vibes.

David Neibert
03-17-2011, 05:33 PM
Now I know whats offered. I know what people have been running. I know reccomended offsets ranges.....

But what is the IDEAL offset for

an 18 *10 rear and 18*9 front rim.

This would be with running a 255 tire in front and a 288 tire in the rear.

Concerns for rear of course are the inside clearence. Just how far can we tuck it in. I'm concerned about wheel well interference however Im more concerned with clearence inside. People are running this size but are generally sbjected to what offsets are out there.

Fronts I'm concerned again with inside clearence but I would also not like it to rub my fender lip.

I guess when we deal with sn95 offset they stick out a bit...And with s197 they stick in a lil bit....

So Id like to know what ofest we could hav ethat would prevent tire to lip rub and still clear inside. In my case I have rolled rear lips

Thanks.....Just thinking here

Damon,

Suggest talking to Brad about what offset/backspacing is on these wheels he sold Steve.

http://www.sccoa.com/forums/showpost.php?p=898197&postcount=4

Pretty sure they are 18" X 10" rear and 18" x 9" front, and they tuck in a lot nicer on the rear wheels than the Boyd Coddingtons they replaced.

David

BLOWN38
03-17-2011, 07:40 PM
Mine don't hang out of the wheel well at all. Although i have the typical subframe offset to the right. Mine rub the upper shock mount. With 285's tho I don't think that would be a problem. I'll try to get get you some measurements, Damon.

XxSlowpokexX
03-18-2011, 12:25 AM
ill more than likely save up for a custom rim like a ccw. But just doing some digging. Another option was widening my rims that I have now..Honestly that be perfect.. But unsure If I want to spand that loot on my stock rims

BLOWN38
03-18-2011, 12:39 AM
I would like to get some 18" late model SC wheels made.:cool:

cudaz101
03-18-2011, 06:54 AM
Damon take your meds bruv, we been over this I duno how many times.:D

Rico...+45mm is a good fit with 10" rears. Thats what my Bullits are and the fit is really nice. I do recall the issues you had with inner clearance but I dont recall the specs of the wheels you had either.

If you want tuck +45MM is max since most casters and even 2pc billet options will only fuss with .25" incraments.

I would not buy anything that required spacers, there is too much out there that will fit just fine to bother with spacers.

Brad

David Neibert
03-18-2011, 10:19 AM
Damon take your meds bruv, we been over this I duno how many times.:D

Rico...+45mm is a good fit with 10" rears. Thats what my Bullits are and the fit is really nice. I do recall the issues you had with inner clearance but I dont recall the specs of the wheels you had either.

If you want tuck +45MM is max since most casters and even 2pc billet options will only fuss with .25" incraments.

I would not buy anything that required spacers, there is too much out there that will fit just fine to bother with spacers.

Brad

Brad,

Are the 18" Saleen speed star wheels you sell, offered in a staggered set ?

David

cudaz101
03-18-2011, 10:23 AM
Brad,

Are the 18" Saleen speed star wheels you sell, offered in a staggered set ?

David

No David, they are only available in 18X9 with the 5-108 bolt pattern.

What are you considering doing? PM if you would rather.

Brad

ricardoa1
03-18-2011, 10:48 AM
Damon take your meds bruv, we been over this I duno how many times.:D

Rico...+45mm is a good fit with 10" rears. Thats what my Bullits are and the fit is really nice. I do recall the issues you had with inner clearance but I dont recall the specs of the wheels you had either.

If you want tuck +45MM is max since most casters and even 2pc billet options will only fuss with .25" incraments.

I would not buy anything that required spacers, there is too much out there that will fit just fine to bother with spacers.

Brad

42mm in the back was what I had and with the 285 rears I got the rub inside on one side. I can only imagine what 45mm would do to the inside rubbing problem. I agree that 45mm works but you with 265 wide tires 275 max IMO
Damon wanted 285 wide tires and +45MM might cause more aggrevation. I decided to go outward more with the new ones. They are about +40mm and should eliminate inner rubbing. On the outside well we will see if how bad it is. But my car is not slammed anylonger so I dont think it will be a problem.

cudaz101
03-18-2011, 10:52 AM
42mm in the back was what I had and with the 285 rears I got the rub inside on one side. I can only imagine what 45mm would do to the inside rubbing problem. I agree that 45mm works but you with 265 wide tires 275 max IMO
Damon wanted 285 wide tires and +45MM might cause more aggrevation. I decided to go outward more with the new ones. They are about +40mm and should eliminate inner rubbing. On the outside well we will see if how bad it is. But my car is not slammed anylonger so I dont think it will be a problem.

Nah, I dont see +40mm being a problem at all. Should be a nice fit IMO.

I got guys running 285's with the +45mm 18X10 with no probs Rici, so I dont know what to tell ya. I know thats the specs of the wheels though. Regardless all good advice but nothing Damon hasnt heard already. HAH

Brad

David Neibert
03-18-2011, 11:12 AM
No David, they are only available in 18X9 with the 5-108 bolt pattern.

What are you considering doing? PM if you would rather.

Brad

Just thinking about some new wheels for my 93 SC that is currently using 17" X 9" Cobra Rs. This car still has stock springs and I don't really want to lower it much if any because I need the ground clearance for the exhaust system. Got any pics of 18" wheels on cars with stock ride height ?

If I did lower it I would only use the 3/4" drop springs.

David

PS: Also considering the 18" Cobra Rs

XxSlowpokexX
03-18-2011, 12:02 PM
Nah, I dont see +40mm being a problem at all. Should be a nice fit IMO.

I got guys running 285's with the +45mm 18X10 with no probs Rici, so I dont know what to tell ya. I know thats the specs of the wheels though. Regardless all good advice but nothing Damon hasnt heard already. HAH

Brad

Yes I been over this with Brad lol But as you can see there are definitely differences in opinions here! I'd hate to pick something up and not be happy. A rim isnt something you can just make fit easily if it doesnt

cudaz101
03-18-2011, 07:00 PM
Just thinking about some new wheels for my 93 SC that is currently using 17" X 9" Cobra Rs. This car still has stock springs and I don't really want to lower it much if any because I need the ground clearance for the exhaust system. Got any pics of 18" wheels on cars with stock ride height ?

If I did lower it I would only use the 3/4" drop springs.

David

PS: Also considering the 18" Cobra Rs

Im pretty sure this is stock ride height but not an SC...
http://www.thecustomwheelshop.com/album/slides/GreenTbirdBullets1.jpg

The end result is going to look better than your current 17's since you are running a tire probably a half to a full inch shorter than stock height. So you might end up being happy with the fender gap running an actual stock height tire. The 3/4" drop springs look nice though.:)

That car should be rolling on Billet David. You know Im right. :D The Black Saleens would look hot too.
http://www.thecustomwheelshop.com/album/slides/Black%20Saleen%20%20Stephen%20Sokol%20Tbird3.JPG

Brad

XxSlowpokexX
03-18-2011, 07:45 PM
what size tire rim and offset on those black saleens?

XR7 Dave
03-18-2011, 07:57 PM
Steve's car with the Boyds has a 265 on the 10" wheel. I have the same wheels here with a 275/40. I don't know what the offset is, but the back clearance is good and they appear to tuck fine. With a rolled fender you'd never have an issue. A 285 would probably be ok too with just an occasional touch to the fender. My wife's car with the 285's on back and only 6.5" backspacing sit out slightly more than this car and they have only ever slightly touched the wheel well when heavily loaded and going over big bumps. I had more trouble with the fronts which are 8.5's with 255's on them. Look at her garage page for pics.

I get confused talking offset vs. backspacing though. To me it is just so much easier to talk in terms of backspace. :rolleyes:

cudaz101
03-18-2011, 08:14 PM
what size tire rim and offset on those black saleens?

I dont know what he is running for tires..Its setup for drift competition. I will ask him.

They are 18X9, 5-4.25 w/+36MM

Brad

cudaz101
03-18-2011, 08:22 PM
Steve's car with the Boyds has a 265 on the 10" wheel. I have the same wheels here with a 275/40. I don't know what the offset is, but the back clearance is good and they appear to tuck fine.

I get confused talking offset vs. backspacing though. To me it is just so much easier to talk in terms of backspace. :rolleyes:


The backspace is 7.25" Dave.

Brad

David Neibert
03-18-2011, 10:48 PM
That car should be rolling on Billet David. You know Im right. The Black Saleens would look hot too.


Brad,

What do you mean when you say "Billet" ? Centers that are machined from billet vs. cast like my Bogarts ?? What wheels are billet ?

David

Kurt K
03-18-2011, 10:58 PM
Brad,

What do you mean when you say "Billet" ? Centers that are machined from billet vs. cast like my Bogarts ?? What wheels are billet ?

David
Dave, are you sure your Bogarts are cast? I thought they were machined from a chunk of billet aluminum.

David Neibert
03-18-2011, 11:13 PM
Dave, are you sure your Bogarts are cast? I thought they were machined from a chunk of billet aluminum.

I meant the Bogarts are billet and my Cobra Rs are cast.

David

cudaz101
03-18-2011, 11:43 PM
That car is over the top in all other categories so why stop??:)

Yea a 2pc Forged Billet wheel instead of a cast wheel. A nice tucked 18X8/10 in either a conservative lip or the deep lip.

I have a set of the PT-22's with a conservative lip for big brakes sitting in the shop and the price is right on them. PM if interested.

Brad

David Neibert
03-18-2011, 11:59 PM
That car is over the top in all other categories so why stop??:)

Yea a 2pc Forged Billet wheel instead of a cast wheel. A nice tucked 18X8/10 in either a conservative lip or the deep lip.

I have a set of the PT-22's with a conservative lip for big brakes sitting in the shop and the price is right on them. PM if interested.

Brad

Brad,

Are those the same wheels as in this post ?

http://www.sccoa.com/forums/showpost.php?p=898197&postcount=4

David

Toms-SC
03-19-2011, 12:06 AM
How would these fit the front and rear? One of my favorite sites just got in some FRPP wheels.

19" x 9" wide
6.6" backspacing
40 mm offset

cudaz101
03-19-2011, 12:08 AM
Brad,

Are those the same wheels as in this post ?

http://www.sccoa.com/forums/showpost.php?p=898197&postcount=4

David

Yes, only these wheels are for Big Brakes giving more calipar clearance. A little less rear lip than Steves. I can send you some photos of the actual wheel if you want.

Brad

cudaz101
03-19-2011, 12:18 AM
How would these fit the front and rear? One of my favorite sites just got in some FRPP wheels.

19" x 9" wide
6.6" backspacing
40 mm offset

Im not sure but 19's do have a little more UCA clearance so I would guess it would be fine. You could even ask your favorite site what they think.

Brad

David Neibert
03-19-2011, 12:20 AM
Yes, only these wheels are for Big Brakes giving more calipar clearance. A little less rear lip than Steves. I can send you some photos of the actual wheel if you want.

Brad

Yeah....I'd like to see the pictures.

David