Topic: Wheel Question
in Forum: C3 General Discussion
Already a Member?
Click Here to Login
Not yet a Member?
Click Here to Register for Free!
Chip, no what I was talking about is a replica of a stock wheel (rally or YJ8 aluminum) but in 16" or 17". So it would look just like stock, but be sized to fit more modern, advanced tires. I don't think I've ever seen or heard of anything like that, but maybe some of the bigger vendors would consider it someday....
1976 Silver/Firethorn. L48, 4spd. Original 2 bolt, vortec heads, 9.4:1 CR, Speed Pro Cam: 224/224@0.050, 112 LSA, Eagle Steel Crank.
SPONSOR AD:: (Our Sponsors help support C3VR)
2011111017209r.jpg)
fp_vetter72 said: Those look nice on that black beauty!! I was looking at the same ones on fleabay.
Those really shoud fit. I did the math on the 120.65.............and yep in comes out to 4.75 inches for the bolt pattern. The offset is 0 so that means it's 4 inches which equates to the center for an 8 inch wheel. The outside diameter is 27.1..........perfect. You know they will clear your calipers being 17". The brake line can be moved if neccessary. Go for it!much bigger than yours but I like those wheels.
corvette440hp
Former Member
Send PM
Cramerton, NC - USA
Joined: 8/22/2006
Posts: 1094
Vette(s): black 1982 coupe slate gray interior, 350 crossfire, 1985 fuel pump, Steeroids R&P conversion
Dave, sorry I misunderstood. Somewhere a while back I saw some discussion on large diameter rally wheels. Ill see if I an locate it and shoot you a PM if I do.
Everyone except Corvette 440, Larry, is missing a measurement factor.
Offset is measured from the center of the rim. The surface of the back of the rim where it meets the hub is the measuring point. If an 8 in rim has this surface at mid point of 4 inches across, there is NO offset.
Offset is then measured in how many inches is from this center point. There is another HUGE factor. There is both Positive and Negative offset. Remember year ago we had Chrome Reverse wheels that stuck way out? Those has a severe negative offset, sometimes refered to as reverse. If more of the rim tucks under the wheel well, it is a positive offset.
Many often refer to the distance from the back of the rim to the center or the mounting point as the offset. Not true, but a common mistake even in some advertising. Most rims are actually a positive offset, bringing the wheel inward (and hitting the calipers)
If the rims were measured from the back that would change the offset simply by putting on wider rims. But measured from center, the backset is always the same measurement dispite rim width. This makes a consist industery measurement, where the other method is not only wrong, but inconsistant.
A spacer corrects a negative offset, but makes a positive offset much worse.
The 8 inch example has 4 inch measurement from the back, it is a 0 offset. a 10 inch rim would need 5 inches from the rear to have a 0 offset. Either way the tire tread center point would be the same, which affects scrub radius, another very important measurement that affect handling. Total outer dia. of the tire also affects scrub radius. Larger rims with narrower sidewalls can maintain proper tire dia.
If meassured the way most have indicated, say 4 inches from the rear of the rim, that is a 0 on a 8 inch, but 1/2 neg offset on a 9 inch rim ( center point 4.5 in.), and 1 inch negative offset on a 10 inch rim (center point at 5 in. )
Hope this clears this up.
|UPDATED|6/9/2012 9:52:37 AM (AZT)|/UPDATED|
kstyer said:
Everyone except Corvette 440, Larry, is missing a measurement factor.
Offset is measured from the center of the rim. The surface of the back of the rim where it meets the hub is the measuring point. If an 8 in rim has this surface at mid point of 4 inches across, there is NO offset.
Offset is then measured in how many inches is from this center point. There is another HUGE factor. There is both Positive and Negative offset. Remember year ago we had Chrome Reverse wheels that stuck way out? Those has a severe negative offset, sometimes refered to as reverse. If more of the rim tucks under the wheel well, it is a positive offset.
Many often refer to the distance from the back of the rim to the center or the mounting point as the offset. Not true, but a common mistake even in some advertising. Most rims are actually a positive offset, bringing the wheel inward (and hitting the calipers)
If the rims were measured from the back that would change the offset simply by putting on wider rims. But measured from center, the backset is always the same measurement dispite rim width. This makes a consist industery measurement, where the other method is not only wrong, but inconsistant.
A spacer corrects a negative offset, but makes a positive offset much worse.
The 8 inch example has 4 inch measurement from the back, it is a 0 offset. a 10 inch rim would need 5 inches from the rear to have a 0 offset. Either way the tire tread center point would be the same, which affects scrub radius, another very important measurement that affect handling. Total outer dia. of the tire also affects scrub radius. Larger rims with narrower sidewalls can maintain proper tire dia.
If meassured the way most have indicated, say 4 inches from the rear of the rim, that is a 0 on a 8 inch, but 1/2 neg offset on a 9 inch rim ( center point 4.5 in.), and 1 inch negative offset on a 10 inch rim (center point at 5 in. )
Hope this clears this up.
Thanks Ken, at least someone understands me
Much more importantly......GLAD TO SEE YOU BACK (Hope you and family are well) I know OFF TOPIC!
corvette440hp
Lifetime MemberC3VR Founder
Eagleville, PA - USA
Joined: 11/1/2001
Posts: 18591
Vette(s): Used to own a 1979 Corvette now owned by JB79
kstyer said:
Everyone except Corvette 440, Larry, is missing a measurement factor.
Offset is measured from the center of the rim. The surface of the back of the rim where it meets the hub is the measuring point. If an 8 in rim has this surface at mid point of 4 inches across, there is NO offset.
Offset is then measured in how many inches is from this center point. There is another HUGE factor. There is both Positive and Negative offset. Remember year ago we had Chrome Reverse wheels that stuck way out? Those has a severe negative offset, sometimes refered to as reverse. If more of the rim tucks under the wheel well, it is a positive offset.
Many often refer to the distance from the back of the rim to the center or the mounting point as the offset. Not true, but a common mistake even in some advertising. Most rims are actually a positive offset, bringing the wheel inward (and hitting the calipers)
If the rims were measured from the back that would change the offset simply by putting on wider rims. But measured from center, the backset is always the same measurement dispite rim width. This makes a consist industery measurement, where the other method is not only wrong, but inconsistant.
A spacer corrects a negative offset, but makes a positive offset much worse.
The 8 inch example has 4 inch measurement from the back, it is a 0 offset. a 10 inch rim would need 5 inches from the rear to have a 0 offset. Either way the tire tread center point would be the same, which affects scrub radius, another very important measurement that affect handling. Total outer dia. of the tire also affects scrub radius. Larger rims with narrower sidewalls can maintain proper tire dia.
If meassured the way most have indicated, say 4 inches from the rear of the rim, that is a 0 on a 8 inch, but 1/2 neg offset on a 9 inch rim ( center point 4.5 in.), and 1 inch negative offset on a 10 inch rim (center point at 5 in. )
Hope this clears this up.
I don't want to get off topic, just need to say...
This is why we miss having you, Ken, around "full time!"
-Adam Wartell
NCM Lifetime Member #1222
Founder: C3 Vette Registry
C4 Vette Registry, C6 Vette Registry
My first Vette, now owned by JB79:
Former Member
Send PM
Cramerton, NC - USA
Joined: 8/22/2006
Posts: 1094
Vette(s): black 1982 coupe slate gray interior, 350 crossfire, 1985 fuel pump, Steeroids R&P conversion
A follow up on Daveo76's question about large size rally wheels I found these at Summit. There are also others available by a company called Wheel Vintiques but they AINT CHEAP.
Hi Chip,
I like what you've done with the wheels. It did take me a while to get my head
around the new look though. I also like the highlight on the gills and the side trim.
Lookin' Good!
Keith
I like what you've done with the wheels. It did take me a while to get my head
around the new look though. I also like the highlight on the gills and the side trim.
Lookin' Good!
Keith
Nobody ever waves when I'm driving the Explorer.
K Woody
Former Member
Send PM
Cramerton, NC - USA
Joined: 8/22/2006
Posts: 1094
Vette(s): black 1982 coupe slate gray interior, 350 crossfire, 1985 fuel pump, Steeroids R&P conversion
Thanks Keith
Limited Member
Send PM
Overland Park, KS - USA
Joined: 7/9/2003
Posts: 916
Vette(s): 1973 Orange Metallic Coupe (orig owner), L82, 4 spd (WR), PS, (A/C & PW (I installed from wrecked 73)), leather, AM/FM Stereo, ran with '65 FI unit earlier & will again some day.
2023 Accelerate Yellow HTC Stingray
JohnRR said: Hi All,
I'm new to this forum and have taken an interest in this thread. The discussion about backspacing and negative offset doesn't seem correct to me. If an 8" wheel has a 4" BS then it has a Zero offset. So if an 8" wheel has a 3.75 BS then it would have a negative 0.25 offset. That would be -6.35mm offset not -19mm. Am I missing something here?
Also, if the wheel has a 3.75 BS, a 1/4" spacer won't fix this. It would make the BS 3.5".
I'm trying to understand all this wheel terminology because I'm installing a set of C5 wheels on my '73.
Thanks everybody,
John
Came up w/ the same conclusion when I did the math. Suspect the -19 mm is an error since the rest is in inches.
Beware of spacers as they increase the load on wheel bearings and the studs.
Nice looking wheels. I believe they're what we called Cragar mags back in the 60s.
|UPDATED|6/28/2012 9:57:19 AM (AZT)|/UPDATED|
1973 L-82 4 spd
in Forum: C3 General Discussion
SPONSOR AD: (Our Sponsors help support C3VR)