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LT--III ET "mag" wheels (aluminum) seem to be a popular choice, and available in custom backspace for a reasonable sum. Cheaper than Forgelines. I'll probably get a set when I need a dedicated 18" track set.
LT--III ET "mag" wheels (aluminum) seem to be a popular choice, and available in custom backspace for a reasonable sum. Cheaper than Forgelines. I'll probably get a set when I need a dedicated 18" track set.
The LT-III ET wheels I see online don't look at all like Corvette Rally Wheels to me. I'm not saying they aren't nice, but to me they look more like Minilites.
Interested also. Currently have 17x8 Torque Thrusts and looking for a change. I'll probably stick with 17's but exploring the Rally wheel options also. Currently, the Circle Racing series 90's and the American VN327's are on my radar. Both are a little more pricey than the steel ones, but should be lighter and there appears to be a better range of offset/backspacing. Those LT-III's look good also, but I'm afraid I may get tired of them also.
I have a stock 72 and want to put on a set of 18 in Rally type rims (Years One type)and tires 18x8 4' backspace in the front and 18x9 5' backspace in the rear , Im having trouble finding the 18x8 4' backspacing what Ive found is 18x8 4.5 backspacing, Im trying not to make any mods like spacers and e brake cable. any suggestions will help before I pull the trigger, Ive been searching for weeks and havent found what I want yet.
I have a stock 72 and want to put on a set of 18 in Rally type rims (Years One type)and tires 18x8 4' backspace in the front and 18x9 5' backspace in the rear , Im having trouble finding the 18x8 4' backspacing what Ive found is 18x8 4.5 backspacing, Im trying not to make any mods like spacers and e brake cable. any suggestions will help before I pull the trigger, Ive been searching for weeks and havent found what I want yet.
thanks Calvin
From what I have found no one seems to make a 17 or 18x8" version with 4" backspace.
Happy to be shown wrong but have been looking for a while as I don't want spacers. In fact they are illegal here.
The stock rally wheels are 8" wide with neg -.5" offset to the outside. Width is measured at the I.D. of the wheel rim / tire lip. But backspace is measured from the O.D. and they are 9.0" wide O.D. This gives a backspace dimension of 4.0" and a frontspace dimension of 5.0" That's a half inch off the 4.5" midpoint of the O.D.
To keep the tire in the same physical location in the wheel well, you want to keep the offset the same. Then the wheel width grows in both directions with wider wheels.
Ex a 9.0" wide wheel with a 10" OD and a factory -.5" offset would have a 4.5" backspace. If it had a zero offset it would have a 5.0" backspace and it would suck the tire corner in away from the fender lip. A 5.0" backspace depth is also about the depth where you need to move the parking brake clip for wheel clearance IIRC.
The 0" offset is very common on other GM cars, and most wheels are built for the volume applications. The C3 Vettes are one of the few that like the -0.5" offset. If you look closely at a Year One 17" Rally on a C3 they tuck in a little more than stock.
The Year One wheels look a lot like REV Classic 107 wheels which can be had at a cheaper price. No -1/2" or -13mm offset versions there either though.
Originally Posted by leigh1322
To keep the tire in the same physical location in the wheel well, you want to keep the offset the same. Then the wheel width grows in both directions with wider wheels.
Ex a 9.0" wide wheel with a 10" OD and a factory -.5" offset would have a 4.5" backspace. If it had a zero offset it would have a 5.0" backspace and it would suck the tire corner in away from the fender lip. A 5.0" backspace depth is also about the depth where you need to move the parking brake clip for wheel clearance IIRC.
But you can't change to a wider tire and keep the wheel in the same physical location in the wheel well. The wider wheel must extend inwards, outwards or both. A 9" wide wheel with 4.5" backspace would both extend the outside of the wheel 1/2" further out and extend the inside of the wheel 1/2" further inwards when compared to the stock 8" wheels with 4" backspace. A 9" wide wheel with 0mm offset or 5" backspace would keep the the outside of the wheel in the same location relative to the fender lip but move the inside of the wheel 1" further inwards.
Last edited by lionelhutz; 05-29-2020 at 01:28 PM.
..... But you can't change to a wider tire and keep the wheel in the same physical location in the wheel well. The wider wheel must extend inwards, outwards or both. A 9" wide wheel with 4.5" backspace would both extend the outside of the wheel 1/2" further out and extend the inside of the wheel 1/2" further inwards when compared to the stock 8" wheels with 4" backspace. A 9" wide wheel with 0mm offset or 5" backspace would keep the the outside of the wheel in the same location relative to the fender lip but move the inside of the wheel 1" further inwards.
You can keep the tire in the same location if you can get the correct offset. And that is hard to do. Most wheels are made with common GM car offsets of 0" and not the -0.5" the corvette was designed for. So you are correct for most readily available wheels because they were not made for our cars. However changing the offset has severe steering geometry complications.
A tire or wheel change needs to be considered at three locations. And the corvette has both inner and outer constraints.
With the same offset if the tread is 1 inch wider, it grows 1/2" on each side. Usually not a problem. Too much wider will sooner or later get you into fender lip trouble though.
As the wheel width gets wider, the sidewalls grows wider at about 40% of that. So a 1 inch wider wheel is a .4 inch wider sidewall split on both sides, probably not a problem. At some point the tire sidewall hits the trailing arm, the rear spring, the rear swaybar, or the car frame above the TA. Lots of inside rear contact areas.
As the wheel gets wider (or the backspace deepens), the first point of contact is the parking brake bracket, with a 15" or 16" rim. That measurement is somewhere around 4.5"bsp A 17" or 18" rim dodges the bracket completely.
You can keep the tire in the same location if you can get the correct offset. And that is hard to do. Most wheels are made with common GM car offsets of 0" and not the -0.5" the corvette was designed for. So you are correct for most readily available wheels because they were not made for our cars. However changing the offset has severe steering geometry complications.
A tire or wheel change needs to be considered at three locations. And the corvette has both inner and outer constraints.
With the same offset if the tread is 1 inch wider, it grows 1/2" on each side. Usually not a problem. Too much wider will sooner or later get you into fender lip trouble though.
As the wheel width gets wider, the sidewalls grows wider at about 40% of that. So a 1 inch wider wheel is a .4 inch wider sidewall split on both sides, probably not a problem. At some point the tire sidewall hits the trailing arm, the rear spring, the rear swaybar, or the car frame above the TA. Lots of inside rear contact areas.
As the wheel gets wider (or the backspace deepens), the first point of contact is the parking brake bracket, with a 15" or 16" rim. That measurement is somewhere around 4.5"bsp A 17" or 18" rim dodges the bracket completely.
So, you felt the need to quote my post to tell me I'm wrong and then explain it by posting the exact same thing I did.
A wider wheel ALWAYS moves the inner and/or outer relative tire locations. It must, simply because it's wider so both sides can not remain in the same location.
Last edited by lionelhutz; 05-29-2020 at 09:58 PM.
A PO had put Enkei wheels on my 79 when we got her. With a 1/2" spacer, they would have been fine, but they were not right for the car.
If you put in longer studs, and secure the spacer to the hub face, have you really added a spacer? Likewise, what if you secured the spacer to the wheels themselves (with longer studs)?
I agree with you on both points. Those are about the only wheels I have found that can be ordered in any custom offset.
Has anyone found any other wheel that can be ordered in a -0.5" neg offset?
I contacted Year One by email about some custom offset alum ralleyes or 18 inchers but do not hold out much hope.
If the spacer is solidly attached I see no problem and that is way they are recommended. However there are still some organizations that do not allow them. But I would still prefer none. I would prefer a stock looking alum 17 or 18" alum Ralleye in a 9 to 9.5 to 10" width. The offset will have to be correct or corrected to get them to fit especially the wider ones.
Cargotzman runs the LT11s in a 9.5 width with a -.5 offset and they look & fit great!
Lots of customer wheel manufacturer could make wheels how you wanted them if you're willing to pay the $$ they want.
REV Classic 100's have a 8" x 17" size with a -0.5" offset.
Neither option looks anything like a factory rally wheel in a larger diameter.
Originally Posted by leigh1322
Perhaps I need to be more blunt.
Zero offset wheels suck on these cars.
They suck the tires in away from the fender. They look funny.
I'll be more blunt too then. A 9" wide, 0mm offset wheel WILL NOT suck the tire into the wheel well when compared to the factory 8" wide 4" backspace wheels. Any wheel wider than 9" with 0mm offset would stick out further than a 8" wide 4" backspace wheel.
A 7" wide wheel with -13mm offset or 3.5" of backspacing would also suck the tire into the wheel well when compared to a 8" wheel with -13mm offset.
Last edited by lionelhutz; 05-30-2020 at 01:26 PM.
It feels like we are talking in circles here. I see your point but am not sure you see mine.
A 9.0" wide zero offset wheel would have an O.D. at the rim lip of 10". It would have a 5.0" frontspace and a 5.0" backspace. Vs the Stock wheel with a 4.0" backspace and a 5.0" frontspace. So yes the outer edge of the wheel would stay in the original position. I think that is what you were referring to. Correct?
However the inside wheel rim edge would be 1.0" closer to the TA arm and will need modifications to the parking brake bracket or the TA arm itself. You are basically adding all the extra width onto the inside. There is just not an extra 1" clearance there on a stock setup. The tire centerline will move in toward the car 0.5" If the tread width is the same you will see the tire corner move away from the fender lip. That was one of my points. The 1.0" inward sidewall intrusion will probably hit the frame kickup, the TAs the rear swaybar and the spring edge.
This tire would clear all of those items easier with a 9.0" wide wheel if it were on a -0.5" offset. Or had spacers.
I am sure a 9.0" or even a 9.5" wide wheel can fit these cars well front & rear as long as the offset is really close to -0.5"
I had my 16 x 10 inch wide Pro-Solo Camaro rims on my Vette for a test fit, and they could have been made to work, but needed mods for both the large vette calipers and an offset adjustment. I had to get all the measurements correct to within 1/8" to get 10" wide wheels to fit under the fenders on a stock 70 Z28. And it would also probably be that tight on a stock C3. Those wheels are now on a Vette with L88 flares so lots of room.
Can we agree to see each others points of view now?
LOL, I can't keep track of which point you're trying to make. Why would the tread width be the same on a 8" wheel and a 9" wheel? That defeats the whole point of using wider wheels.
02-20-2019, 03:42 PM
18” Rallye wheels, what is the best?
