Author Topic: Wheel Fitment (Read 32085 times)

OldMage · « **on:** Aug 16, 2004, 04:42:15 am »

Copying posts from other threads to here. I'll edit them later into a single massive post, or at least so the series of posts "flows". I know a lot of things will be redundant until I edit for just the needed info.

OldMage · « **Reply #1 on:** Aug 16, 2004, 04:44:01 am »

My Centerline "Hammer" rims are 15x7 w/ a +5/16" offset (8mm = .31496", 5/16" = .3125"), making the backspace 4 5/16"

Don't forget, an 7" wide rim actually measures 8" across the bead lips. That means a 7" wide rim has 0 offset with a 4" backspace.

Borrowed from AmericasTire:

Borrowed from TireRack's site:

Offset:
The offset of a wheel is the distance from its hub mounting surface to the centerline of the wheel. The offset can be one of three types.

Zero Offset:
The hub mounting surface is even with the centerline of the wheel.

Positive:
The hub mounting surface is toward the front or wheel side of the wheel. Positive offset wheels are generally found on front wheel drive cars and newer rear drive cars.

Negative:
The hub mounting surface is toward the back or brake side of the wheels centerline. "Deep dish" wheels are typically a negative offset.

I wish I could find something about backspace. If you lay a rim on the ground, t's the distance measured from the ground to the mounting surface. It includes the lip on the back side (that's why a 7" rim has a 4" backspace, not 3.5")

OldMage · « **Reply #2 on:** Aug 16, 2004, 04:46:54 am »

Specs for our cars is 110mm backspace (+8mm offset for 7" wide rim), 60.1mm center bore, 4x4.5" (4x114.3mm) bolt circle.

OldMage · « **Reply #3 on:** Aug 16, 2004, 04:50:31 am »

Quote

Contact NavySupra on the Celica-Supra forums. I think he was the one who looked into getting the GT-S rims custom made. But the price for a set was over $2000. The guys that did the ROH Synper wheels on the Celica-Supra forums. Ended up getting screwed over by the manufactorer. I think the closest they could make those was with a 18+ offset. Which in some cases. You might have to use spacers.

8" wide rims (9" across the bead lips) will require a different offset than 7" wide rims do. I think I'd actually expect the offset to go down to keep things where they belong, but 10mm is less than 1/2", so I'd be surprised if it really causes problems. Not sure that I'd want the wheels sunk deeper into the wheel wells tho. I think 0 offset would be preferred w/ 8" wide rims (4.5" backspace).

9" total wheel width (228.6mm)
0 offset/wheel center = 4.5" (114.3mm) backspace
stock GTS backspace = 110mm (~4 5/16")
4.3mm difference = 0.1693" (1/8" = 0.125", 3/16" = .1875")

If my math is right, "perfect" offset would be -4mm. 4mm is nothing to worry about, so 0 offset would be fine for 8" wide rims. +18mm isn't too bad, it's less than 3/4" (0.708" actually) from "pretty good". Using spacers w/ custom-made wheels is ridiculous. It goes back to the same problem the custom wheels were meant to solve in the 1st place.

OldMage · « **Reply #4 on:** Aug 16, 2004, 05:20:06 am »

Backspace is the distance from the rear outside edge of the rim (outside edge of the tire bead lip) to the mounting face. It's not a + or - number, just a measurement. Backspace usually doesn't change much, regardless of wheel size or offset. This is what places the suspension loads where the designers intended.

Offset is a measurement from the 'imaginary" center-point of the wheel's width to the mounting face. FWD rims have high positive offsets (usually +30 or more), which means the mounting face is 30mm closer to the face of the wheel than the center-point. Old RWD rims had zero or even some negative offset.

For our cars, the 14x7 alloy has 110mm of backspace (~4 5/16"), and +8mm offset. I haven't measured the backspace on any of the steel or 14x5.5 alloys, but I think it's close to the same. A narrower wheel will have a more positive offset to maintain the same backspace. A wider wheel, would have less offset.

Another confusing thing is that 7" wide rims actually measure 8" from outter edge to outter edge. Wheel width is measured between the bead faces, even tho backspace is measured from the outside of the bead lip.

OldMage · « **Reply #5 on:** Aug 16, 2004, 05:40:53 am »

No, don't want 0 offset, tho it would probably work. The 7" wide alloys have an offset of +8mm. Narrower wheels have an offset of ~+20 I think. Backspace remains constant, I believe at 110mm (~4 5/16"). Offset changes depending on wheel width.

17" wheels are for looks, not performance. But I'm sure there's something in blinding chrome available... You'll need hub adapters to mount any of the current FWD rims (high offset). Centerline should have some rims available in proper backspace in 17".

OldMage · « **Reply #6 on:** Aug 16, 2004, 05:46:04 am »

Quote

yes we have +20 offset....wheels are kind of hard to find in 4x114.3 in the right offset. look for wheels that were made for a rwd. probably anything from +15 to +25 or +30 will work. veilside, einke and several other companies make some wheels in the right offset and lug pattern. I will post them all later.

No, you only have +20 offset w/ the narrower wheels. Offset changes w/ rim width, but backspace *rarely* changes. You'd have a tough time getting a 7" wide wheel w/ a +20 or more offset on a Celica. And most wheels these days are +30 or more.

If you're not sure what the terms are here's a quick run-down:

Offset is the distance, + (toward the outside) or - (toward the hub/brakes), from the center-point of the wheel, width-wise. The offset of GT rims is +20mm, the offset of GT-S rims is +8mm.

Backspace is the distance from the outter edge of the wheel lip to the mounting surface of the rim. I believe the spec'd backspace for GT-S/Supra rims is 110mm.

So here's the math. A 7" rim actually measures 8" from edge to edge (gotta include the lip). So a 4" (101.6mm) backspace would be 0 offset. Add 8mm & you get 109.6mm backspace.

I don't know for sure if the narrow alloys are x5" or x5.5", but I've done the math & get backspaces between 3.75" to 4" for GT & ST Celicas. There's a lot less room for error on a GT-S w/ the wider wheel & tires.

So I guess a 0 offset wheel *could* work on a GT, you just have to check the fit w/ the tire mounted. And offsets from 0 to 15 *might* work on a GT-S as long as you test-fit the tire/wheel combo to be sure.

mario · « **Reply #7 on:** Aug 20, 2004, 06:44:43 pm »

it would be nice if people posted links maybe here to where we can GET wheels for our cars.

OldMage · « **Reply #8 on:** Aug 20, 2004, 11:51:05 pm »

That's part of the problem, Mario. They don't really anymore. Centerline is one of the few that still has wheels that will fit our cars. I personally have come to hate caring for bare polished aluminum, but some don't mind I guess. I've also found that the rims are fairly soft (they take dents from potholes, curbs, etc). This means that I've got a vibration that re-balancing the wheels won't fix <_<

For the most part, it's their "Billet Wheel Series" that can be ordered for our cars.

You can also check their "Wheel Deals" for clearance-priced models. Good deals if you don't mind taking care of them.

I think this is the best looking wheel in the "Deals" section right now, and only $89/ea!!!

Centerline Pulsar (click pic for details)

These are the only other "Deals" option for us: (they're fitted for 4-lug Mustang, but at least they're 0-offset! 16x8s, and only $99/ea)

Centerline Fluted Hammer (click pic for details)

Then there's always the custom made-to-order ones:
Centerline custom wheels
I like the "Ventura" personally (original name is "Pacer"). The "Big Sur" was the "Thruster", which was also on my "likes" list. The "Catalina" used to be "Saber"...

Ventura

BigSur

Catalina

mario · « **Reply #9 on:** Aug 23, 2004, 03:46:03 am »

i really like the Thrusters.. maybe this is something i can look into during the spring time... but i'd really hate to give up the Supra wheels.

But i have a hybrid to build before i can blow money on wheels.

dynamic73 · « **Reply #10 on:** Aug 23, 2004, 06:40:23 am »

I think I like the Ventura's the best. Wonder what the center bore is? Glad to see their making custom fit wheels. Wish they where CHROME.

mario · « **Reply #11 on:** Aug 23, 2004, 05:50:45 pm »

Ok do ours cars take the same wheels as the old Z cars? I know Z's have alot more aftermarket support then Celicas, and i think i remember somebody saying once they ran Z wheels on their Celica... maybe they weren't a members of this forum though, i can't remember.

Teranfirbt · « **Reply #12 on:** Aug 23, 2004, 06:12:16 pm »

Yes, you can run Z wheels on our cars.. I think the GTS wheels would look awsome on an old Z car..
Although the center bore might be different, you'd have to check on that.

Justin Martin · « **Reply #13 on:** Aug 23, 2004, 06:36:52 pm »

The center bore on the Z's is 66.1mm, versus 60.1mm on our Celicas. They use a smaller lug though. http://www.custom-spinning-car-truck-rims-...lt_patterns.htm

If I remember correctly, the '70-'77 Z's use a similar offset as the Celicas, and I suspect the '78-'82 280ZX's do too. Not sure about the 1st gen 300ZX, they look like they use a high offset.

Teranfirbt · « **Reply #14 on:** Aug 23, 2004, 06:48:55 pm »

I'm pretty sure you can get rings to make the bore size right..