performance wheels and tires
Safety Car
Joined: Dec 2004
Posts: 4,071
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From: San Diego CA
Can't fit much more than 255 wide tires on 8" wide wheels, though. If you want to keep up with modern cars you've gotta go with at least 275 wide tires and no more than a 45 aspect ratio.
Team Owner
Joined: Apr 1999
Posts: 21,953
Likes: 1,445
From: Reno Nevada
2024 C3 of the Year Finalist- Modified
You have to remember that this poster has a 496 ci BBC roller cammed motor. Tires become a big deal over 500 TQ and 600+ becomes something hard to even drive agressively
Safety Car
Joined: Dec 2004
Posts: 4,071
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From: San Diego CA
The only "simple" way I can think that you would make that fit is by going with probably offset trailing arms with a zero or even slightly negative offset (negative is inward right?) and fender flares.
But the whole topic is where to get the wheels to fit the tires. I would imagine cragar or american racing can make you a set that will fit.
Melting Slicks
Joined: Dec 2003
Posts: 2,941
Likes: 1
From: Fidalgo Island Wa
I can keep up just fine now, with the Bowtie Overdrives tranny I just put in.As I said,I'm not racing....but I was eventually planning on offset trailing arms anyhow.255's up front,& whatever will fit out back
Thread Starter
Instructor
Joined: Nov 2006
Posts: 173
Likes: 0
From: hampden ma
hey guys...i don't know if it will help but i forgot to mention the car had large rear flares when i got it ...does this help out or is the clearance more of an inboard/ caliper issue....thsnks
fred
fred
Melting Slicks
Joined: Dec 2003
Posts: 2,941
Likes: 1
From: Fidalgo Island Wa
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Team Owner
Joined: Apr 1999
Posts: 21,953
Likes: 1,445
From: Reno Nevada
2024 C3 of the Year Finalist- Modified
I think that your window straps are a nice touch. They are required at Bonneville Salt Flats for any car going over 175 mph
hey guys...i don't know if it will help but i forgot to mention the car had large rear flares when i got it ...does this help out or is the clearance more of an inboard/ caliper issue....thsnks fred
Because of the size of the C-3 caliper the wheel has to have clearance or you have to use things like 1/4 inch spacers. My Centerline wheels were made for large calipers and don't have a problem. Since you have flares I would just order some rear 18X12 with 4.5 or 5 inch BS Then buy some 345/35/18 rear tires. Your also going to need rear Smart struts
hey guys...i don't know if it will help but i forgot to mention the car had large rear flares when i got it ...does this help out or is the clearance more of an inboard/ caliper issue....thsnks fred
Because of the size of the C-3 caliper the wheel has to have clearance or you have to use things like 1/4 inch spacers. My Centerline wheels were made for large calipers and don't have a problem. Since you have flares I would just order some rear 18X12 with 4.5 or 5 inch BS Then buy some 345/35/18 rear tires. Your also going to need rear Smart struts
Drifting
Joined: Oct 2003
Posts: 1,486
Likes: 10
From: Big Pine Key FL
I made and installed matching windshield hold down clips too.
bassets clear the corvette calipers... and they also clear wilwood SL4's
To the tire question Yes there are V & Z rated 15 inch tires out there but the choices are FEW. Tire diameter gets to be an issue at some point 26-27 dia is the right range... That said I have 25.6 on the front and 28 on the rear.
You have to ask what you are gonna do with the car. Be honest to yourself.
I personally don't like the LOOK of 17's and 18's. They look ok if you give them the correct backspace (big deep dish) but you almost have to go to a custom racing wheel to get that look.
I may end up with 17's in the end but for now its donuts not rubberbands for me
bassets clear the corvette calipers... and they also clear wilwood SL4's
To the tire question Yes there are V & Z rated 15 inch tires out there but the choices are FEW. Tire diameter gets to be an issue at some point 26-27 dia is the right range... That said I have 25.6 on the front and 28 on the rear.
You have to ask what you are gonna do with the car. Be honest to yourself.
I personally don't like the LOOK of 17's and 18's. They look ok if you give them the correct backspace (big deep dish) but you almost have to go to a custom racing wheel to get that look.
I may end up with 17's in the end but for now its donuts not rubberbands for me
Thread Starter
Instructor
Joined: Nov 2006
Posts: 173
Likes: 0
From: hampden ma
thanks guys for all the input....do i gain anything with the offset arms? or are the caliper clearance and parking brake bracket mount still an issue?? what other suspension mods shud i make for beeeeg tires?? 
fred
fred
Melting Slicks
Joined: Jan 2004
Posts: 3,247
Likes: 210
From: Detroit MI
How big are your rear flares? If they're like mine, you want to run wide wheels with close to stock backspacing (~4") to fill up the flares. Otherwise, the tires will be swallowed up by the flares.
Safety Car
Joined: Dec 2004
Posts: 4,071
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From: San Diego CA
The biggest problem is indeed the calipers. Small spacers and/or certain wheels cures that issue most of the time.
Drifting
Joined: Oct 2003
Posts: 1,486
Likes: 10
From: Big Pine Key FL
Safety Car
Joined: Dec 2004
Posts: 4,071
Likes: 0
From: San Diego CA
By 1/2 I'm imagining you mean 1/2" diameter studs, right? Stock is 7/16 IIRC. I would imagine those should help. How much ya think your rat/bat mobile weighs? How much ya think the wheels weigh?
One of these days I'll get my studs upgraded to something a little beefier. Luckily the '81 is already one of the lightest vettes ever made stock and mine is even lighter. Until I start pushing some serious ponies to the back (400+ hp) I ain't too worried about them breaking.
One of these days I'll get my studs upgraded to something a little beefier. Luckily the '81 is already one of the lightest vettes ever made stock and mine is even lighter. Until I start pushing some serious ponies to the back (400+ hp) I ain't too worried about them breaking.
Drifting
Joined: Oct 2003
Posts: 1,486
Likes: 10
From: Big Pine Key FL
By 1/2 I'm imagining you mean 1/2" diameter studs, right? Stock is 7/16 IIRC. I would imagine those should help. How much ya think your rat/bat mobile weighs? How much ya think the wheels weigh?
One of these days I'll get my studs upgraded to something a little beefier. Luckily the '81 is already one of the lightest vettes ever made stock and mine is even lighter. Until I start pushing some serious ponies to the back (400+ hp) I ain't too worried about them breaking.
One of these days I'll get my studs upgraded to something a little beefier. Luckily the '81 is already one of the lightest vettes ever made stock and mine is even lighter. Until I start pushing some serious ponies to the back (400+ hp) I ain't too worried about them breaking.
I ESTIMATE the car is around 2800 lbs.
The wheels are 16 lbs each for the front and 22 lbs each for the rear
http://www.bassettwheel.com/dhole_asphalt.html
I have also replaced the stock calipers with Wilwoods.
Ultrashield alloy seats
The only other things are Percy's speedglass windshield and rear window (77 Monza Hatchback).
Burning Brakes
Joined: Dec 2003
Posts: 1,004
Likes: 7
From: Adelaide South Australia
Nobody seems to be concerned with wheel bearing loads here.... ???
The stock wheel bearing design is not that fantastic even with the stock rims and tyres. Wheel bearing wear is an issue with early C3's. The wider the rim, and especially the bigger the offset, the greater the load and increase in wear will be. Not to mention the increased load with higher cornering G's
Just keep that in mind too.
The big benefit is of course, if going with alloy wheels, is the reduced unsprung weight which apart from improving power to weight performance, also allows tyres to maintain contact better as suspension can respond quicker with less inertial mass.
I am particularly interested in any alloy wheels which are available which look similar to the stock rallyes (chrome bumper C3's) in possibly a 17" diameter.
Is there anything available?
I noticed that Grameinvette's car (above) has some nice looking aftermarket larger wheels, but can't determine if thay are alloy, and what size they are. What are they, Graeme?
cheers
The stock wheel bearing design is not that fantastic even with the stock rims and tyres. Wheel bearing wear is an issue with early C3's. The wider the rim, and especially the bigger the offset, the greater the load and increase in wear will be. Not to mention the increased load with higher cornering G's
Just keep that in mind too.
The big benefit is of course, if going with alloy wheels, is the reduced unsprung weight which apart from improving power to weight performance, also allows tyres to maintain contact better as suspension can respond quicker with less inertial mass.
I am particularly interested in any alloy wheels which are available which look similar to the stock rallyes (chrome bumper C3's) in possibly a 17" diameter.
Is there anything available?
I noticed that Grameinvette's car (above) has some nice looking aftermarket larger wheels, but can't determine if thay are alloy, and what size they are. What are they, Graeme?
cheers
Last edited by OzzyTom; May 16, 2007 at 09:26 PM. Reason: added picture