Same Year Different Sized Tires
Thread Starter
Racer
Joined: Aug 2013
Posts: 250
Likes: 1
Same Year Different Sized Tires
Since buying a 93 6 speed in October I've been reading up as much as I can & came up with something I haven't seen mentioned. I may be wrong, but apparently the FX3 equipped cars came with 275-40-17s all round while the others came with 255-45-17 in front & 285-40-17s on the rear. I believe the wheel sizes were different as well.
My questions............are my above statements true?
Secondly, does anyone know the rationale behind this?
My questions............are my above statements true?
Secondly, does anyone know the rationale behind this?
Drifting
Joined: Sep 2012
Posts: 1,284
Likes: 3
From: Murphy NC
You are correct. The base cars got 17x8.5 fronts and 17x9.5 rears, where as the FX3/Z07 cars got 17x9.5 all around.
I'm guessing as the FX3/Z07 cars run the same size all around for easy of use on the track and can be rotated, but that is just my guess.
I'm guessing as the FX3/Z07 cars run the same size all around for easy of use on the track and can be rotated, but that is just my guess.
Le Mans Master
Joined: Jun 2009
Posts: 6,528
Likes: 752
From: South Dakota
Actually the Z07 cars had the same size on all four. The Z07 required the FX3 option too.
The Z07 was 17 x 9.5 with 275/40/17 tires all around
All others were 17 x 8.5 with 255/45/17 front and 17 x 9.5 with 285/40/17 rear.
I think the reason was to decrease tram lining and make a less sensitive steering on the base cars.
The Z07 was 17 x 9.5 with 275/40/17 tires all around
All others were 17 x 8.5 with 255/45/17 front and 17 x 9.5 with 285/40/17 rear.
I think the reason was to decrease tram lining and make a less sensitive steering on the base cars.
Team Owner
Joined: Dec 1999
Posts: 34,873
Likes: 487
From: Lacey WA RVN 68-69
NCM Sinkhole Donor
One problem with the larger (wider) front tires was having the tires wander on road surfaces where lots of traffic would create ruts in the pavement. The wide tires would "grab" the edges of the ruts and tend to move toward the edges. The narrower front tire helped to reduce that grabbing sensation.
But having the same size tire on all four corners does allow for tire rotation which allows for longer tread life.
But having the same size tire on all four corners does allow for tire rotation which allows for longer tread life.
Melting Slicks
Joined: Mar 2008
Posts: 2,351
Likes: 222
From: Delta B.C. Canada
2023 C7 of the Year Finalist - Unmodified
2019 C4 of Year Finalist (appearance mods)
2015 C4 of Year Finalist
One problem with the larger (wider) front tires was having the tires wander on road surfaces where lots of traffic would create ruts in the pavement. The wide tires would "grab" the edges of the ruts and tend to move toward the edges. The narrower front tire helped to reduce that grabbing sensation.
Le Mans Master
Joined: Jul 2009
Posts: 6,381
Likes: 66
From: SF bay area C.A.
C4 of the Year Finalist
I'm running 285's in front and when I get in the truck ruts it's like it has a mind of it's own. I was actually pulled over by a Leo once because he thought I may have had a bit too many spirits and when I told him about the handling problem he had a big laugh. 
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2
Michael S. Palmer
Team Owner
Joined: Sep 2003
Posts: 25,386
Likes: 2,737
Consistently doesn't work here - if you drove a car that "tram-lined" that car would do it every time on that same stretch of highway if it entered the same section/groove of the surface. Every time and every driver!
Thread Starter
Racer
Joined: Aug 2013
Posts: 250
Likes: 1
Just so I'm clear on this. Are you saying that this is something that happens to Corvettes more than the "average" car, that it happens predominantly to cars with "wide" tires or what?
Safety Car
Joined: Jan 2004
Posts: 3,556
Likes: 13
The wider the tire the more prone to tracking the car is.
Also bear in mind ,the C4 started out as a true "perf" handling car , as the years progressed ,the suspension got softer and softer due to new owner
( the type that drive to the golf club on Sunday ) complaints about the hard suspension and it's handling characteristics so the base cars ended up as "luxury / perf " cruisers
As you can be from this chart
http://www.vettenet.org/susp_chart.html
the Z51 "perf handling " option in '96 was softer than the base FE1 suspension in '91
Also bear in mind ,the C4 started out as a true "perf" handling car , as the years progressed ,the suspension got softer and softer due to new owner
( the type that drive to the golf club on Sunday ) complaints about the hard suspension and it's handling characteristics so the base cars ended up as "luxury / perf " cruisers
As you can be from this chart
http://www.vettenet.org/susp_chart.html
the Z51 "perf handling " option in '96 was softer than the base FE1 suspension in '91
Advanced
Joined: Aug 2013
Posts: 71
Likes: 2
From: Oregon
On Highway 26 up here in Portland we have some nasty ruts. my 91 Z28 would hit these ruts and pull the car back and forth. I hated it so much I stopped driving on that stretch of the highway.
My 40th has the wider rear tires, and it has even wider then stock now. 315's on the rear. it doesn't have nearly the tracking issues my Z28 had but if I goto change lanes I really have to hold on because going from one set of ruts to the other can be dicey
My 40th has the wider rear tires, and it has even wider then stock now. 315's on the rear. it doesn't have nearly the tracking issues my Z28 had but if I goto change lanes I really have to hold on because going from one set of ruts to the other can be dicey
Safety Car
Joined: Sep 2010
Posts: 3,752
Likes: 190
From: Indiana PA
Interesting fact is that the C5/Base C6/C7's all come with narrow 245 or similar front tires and larger rear tires. Even the C5Z06 only came with 275/40/17's up front and 295/35/18's out back.
C4's can wear some BIG rubber, this is an advantage. I might just try some 18X9.5 wheels at all fours on my C4 and some BFG Rival 295/35/18's at all four as well. Where as the C5 and S2000 in the same SCCA auto-x class, cannot wear tires that big. Hehehe.