I’ve looked through a bunch of archived threads and only gotten confused. I want 12” corvette brakes on my 88 coupe, and that means upgrading from the stock 15”s. That means I want some decent wheels and tires.
Coilovers and going beyond 16-17” on the back, I should be able to run 265 or 275 wide on the back? I found wheels that come in 8” and 9” wide, they’re both 35mm offset though. What I read indicated +35-38 offset on the back should be fine but will that be alright up front?
Please specify 84-87 or 88. For example, on the 88 rears you need to go 18" to clear the knuckle for 9" wheels... unless you want or need the rear wheels to stick out about an inch past the body.
Please specify 84-87 or 88. For example, on the 88 rears you need to go 18" to clear the knuckle for 9" wheels... unless you want or need the rear wheels to stick out about an inch past the body.
Ok I mentioned 88 coupe, yup it’s for an 88. Besides that will +35mm offset look alright on the front? If not can I fix it with spacers or something?
If you want the front wheel protrusion to be stock from the 15's, then you need a 7" wheel with a 45mm offset. The 35 mm offset sticks the tires out about 1/2" further. What looks good to 1 person looks like crap to others, so it is best to reference actual dimensions or look at pictures, find what you like and then ask for wheel details.
On my car, the front and rear wheels are flush with the beltline molding at the top and it gives the car a pro-touring stance which I like, but again opinions vary.
[This message has been edited by fieroguru (edited 01-13-2023).]
If the front is lowered, it tends to make the wheels look more "tucked under". I have always preferred 38-48 mm offset on 7" wide wheels, for the front of an 88. But I realized I could live with a 35 offset, provided the rears are wide enough, and the front is low enough.
[This message has been edited by Raydar (edited 01-14-2023).]
I am debating whether I want to run an R18 9.5” wide rear wheel or R17 9”, both paired with a 17” front wheel. My car is an 85 with adjustable coilovers in the rear. I think it would look better with an 18 in back but tire prices jump like crazy going from 17 to 18. Is there any performance benefit? Tire would be 255 regardless. 18” tire would be a larger diameter so a larger contact patch due to contact patch length, but more unsprung weight, about an extra 2 lbs plus whatever extra the tire would weigh with its additional diameter.
Going from a 17 to an 18, you could go down to a lower aspect ratio. (255/45-17 to 255/40-18), to maintain a similar diameter. That, unless you have the capability of reprogramming revolutions per mile. Otherwise, your speedo will read low, compared to your real speed. Also, a 40 series tire will ride a good bit harder than a 45. And that's not even considering the unsprung weight that you menioned. It's why I have stuck with 17s. (I do 235/45s in the rear and 215/45s in the front.)
Just my opinion. Others may differ. I tend to like to keep my spinal disks uncompressed, and my fillings intact.
[This message has been edited by Raydar (edited 01-15-2023).]
I want to chime in here; A) The Fiero does not have a very advanced suspension design- The arms and spindles are steel (Heavy) and the shocks are not electronically controlled. So the Fiero does not do well with HEAVY wheel/tire combos. I took 3 lbs off of each rear and 6 lbs off each front when I installed my 16 x 7 wheels and 205 & 225/55 tires- it really improved the feel and performance of the car. Keep your wheel/tire combo as light as possible (Bigger wheels add a lot of weight)
B) Back in the 80s, a co-worker won a Shelby Charger...It was one of the first cars to use really short-sidewall tires. He was driving thru a cloverleaf onramp and hit a 2 x 4 which stripped the tire off the wheel, so that he ran off the on-ramp and crashed. I made a decision to never go below a 4" sidewall.
Everyone goes crazy for the biggest/widest tires and the biggest brake discs- keep it light and the car will be better. I used to want gigantic wheels and tires on my Mustang & Firebird, but when I switched to those lighter wheels and tires on the Fiero, I really finally understood what Colin Chapman (Lotus) meant when he stated "Add Lightness"
[This message has been edited by cvxjet (edited 01-15-2023).]
Going from a 17 to an 18, you could go down to a lower aspect ratio. (255/45-17 to 255/40-18), to maintain a similar diameter. That, unless you have the capability of reprogramming revolutions per mile. Otherwise, your speedo will read low, compared to your real speed. Also, a 40 series tire will ride a good bit harder than a 45. And that's not even considering the unsprung weight that you menioned. It's why I have stuck with 17s. (I do 235/45s in the rear and 215/45s in the front.)
Just my opinion. Others may differ. I tend to like to keep my spinal disks uncompressed, and my fillings intact.
Tires I’m looking at on fitmentindustries are a lot more common in 35 and 40 series for 18” wheels, I’m really looking at 235/40/18 for the front and 255/35/18 rear. I haven’t plugged that into a diameter calculator yet but that sounds smaller than the stock tires. My speedo is already off with the 3800sc and my stock wheels/tires so it’ll need calibration anyways. Smaller diameter tires will have the effect of giving it quicker gearing too, correct?
I’m about ready to get these, gonna wait for advice from the people here though. Those tires on 18x7.5 38mm offset up front, 18x8.75 33mm in rear. Thoughts? I haven’t really seen that kind of combo in the old threads I’ve been looking at.
I want to say that on my Fiero GT Getrag 5 speed, the 225/55-16s make the speedo as close to perfectly accurate as possible. Diameter of these are 25.75" vs the stock 86-88 GT rear tire diameter of 25.15".
Here is the wheel fitment graphic that someone made up years ago for our Fieros- may be helpful;
(Note: To view it large, right click and then "Open in new tab")
[This message has been edited by cvxjet (edited 01-16-2023).]
My 16 x 7 wheels weigh 13-14 lbs each. The General G-Max Tires weigh 21 and 23 lbs each.
The super low-profile tires have some minor benefits at max performance- but the new cars have advanced suspension (Super light arms & spindles, electronic shock absorbers) so they can deal with all of the weight. Our Fieros do not have these advanced parts.
On a smooth track you may see a small difference in cornering performance and handling feel...But straight-line performance (Accel and braking) will suffer from the added (Rotational) weight.
On a non-smooth track or on regular roads, the heavy tire/wheel package, along with short sidewalls will make the car ride and handle like a truck.
Back in 2010-12, C&D did a test with a VW Golf- basically increasing the wheel diameter while staying with the same tire type. You will notice that the Accel' suffers from the bigger wheels, while there is an improvement in both braking and lateral G. But the 15 and 16 TIRES were narrower than the 17-19 wheel tires. So that would improve those performances but also should have HELPED the accel with better off-the-line traction. So going to some 225 wide 16" tires would probably have given the best all-around performance.
One last thing; Back in the 80s, my Comet GT was set up for handling (Shelby mod + shocks-stabilizer bars-alignment) My original wheels were 6 3/4" wide...while driving, I could wiggle the steering wheel and feel the car wiggling back and forth on those "Floppy" sidewalls- Later I found some 8" wide wheels, and the change was amazing- Wiggling the wheel, the car would change direction instantly (I did not (Always) bang my head against the window- but it was close!) What this means is that wheel WIDTH is more important than super-low sidewalls.
[This message has been edited by cvxjet (edited 01-18-2023).]
I would use the pretty much the same size tire asides from radius, the contact patch is longer with the taller wheel so it would be slightly larger, and I think that 18” rim would weigh slightly less than the stock lace rims. I think the tires would weigh similarly per width since they are very close to same OD as stock and 18” tire has less sidewall. I am not looking to run super skinny sidewalls, I don’t like that look, just trying to maximize contact patch while having everything fit as well as possible. The 18’s have a lower offset compared to the 17s and the diameter will help clear the knuckle. The 17” wheel and tire combo would end up being shorter than stock gt wheels and tire combo.
I will most likely end up going 17s due to tire prices going up like 100$ a tire from 17” to 18” rims, and I want to run a 200TW tire which won’t last long.
Originally posted by zkhennings:The 18’s have a lower offset compared to the 17s and the diameter will help clear the knuckle. The 17” wheel and tire combo would end up being shorter than stock gt wheels and tire combo.
Also, for a more comfortable clearance, it would be preferred for the inner plane of stick-on wheel balancing weights to be located outboard of the strut.
Also, for a more comfortable clearance, it would be preferred for the inner plane of stick-on wheel balancing weights to be located outboard of the strut.
I'm also running Enkei Kojins 18x8 35mm offset in the front, 18x9.5 45mm offset rear. Currently, the car has a stock 85 front suspension with Will's antidive setup, and 2" drop spindles, and the rear is an 88 cradle with rod end lateral links. I don't think these wheels will be on it anymore after my next round of brake/chassis mods.
those will look great. i look forward to seeing them on the car.
------------------ "I am not what you so glibly call to be a civilized man. I have broken with society for reasons which I alone am able to appreciate. I am therefore not subject to it's stupid laws, and I ask you to never allude to them in my presence again."
I invited Lou Dias to trash me in my own thread, he refused. sorry. if he trashes your thread going after me. I tried.
[This message has been edited by ericjon262 (edited 01-22-2023).]
