I want to get a set of wheels for my 1984, and I want to maintain the stock tire size. I have the z51 suspension, but the last owner put 225/50r16 tires on it so I don't know what either width rim looks like with the right sized tire. I want to get either a full set of 9.5" or a full set of 8.5". Which width rim looks best with the 255mm wide tire?

 

The correct size tire for all the early wheels is problematic to get hold of, either crazy money or a track tire that can cosplay as a street tire.
Your best bet is aftermarket wheels or some later C4 wheels that you can still get tires for and use the needed spacers to correct the offset.

Factory wheel info: https://mirrockcorvette.com/c4-parts-guide/wheels/

 

I will be throwing on some 18" rims because of the amount of tire options available, I mainly just don't know what width to do with a 255mm tire. I was thinking of getting 18x9.5 for all 4, but I don't want the tire to look stretched. Did the tire look stretched on the z51 rear wheel?

 

I may not be understanding but generally you select a wheel size and offset that you want that fits the car, than pick the tire size that fits the wheel.

 

Like most tire threads on this forum its (almost always) about the look which is sad.

 

Track, DD, or weekend cruiser? With the 16x9.5, Toyo has a 275/45r16 racing tire. The grip on turn pikes and corners would be fun.

 

With a stiff Z51 suspension from 1984, I'd be concerned about my teeth fillings going to 18's. 275/40-17s aren't going away anytime soon. 17's should work OK. If they are still available A-mold sets came configured for early cars.

 

There are tons of tires available in 245/45R17 (at least 62) which would be well suited to a 17 x 8.5" wheel. This could be an appealing choice if you can accept a 245 section width due to the broad spectrum of available tires to choose from. Wheel availability might be an issue in 17 x 8.5", but 17 x 9" or 17 x 9.5" wheels would only be a slight stretch.

With modern tire technology and some very good tires available in this size, performance should not be degraded compared to mediocre tires in larger sizes, especially considering the recent trend of fitting all season tires to C4s.

 

I understand the question, and I won't dis someone for being concerned about looks. 99.9% of Corvette owners never drive their cars on a track or even autocross them, and although many of the rest think they "drive aggressive in the turns" on the street, they have no idea and they don't need a track setup. If I had a nickel for every person that thinks they are a hot-**** driver because they went up Tail of the Dragon but who really couldn't drive their way out of a paper bag, I'd be Elon f'n Musk. We find aftermarket wheels and tires that both look good and perform well in modern terms.

For a 255, I would look at a 9 or 9.5 rim widths. 255/40/18 is 26" tall, which is actually the same as stock 255/50/16s. There are plenty of tire options in that size, and I recommend the Continental ExtremeContact Sport 02 for all but ice and snow driving. For the wheels, you are looking for a bolt pattern of 5x120.65mm (not 5x120!), which is the same as 5x4-3/4". You need a net offset of 32-38mm. If you find wheels with more offset than that, you can use spacers to subtract offset: e.g. with a wheel that was made with 50mm offset you could use a 1/2" (12.5mm) spacer to get a net 37.5mm offset, which would be great. Keep in mind that spacers will probably require longer wheel studs. Somebody on this forum has found wheels with 40mm offset that work fine without spacers, and I can never recall the name of the wheel company. It was three letters, like ECR or something. Maybe you can dig that up in a search.

If it were me, I would look for an 18x10 or 18x10.5 set of wheels and shoe them with 285/35/18 tires. You're going to have to watch the offset more carefully with the wider fitment. some people here have successfully use 11" ZR1 rear wheels on early C4s like yours. Those have 36mm offset, so that's what I'd shoot for. Here's a pic of 18x10.5s with 285/35/18 on my friend's 95, but keep in mind that your early Z51 has lower ride height from the factory and will therefore look better:

 

Just run 275/40r17 on all 4 corners, all the 17x9.5 wide stock wheels will work for this. The front on mine is a 17x9.5, the rear is 17x11