15" vs. 17" wheels, that big a difference?
 

The tires on the stock wheels on my 79 were on it when I bought it 11 years ago so even though they still have plenty of tread left, they are getting old. Been reading posts about much improved handling by going to a 17 or even an 18" wheel. Is it that noticeable of an improvement?

Suspension was redone back to stock a few years ago and the steering is tight, especially after making just one small adjustment on the steering box, so it already handles very good.

New 15" tires are about $850, tires and 17" wheels are about double that. I like the look of the stock aluminum wheels but if there really is that big a difference, maybe that's what I'll do.

What say you guys?

This may be apples to oranges but I went from 16s on my street rod to a 17/18 setup and the handling and responsiveness improvement was very pronounced. Feels much more nimble but gives up a little on ride smoothness.

Looks way better with the bigger wheels.....

It sounds like you like the look and the idea of keeping your car more original. Switching to 17 or 18 inch wheels will allow you to mount more aggressive performance rated tires than what are available in 15 inch. Unless you plan to install larger brake calipers and rotors or plan to drive more aggressively, I would keep your original aluminum wheels and 15 inch tires. BFG's and Coopers are great all around tires that are more than adequate for a stock or mildly modified Corvette.

Stick with the 255-60-15 Bf good rich white letter radicals old school look....Keep your aluminum rims and save the money......Leave the race track handling to the 40-60 thousand dollar newer vettes...

If you like corners 17s do help, tires are way cheaper than 18s.
Sumitomos are a little over 500 for 4. A set of 4 15" coopers is a little less;18s will run you around a grand for 4+-

Thanks for all the replies. I live in the mountains and do like the curves. I have a 350Z with 18" wheels and I can sure lean on it way harder than my Vette. Two different cars, I realize.

These are very similar to the stock wheels. 17" might just look close enough to original to suit me.


https://cimg3.ibsrv.net/gimg/www.cor...28f0726f63.jpg



https://cimg4.ibsrv.net/gimg/www.cor...d95d0d6e68.jpg

I went to 17s on my 79 and could tell the difference - as stated above, feels more responsive but loses a little smoothness. It wasn't huge difference in my opinion, but you could feel it.

I think the stock caliper/rotor still looks OK with 17s. Not sure it would with 18s though. I like the Ansen style slots, always thought those look as good as Cragar SS.

If you like cornering you will really like the feel of the bigger wheels, make sure you shrink your aspect ratio to maintain the same diameter.

I like the look of the slots myself, they would pop in a 17.

Sure are a lot of butt dynos saying 17s are absolutely the way to go...
More than likely they all had worn tires/not as good if tires as they had put on and thus th butt dyno results.
You can get performance tires in any size and doubt unless you road course it and need stiffer sidewalls you'd ever really notice a difference except for the looks.

Good points. I'd probably stick with 15s just so I don't have to deal with buying rims that fit in the 18" size. AND- it's not like I'm out hot-rodding anyway.

Also, my 68 has some oddball Red-nylon(?)-looking bushings in the front control arms and rides relatively rough (when I bought it, it came with some paperwork about Guldstrand suspension stuff-- it's quite stiff). I did change my sway bar bushings from some stiff nylon(? barely flexible) to poly a few years ago.

One downside is that those 15" tires are relatively expensive for the performance quality. Compared to 18" tires which you can buy with much better ratings qualities which are now relatively cheap...... of course, to buy the rims that I'd like, well that would be quite the expense:)

But, as long as I'm pondering..... does anybody make an 18" rally wheel in polished aluminum that would fit, and take our center caps? (geez, I really don't need to do this:))

It's car money


https://cimg5.ibsrv.net/gimg/www.cor...e6fc78c304.jpg

:rofl:

No one said anything about making a car faster or more powerful, so I don't see the relevance of a "butt dyno"or any other dyno for that matter.
My comments where about cornering feeling of responsiveness - which was noticeable but not worlds apart. By the way, I had BFGs in fairly good shape when I went to the 17s - not worn out at all.

Its not so much that the wheel size makes the big difference, its the tires that are available for a 17/18" are MUCH better vs a 15".
I pulled up the stock 15" tire size on tire rack vs the common 17" and 18" sizes people switch to... HUGE difference in the quality of tire available.

Stock 15" size (you will need to sort on the left by Performance Category->All-Season->Performance All Season)
https://www.tirerack.com/tires/TireSearchResults.jsp?zip-code=&width=225/&ratio=70&diameter=15
There's literally only two tires and they're only all season! Those same two compounds are also all that's available with the popular 255/60R15 size people go to.

A Popular 17" size is 255/40/R17:
https://www.tirerack.com/tires/TireS...earDiameter=17
If you sort by summer tires there's 39 to choose from! Ranging from nearly all-season tires to barely road legal semi-slicks.
Some people step up to 255/45R17 as the 40 is a smaller diameter than stock.
Also popular is 285/35R18 or 285/40R18, which arguably has a few even better compounds but are more expensive.

However, if you're not driving at or near the limit, just cruising on the street, etc, then you may as well keep the stock tires and the old school looks.

If you enjoy driving very spiritedly in canyon roads, highway on ramps (within the legal limits... :leaving:), and especially if you go to the track, the difference in tire is like having a whole new car.

I agree - how you drive and tire quality are both a factor. I don't track my car, but I would say I do some "spirited" driving.

Plus, I would be remiss if I did not point out that you need to pay attention to tire sizing to make sure you get the same diameter. It can take some searching to find the right size.

The short answer is that 17/18 inch tires will make a HUGH difference in the way the car not only handles and steers BUT will actually ride BETTER than the crap tires available in the 15 inch size. Anyone who says the change is not that noticeable is either sleeping or put on a junk 17 inch tire in place of the BFG radial TA or another S/T speed rated 15 inch tire.

The 17 inch Z rated tire is made with modern design and technology, will have a lower aspect ratio, will have generallly softer rubber for superior traction in the dry and wet, and is MUCH stronger than the typical 15 inch select few tires available for a C3.

I have upgraded/changed every single component in my C3 suspension over the last 30 years and finally gave up on the 15 inch wheels since I could not find a decent 15 inch tire that was not a raised white letter standard passenger car tires offered on a Toyota Corolla that had even moderate performance...in fact the modern corolla has BETTER tires than a BFG TA 255/60/15 tire.


I now have 255/45/17 ZR tires that are fantastic AND offer a superior ride to my former BFG TA'a.

If all you want is the looks of the ballon 255/60/15 with zero performance, a wandering steering and bouncy ride, then stick with the 255/60/15's. If you are looking for a noticeable improvement in performance traction, dry and wet braking, superior steering response, and a BETTER ride.....GO 17/18 ultra high performacne ZR/W/Y rated tires NOW!

You can get find way more choice in better 17" and 18" tires compared to what's generally available in 15". It should be obvious to everyone that the car will drive better on better tires and it will also be safer to drive.

I've switched my 65 Impala to a 17"/18" combination from 15" BFG's and it drives much smoother and more precisely now, if you can believe it of that boat sized car. I had to throw it around hard in an emergency and it handled the situation like a champ. I'm quite sure the outcome would have been bad with the BFG's. They wallowed and slid around too easily to pull that kind of maneuvering off.

I have one vette with a Borgeson power steering unit and the other with 17's. The Borgeson equipped car handles much better than the stock power steering car.

Sad but true 14, 15, 16 and 17" are going away and the new norm will be 18+.

My 71 with the Borgeson and the 15's handles great. I have no issues. I have 225 / 15 at 32# cold.

The ride does suffer with the larger diameter tires unless you make suspension changes... just a heads up..

If you don't want the car to look funny - try to stay very close to the original tire's diameter to fill the wheel well.

Part of the problem is that people put aftermarket rims on the car. the rims weigh more than the stock setup (tire + rim) and then the handling goes out the window.

Yes I have tire experience - I worked on the run flat tires in the mid 70's as an engineer... :D

From another post on suspension and Wheels that I posted a while back:

I have a 78 L-82 4 speed car with the gymkhana sport suspension (67,000 miles) that I have owned for 34 years and I have tinkered with the suspension one part at a time over all those years to achieve the perfect balance of superb handling, steering response and a firm but not harsh ride. Not knowing if you have a base suspension (most likely since most did not have the sport suspension from the factory) or the sport suspension, below is what you need for truly sportscar handling with a great ride for your 78:

Front:

550 lbs front coil springs/1 inch lower than stock-$100
1 1/8 inch solid front sway bar (OEM Bar size)-$200
poly upper and lower control arm bushings-$50
Bilstein HD shocks-$150
Front Spreader Bar-$100
Custom blueprinted/rebuilt OEM steering box- GTR 1999-Gary Ramadei-$300
This modification will make your OEM box about as good as it gets with the OEM steering and very close to a borgeson.....not quite but close
Rear:

360 monospring-$300
Bilstein Sport shocks-$150
OEM Style Rear Sway bar (not the aftermarket type bars. I highly discourage NON OEM/GM style rear sway bars)-7/16 or 9/16 or 3/4 inch (I have this one replacing the stock 7/16 inch bar)-$200
Competition adjustable strut rods with heim joint ends-$200

Total Cost $1750

This suspension will get you a FAR SUPERIOR suspension than what came on the car when it was new, X3 if the car had a base suspension from the factory. You will need to add 17/18 inch rims and tires (ZR rated only W/Y sub rating) later to maximize the superior suspension setup. I have ultra high performance summer only tires Front-255/45/17 ZR and rears 255/50/17 ZR's.

https://cimg2.ibsrv.net/gimg/www.cor...9aec119d86.jpg

This is ^^^the basic C3 suspension design pretty much unmodified from its original design but maximized for handling, steering, response and grip....I will say this again, the ride is far superior to the OEM gymkhana suspension that came on the car with 255/60/15 crap tires and is very compliant. A neighbor who has lexus LsS460/430 sedans recently rode in my 78 and he commented more than once about the power is great BUT he could not believe how well and tight the ride was....kept saying it.

BTW-the SLP rims and tires above weigh LESS than the OEM aluminum 15 inch rims and 255/60/15 tires..I weighted them both.......................just saying

I said this way back in the beginning of this thread...This ^^^^ will get you a fantastic ride, superb handling, all with basically a stock designed suspension with 17 inch ultra high performance summer only tires.............

I will also add that Karol on this forum with his base stock suspension,L-82 4 speed, and 15 inch aluminum OEM rims with 255/60/15 Radial T/A's, just this past weekend rode in my 78 ^^^^ and then in a back to back comparison we rode in his 78 unmodified base suspension L-82 and he could not believe how much BETTER my car rode than his car (not to mention handle). He loved the rebuilt/upgraded 355 L-82 but raved about the ride....This example is an immediate comparison of real world results, no theory here, with a direct comparison of the 2 suspension types...Not sure what else to say here about this subject.

Even in a 17" tire that is the same diameter (27") as my 15s there are not many choices. 255/50R17 is the same and 245/50R17 is 26.6". Very few choices and I really don't want to go to 18".

One of the choices is Nitto. Anybody have anything good or bad to say about them?

I'm thinking the NT 555 G2.

http://www.nittotire.com/find-a-tire...ameter=17#size