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St. Jude Donor '09-'10-'11-'12-'13-'14-'15-'16-'17-‘18-'19-'20-'21-'22-'23
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.
I have never seen a group of people who love to argue for the sake of arguing more than this bunch...outside of my wife that is. I find it very tiring.
Since I have been on this forum only a relatively short time and seen this ridiculous argument 'discussed' no less than 3 times already, I think I am just going to keep cutting and pasting my response.
Originally Posted by PainfullySlow
God I really don't want to get in the middle of a pissing contest so I will try to explain as I know a bit about tire construction.
What he was trying to say was that a 15" wheel with a 27" tall total profile has a much larger sidewall than an 18" wheel would having that same 27" total profile.
(27-15)/2= 6" sidewall height on the 15" wheel
(27-18)/2= 4.5" sidewall height on the 18" wheel
The taller the sidewall, the more it moves around...this is basic physics. This is called 'carcass flex'.
So, it is actually true that a 15" wheel with 27" total profile will absorb bumps better because of that extra carcass flex. It also means that the 15" option will not handle as well as the 18" again because of that same carcass flex.
Assuming that we are still talking a total 27" circumference:
15"=softer ride, poorer handling
18"=harsher ride, better handling
I know a thing or two about how tires affect ride and performance =)
Maybe I need to be a bit more concise so I will try to make a guide that should help future visitors to this thread.
THE ULTIMATE WHEEL/TIRE DEBATE - 15" or 17+"
I am going to break this down into several categories. If too many words in a row put you to sleep you can try reading a section at a time.
APPEARANCE/AESTHETICS
Here is the crux: no one but you gives a giant, steaming pile of flying squirrel poo what you think. It is subjective, meaning you like what you like and the other person likes what they like. It is ok for everyone to not like the same thing. Please read that last sentence 3 (or 300) times until it sinks in. Some people like the original 'fat tire' look of the 15;s. Some people like the more modern, lower profile tire look and both are ok.
Screaming your opinion over and over does not make you 'right' and it isn't very likely to sway the other persons opinion either. All it does is make you an ***. How many people have converted to a different religion based on a pamphlet that an annoying person at your door gave you? I will wager, none.
ORIGINALTY
This is not open to debate (although on this forum I would not be shocked to see someone try) but our cars came with 15" factory wheels. This gives it the classic appearance and classic handling characteristics of that era.
If originality matters to you (and it is ok if it does or if it doesn't. Refer to the above section on opinions) you must have 15" wheels on your car.
PERFORMANCE
It is an irrefutable fact that all things being equal (tire compound, temperature, tire pressure, etc. (for LH: Earths gravity, road conditions, not in a vacuum, not in a volcano, etc., etc., etc.)) that the shorter the sidewall, the better the tire will handle. This has been proved time and again through science. I know a lot of people here tend to throw silly things like facts out the window when trying to make a point but if I have to I can go into this down to a basic physics level. Look up 'irrefutable' if you do not know the meaning and please do it before you click the 'reply' button.
The stiffer the sidewall (either through size or material composition), the better the car handles. In laymans terms that means that a 6" sidewall on a 15" tire must flex more than a 4" sidewall on an 18" tire, consequently the 15" tire must handle worse than an 18" tire of the same compound. If you need a visual aid, take a 4' section of 1x3 wood and bend it. Now take a 1' section if 1x3 and bend it. Note which one moves more? #becausephysics
As a final note on performance, it is also a well known fact that the more modern sized tires are also available in more aggressive tire compounds and with better tire construction methods. This will also aid in performance as well as mitigate the harsher ride from the shorter sidewall. Note that I said 'mitigate' and not 'negate'. More on this below.
RIDE QUALITY/COMFORT
It is also an irrefutable fact that all things being equal (tire compound, temperature, tire pressure, etc. (for LH: Earths gravity, road conditions, not in a vacuum, not in a volcano, etc., etc., etc.)) that the shorter the sidewall, the worse the ride quality will be. This is due to the same reason that detracts from the performance of the tire; sidewall (carcass) flex. The more that the sidewall flexes, the more it absorbs bumps/road imperfections and the less work the suspension has to do. Again, this has been proven through science. If you need a visual aid, try to compress a tennis ball and then try to compress a dodge ball. Which one compresses more? Larger sidewall=less bumps.
What this means is that the 15" tires with their large sidewalls will give a smoother, less bumpy ride than an 18" tire with its smaller sidewalls.
The only caveat to this is that the newer, more modern tires have better construction methodologies than the tires of yesteryear and there have been improvements in both chemistry and construction that allow those 18" tires to ride a bit better than you would think. This does not mean that they ride better than their 15" counterparts. They don't.
SAFETY
The third irrefutable fact that all things being equal (tire compound, temperature, tire pressure. etc. (for LH: Earths gravity, road conditions, not in a vacuum, not in a volcano, etc., etc., etc.)) that the better the tire compound, the shorter your stopping distance will be. This assumes that your brakes have sufficient stopping power to overcome the coefficient of friction and cause the tire to skid (locking the wheel).
Now, I cannot say for certain that the older 15" tires are made from a different compound than the more modern tires. I am certain that there must be tests out there with stopping distance but frankly I am too lazy to look it up. Until we know for certain what the stopping distances are or the chemical make up of each tire, discussing this subject is an exercise in futility.
'GOOD ENOUGH'
I see this argument a lot and it usually goes something like this: 'It worked just fine 50 years ago so there is no reason that it shouldn't work just fine now'.
While this is true, the biplane gave way to jet engines, the abacus to the calculator, and the telegraph to the telephone. Just because something is more modern does not automatically make it bad...or necessarily better although I think you will find evidence stating that the latter is true more than the former in most things.
There are two sides to this discussion: If you could make your car handle better, why wouldn't you?
To this crowd, the performance aspect of the tire outweighs the other factors such as aesthetics. This is a matter of preference, and it is an opinion. Read above regarding opinions.
The car looks better with 15" wheels and handles just fine from the factory
To this crowd, the aesthetics aspect of the tire outweighs the other factors such as performance. This is a matter of preference, and it is an opinion. Read above regarding opinions.
IN CLOSING
This is my personal opinion on the subject. I prefer the look of the 15" tires however I am not willing to give up the handling characteristics of the larger tires. As such I chose a compromise of 17" wheels which gives me a little bigger sidewall to get the appearance that I desire without giving up too much of the performance characteristics.
If I were to build a show car, or a car that never gets driven: I would go with 15" wheels strictly for the aesthetics.
If I were to build a race car or a purely performance car: I would go with the 18" wheels strictly for the performance.
If I were to build a daily driver: I am going with the 17" wheels as a compromise between all factors.
I am hoping to have my car roadworthy by the end of this coming summer at which time I will have a set of 15" wheels with new tires on them as well as a set of 17" wheels with my Nitto tires on them. I plan on doing a side by side comparison, including video, and scoring each one on the above characteristics. Hopefully that will help put an end to some of this lunacy.
In the end, do whatever the hell you want to your car, and let others do the same free of snide comments, nasty digs, and just plain douchebaggery.
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.....
Last edited by silver74vette; 10-25-2017 at 09:08 AM.
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.
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+-
St. Jude Donor '09-'10-'11-'12-'13-'14-'15-'16-'17-‘18-'19-'20-'21-'22-'23
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.
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.
Last edited by cooper9811; 10-25-2017 at 12:39 PM.
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
Originally Posted by OldCarBum
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.
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)
St. Jude Donor '09-'10-'11-'12-'13-'14-'15-'16-'17-‘18-'19-'20-'21-'22-'23
Originally Posted by carriljc
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)
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.
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.
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... ), and especially if you go to the track, the difference in tire is like having a whole new car.
Last edited by supervette64; 10-25-2017 at 01:32 PM.
Reason: Fixed URL hyperlink
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.
Last edited by cooper9811; 10-25-2017 at 01:45 PM.
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...
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.
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.
St. Jude Donor '09-'10-'11-'12-'13-'14-'15-'16-'17-‘18-'19-'20-'21-'22-'23
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?
10-25-2017, 09:01 AM
15" vs. 17" wheels, that big a difference?
), and especially if you go to the track, the difference in tire is like having a whole new car.
