The tires on my new to me 1974 coupe are date coded from 2007. Since I need to replace the tires, instead of sticking with another 15" set, I'm looking at moving up to 17" tires on the American Racing Torq Thrust II (VN5157861) wheels. I've been reading everything I can find on the forum on various wheel and tire combinations. I'm on a stock setup and I'd like to move to a wider tire. I'm encouraged by the number of people that seem to be running 255/50R17 with no issues. Many of the posts I've read though are from 10+ years ago and the only tire that seems to come in that size right now is the Nitto NT555 G2. Unfortunately I live in MN and I'm a little scared by this info from tirerack.com:I have no plans to drive the car in the winter, but I may still want to drive it in the fall when temperatures might be in the 40s or 50s during the day and dip lower at night. I haven't quite figured out my long term winter storage solution yet and the car is currently in my garage for this winter (temps in the garage don't usually dip much below freezing, but they can). I was thinking I could use the current old tire setup for the car to sit on in the winter, but would potentially have to swap everything before I want to be done with the car in the fall.


Right now my car has 235/60R15 tires on it, but if I'm reading correctly, the original tire size for this vehicle would have been GR70x15 which translates to 225/70R15. I'd like to try to stay close to that original tire size so the gear ratio is less affected (I have a 4-speed and I believe it is the standard 3.36 ratio, but haven't been able to verify that). If I decide not to go with the Nitto tires, it would seem I am stuck moving to a 235/55R17 (where there are a lot more tire choices).

Wondering if anyone has any suggestions or can share related experience. Thanks!

Did manage to find this similar thread: https://www.corvetteforum.com/forums...r17-tires.html
But hopefully there might be some new thoughts.

 

My experience with summer tires is exactly as descibed. You do not want to drive them at 40 deg F for any reason. They sure did work great in the summer, though.

If you want an all-season tire with good performance, look at buying 18" wheels instead. There are a LOT more tire options, including several choices of Michelin Pilot Sports

 

Look into Michelin PS2. See if they have the same restrictions. I have, when I had to, taken them out in colder weather. But my absence of evidence of cold weather damage in not evidence of absence. I have tracked these tires and they stick well.

 

I've had "summer only" tires on many different cars over the years. Yeah I'm in Texas but we do get snow and ice and temps well below freezing occasionally. The summer tires suck on snow and ice as expected but they have never suffered any damage. I have Nitto 555 on my vette (255/50-17) as well as my daily and they are fine.

 

I have NT555s in Minnesota, no issues here. Then again without a heater I’m not driving it much when it’s that cold out anyways (especially now that the snow and salt is out too.) I have 275/50r17s in the rear to go with my suspension mods, but 255/50r17s should fit just fine on all 4 corners of a stock car assuming your wheels have 4” backspacing.



If you’re willing to wait until next year these are something to consider. I’m still waiting to see the sizes available though.

 

What size tire are you running in the front? What did you use for the white lettering?

Thanks for pointing out that thread on the Pro-Trac Street Pro III. Looks like it could be interesting, but not sure if I'll be able to wait much into 2026. I'd like to be able to drive it in the spring and not sure it's really that safe it is to be driving on tires from 2007. I'm encouraged by your experience with the Nittos. Maybe I'm being too paranoid about the cold. I really won't be driving the car if it is below 40 degrees, but was worried about storing the car on the tires through the winter. How do you store your Vette during the winter and do you leave the Nittos on?

 

I have 255/50r17s on the front. The decals are from Tredwear. I like the look, but I’m not impressed with the longevity like I talked about in the thread.

I leave the car parked in a heated garage in the winter. I’ve only had the Nittos over last year, but didn’t have any issues leaving them on. I’ve heard of people increasing their tire pressure to reduce the chance of getting flat spots.

Good choice not driving on tires that old. When I first got a different ‘76 it was on tires from 1989. That was a fun drive home.

 

If you choose 245/50x17, only .4" smaller in diameter, you will have more choices in All Season category.

 

SLP 17 inch rims with Kuhmo 255/45/17 ZR Ultra High Performance Summer Only tires in front and 255/50/17's UHP summer only in the rear. The 255/50/17 is the same overall diameter as the OEM 255/60/15-27 inches.^^^^. Due to the 3.70 gears I wanted to not use a smaller rear tire which would increase the rev's even more at speed! I use the 245/45/17's in the front which lowered the car 1 inch, allowing for the proper forward rake, back to front, instead of the tail dragging, rear lower than the front look of most C3's, especially the later years, 78-82.

Go with 18 inch rims, if you can, since there are many more options in that tire size.

As for the warning posted above about summer only tires being used with the precautions mentioned, I have never had an issue using UHP summer only tires in colder temps below 40 degrees and I have much experience with this scenario for many years, past and present.

Just for context, besides my 78 L-82 above with UHP summer only tires, I currently have Cooper RS3-S's on my 1994 Mustang GT for several years now, Michelin Pilot Sport 4S's (in my opinion the best UHP summer tire currently available) on 2 other cars, one a daily driver, and a no name UHP summer only tire on my DD Chrysler 300 2008. I will and do drive any of the cars, aforementioned, in temps below 40 degrees and MUCH lower with zero adverse effects. I would never drive a summer only tire in snow conditions since the tread is useless with snow. In addition, just like with any tire, extreme cold will harden the softer rubber on a UHP summer tire more than an all season but I have never experienced dangerous driving with these tires in very cold weather. When driving an UHP Summer only tire in extreme cold, I am just more cautious with aggressive driving. As for potential tire damage, lets just say, I don't buy that warning (sounds like the BS of trade tires every 5-7 years with no damage or wear, even when stored in a garage) and never have experienced such an occurrence, with an n=10+ UHP summer only tires over 20+ years....many sets!

 

Thanks for the suggestion. Does look like there are a lot more choices in that size. I've been using the Les Schwab tire size calculator (https://www.lesschwab.com/article/ti...d-you-get.html) to compare tire sizes. Comparing the original 225/70R15 to a 245/50R17 says that is a 2.76% difference (0.75").
I've also been using this calculator (https://tiresize.com/gear-ratio-calculator/) to see what the impact of varying tire sizes is on the gear ratio. Looks like 245/50R17 would be a 0.10 increase.

Not sure how much of an RPM difference that would make, but I'm trying to avoid smaller diameter tires to keep the RPMs lower. Haven't had much experience with the car yet cruising at higher speeds, but it seems to already run at pretty high RPMs.

 

An excellent tire..

Michelin Pilot Sport All Season 4 Ultra High Performance All-Season Tire for Sportscars in 245/50ZR17

 

No overdrive will do that for you.

I would avoid sizes less than 27” for aesthetic reasons too. C3s already sit pretty high from the factory, and smaller diameter tires will only make the gap between the tire and the fender larger.

 

Try a comparison between 255/60x15 to the 245/50x17.

 

Is your car lowered at all or is this sitting at factory height?

 

Sitting at factory height, GM F41 springs.

 

I would go with a all season tire of some brand. My current hot rod is a 80 Camaro with 18" General all season tires. Never had it on snow or ice but I think it would be OK?
As said above I would go with 18" due to the larger selection tires and wheels.
Pic of my 71 with 275/40-18 rear with TT2's 8" wheels. 245/40-18 front TT2's 7" wheels. Gray spokes.
Pic of my 80 Camaro with polished TT2's. Same wheel size.


Just as a side note how many of us old guys drove on wide 60 series all winter. Hard to believe we lived? LOL.

 

I run 235/55r17 on 17X8 Superlight wheels, with a 4" backspacing. They are 27" tall,


just the same as 225/70r15's. Tirerack has 76 different tires for sale right now.

 

Love the minilite rims. Where did you get them? I have a sort minilite rim, but like yours better. More like the type John Greenwood used to run.

 

As the owner of a very nice 70 LT-1 I'm caught between the keep it pure stock or make modifications, I bought the car to drive so to me the magic of the LT-1 is the motor and the only mod I'm considering is a wheel and tire set-up like what Barry has on his LT- 1 but I worry about the low profile ride quality and wonder what shocks would be best so please chime in..

 

If anything the ride quality improves going to a larger diameter wheel. More firm and direct for sure, but it doesn’t have the bouncyness/squirrelyness of 15s. You would have a night and day difference going to a 17” or 18” setup with summer tires and Bilsteins, especially coming from those good looking albeit heavy P02 hubcaps.