68-69 GM-A rear tires. 295/40-18 vs. 295/45-18

[OLDFLM]

FWIW I've been running the 295/40/18 Falkens on the back of my 71 Firebird for over a decade and love the 40-series in the rear. I'll be changing the front 255/45/18 to a 255/40/18 soon when I replace the tires.

[STREETFIGHTER50]

Not much Summer tire selection in the 295/40-18 size. For a matching front and rear set it looks like Nitto NT555 G2 is my only choice. I really like the Falken Azenis FK510, but they don’t have a 295/40-18. How would y’all feel about mixing the Azenis FK510 front with the stickier Azenis RT615K+ for the rear? This car will be driven only on nice sunny weekends. Cruising and some spirited driving when up in the hills.

[andrewb70]

What's wrong with the 615s with 295/40 and 255/40 front?

[STREETFIGHTER50]

FWIW I've been running the 295/40/18 Falkens on the back of my 71 Firebird for over a decade and love the 40-series in the rear. I'll be changing the front 255/45/18 to a 255/40/18 soon when I replace the tires.

What size rim do you have up front?

[STREETFIGHTER50]

What's wrong with the 615s with 295/40 and 255/40 front?

Wouldn't a 245/45 be better on the 8” rim? I was thinking 255/40 might be too wide on the 8”. Also, this would be the first time I’m considering these softer 200 tread wear tires. I’m guessing these don’t last long.

[OLDFLM]

My fronts are 18x8 and the 255 fits that rim width perfectly imo! 18x10s out back fwiw

[71OLDS]

A 255/45/18 is OK on an 18x8 rim but not a 255/40/18. You can check any tire brand on Tire rack or other tire sites and see:

255/45/18 = 8" - 9.5" rim
255/40/18 = 8.5" - 10" rim

-Joe

[andrewb70]

A 255/45/18 is OK on an 18x8 rim but not a 255/40/18. You can check any tire brand on Tire rack or other tire sites and see:

255/45/18 = 8" - 9.5" rim
255/40/18 = 8.5" - 10" rim

-Joe

I may have use the 255/45. It's been a while. Check heights. You want the front to be about an inch less diameter than rear.

[71OLDS]

A few other options with the 295/40/18 and 245/45/18 combo:

1. Nitto 555G2s front and rear. I good reliable tire - not real sticky but gets the job done and is safe in the rain.
2. Nitto NT05s rear Nitto 555G2s front. There's your 200TW tire rear - stickier - don't get crazy in the rain - same as above for front.
3. Nitto NT05s rear and Michelin Pilot 4S front. same as #2 for the rear - much higher end tire on the front - incredible for corners and for both wet and dry traction. It's expensive but I'm running this tire on the front of my 442 now and love it. I have Nitto drag radials for even more grip for launching but like to combine with the MP4S on the front to make things a little safer overall when I get caught in the rain.

[STREETFIGHTER50]

A 255/45/18 is OK on an 18x8 rim but not a 255/40/18. You can check any tire brand on Tire rack or other tire sites and see:

255/45/18 = 8" - 9.5" rim
255/40/18 = 8.5" - 10" rim

-Joe

This is trip. I just saw what you were saying in TireRack. You would think the opposite lol!

[STREETFIGHTER50]

A few other options with the 295/40/18 and 245/45/18 combo:

1. Nitto 555G2s front and rear. I good reliable tire - not real sticky but gets the job done and is safe in the rain.
2. Nitto NT05s rear Nitto 555G2s front. There's your 200TW tire rear - stickier - don't get crazy in the rain - same as above for front.
3. Nitto NT05s rear and Michelin Pilot 4S front. same as #2 for the rear - much higher end tire on the front - incredible for corners and for both wet and dry traction. It's expensive but I'm running this tire on the front of my 442 now and love it. I have Nitto drag radials for even more grip for launching but like to combine with the MP4S on the front to make things a little safer overall when I get caught in the rain.

So no weird issues mixing front and rear tire compounds right? 300TW front/200TW rear? My nephew has the FK510’s on his BMW. I really like them. Also, I’m leaning more towards a Falken set so I can rotate them side to side. If I can fit 255/45-18 front that would be great. Hopefully I can get away with just removing that center screw in the fender. I will not be driving this car in the rain. Only on nice days

[71OLDS]

Nah - no issues mixing TW ratings. I've got 100TW rear and 300TW fronts right now and the car drives great. You certainly can run the 255/45/18s on the 18x8 but it's just such a tall tire and for all the reasons I mentioned on post #10 here, I would still suggest the 245/45/18. If you decided to go with the 255/45s, just make sure your BS is perfect if turning radius (making U turns etc) is important for you. Also I believe your front and rear will be almost the exact diameter - or maybe only .1" taller in the rear.

[cdrod]

Here's another good tire combo with excellent wet & dry traction:
Continental Extreme Contact Sport tires 340 AA
Front: 18x8 4.5"BS with 26.7" tall 245/45ZR18
Rear: 18x9 5.25"BS with 27" tall 285/40ZR18

[STREETFIGHTER50]

Just got em back from the tire shop. These 295/40’s are thicker in person than I was thinking. Do RT615’s run bigger than other brands? A 45 series would definitely be way too tall. Should fill up my rear fenders much nicer

[andrewb70]

Just got em back from the tire shop. These 295/40’s are thicker in person than I was thinking. Do RT615’s run bigger than other brands? A 45 series would definitely be way too tall. Should fill up my rear fenders much nicer

They definitely run wider than the Nitto 555s in a 295/45

[Tidony]

Just got em back from the tire shop. These 295/40’s are thicker in person than I was thinking. Do RT615’s run bigger than other brands? A 45 series would definitely be way too tall. Should fill up my rear fenders much nicer

Any pics of them mounted on the car?

[STREETFIGHTER50]

Oops I forgot to post these pics up. The 18x10” 5.97” BS with 295/40-18 Falken RT615 tuck in nicely. Really centered in the wheel tub. I had to adjust the exhaust just a little bit.

Before with the 18x9” 275/40





Size comparison between the 275/40 Toyo Proxes T1 vs. 295/40 Falken Azeni 615+

[Cheveezy]

Looks great!

[Mr Nick]

Nailed it!

[STREETFIGHTER50]

Thanks for all the info y’all! I really do like these a lot more than the previous set