[HWYSTR455]

255s on all 4 corners is fine, and allows for rotations. And yes, 275, pretty much just the contact patch. 8s all around is fine too, though it will limit you to a 255, anything bigger requires a wider wheel.

Eagle GT all season W rated tires are about $130, that's cheap for the tire you're getting. And have a 400 wear rating. I saw some NANKANG tires on Discount for $110, but I have no experience with them. (Still inexpensive for an 18).

.

[glenn911]

On mine, I am going to measure my current ride height and then contact PTFB and see what they can provide that would maintain close to my current height, but obviously stiffer to avoid bottoming. All the research I did says that 255/50/17 on 17x9 wheels at all four corners is very easy on a 2nd gen bird. So a simple spring change must be the answer...several guys on here running the same tires but with aftermarket springs. Does anyone know the proper spot to measure ride height?

[HWYSTR455]

Originally Posted by glenn911

On mine, I am going to measure my current ride height and then contact PTFB and see what they can provide that would maintain close to my current height, but obviously stiffer to avoid bottoming. All the research I did says that 255/50/17 on 17x9 wheels at all four corners is very easy on a 2nd gen bird. So a simple spring change must be the answer...several guys on here running the same tires but with aftermarket springs. Does anyone know the proper spot to measure ride height?

Your current ride height is already skewed by an inch, not sure they are going to be able to do much with that measurement. Technically, you should be measuring the spring, free height, number of coils, and coil diameter. Any spring supplier is going to calculate from a baseline that is based on factory specs, so it's going to be a crap shoot. And most performance spring suppliers provide springs that are going to lower the car (which is desirable from a performance standpoint), making your situation even worse. Theoretically you should also measure the suspension travel, and corner weights, but not going to dive in that deep.

You might get lucky though with just going to a higher rate spring, since an inch really isn't that much. But you would have to choose a higher rate spring that has no drop for the most part to be sure.

I think it's a lot easier to just go to a tire that mimics the factory height and be done with it. Allows you to follow examples and setups others have already worked out and done homework on.

Maybe someone who is running that size tire can chime in, or maybe find someone that is and ask.

Just a thought, might want to check your core support/body bushings, see if they're mashed or need replacing. You can loose an inch easy when those are boogered.

.

[glenn911]

Thats why I went with a 27" tire. That is a factory height tire, just wider.

[72blackbird]

PTFB's GT front springs will work with a 255/50R17 on a 17 x 9 rim- more than one 2nd gen Firebird owner has run this combo on his car with success. I think a 255 is about as wide as you can go with this spring's ride height however- I know it won't work for me. A 275/40R18 is only 26.66" tall but much squarer in the shoulder than a 255/50R17 even though it's 27" tall, and will come in contact with the wheel wells. I am running stock WS6 rear leafs and I have good clearance with this spring, but I did cut the fender lips and rolled them back to make sure there's no contact there.

Ride height is measured at the front and back of the rocker panels- 8" is supposed to be the stock measurement, give or take 1/4". Of course for lowered cars this number goes out the window. And if you have old, worn body bushings and tired springs this number will no doubt not be accurate either.

Geno

[HWYSTR455]

Originally Posted by glenn911

Thats why I went with a 27" tire. That is a factory height tire, just wider.

You are correct, and not sure why, but I was thinking a 26" tire was OE. My bad! (Brain was stuck in a loop there!). It's been so long since I've run OE size tires, guess that's part of the reason. (Swear, has NOTHING to do with age!!)

I can imagine that a wider tire than OE, at OE height, would have clearance issues, considering the shape of the inside of the well opening. And that's the basis for the Herb Adams mod (trimming the inner and rolling the lip).

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[glenn911]

http://i876.photobucket.com/albums/a...ps043548be.jpg

Here is the damage, or lack there of. Wish I could get the darn photos to display!

[HWYSTR455]

Have to resize them so they're not too big...(photos)

That doesn't look too bad from the pics, but can't tell if the outside shape of the fender/quarters got distorted or not.

That's pretty close, you might be able to beat it up enough to where it doesn't grab.

.

[glenn911]

Funny thing is I did measure my ground clearance at the specified locations and got 9" at all four points, factory with 27" tires is supposed to be 8". That is with old bushings and springs!

[HWYSTR455]

Originally Posted by glenn911

Funny thing is I did measure my ground clearance at the specified locations and got 9" at all four points, factory with 27" tires is supposed to be 8". That is with old bushings and springs!

Well, the old F, G, L, N series type doesn't align perfectly with today's aspect-ratio sizing, maybe that's where the discrepancy is? Pulling straws, but it's a thought.

Pretty obvious what your choices are though. Shorter tire I think is the better of the two, but that's my personal opinion. I know running 40s on 17s is proven and widely accepted. Think Year One listed 40s as recommended tires for the Rally wheels even (275s). On the 8" wide, they list a 245/45.

.

[70455HOVert]

Got my set of 4 18x8's in this week. Went cheapo on the tires, 280 treadwear, but they were $76 each with a 30 day money back. 255/45/18

I'll take some before and after shots next weekend when I get them mounted up.

Also, I took some measurements...inside the wheel behind the center cap is 2.625", the center cap is 2.69" wide, and the Rally II cap is 2.81" wide.

[Captainofiron]

For those of you guys wanting a big inch tire and white letters, I saw a new Challenger this weekend with I think 20s and it had Falken Tires with white letters, looked pretty cool

[70455HOVert]

I'll have to ask Discount about them. They carry Falken. I also wonder if they might have just been colored in with the Duplicolor tire system. A quick search turned that up on the internet.
http://www.duplicolor.com/products/hotTires/

[Captainofiron]

Originally Posted by 70455HOVert

I'll have to ask Discount about them. They carry Falken. I also wonder if they might have just been colored in with the Duplicolor tire system. A quick search turned that up on the internet.
http://www.duplicolor.com/products/hotTires/

its possible, it was driving past me yesterday so didnt look closely at it.

looked good though
just did a quick google search, they are "Falken Azenis"

[The Champ]

Or - if you'd like redline's - Diamond Back makes them in 14 - 20" sizes.

[70455HOVert]

I only see 13"-17" in redline...am I missing the others?

http://www.dbtires.com/store/shopselecttire.cfm?size=

[The Champ]

20's - are on page 30 of the catalog

http://www.dbtires.com/2013_catalog/hi/30.htm

18's - are on page 28 of the catalog

http://www.dbtires.com/2013_catalog/hi/28.htm

[70455HOVert]

Thanks.

At $300 a pop, I'd never get the treadwear out of them before they'd be too old!

[The Champ]

You won't get the treadwear out of any tire before the tires will be too old...

I spent $250.00 each (average) for my 15's on my '64, but I like 'em!

I look at the cost per year of enjoyment - not the price per tire...

[HWYSTR455]

Originally Posted by 70455HOVert

...........Also, I took some measurements...inside the wheel behind the center cap is 2.625", the center cap is 2.69" wide, and the Rally II cap is 2.81" wide.....

Great info, thank you! Will probably order the caps in a week or so, will have to at that point determine the best approach to attaching. Would drive me nuts if they weren't centered in the wheel properly. Would look like the beginning of Outer Limits going down the road!

I was looking at tires yesterday, since it's going to be my son's car, all-season and safety are major concerns. I was looking at the General G-Max tires, 275/40s were like $165ea. That's still not bad, I've paid more for 17s before.

I also agree with The Champ, have to look at total cost over the life of the tire. Now for higher-HP cars, that is a lot shorter of a time span, but you get what you pay for, even when it comes to fun.

.