[Steve C.]

Anyone run this tire on their 2nd Gen Firebird or Trans Am ?

P305/45-17

27.9" dia
11.9" SW
10.6" TW
Measured rim 10" wide

I'm currently running the Nitto NT555R size 275/60-15 (27.76" dia / 11.10"sw) on a 8" wide wheel with a 3-7/8" back space.

Pictured here:

https://www.hotrod.com/articles/0712...ront_left_view

I'm considering a change.


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[leeklm]

How did you like the Nitto tires for the street? I was originally going to purchase the SS for my 1st gen, but since I have a dedicated set of drag tires, was considering the lower cost, longer lasting Nitto for the street wheels.

Sorry for the side track to your question.

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[Colin70TA]

Steve,
Although I am running 275/40R18's NT05's in the back right now before that I had 295/40R18's NT555's and they fit just fine on the 70. They would rub a little bit on the tailpipes but only under hard cornering from what I could tell. The rims and tire still tucked in well inside the 1/4's. I can't see 305's not fitting if you get the backspacing correct.

PS. Motor is in the car and running, just getting break in miles on it now before bringing it to a chassis dyno. Thanks again!

[Colin70TA]

Hard to get a pick since it's dark out but this is with the 275' about an inch tucked in and 1/2 space inside before hitting the leaf

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[Steve C.]

Very encouraging knowing the 18" tires worked. For personal reasons I'd like to stick with the smaller 17" wheel, and make sure it fills the wheel opening. No short tires. The current Nittos are a nice fair weather street tire.
Thanks for the input.


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[Colin70TA]

I would have liked 17's with a bit more side wall but I needed 18's for my front brake package. I think the only downside to 17's is that it seems there are becoming less tire sizes available that fit our cars properly, at least I noticed this with the differnet autocross tires that are made. Not sure if it's a trend throughout the differnet lines.

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[Steve C.]

If this project goes forward my intention is to use the M/T ET Street S/S P305/45-17 in the rear and run a 235/50-17 tire in the front which is 26.3" diameter. The diameter of these tires are almost the same as the tires pictured in the link I posted above. Thus the stance of the car will not alter much at all. The section width of the tires are very similar as well. Then upgrade my front brakes to the Wilwood 6-piston front kit with a 12.88" rotor.


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[HWYSTR455]

The actual tread width may work, but one thing you also need to keep in mind is the tire 'bulge' of the sidewall (section width). That can contact the leaf 'buckle' that holds the leafs together, especially around turns.

With 3" tailpipes, there too you will struggle, as suggested. If you tank doesn't have the corners cut/rounded, you may find trouble there too.

I rolled my quarter lips, shortened the housing @ 1/2" on each tube, and in attempting to determine max width, no seat belt bump, it appeared I may be able to get a 315 in there, with an 11" wide wheel. Areas noted above were the spots of concern. Depending on the tire, MAYBE even a 325.

I've run 305s 18s with no sweating, but it's difficult to get a matching set based off the 305s. Since mine is a pro-tour type build, that was a no-go for me. I dropped back to 295s or sometimes 285s, just to avoid mismatch of tire brands/tread patterns. Also allowed me to have a slightly better wheel selection. (can use some off the shelf wheels).

If you're running an OE wheel, make sure you check both sides, there seems to be less clearance on the passenger side. I corrected that in my case, by having the housing adjusted when I ordered it. Have listed the order info here before on the housing, can search it.

Morning brain dump!

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[Steve C.]

Thanks. Undecided on the wheels so far, trying to avoid costly custom billet wheels for now. For me during High School in the 60's the Torque Thrust style was popular and they have been my go to choice. But I'm also considering these linked below in 17-inch. Will do some measuring first before we have to make a choice.

American Racing VN501 500 MONO CAST

https://www.americanracing.com/produ...black-machined


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[HWYSTR455]

Wow, those are nice, and very affordable! They only go to 9" wide tho, so that will limit your tire size.

A 295 suggests a wheel width of 9-11", and a 315 suggests a 11-12" wheel. There wasn't a listing for 305 on a couple I looked up, but suspect it would be a suggestion of 10-11".

A narrower wheel than recommended, will change the center section of the tire, and potentially the height too. It will 'squeeze' the tire, it will bulge more, for one, so you might not be able to get even a 295 on there with a 9" wheel.

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[Steve C.]

Well that puts a damper on the situation. I did not notice the the 9" only.


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