Ok, my turn for tires

[Waffles]

OK!

So you guys may have read about the guy gonna build me a 9" 3.50 posi 31 spline rear end.

At his shop he also does rear end narrowing and wheel widening.

Nows as good a time as any if I want to do a mini tub... so I can get some fatter meats in the rear. (invoke sexual joke now. you're welcome. I set you up for this one.)

First... how much of a mini tub should I go? If I had my magnum500s widened, or went to a different rim since these mags are in good condition for being originals from another 70, what size width should I go to in the rear? I wanna keep like a 15" profile, but what width would you recommend just for the mini tub, so I can keep my rear seat functional?

Also, Its about time I picked up some tires that are worth a damn. These Radial T/As look bitchin, but we all know they suck. What street legal tires would you recommend that come very wide for if I put in a mini tub?

Thanks fellas. MF.com is ok for general discussion but generally sucks for tech advice.

[daveSanborn]

What street legal tires would you recommend that come very wide for if I put in a mini tub?

Goodyear GS-D3 F1's  (the wider tires pictured are the 275/40/17's)



A 275/40/17 is IIRC 10.8" wide.  In order to go wider than this.... such as a 295/315/335 series tire, you usually have to either narrow the rearend, run an aftermarket coilover rear suspension (losing the leaf springs), tub/mini-tub the rear wheelwells.... or any combination of all three.

If I were you.... I'd avoid narrowing the rearend and mini-tubbing the wheelwells and just use a 275/40 series tire.  These tires when viewed from the rear give the car the appearance of a "steam roller" and will not only look killer, they'll provide a much larger footprint/contact patch on the road.

Narrowing the rearend without mini-tubbing does nothing for you, but change your BS on the wheels that you use.

Mini-tubbing a fold-down seat/rear seat car has numerous complications that you'd probably rather avoid.... do you feel like sectioning your fold down seat?  Removing a 2" strip right down the middle of all the pieces and then welding them back together?  Custom upholstery?  Read PITA.

Without altering the rear seat, the most you could gain by mini-tubbing would be approx. 1/2" per side.  This is a LOT of work for just a little ole 1/2" more clearance inside the wheelwells!

275/40 series tire will require a 9 to 9.5" wide wheel.

[Waffles]

point made! I like those tires too. I was planning on doing the mini tub and shortening it, but will just avoid that and maybe have him widen my wheels some? We'll see. Thanks Dave.

[70_Fastback]

What do one of those pretty pup 275's run...

[70_Fastback]

Because I think that's the size I will go with on my 9" rears.

[daveSanborn]

What do one of those pretty pup 275's run...

Price @ TireRack

Read the Reviews here...

Here's a pic of them installed on sons' '68.  I used to have a better picture taken from directly behind the car that showed how wide they looked, but I can't seem to locate it.

[Starfury]

GS-D3's are awesome tires...but at the same time I wouldn't put them on a drag-style car.  My roommate had them on his 97 Trans Am and they grab very well, but they're oriented more for sporty handling than pure acceleration.  If you're going for the most traction possible in the rear (to help get power to the ground), I'd probably be looking at BFG's DOT-legal G-Force drag tires.

[daveSanborn]

BFG's DOT-legal G-Force drag tires

How are these tires on a street car.... in the rain.... taking a corner?

Drag radials have their place, and IMO it's not on a primarily street driven car.

Throw those suckers on when you're heading to the track, but for everyday driving?  Not for me.

[Fast68back]

Dave, what size are those front tires?

[daveSanborn]

size are those front tires?

I'll verify in the AM, but I'm 99% certain they're 225/55/17.

We originally installed a pair of 245/45/17's and they would just barely rub/scrape.  We obviously couldn't have that happening....

[Starfury]

How are these tires on a street car.... in the rain.... taking a corner?

Drag radials have their place, and IMO it's not on a primarily street driven car.

Throw those suckers on when you're heading to the track, but for everyday driving?  Not for me.

Well, even those GS-D3's are pretty squirelly in the rain (although they're very good for a "summer" tire).  You're right though, DOT legal drag tires are going to suck cornering, while that's the Goodyear's strong point.

I was going to recommend something like the BFG G-Force KD, which was a pure summer performance tire (non-directional tread)....but apparently they don't make that tire anymore.  You're limited to the KDW or KDWS.  They don't even make the original KDW, either, just the newer tread design version which used to be called the KDW2.  The KDW is an alternative to the GS-D3 with slightly longer tread life and slightly less traction.

So basically, you're right.  Given current tire options, if you don't want to run a drag radial on the street, GS-D3's are the way to go.  Just make sure you inspect them very carefully before having them mounted; Goodyear's quality control isn't exactly top notch these days.

[Laurie S.]

What's wrong with radial T/As?  I like mine. 

[Starfury]

They absolutely suck, performance-wise.  I have them too, and while I love the looks, they simply don't grab.  The tire design hasn't changed much since it was introduced (decades ago).  The tread is a crappy design and is a very hard rubber (440 UTQG) for a 50k mi tire, and the sidewalls suffer from serious flex issues.

They're even worse in wet weather.  Have you driven in the rain lately?  I have trouble getting started on a flat road without spinning a tire, let alone at one of the many stops on hillsides around here.

[daveSanborn]

What's wrong with radial T/As?

I have to agree with Tad.  While the Radial T/A is a popular tire, when you're looking for traction it is woefully inadequate.  Hot-rodders around here refer to T/A's as "cardboard" tires, because they're so slippery.

[Laurie S.]

Uh, I live in the desert, so we don't get slippery streets that often.  And, when it's raining I sure as heck won't be driving Trouble in it.   :rof

[Starfury]

Even in dry weather, they're pretty crappy.  But then, I'm at the point with my car where performance is more important than looks.  It doesn't sound like that's the kind of car you have.

When I swap to 16" wheels, I'm putting on a set of BFG G-Force Sports.  They won't look as nice as Radial T/A's, but they'll grab and handle a lot better.

[68EFIvert]

I have the KDW2's and think they are a great tire.  I have my traction issues but that is not a tire problem rather a heavy right foot at times.  The tread pattern is like no other.  I am running 275 35/18's.  Here is the best picture I have of them.

[Fast68back]

What's wrong with radial T/As?  I like mine. 

And how many miles do you have on them? They got more mileage on the ramp to your trailer than the road..... 

[Laurie S.]

No, I drove the car for about 5 miles before pulling the engine.  And, that wasn't mileage in and out of the trailer.  I don't intend to drag race the car, but it will be driven for performance once the 390 is ready for it.  I'll see if I notice anything with the tires, but I doubt it.

[Starfury]

Drive for 50 miles with those tires, then swap to a set of GS-D3's.  You'll notice a difference;)

[Laurie S.]

Maybe, but a muscle car screams for T/As.    ;D

[daveSanborn]

a muscle car screams for T/As

With this I agree.  The T/A tire has been around so long that it almost looks "stock" on a muscle car.

[Waffles]

Well I know. They look bitchin on my car, but they hardly are a performance tire of any kind, and on wet pavement i feel threatened for my life. lol

[tarafied1]

I had a set of 50 series BFG T/A's on my Crager SS mags. They are over 20 years old and hard as a rock. Still have tread and I can smoke 'em all day long! I had rear wheel steering with those if you know what I mean! And yeah they do look right at home on a muscle car.