295/50 15 vs. 275/60 15? Which is better?

[HI Cobra]

Thanks Buzz,

Nice reminder of how great these toys look. Mine isn't polished but at least
my wife understands why I enjoy it. She does enjoy the right seat.

[rustyBob]

Toms car looks great with that tire/wheel combo and the tires sit up inside the wheelwell just enough that they look like they fill the well up.The wider tires dont look good( my opinion).
the wide tires look good on a Camoro or Mustang from the 70's but not a Cobra.

[Larry N Johnson]

Originally Posted by timsullivan

Okay, thanks for the feedback and opinions on BFG vs. Goodyear’s. Now, if you’re a poor boy like me and can only afford those stupid, ridiculous and hard as nails old 15" tires and wheels which is a better REAR tire size when running 255/60-15 on the front tires: 275/60-15 or 295/50-15 and why in your judgment? Thank you in advance for your thoughts.

Answer: If you run a 255/60-15 front, then you want a 275/60-15 rear because a 295/50 -15 would be smaller diameter than the front. That makes the car look silly from the side.

On the other hand, if you want a 295/50-15 rear, then the 235/60-15 front has a nice diameter match.

On an FFR, the 295/50 fits perhaps better than the 275/60-15 rear as there is less space than other makes.

If I had a Kirkham, it would have Thomas Kirkham's recommended 275/60-15 rears for sure. Fronts whatever they recommend, as long as the fit w/out rubbing. A Kirkham has a lot more tire space in front than an FFR, BTW. Street manners are very important and anything that makes for safer smoother driving is "better" in my opinion.

BTW, if you want a decent old school tire that performs well, look at Mickey Thompson Sportman S/T tires from Performance Plus Tire. Like $472 a set delivered! Now, maybe less as they are advertising "free Freight".

[Ralphy]

Anyone have any experience with Hoosiers?

Hold on......................... Just found this site.
http://www.americanraceronline.com/r...cobra-kit.html

[Got the Bug]

Originally Posted by Ralphy

Anyone have any experience with Hoosiers?

Hold on......................... Just found this site.
http://www.americanraceronline.com/r...cobra-kit.html

I think they've been "under development" for a while. Look forward to seeing any new options available.

[Ralphy]

Originally Posted by Got the Bug

I think they've been "under development" for a while. Look forward to seeing any new options available.

I sent a inquiry asking what they're doing.
As far as Hoosier goes, it looks like they offer a Drag Street tire only
in 295/50 15.

[chas427fe]

I have had the Mickey Thompson S/T in 295/50-15 on order since February 17th from Perfromance Plus. They are on back order from Mickey Thompson. So if you are wanting them, you will have to wait or find them somewhere else. Chas

[Bob In Ct]

OK, so who is the source for the 15 inch Avons? Do I have to convert the sizes? I'm running Yoko 245/60-15 in front and 275/60-15 in the rear.

Bob

[Tom Kirkham]

http://www.rogerkrausracing.com/
http://www.sascosports.com/products/...php?type_id=39

[FUNFER2]

I like the wider tire in the back, it looks like how all "muscle cars" should look.
And I personally don't like 17" wheels because it fills the wheel well with the wheel, not with tire. The problem is there is not much for a selection of tires in 15's. Even the Good Year Eagle II's are hard to find. That's why I had the "Group buy" for the Billboards.

If we all want to have another of my group buy for the Billboards, I can call the company I dealt with and see what we can do.

Someday, I'll have to get 17" I suppose, and I won't like it.

Here's my 15x8 and 15x10 wheels.
Tires-
Front-235/60
Back- 295/50

[JCoop]

Just so you can see the steroid-silly look with Nitto drag radials 335s rear and 275s front on my older SPF:


Loved the grip both on a straight line and in the twisties, so when I got my next SPF, I thought 15s were really the way to go so opted for for a set of handcut GY slicks from Roger Straus, mounted on Vintage Wheels' BRM 15s for track work:


However, I really think 17s offer the best choice in rubber, IMHO. I just mounted a set of Nitto 555s 315s rear and 275s front onto PS Engineering wheels. Almost as good as the drag radials but don't pick up stones as badly. Everybody gives me hard time with having tires other than GY or BFG but these offer the best value. Great performance for a very reasonable cost.

[FUNFER2]

I like the GY's better, for pure looks anyway but you're correct, the 17's have more tires available. In a hand full of years, we won't have any 15's to use, and that's too bad. I like the wheel wells to be filled with tire, not wheels. It makes the Cobra look like a hot rod, and I love hot rods.

The popular look today is the "Pro Touring" with old muscle cars like the Camaro, birds, Vetts,..ect... and the 17-20" with a real low stance looks cool, just not on a Cobra. It may be that it's such a small & short wheelbase and lots of tough looking bulges ?

Someday, I'll have no choice but to buy the 17's.

[Gunner]

Originally Posted by FUNFER2

In a hand full of years, we won't have any 15's to use...

Not necessarily. There is a big enough body of cars that use these sizes that someone will keep them in production, the way you can still get correct tires for most 1920s-30s vehicles. (Check out Dunlop's classic offerings sometime!)

Hell, you can still get TRX tires, and they only fit about four vehicles for two or three years, thirty years ago.

[Voyager]

I’m still struggling with this one. Focusing strictly on sizes (not brands), it appears the consensus is either 255/60-15 front & 275/60-15 rear or 295/50-15 rear & 235/60-15 front.

What I don’t see is an agreement on which is better for a mixture of in town cruising & semi-spirited back county road driving (no track time).

Does a 255 meander/tramline when cruising?

Does a 235 under steer when pushed around a corner?

Does a 275 induce over steer too easy?

Does a 295 increase NVH?

Or is it all a wash and end up being a “whatever looks best to you” thing?

The tires will go on a Superformance with about 450-500 hp.

[Fordzilla]

I have a 69 Mustang Pro-Street car & run 15" Magnum 500 rims. It's a straight line 1/4 mile car so I go with the widest possible & the best quality tire for the money. BFG Drag radials last longer but Mickey Thompson ETs will hook better. Buy what you like & what works for your particular driving application. If your car has any nuts, you'll be buying plenty of rear tires so you can sample all the manufacturers offerings

[Voyager]

My SPF Cobra is almost done. I’m going to stay with the “OEM” tires (BFG 255/60-15 front & 275/60-15 rear). I assume the 515 hp & 531 tq KC engine will make short work of them.

[Excaliber]

How big a tire and a proper balance of handling for a more neutral feel is also dependant on which tire you run.

Sounds like the thread starter here is going with something like BFG's or maybe GT-II's. He NEEDS 295's in the back with those low traction non-sticky type tires. The rear end will get loose, he will not experience understeer with these tires. Go BIG in the back to keep the rear end planted (good luck with that). One might consider SMALLER in the front in hopes of moving toward under steer to balance the rear which WILL have over steer.

Avons, Bill Boards and other sticky tires will call for different size's front to back for the balance.

I have two sets of wheels and tires, Goodyear GT-II's for the street and Goodyear hand grooved slicks for the track. On occasion I drive the slicks on the street, like today. The difference in "confidence" in the car is night and day. With The GT-II's I'm ALWAYS on the edge of loosing traction and cannot relax for any shift or any corner. They will get away from you in a heart beat, rear end comes around, or they just go up in smoke with a bit to much throttle. Running the slicks, I never worry about the next shift, in or out of a corner or in a straight line. I KNOW those tires WILL bite unless I'm deep in the throttle and being stupid. NO WAY that rear end is coming around unless I want it to with throttle over steer. It's FAR less stressful driving on tires with traction than without.

[Ralphy]

I found this chart that is helpful. It's at the bottom of the page at the link.


Adjustment.............More Understeer.......More Oversteer
Front tire pressure........Lower.....................Higher
Rear tire pressure.........Higher.....................Lower
Front tire section.........Smaller....................Larger
Rear tire section..........Larger.....................Smalle r
Front wheel width........Narrower..................Wider
Rear wheel width.........Wider......................Narrower
Front wheel camber......More positive...........More negative
Rear wheel camber.......More negative...........More positive
Front springs...............Stiffer..................... Softer
Rear springs................Softer..................... Stiffer
Front sway bar............Thicker/stiffer..........Thinner/softer
Rear sway bar.............Thinner/softer..........Thicker/stiffer
Weight distribution.......More forward............More rearward
Front aerodynamics......More downforce........Less downforce
Rear aerodynamics.......Less downforce.........More downforce


http://www.roversd1.nl/sd1web/suspension.html

I guess one issue is running conventional geometry with a neutral weight biased car. It would tend to over-steer. Plus the wider tires. I also understand with less caster a car will steer easier. Something to think about if you have no power steering.

[RallySnake]

In the 24 years I've been driving my Arntz Cobra, I've burned up LOTS of tires. When you run a SCCA Solo2, you really find out how good your tires REALLY are.

The first set came on the second hand rims that I purchased. They were BFG's. The problem is that the hard rubber compound just doesn't grip well on a light car. They would let go gradually and I was able to do some phenomenal drifts with them. If you like making your passengers scream, these are good tires.

Most of the tires I have used since then are no longer made. The Yoko Avid S/T’s I have on the car now have been pretty good. But, the rears have worn to the point I have to replace them. If a lotto ticket pays off, I just might be able to afford the Avon’s. Since I run through a set of tires every year, it just does not make sense to spend $1,600 for a set.

I have found that larger tires on the rear do not make much difference. It doesn’t matter if they re 305’s, 295,s or 275’s, it’s the rubber compound makes the difference. However, I have found that using larger tires on the front really helps handling. If you want to get around a track quickly, you want your front tires to be as large as your rear tires. Unfortunately, 275 tires look a little wacky on the front of a Cobra, so I compromise with 255/60/15’s.

The Mickey Thompson Sportsman S/T tires look like the best, affordable choice right now. I would really like to hear from someone who has run a Solo2 or Autocross with them. Do they have a gradual breakaway? Do they give audible warning?

[Larry N Johnson]

I have used M/T Sportsman S/T for 2 years now, but no AutoCross experience.
I can say they balance way better than any other tire that I have used, mainly GY Eagle GTII's. The S/T are fantastic street tires IMHO!