Tire Choice for 15 inch Wheels

[Nick B]

Is anyone running Cooper Cobra Radial GTs, (or any other brand) Size P255/60 R15 on the rears?

I'm using 15 inch wheels for a period look.
The original 10.5 inch wide Goodyear bias ply from 1965 would equate to about 267/55 giving a sidewall of 5.78 inches (rim to tread)
Factory Five recommends 275/50, which have a sidewall of 5.41 inches (rim to tread) - just slightly under the original
The Cooper Cobra Radial GT, Size P255/60 R15 have a sidewall of 6.02 inches (rim to tread) - just over original
I think I like the look of more sidewall rather than less, even though it's a narrower tire than either the original or the recommended 275. Since they're narrower, I don't think the taller aspect ratio should cause any issues with rubbing, but I'd like to be sure.

The build is a MkIV Roadster and I'm planning to use the recommended size of 235/60 on the fronts.

Please let me know what you think, and please share pics if you have them.
Thanks!

[GoDadGo]

235/60 15's up front with 295/50 15's out back look the best to me.

Most run BF Goodrich or Cooper Cobra's since the Avon tires are through the moon on their price.

I truly love the way these cars look with 15" wheels, but those sizes are getting tougher and tougher to get as you know.

For the record I wanted to take that path, but ended up running 245/45 17's up front with 285/40 17's out back in an attempt to get close to that 15" look.

Good Luck From The Dark Dart Side!

[Nick B]

Thanks GoDadGo,

295/50 is almost a perfect match to the original sidewall, and Cooper Cobras are available in that size, but would 295s fit without rubbing?

[KDubU]

I had MT’s on mine and they were fine although mine was a street cruiser only. MT’s or Cooper will work and the Avon’s are really nice but pricey as mentioned.

[Real time recon]

020.jpg
BFG 15" Radial T/As...
P/235/60R ...front
P/275/50R...rear

[Real time recon]

IMO the best looking tire for a Cobra ever made...IF only they would make these in DOT approved street legal version they would sell a Ton of them.
>> https://www.jegs.com/i/Goodyear/478/...SABEgLm3PD_BwE

[GoDadGo]

Looks like Kyle (KDubU) gave you the Best & Most Correct answer from real world experience for these cars.
Shown below are the height and width of these tires and I threw in what my car is wearing just as a reference point.

295/50-15 Cooper.................26.81" Height......12.20" Cross Section
295/50-15 BF Goodrich..........26.65" Height......12.10" Cross Section
285/40-17 Nitto....................25.98" Height......11.42" Cross Section

Nitto 245/45-17 & 285/40-17 on my Naked MK-4:
https://youtu.be/PCngiKoopkA

What they look look like with the body on my Dark Side Ride:
https://youtu.be/CaRlqMmKIzk

Bringing the front width down to 235's while increasing the rears up to 295's will give the car some rake while filling out the rear fenders far better than the set up I'm running...You just need to get your wheel width and back spacing combo dialed in and all will be right with the world...

The Factory Five 15" Wheels Will Be Perfect In My Less Than Humble Opinion!

[Jeff Kleiner]

Thanks GoDadGo,

295/50 is almost a perfect match to the original sidewall, and Cooper Cobras are available in that size, but would 295s fit without rubbing?

Yep. Used them on a Mk4 I built for a customer a few years ago. Factory Five Halibrand replica wheels (8" front, 9" rear) with 235/60 and 295/50 using a Fox width rear.



Cheers,
Jeff

[Murd]

I have the 295 coopers. That seems to be the go to size, there are some Mickey Thompson’s that are similar too.
I get a tiny rub on the drivers side rear fender on big bumps.

[rich grsc]

You should have zero issues on a Mrk IV with a 295/50/15, if the body work and install is correct. That what I run on my Mrk III, and after the body work it no longer makes contact. A 255 is WAY too small for the rear.

[Avalanche325]

Put your steel toe safety shoes on.....here we go.

I don't think any tire with a tread rating of 360+ has any business being on a Cobra. (no matter what it says on the sidewall) It takes a very capable car and hobbles it, reducing its acceleration, braking, and handling capabilities. Tires are the single most important piece of a cars suspension. Tires are also what actually stops your car when you hit the brakes. Yes, you will be able to lay claim to "I spin the tires in the first four gears", but for the wrong reason.

Traction of A (AA is the top) and temperature rating of B (110-115mph) are not what you want on a high performance car.

I run 200TW and I can still easily overwhelm them accelerating and braking with Wilwoods. I can't imagine losing cornering and emergency maneuvering ability. If you plan on doing anything more than cruising to the local car show and back, or having any decent amount of HP, I urge you to consider tire performance as much as cosmetics.

I know that we all do different things with our cars. But pretty much all of us drive them on a highway, where my concerns are very much in effect.

[GThompson]

Has anyone tried Hoosier TDs? I’ve been looking for info on them but can’t find much. I’ve seen them on a couple of Cobras at SVRA races but don’t know if they’re street-legal (not a big deal for me, my Daytona may not get registered in the next 5 years (NY, I’ll leave it at that...), I’m just using it for autocross for now). Thoughts?

[KDubU]

See if this works. These are MT’s 295’s on the rear.

6E24914F-CB30-4250-B0EA-FFAC8B9D403B.jpg

94F0D41C-8CE4-4116-8D11-47FA4B348676.jpg

[Jeff Kleiner]

Has anyone tried Hoosier TDs? I’ve been looking for info on them but can’t find much. I’ve seen them on a couple of Cobras at SVRA races but don’t know if they’re street-legal (not a big deal for me, my Daytona may not get registered in the next 5 years (NY, I’ll leave it at that...), I’m just using it for autocross for now). Thoughts?

Here's what Hoosier has to say:

"WARNING: DOT labeled Hoosier Racing Tires meet Department of Transportation requirements for marking and performance only and are NOT INTENDED FOR HIGHWAY USE. It is unsafe to operate any Hoosier Racing Tire including DOT tires on public roads. The prohibited use of Hoosier Racing Tires on public roadways may result in loss of traction, unexpected loss of vehicle control, or sudden loss of tire pressure, resulting in a vehicle crash and possible injury or death."

Jeff

[Nick B]

Thank you to all for sharing your knowledge and pictures. All immensely valuable info. Your cars all look great and I now have a clear idea of my options. Looks like I'm going with 295/50s on the rear.

Good comments from Avalanche and Rich on performance and safety. I initially considered 255s for aesthetics, as one of the build videos mentions this option, but I agree they'd be too narrow. Both the BF Goodrich and Coopers in the 295/50 size have a tread rating of 105 (pretty soft), so grip should be fine. I do love the authentic look of the bias plys, and they should be fine on DRY pavement, but I live in NJ and probably couldn't get the car registered if I showed up with those. If I had unlimited money, I might buy another set of wheels and use the bias plys for shows. Then again, if I had unlimited money, I might look for something with a CSX chassis number!

[Nick B]

Jeff,

One of the best build and bodywork threads I've seen! Thank you for sharing the links.

Nick

[rich grsc]

Cooper's on the rear, Goodyears on front. Now have Avon's all around. The Cooper's are a good tire, regardless of what some may say. I know people who autocross with them, and run good times. I ran mine till they aged out and became too hard, and I tend to push it some. I found a set of Avon's with less than 100 miles on them for the cost of two Coopers, wasn't about to pass that up. Now that I've driven with them, I'll suck it up and buy new ones when these are gone. You can drive on the side of a wall with them

PJ3.jpg

[Greg K]

The tread wear rating for the Coopers is 440, not 105. The 105S is the service description for the load and speed rating.

Both the BF Goodrich and Coopers in the 295/50 size have a tread rating of 105 (pretty soft), so grip should be fine.

[Nick B]

Greg, Thanks. Yes, I just figured that out too. I may still go with Coopers or BFG as lots of folks seem happy with them. The BFG treadwear rating is 400. I can't find Avons. Does anyone have a source for those?

[Greg K]

Don't be shocked... http://rogerkrausracing.com/pdfprici...6ZZ%202020.pdf

Greg, Thanks. Yes, I just figured that out too. I may still go with Coopers or BFG as lots of folks seem happy with them. The BFG treadwear rating is 400. I can't find Avons. Does anyone have a source for those?

[feadam]

15 inch cooper cobras with good year tread wear letters image our cobra.jpg

[Nick B]

Great picture, feadam. Where'd you get the lettering for the tires?

[feadam]

It's called tread wear they are in Alabama the letters glue on

[yel911]

Goodyear's 285/60/15
Cobra letters.jpg
FYI, "Tire Stickers" out of Los Angeles

[Real time recon]

020.jpg
BFG 15" Radial T/As...
P/235/60R ...front
P/275/50R...rear

^^^ Just saw that Mickey Tompson makes 15" Tires (in the above sizes I posted) ^^^ Jegs 60 has em in stock for $703.96 Total (4) tires.
The front ones are M.T.s "Sportsman S/T" tires.
The rear are M.T.s "ET street radial "tires

[Real time recon]

Anyone have any experience with Mickey Thompson ET street S/S radials on the Cobra ?
these >> https://www.mickeythompsontires.com/.../et-street-s-s

[Real time recon]

>>> https://www.youtube.com/watch?v=z8L691S_2V4

[Jeff Kleiner]

If all you're doing is going in a straight line they're great but I'm not a fan of drag radials on a car that also has to turn because of the squirmy sidewalls (which would be exacerbated on a 15").

Jeff

[Duke]

https://thefactoryfiveforum.com/show...size%26quot%3B

Avon 225/60R15 & 245/60R15 for reference.