Tire to Rims sizing help

[Legendary]

My friends have a pair of drag radials that he wants to sell to me. Right now they sit on his weld racing rims. I think they are 15x8 or 9. He said he think the tire size is 255 50 r15. Will these fit on my stock honey comb rims?

And if they do:

I have 225 60 r15 tires all around. With those tires make my car sit lower in the rear? My car sits evenly right now but I don't want to be higher in the front.

 

[maverick0716]

What are honey comb rims? Are they 15x7? 255/50/15 will be a VERY tight fit and I would not reccomend it......but I guess it's possible. And yes the 255/50/15 will be lower than the 225/60/15.

 

[88stangmangt]

i dont think they would only be 255's on a 9" rim???? anyway yes they would fit on the ten holes if that is what your talking about. just look on the side of the tire it will tell you everything you need to know.

 

[Legendary]

These are the rims they will go on. They have alot of meat on them and I'm hoping that would counter the fact that they are a shorter tire.

 

[maverick0716]

i dont think they would only be 255's on a 9" rim???? anyway yes they would fit on the ten holes if that is what your talking about. just look on the side of the tire it will tell you everything you need to know.

You'd be suprised. Let's take 255/60/15 and 255/50/15 for example. It's a lot easier to get the 60 series tire to fit on a narrow wheel than the 50 series.....its not just the width thats the issue.

 

[Legendary]

So it would work but it's not reccomended. Would it be dangerous? Even though the Dr's are 50 and mines are 60's the Dr's seem taller. I just don't want a ugly sitting car!

 

[yelbigbirdlow]

im not sure if it was a typo on legendary's part but i know him personally and i think he has 16'' rims. so if im wrong ill just ask this for my own knowledge. can a 15'' tire fit on a 16'' rim of these same dementions stated above 255 50 r15/

 

[Legendary]

It's size 15. But thanks for the concern.

 

[BADPONYsc]

A) Those aren't honeycomb rims, they're turbines (87'-90'). But that doesn't really matter, because both are 15"x7".

B) I have never heard of a 255/50R15 tire. 255/60R15 is a common size, but the only 255/50 tire I see in any of my catalogs is for a 16" rim (255/50R16). If you're not exactly sure of the size of the tires, I'd be willing to bet that they are 255/60R15's.

Tire sizes go like this.... let's take a 225/60R15 - the 225 is the tread width in millimeters, the 60 means that the hieght from the rim to the ground (or from the rim to the top of the tire) is 60% of the 225mm. The last number is obvious....the size of the wheel. So the 50 or 60 number (or 35, 40, 45, 70, whatever) is only relative to the first number, the tread width.

If the tire is indeed a 255/60R15, that is a 27" tall tire. I have used this tize tire before. It was a regular street tire, but the measurements are still the same. If you have tailpipes, this tire size may rub on them (which can be adjusted), and the quad shocks may also rub. There could also be a little inner fender rubbing, but nothing a little "massaging" with a hammer won't fix. All of these issues are also affected by whether the car is lowered or not. The lower the car is, the more these rubbing issues will be a problem.

It takes a pretty big difference in tire height to actually be able to see it visually, aka: car looks jacked up in the rear. When I had the 255/60's in the rear (27" tall) and the skinnies on the front (about 25" tall), the car was not jacked-up looking in the rear. You could see the difference in tire hieght, but the car wasn't all raked in the front.

As far as "safety" goes.... the general rule is that the tire's tread-width should not be more than 1" wider than the rim's width, although people exceed this number all the time. I think it's more of a tire-wear issue than an actual danger issue. Although, with an extremely huge tire on a small rim, the handling and stability will definately suffer...along with irregular tire wear.

I've had both a 295/50R15 and a 275/50R15 on my 15"x8" rims, so I don't think a 255 on a 15"x7" would be a problem. The tire height will definately be taller than a 225/60R15, but like I said, it won't jack the rear way up or anything.

If the tire is indeed a 255/50R15 (which again, I've never heard of), it would work fine on a 15"x7" rim. If a 255/60 is 27" tall, I would guess that a 255/50 would be somewhere around a 26" tall tire....which is very close to a stock 225/60R15.

Sorry for the rambling.... I've just done alot of experimenting with tires/sizes and learned alot of these things the hard way.
Hope this helps!

 

[Legendary]

WOW! Thanks for the break down. Good info!

When you said the handling and stability will definately suffer what do you mean? Is it ok for cornering? I have the torque arm set up on my car so the ride is a little rough already.

 

[BADPONYsc]

Not that it would be "un"stable, just less stable. A tire that is larger than the recommended size for a wheel will be less firm in turns and at high speeds.... but will still be managable. A tire that is the proper size for a wheel will be firm and tight in turns and high speeds. A huge fat tire bulging out on the sides can get a little "squirrely" at high speeds. The main thing with going with a bigger tire than recommended is that it may wear unevenly and decrease the life of the tire. Same with keeping the right pressure for a tire. Too much air pressure will make the tread "balloon" out in the middle and the middle of the tread will wear out quickly. Too little air pressure will make the sidewalls sag and will wear out the sides of the tread quickly.
I guess it really depends on what you're doing with the car. If it's drag racing "in a straight line" kind of thing, then a big fat tire is best. If it's road racing "corner carving" you're doing, then a properly matched tire/rim combo would be best I would think.
I dunno... All I know is that I had 255/60R15's on my 15"x8" Welds and they didn't bulge out at all. They were just more tall than anything else. When I had the 295/50R15's on the same 15"x8" wheels, they bulged out big time. You could push the rear of the car side to side and watch the car rock back and forth on those ballooned sidewalls. They handled fine though. They were just regular street radials. Drag radials are different than street tires though. Their sidewalls are thinner and designed to wrinkle upon launch. I have a set of 275/50R15 Nitto Extreme drags on an extra set of 15"x8" Welds and I don't know if it's the construction of the sidewalls or the fact that there's no tread at all left on them, but at high speeds ((50+ mph) the rear of the car will sway around a little and feels kind of unstable. I only use them for racing and really don't like to use them on the street very much.
Anyway, might as well try them and see if you like them. Getting tires swapped out is pretty cheap. Just save your old ones.

BTW - looking back at your original post, you were worried that a 255/50R15 would sit lower than the front 225/60R15's.... if there is such a tire as a 255/50R15, it would be a tad higher, if not about the same, as the fronts.
If it's a 255/60R15 (more likely), it will be about 1.5" overall higher than the front tires, so it would sit about .75 of an inch higher in the rear....give or take a little.
Ok, I'm rambling again.... hope this helps!

 

[Legendary]

I've made a mistake in calling it a drag radial tire. I believe there are regular radial tires. That should better when it comes to cornering anyway right?

 

[maverick0716]

I have a set of 275/50R15 Nitto Extreme drags on an extra set of 15"x8" Welds and I don't know if it's the construction of the sidewalls or the fact that there's no tread at all left on them, but at high speeds ((50+ mph) the rear of the car will sway around a little and feels kind of unstable. I only use them for racing and really don't like to use them on the street very much.

You think drag radials are squirrely you should try ET Streets, lol

 

[BADPONYsc]

Yeah, my friend has the ET streets and he says that it scares him to death to drive around with them on, even when it's dry! The Nitto's I have I got used (and free) and they have absolutely NO tread left on them. I don't know if it's because of the no-tread, or if those tires are just like that, but the rear of the car will sway side to side sometimes, anywhere over 50mph. Both my friend and I have a seperate set of rear Welds with regular street tires on them.

Legendary - if those are regular street tires, then they are definately 255/60R15's. I've never heard of a 255/50R15.... but who knows? They will be better for street driving, period. When talking about hard cornering, the front tires are more important, I would think. I still think they'd be fine on a turbine.

 

[Michael Yount]

The challenge here is that the tire ideally needs a certain width rim to allow it to put all it's tread width on the ground. The narrower the rim width gets for the same size tire, the more the wheel 'pulls' the outside/inside tread up off the pavement. So you may not be putting the full footprint of the tire down if the rim width is too narrow relative to the section and/or tread width of the tire. That may limit your straight line traction. Cornering exacerbates things even more. When the rim is too narrow for the tire, the tire tends to roll over on the side wall more easily - again, not good for lateral traction. So, simply putting a bigger tire on doesn't necessarily mean you'll have more traction. These issues are magnified (made worse) when the wheel diameter is smaller (15" vs. 17"), and/or when the tire aspect ratio is bigger (it's worse for a 70 series tire than for a 50 series tire).

My brother has been in the wheel and tire business for over 30 years. The rule of thumb they use in his shop is to not have the section width of the tire (the 225, 255 number) in inches (225 is in millimeters -- 225/25.4=8.85") exceed the rim width by more than 2 inches. So a 225 tire needs to be on a rim that is at least 6.85" wide. That's why the stock 225 tire comes on a 7" rim. Doing the math - a 255 tire has a section width of 10.03". 10" - 2" = 8". You'd want the 255 tire on a rim that was at least 8" wide to properly support the tire.

Hope that helps.

 

[Js5ohLX]

I work at a tire shop, you can buy 255 50 r15's, you can mount them on 7 inch rims, yes they will wear funny, the center of the tread will wear out first. There really isn't a safety concern involed, but you really won't get enough traction to make it worth doing. With rubbing and tire wear, on a 7 inch rim, it's a waste of effort.

 

[1HOT5L]

Good call js5ohlx

 

[Legendary]

I talked to my friend that has the tire and they're actually 275 60 r15. Should I pass on this or it'll be fine?

 

[Michael Yount]

If you like the tires and the deal is good, I'd get them, and then look for a wider rim to mount them on -- just use them at the track. They will physically mount on your wheels, but what you'll have is a big, heavy tire that won't keep all of it's tread on the ground either in a straight line or while cornering. Since they're 275 instead of 255, you need at least a 9" wide wheel to really take advantage of them.

 

[maverick0716]

275 60 15's BARELY fit in the wheel well.....and I mean barely (can't even stick your finger between the fender). It's because they're so tall as well.