Vintage Mustang Forums banner

1 - 17 of 17 Posts

·
Registered
Joined
·
1,103 Posts
Discussion Starter #1
First off im sorry - im sure if you search for "wheels" or "tires" my name will crop up a lot /forums/images/icons/laugh.gif

My current 14x6 wheels have P205 70R14 all round

My new ones are 15x7 - now the question: a stupid one it may be but less stupid than posting "i spent $400 on tires that dont fit" /forums/images/icons/tongue.gif

Is P20570R14 the same diameter/radius as P20560R15 ?

Its height of the tire thats the biggest issue with fit (i think!)

So is P205 different for each size of tire?

Thanks,

Gary
 

·
Registered
Joined
·
5,196 Posts
The P designates a Passenger tire.

The 205 denotes the section width in millimeters.
205mm wide / 25.4 = 8.07 inches.

The 70 and 60 denote the aspect ratio , which is the height of the sidewall as a percentage of the section width.

P205/70R14
70 x 205 / 2540 = 5.65 inches of sidewall
2 sidewalls at 5.65 + 14" rim = 25.3" overall height

P205/60R15
60 x 205 / 2540 = 4.84 inches of sdewall
2 sidewalls at 4.84 + 15" rim = 24.68" overall height

Calculating Tire Sizes
 

·
Registered
Joined
·
1,869 Posts
205/70/14 =25.3in. tall
205/60/15 =24.7in. tall
P205=P205 no matter the side wall ratio.
 

·
Registered
Joined
·
16,014 Posts
205 is width, the second number 60 or 70 is the profile of the tire (meaning the height of tire from rim to tread) so profile will tell you the overall diameter of the tire. Profile is a proportion of the width so a 235 50 tire is actually taller than a 205 50 tire.

Confused yet?

Take sometime to educate yourself at www.tirerack.com/tires/tiretech/general/sidewall.htm tons of info around that site. And stop killing so many kittens /forums/images/icons/tongue.gif.
 

·
Registered
1965 2+2 Vintage Burgundy A-code C4
Joined
·
3,875 Posts
The others are correct, as to sspect ratio, width, etc. The Tirerack.com tip is very beneficial, you can get tread width, section width and lots of useful info. The other thing I'll point out is that all tires are not created equal.....for example a BFG T/A radial in a 215/60R15 size will be a bit smaller in diameter than other brands of the same size. So once again, go to the tirerack specs page and comparison shop.....Your particular car would do much better with 225/60-15s, IMO.
 

·
Registered
Joined
·
1,103 Posts
Discussion Starter #6
To explain a bit more clearly - i need a tire thats total height is about an inch TALLER than P205-70-R14

The tire sizing i understand, but am still confused by the Aspect Ratio.

Working it out that way, P215 = 20.07" overall height, but i was under the impression that P215 would be taller than a P205 tire, and the way im understanding it now if the aspect ratio stays the same, but the section with increases the tire gets lower but fatter /forums/images/icons/crazy.gif

Case in point - choosing tires for my '68 coupe with 15x7 rims and 4 1/8 backspacing.

I'm in way over my head here! /forums/images/icons/laugh.gif

Thanks,

Gary
 

·
Registered
Joined
·
1,103 Posts
Discussion Starter #7
<blockquote><font class="small">In reply to:</font><hr>

Your particular car would do much better with 225/60-15s, IMO.

<hr></blockquote>

I wanted BFGoodrich Radial T/A tires P225/60-R15

BUT, from what ive seen the ideal backspacing for this is 4 1/4, whereas mine is 4 1/8

Bascially i have no experience with tires and want to make sure they dont rub!

BTW, the car currently has P205-70R14, which i never had problems with (except the rusted wheels they were on)

Thanks,

Gary
 

·
Registered
Joined
·
1,255 Posts
So the good news is, it will fit. The bad news is you have a smaller tire. It you can't exchange them, it's not that big a deal to be a little smaller. As long as you have the offset on the new wheel right, the only thing wrong will be that the speedometer will be off.

In the future you might try this site for assistance www.miata.net/garage/tirecalc.html.
 

·
Registered
Joined
·
1,103 Posts
Discussion Starter #9
<blockquote><font class="small">In reply to:</font><hr>

The bad news is you have a smaller tire. It you can't exchange them, it's not that big a deal to be a little smaller

<hr></blockquote>

LOL, no - i meant asking this question was a better idea than posting in two weeks that i bought the wrong tires.

Come on, you dont think im THAT stupid ?/forums/images/icons/laugh.gif

Gary
 

·
Registered
Joined
·
5,196 Posts
Is this what you are looking for:

<pre>
Width Height
205 70 14 8.07 25.29

205 70 15 8.07 26.29
205 65 15 8.07 25.49
205 60 15 8.07 24.68

215 65 15 8.46 26.00
215 60 15 8.46 25.15
215 55 15 8.46 24.31
</pre>
.

<blockquote><font class="small">In reply to:</font><hr>

Working it out that way, P215 = 20.07" overall height

<hr></blockquote> Did you add the sidewall height in TWICE? There are 2 sidewalls - one above & one below the rim....
 

·
Registered
Joined
·
1,103 Posts
Discussion Starter #11
Bingo - exactly it, thanks Bob.

I reckon P225-60R15 on the rear will be fine - high enough, but low enough not to worry about the sidewall rubbing the fenders.

On the front, well - i would like to think P225-60R15 would work...... but i would be guessing, cause i mean those wheels turn, right? /forums/images/icons/laugh.gif

Thanks,

Gary

------

My mistake, worked it out wrong - only added one sidewall
 

·
Incorporated Sell Out
Joined
·
17,130 Posts
We have 215 60/15 on my Dad's 65 with TCP control arms. The front fenders needed to be rolled to clear on a TTd 15x7 with 3.75 backspace
 

·
Registered
Joined
·
1,103 Posts
Discussion Starter #13
AFAIK, 67/8 wheelwells are larger than the 65 ones, plus i have almost 3/4 inch more BS, but i wonder is that enough to run P225's on the front.

Thanks,

Gary
 

·
Registered
Joined
·
1,255 Posts
Actually I did read your post as if you had already paid for the tires. /forums/images/icons/blush.gif Most things seem to go that way for me... I buy something, then a week later I read something or learn something new and wish I'd done it slighlty different.

But being that you have not spent your money I would suggest a larger tire. On my Fastback I used the Vintage 45, 16x8. The tires are 245/50 and 225/50. Lowered one inch in the back and two inches in the front. Has a nice road race stance. Looks and works real good.

Good Luck,
 

·
Registered
Joined
·
1,103 Posts
Discussion Starter #15
I would like the tires to almost fill the wheel wells, but there's a fine line between rubbing and perfectly planned /forums/images/icons/crazy.gif

I mean, it's a stock '68 - i have heard of people having P235's rubbing , also been told some are running P255 with no problems.

Really, im almost in over my head - and i'm trying to make an educated decision based solely on this post.

Thanks,

Gary
 

·
Registered
Joined
·
1,255 Posts
The trick is in the offset. I can't speak for the '68, but if you call the guys at Vintage Wheel Works they can tell you if it will fit. They were exactly right on mine, fit perfect, no problems at all. Vintage Wheel Works: 562) 906-8600
 

·
Registered
1965 2+2 Vintage Burgundy A-code C4
Joined
·
3,875 Posts
I'm pretty certain you can do it. I have 245/60-15s on 15x7 inch rims with 4.25" BS on my 65. I had to roll them, but they fit otherwise. You have much more space and flare than I do, so the 225s should fit with no problem, even with 1/8" less BS. 225s all around would be a nice balanced package. If in doubt, get the tire guys to mount you one up and try it on the front and back. Install on front/let lift down/bounce on it/turn wheel/repeat for back wheel. This should clear up any doubts....Hey, I would cram 275/60s on the back of my 65 if I could make them fit!
 
1 - 17 of 17 Posts
Top