Pinto Car Club of America

Welcome to FordPinto.com, The home of the PCCA => General Help- Ask the Experts... => Topic started by: dholvrsn on August 23, 2006, 06:52:19 PM

Title: tire question
Post by: dholvrsn on August 23, 2006, 06:52:19 PM
What's the biggest tire that one could conscientiously mount on a 5.5"x13" mag wheel?

How about not so conscientiously? :evil:
Title: Re: tire question
Post by: goodolboydws on August 29, 2006, 09:22:29 PM
A 5.5" width wheel equates to 139.7mm, according to my calculator.

In general practice, having a tire with a section width no more than an inch and up to 2 inches wider than the wheel width, on a smaller, narrower wheel such as this, is still going to be reasonably safe.

Since an inch is 25.4mm, adding that 1 inch to your wheels' width, (which is measuring from the INNER  side of the bead flange across to the matching flange-the part that touches the outer side of the tires' bead) would give you a 165mm section width tire, adding a second inch would get you up to a 190mm section width tire.

The closest actual tire size to that on the safer side would be a 185.
(If I remember correctly, 185-70-R13's is what I used on my 4 speed '71 sedan on 5.5" slotted aluminum American Racing wheels, and that was a MOSTLY good running street combination which I used for many years with the light car, especially when using aftermarket traction bars and an antisway bar..... But Winter driving in the North still needed a very light touch on the stop and go pedals to keep the car going where the steering wheel pointed it.) 

Wider than that is up to you, but your real world performance may suffer dramatically with a light weight car (as mine did), in low friction conditions (snow/standing water, etc.) as the weight per square inch of the tire' footprint continues to decline as the width of the footprint increases, so bad weather traction rapidly decreases as tires get wider. Not as important in truly dry, warm weather areas.

Also, consider this:
When you DO mount a significantly too wide tire onto a relatively narrow wheel, the sidewalls of the tire are forced to fold inwards somewhat from their molded in neutral position, and the section width actually comes out narrower than it would have if mounted on the proper width wheel.

A tires' performance profile is generally designed around a specific wheel width, so getting a tire that is within the recommended range for a particular wheel is always safe idea, and usually a smart one too.

A little bit of too narrow wheel and too wide tire isn't too bad on a street car, if appearance rather than performance is your main thing, and you never intend to push the limits of your cars' ability to go through turns at speed, for example, but running those too wide tires will result in compromised tire performance, and shorter tire life as the tires' tread will always be attempting to lift at it's edges when being used at "normal tire pressures, with the relatively low weight of the vehicle not being enough to "flatten" the wider, (and higher load rated) tire onto the pavement. Compensating for that tendency requires lowering the tire pressure, which makes the cars' handling suffer, even if the vehicles' perceived "ride quality" (as in softness) improves.

And one more thing.
TRY not to change the tires' HEIGHT too much, even if you do go wider, as the rear ends' final ratio will be dropping in lockstep with each tire size height increase, and a lot of Pintos don't have much (if any) torque to spare down low. Too tall tires, coupled with a lot of nice looking new, wide rubber now firmly gripping the road will make an unaltered Pinto want to fall on it's face rather than lighting them up, with anything less than a high rpm take off. 
Title: Re: tire question
Post by: wagonmaster on August 29, 2006, 10:32:50 PM
185/70-13 is probably the largest tire you will find these days and most tires manufacturers have settled on 175/70-13 as their largest offering. I personally prefer 195/70-13 for the little additional rubber on the ground. Over the years that I had my '77 Squire (close to fourteen years), the car felt more stable with the 195s and it didn't feel like the tires were going to break loose every time a long sweeper was taken at speed. I also felt that the extra rubber made the car stop more surely with less lockup. Since I have not been able to find 195s anymore, I have gone to 185s and the above mentioned areas have suffered some.
Title: Re: tire question
Post by: earthquake on August 29, 2006, 10:42:45 PM
I have 205-60-13s on mine.I believe they are still available from BF Goodrich.
Title: Re: tire question
Post by: FCANON on August 30, 2006, 09:38:57 AM
Pepboys sells a 205/60 13 as well....Futura is the tire brand

I've had good luck with them so far running them for 5 years on my Falcon wagon (13's on this car)

I have have been looking for some muscle looking tires for my Pinto wagon. I ended up using 14's on the back.

Frank
Title: Re: tire question
Post by: dholvrsn on August 31, 2006, 12:17:43 PM
My previous Pinto had 205-70-13 radial tires on the same wheels. I wonder if that's okay for my current Pinto. Actually, I wonder if it's okay to go bigger, if I can still find the tires, without getting into trouble.

Gotta fill up those fenderwells. :laugh:

Will see what Ben Fish in Sioux City has sitting around after Thanksgiving or Christmas.
Title: Re: tire question
Post by: goodolboydws on September 03, 2006, 12:54:38 PM
Oh heck, I thought that you actually wanted real world tire to wheel fitment advice, not just to fill up those wheel wells.


this may help:


Tire Size Comparison

Specification  Sidewall  Radius  Diameter  Circumference  Revs/Mile  Difference
165/70-13         4.5in  11.0in    22.1in         69.4in        913        0.0%

175/70-13         4.8in  11.3in    22.6in         71.1in        891        2.5%
185/70-13         5.1in  11.6in    23.2in         72.9in        869        5.0%
195/70-13         5.4in  11.9in    23.7in         74.6in        849        7.5%
205/70-13         5.6in  12.1in    24.3in         76.3in        830       10.0%
215/70-13         5.9in  12.4in    24.9in         78.1in        812       12.5%
225/70-13         6.2in  12.7in    25.4in         79.8in        794       15.0%
185/60-13         4.4in  10.9in    21.7in         68.3in        928       -1.6%
195/60-13         4.6in  11.1in    22.2in         69.8in        908        0.5%
205/60-13         4.8in  11.3in    22.7in         71.3in        889        2.7%
215/60-13         5.1in  11.6in    23.2in         72.8in        871        4.8%
225/60-13         5.3in  11.8in    23.6in         74.2in        853        6.9%
235/60-13         5.6in  12.1in    24.1in         75.7in        837        9.1%
185/50-13         3.6in  10.1in    20.3in         63.7in        994       -8.2%
195/50-13         3.8in  10.3in    20.7in         65.0in        975       -6.4%
205/50-13         4.0in  10.5in    21.1in         66.2in        957       -4.6%
215/50-13         4.2in  10.7in    21.5in         67.4in        940       -2.9%
225/50-13         4.4in  10.9in    21.9in         68.7in        923       -1.1%
235/50-13         4.6in  11.1in    22.3in         69.9in        906        0.7%
245/50-13         4.8in  11.3in    22.6in         71.1in        891        2.5%
255/50-13         5.0in  11.5in    23.0in         72.4in        875        4.3%

And remember, the cars' final drive ratio will be changing with the tire size change.
Title: Re: tire question
Post by: 77turbopinto on September 03, 2006, 01:16:33 PM
Great info GOBDW.

Also, keep in mind that those dimentions are ESTIMATES.

Bill
Title: Re: tire question
Post by: dholvrsn on September 03, 2006, 07:34:17 PM
So was I pushing it on having those 205s on my '80 Pony and thinking about putting them on my '79 wagon?
Title: Re: tire question
Post by: goodolboydws on September 04, 2006, 10:49:54 AM
Sorry.
The tire data posted was from a tire comparator site into which I punched the various tire sizes shown. I forgot to also post the sites' URL.

I'll do better than that now.

Here's the original URL on which I found the link for the tire size comparator. It is one of the most extensive link sites for automotive related technical data that I have yet found. A good thing to bookmark.

stealth316.com/1-tech.htm

Scroll down lower on the page for general sites not specific to the Stealth.

Look for Miata.net, that's the tire comparator I used.

Title: Re: tire question
Post by: earthquake on September 05, 2006, 10:34:37 PM
I checked today and BF Goodrich still makes a 235 and a 265-50-14.I have the 265s and they fill the wheel wells nicely.
Title: Re: tire question
Post by: edselbill on December 14, 2006, 09:13:29 AM
Okay... here I am.  Total newbie to the site and Pinto Specs.  I've read all below but am still unsure.  Can anyone help with suggestions.

I just bought a totally restored '77 V6 Squire.  She has what I would term, the factory "Rally" wheels  (Black, with silver trim, centercap with red decals, and trim rings -- not the slotted mags I had on my '79).

The tires on it are brand-new, Uniroyal Tiger Paw 185-70's, Blackwalls.

Problem is...

1)  They look too small for the car / wheel wells
2)  Because of the short sidewall, the car rides like they are made of stone... too firm, too much banging.


What I want...

1)  As close to original looking as possible.  I am not looking to make the car look mean, over-tired, aggressive, racy, etc..  So, I don't want big wide monsters or anything sticking out of the fenderwells.

2)  I want to soften the ride as much as possible / higher aspect ratio

3)  Whitewalls

4)  To properly fill the fender-wells without over doing it.

5)  I live in the Northeast, so light snow and wet traction is necessary.

What do you suggest....?

I have found:

Coopers Trendsetters -- 175-80's and 185-80's
Kelly -- 185-80's and 175-80's
Komho -- 185-80s and 185-70's


I see below that people are hunting down 195's and even 205's, but that sounds a bit more aggressive than I think I want.  But, without seeing an example, I can't judge.

Do 185-80's, with a 24' hight do the trick or should I be looking for bigger?