Tire Help

[Adam H P15 D30]

10 hours ago, knuckleharley said:

Thanks,I didn't know that. I am trying to avoid buying anything at the moment,but it's good to know for "later" if "later" happens. Right now my focus is on paying off my bills and getting my estate in order.

Oh how well I know that drill...  

[harmony]

On 2/26/2021 at 10:11 AM, Sniper said:

They make bias looking radial tires

 

https://www.cokertire.com/tires/american-classic-bias-profile-radials.html

 

Speedometers are calibrated to read a certain speed for a given RPM at it's input.  I want to say 1000 revolutions equal 1 mile, but I may very well be misremembering here.

 

The factory can calculate how many inches a tire travels per rotation, it knows the gear ratio in the axle and comes up with a tooth count on the speedometer pinion gear in the transmission, this is the gear that drives the speedometer cable, so send the proper input to the speedometer.

 

If you change the tire height or the rear gear ration then you speedometer will read off, it will not be ok below 50 and be off by 5 mph above 50 unless there is something wrong with the speedometer itself, a speedometer shop can fix that. 

 

If you had a selection of speedometer pinion gears you could correct the tire or gear change difference.  Plenty of online calculators out there to sort that out, BUT you will also need to know the number of teeth on gear that drives the speedometer pinon and I don't know what that is for our rides.  The mentioned speedometer shop can usually make up a ratio adapter that will go inline between the speedometer pinion gear and the speedometer cable to correct for any gear or tire size changes, they will be able to tell you the info they need to do that. 

 

 

I'm also in need  of new tires but confusing is an understatement for this mindboggling process.  The link you supplied Sniper is the tire I have been looking at, sort of,,,  But why can't the tire companies all be on the same page and speak the same lnaguage???.  Some tires are classified by the first thing being a letter of the alphabet, F, G, H etc, some start with a number, 195. 205, 225, etc,  some start with a higher number like 600, 650, 710,  etc.   When you look at the "Tire size helper chart", it doesn't "help" it just confuses.  Sorry, enough ranting,,, 

Who is the parent company of who???  My point being , Lucus also has that American Classic tire, https://www.lucasclassictires.com/760R15-American-Classic-3-1-4-Whitewall-Radial-700304L.htm  It sure looks like the same tire. Same SKU number. But the specs are different.  The overall height is different -  lucus 28.87  Coker  29.80   tread width - lucus 4.9  coker 4.35  If it's the same tire, the numbers should be the same, shouldn't they???  Coker mentions rim width 5.6-6.0  Lucus doesn't say.    Bias ply tend to be skinnier.  Do the look alike also have the same skinny width?  Coker says the section width is 7.60  Do they mean the tire is 7.60 at the widest point? The reason I ask that is my tires are Remingtons, G78.  Over all diameter 27 3/4 . My understanding is that originally they were 28.7 overall.  My width is 8 inches at the widest point, which is right where the outer edge of the 2 3/4" whitewall is.  My tread width is 6 inches.  I can't seem to find any tires my size with a 3 plus inch WW, with treads 6 inch wide. 

Ohhh, I forgot to mention that I have bias ply so maybe I'm talking apples and oranges when I bring up my tire size.  However an important thing to mention is that my front right tire when the wheel is turned hard to the left, rubs on the rubber brake line retainer clip.  That's not a good thing.  I think I can grind away a bit of that clip with a die grinder, and maybe rotate it a bit so it might not rub.  In case your wondering, no the rubber brake line isn't in danger.  My point is, I want a skinny tire.  Since I have 6 inch tread and the American Classic has less than 5 inches, that might indicate that the tire is skinnier than mine .  Mine being 27 3/4" diameter and the American Classic is either 28.87 or 29.80 diameter, depending on who you buy it from (yeah, that makes sense right, haha! )   How would this effect my speedo read out? Maybe my speedo isn't accurate now, because of my tires being smaller than original. 

[Sniper]

Tire labeling changed over the year, 6.00x15 wold be an older labeliing system followed by the alphanumeric (G7)8 system you mentioned and finally the system we see today, like P225/90R15.  Tire companies pretty much followed suit as the systems changed over year.

 

The same size tire from two different manufacturers should be withing the same specs as the others, or very close.  The discrepancy you are seeing between Lucas, a reseller, and Coker, the manufacturer, is most likely a data entry error and I would go with the manufacturer's info, or call and verify.

 

Smaller tires make the speedo read faster, larger one make it read slower.  If you have a smart phone there are lots of apps out there that will tell you how fast you are going and you can use that to double check the speedometer.  Heck, google maps tells me how fast I am going and my speedo is close enough for government work, lol. reads a hair fast which is better, less chance of old lead foot getting a ticket.

 

Years ago I was doing donuts in the parking lot of the Mall of Memphis in my old 64 300 and the brake line retaining clip cut a nice slice in my sidewall, oddly enough same tire as yours.  I rotated the clip 90 degrees and it had enough clearance to never do that again, did both sides just to be safe.  Then I bought a new tire.

[Sam Buchanan]

9 hours ago, harmony said:

I'm also in need  of new tires but confusing is an understatement for this mindboggling process.  The link you supplied Sniper is the tire I have been looking at, sort of,,,  But why can't the tire companies all be on the same page and speak the same lnaguage???.  Some tires are classified by the first thing being a letter of the alphabet, F, G, H etc, some start with a number, 195. 205, 225, etc,  some start with a higher number like 600, 650, 710,  etc.   When you look at the "Tire size helper chart", it doesn't "help" it just confuses.  Sorry, enough ranting,,, 

Who is the parent company of who???  My point being , Lucus also has that American Classic tire, https://www.lucasclassictires.com/760R15-American-Classic-3-1-4-Whitewall-Radial-700304L.htm  It sure looks like the same tire. Same SKU number. But the specs are different.  The overall height is different -  lucus 28.87  Coker  29.80   tread width - lucus 4.9  coker 4.35  If it's the same tire, the numbers should be the same, shouldn't they???  Coker mentions rim width 5.6-6.0  Lucus doesn't say.    Bias ply tend to be skinnier.  Do the look alike also have the same skinny width?  Coker says the section width is 7.60  Do they mean the tire is 7.60 at the widest point? The reason I ask that is my tires are Remingtons, G78.  Over all diameter 27 3/4 . My understanding is that originally they were 28.7 overall.  My width is 8 inches at the widest point, which is right where the outer edge of the 2 3/4" whitewall is.  My tread width is 6 inches.  I can't seem to find any tires my size with a 3 plus inch WW, with treads 6 inch wide. 

Ohhh, I forgot to mention that I have bias ply so maybe I'm talking apples and oranges when I bring up my tire size.  However an important thing to mention is that my front right tire when the wheel is turned hard to the left, rubs on the rubber brake line retainer clip.  That's not a good thing.  I think I can grind away a bit of that clip with a die grinder, and maybe rotate it a bit so it might not rub.  In case your wondering, no the rubber brake line isn't in danger.  My point is, I want a skinny tire.  Since I have 6 inch tread and the American Classic has less than 5 inches, that might indicate that the tire is skinnier than mine .  Mine being 27 3/4" diameter and the American Classic is either 28.87 or 29.80 diameter, depending on who you buy it from (yeah, that makes sense right, haha! )   How would this effect my speedo read out? Maybe my speedo isn't accurate now, because of my tires being smaller than original. 

 

 

A whole lot of over-thinkin' going on here.   ?

 

In regard to the tire rubbing on the brake line bracket....I had the same problem....until I checked clearance with the tires on the ground. What was rubbing with the car on jacks wasn't a problem with the suspension compressed with vehicle weight.

 

Tire nomenclature has changed a lot over the decades. When 'vintage' tires are manufactured from old molds the old numbers are carried over to new stock. If you purchase tires that are pretty close to standard size you will have satisfactory results. I bought Coker Classic bias tires (H78, but a little narrower would work great) and have been happy with them considering the characteristics of the bias design. Many have Coker radials and they also seem to be a good choice. Speedo error will be small as long as your tires are pretty close to original diameter.

 

Edited March 23, 2021 by Sam Buchanan

[p15-1948]

It was pretty common in the day (50/60/70's) to move up one size when putting new tires on the car.  General consensus was the larger tire gave a better ride.  Worked Firestone retail in the sixties before moving to one of Goodyear's distribution centers.