Author Topic: To Polyglas or not to Polyglas?  (Read 2528 times)

Offline OzCuda

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To Polyglas or not to Polyglas?
« on: May 25, 2006 - 07:51:25 PM »
G'day Guys, I've been looking into tyre options for my factory Magnums and came across the reproduction Goodyear Polyglas tyres on the Kelsy Tire site.  Wondering about people thoughts on taking a non-numbers matching resto to the point where you are trying to use factory correct rubber.

What are they like to drive on?

Do they look the biz when you are done because they are correct or do they just look a bit skinny?

Anyone have info on the sizing specs?  My Barracuda came with F78-14s (on 5.5" Magnums - well that is what is still on the spare) which according to the Year One catalogue equates to 205/75/14s.  Most tyre manufacturers recommend a max width of 215/70/14 for 5.5" rims while on the Kelsy site they recommend E70-14s (205/70/14) for minimum 6" rims and F70-14s (215/70/14) for minimum 7" rims, which is different to the other manufacturers.  If I can use 'modern' 215 width tyres on the 5.5" rims, can't I use F70 (215 wide) tyres now???    Any ideas?
'70 Barracuda




Offline Bullitt-

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Re: To Polyglas or not to Polyglas?
« Reply #1 on: May 25, 2006 - 07:57:07 PM »
bias plys had better rear traction, the steering is tighter, but dont stop nearly as well. IMHO      I have had 235/60s on 5.5 rims with no problem. 
Wade  73 Rallye 340..'77 Millennium Falcon...13 R/T Classic   Huntsville, AL
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Offline OzCuda

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Re: To Polyglas or not to Polyglas?
« Reply #2 on: May 25, 2006 - 08:48:01 PM »
Thanks Bullitt99.  The 235/60s on 5.5s is interesting as I can get those locally in Australia.  Any concerns with driveability?  Any roll when cornering? Did they bulge much?
'70 Barracuda

Offline Bullitt-

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Re: To Polyglas or not to Polyglas?
« Reply #3 on: May 25, 2006 - 09:15:36 PM »
I never ran the bias ply 235s on the front. I currently have 235/60 t/a radials on the front. No issues observed. Here is a pic with the 235/60s on the right & a 235/55s on a 17x9" riim. There is a bit of bulge but judge for yourself.  :bigshades:
« Last Edit: May 25, 2006 - 10:24:14 PM by 4cruzin »
Wade  73 Rallye 340..'77 Millennium Falcon...13 R/T Classic   Huntsville, AL
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Offline Killer_Mopar

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Re: To Polyglas or not to Polyglas?
« Reply #4 on: May 25, 2006 - 11:58:26 PM »
bias plys had better rear traction, the steering is tighter, but dont stop nearly as well.

I dont understand how they could have better traction but not stop as well. Wouldn't the better traction cause it to stop better :clueless: ???
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Offline Bullitt-

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Re: To Polyglas or not to Polyglas?
« Reply #5 on: May 26, 2006 - 06:13:41 AM »
It could have something to do with the sizes I am comparing, I had 215/70 polyglass but 235/60 t/a's. Mainly stopping in the rain the radials have a much more aggressive tread pattern. As for acceleration, maybe the reverse is the case, more rubber on the ground, but my experience was I couldn't get a burnout before but with the radial t/a's they break loose much easier & I even get a bark going into 2nd under heavy throttle. I have no doubt the radials handle better overall.   
Wade  73 Rallye 340..'77 Millennium Falcon...13 R/T Classic   Huntsville, AL
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Offline ShelbyDogg

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Re: To Polyglas or not to Polyglas?
« Reply #6 on: May 26, 2006 - 11:26:09 AM »
Bias ply tires grab the lines on the road, You will not be happy with the steering and jerkyness everytime that you drive over one.  235/60s on a 5.5 tire is too skinny
Rob

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Offline MyMopar

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Re: To Polyglas or not to Polyglas?
« Reply #7 on: May 26, 2006 - 11:29:01 AM »
Bias plys do not provide better traction and handling, that is why the tire mfgs went to radials.  Be very careful in the rain w/bias tires if you go out in the rain.  
Here is the reasoning, when someone wants to do a major smoke show they go with bias because they provide the smoke and have less friction from spinning than a radial.  Bias tires are also prone to flat spotting and feeling square when cold or stored for a period of time.
1969 (OO===]|[===OO)
1973 (OO/=====\OO) <---SOLD
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Offline Chryco Psycho

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Re: To Polyglas or not to Polyglas?
« Reply #8 on: May 27, 2006 - 05:34:31 AM »
I doubt you would be happy with Polyglas tires , they ride harder & corner much worse then radial tires

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Offline MEK-Dangerfield

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Re: To Polyglas or not to Polyglas?
« Reply #9 on: May 29, 2006 - 02:31:56 PM »
I doubt you would be happy with Polyglas tires , they ride harder & corner much worse then radial tires


   :iagree:  :iagree:  :iagree:

  Yep,
      There is a reason they aren't used on newer cars anymore.  :grinyes:

  Mike

Mike

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Offline OzCuda

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Re: To Polyglas or not to Polyglas?
« Reply #10 on: May 30, 2006 - 10:55:14 PM »
Thanks for the advice guys.  Crunched the numbers on the polyglas tyres and they could end up around $450 AU per tyre based on the average x3 for landed products, which is a bit expensive.  Thinking now I'll go 225/70/14s which is one size above max recommended which used to work as a theory when buying tyres for the Jeep so maybe can push it.  Anyone think this won't work????
'70 Barracuda

Offline Chryco Psycho

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Re: To Polyglas or not to Polyglas?
« Reply #11 on: May 30, 2006 - 11:44:10 PM »
a 225 70 should be fine on a 5.5" rim

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Offline 71340RT

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Re: To Polyglas or not to Polyglas?
« Reply #12 on: May 31, 2006 - 10:24:10 AM »
I have 225/70/R/14 BFGoodrich radial TA tires in my 71 Challenger RT and they ride and handle great. I had them on 14X5.5 rims but switched to the correct 14X6 on the Challenger now but never had any problems with the 14X5.5 combination.


70 Plymouth Cuda 340 4-speed
71 Dodge Challenger RT 340 automatic
1973 Dodge Challenger 360 automatic EFI
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Offline OzCuda

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Re: To Polyglas or not to Polyglas?
« Reply #13 on: May 31, 2006 - 06:12:55 PM »
Thanks guys  :thumbsup:
'70 Barracuda