Yes, you "drive them round" every day. We had a 1-ton Dodge van with 8.00/16.5 bias nylon tires on it years ago. Three guys couldn't push it out of the garage. After we replaced them with steel belted radials, I could push it out alone. The bias took a "set" (aka flat spot) on the contact patch where it was parked.
God Bless, jd
2003 Jayco Escapade 31A on 2002 Ford E450 V10 4R100
hilldude wrote: The old nylon bias tires always did that, they dont get better they will always be flat untill run a few miles.
Yep. The only cure is to go to radials.
My parents' old 72 Chinook did that like crazy until they put radials on it.
Interestingly enough this is common on airliners too. First taxi out of the day on cold flat spotted tires and thump, thump, thump until the tires warmed up. Radial tires cured that too.
tatest wrote: The tires are not round, or out of balance, or you have both problems. It is not something that improves with age. You might be thinking of flat-spotting, that is not what is happening.
When all tires except Michelin X and Pirelli's Cinturato were bias ply, and nylon was introduced as a replacement for cotton tire cord, there was problem with unbelted nylon tires flat-spotting while parked for a long period of time, but that was something that went away in 2-5 minutes of driving.
Changing to polyester for tire cord, and putting circumferential belts on tires (glass, aramid, steel belts) made the flat-spotting problem disappear.
Unbelted bias-ply tires are still available, and you should be able to find examples that are truly round. They are used in racing, implement and other off-road applications, as well as smaller size trailer tires. It sounds like you've gotten your hands on some really low quality trailer tires. Good bias tires are hard to find.
you can find bias tires but why would you in amey modern aplication.
Bill
2003 BOUNDER 38N
5.9 CUMMINS 300 HP
ALLISON 3000MH TRANSMISHION
TOWING HONDA CIVIC ON ACME TOW DOLLEY
WILDEBILL308 wrote: you can find bias tires but why would you in amey modern aplication.
Bill
Bias ply tires are ideal of off-road use, especially rock crawling. On my Xterra I run a set of tires on the street and a set off-road. My off-road tires are 33x10.50r15 Super Swamper Boggers. The Boggers are Bias ply. These tires are ideal for off-road use. I can run them at 12 PSI with with no signs of flexing until hitting rocks or tree stumps. These tires are designed for mud bogging, but I use them on rocks. These tires have some serious gashes in them, but are still solid and true.
If left sitting for long periods of time (like weeks), the Boggers will get flat spots.
-Michael
Michael Girardo :: michael@ecxc.com
2009 Jayco Greyhawk 31FS Class C Motorhome
2006 Rockwood Roo 233 Hybrid Travel Trailer Four Green Feet
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