Question Hi,
I have a 85 chevy sprint. I have owned these great little economy cars sense they came out in 1985. I bought one new in 86. They got 55+ mpg new. They came with P145 80R 12. They were BF Goodrich or bridgestone tires. I got almost 95,000 miles on my tires on my 86 i bought new. After you worn out the orignal tires you couldn't buy them anymore. It seems it is still that way. The tire shops want to sell you 155 70 which is shorter and wider tire. Everyone I talk to and myself will tell you,you'al loose about 4-5 mpg on highway. Why can't you buy the orginal tire. I did find a tire that sayes its a 145 80 but its not.The tread pattern on the road is much wider and it is about 1 inch shorter.
sincerly
Lindsey
AnswerLindsey,
This sounds more like a complaint than a question, but I'll try to explain what's going on.
Even in 1985, 12" tires were a rarity, and needless to say, setting up a factory to produce tires that don't sell in large quantities increases the cost. Since one of the advantages of these small tires is low cost, this becomes self-defeating. So manufacturers tend not to produce these tires.
As far as fuel economy goes: You should be aware that the amount of tread rubber affects fuel economy. The more the tread rubber, the more fuel consumed. So new tires have more rolling resistance than worn out tires, and so it doesn't tell you much if you comparing the fuel economy after changing tires - It's going to be worse.
Now the last comment you made about a tire that is labeled a 145/80, but isn't. Some tire manufacturers consolidate their production into groups and produce a variety of sizes out of the same mold. For example: a 145/80 is dimensionally close to a 155/80, as well as a 155/75, and if the mold is sized so it produces a tire that is close, then it's possible to economically produce low volume sizes. So in some repects, they are doing you a favor by having a tire that works for your application.
Hope this helps.
