DC said:
In my stupidity, I told the shop that I had a 2000 Civic when I actually have a 2001 (I got mixed up because I bought the car in 2000). Their computers automatically look up what size tires they are according to the year and model, and so they mounted a P185/65R14. It should have been a P185/70R14. I'm going to go back and see if they'll be willing to exchange it for me, hopefully I can just pay the mounting costs.
What are the implications of driving on wrong size tires? Is it a serious safety issue? If my understanding of tires sizes is correct, the difference between the two tires is in the section heights (185 x .70 = 129.5mm vs. 185 x .65 = 120.25mm). Which would make my car sit about 20mm lower.
Isn't it only about half this much, at 9.25 mm lower?
Yes, the diameter is less by about 20 mm, but it's the radius change that should equal the height change.
(9.25 mm = 0.4 inches)
Anyway, the trim height (an alignment specification) has now changed. This affects camber. Camber is the tilt of the tops of the tires away from the vertical when looking from the front of the car at the tires. Lowering the car tends to tilt the tires inward. Too much tilt of the top inward (= excessive negative camber), and tire wear will result on the inboard side of the tires.
But is this amount of lowering all that much?
Googling at www.groups.google.com for {camber lower civic tire wear} yields a lot of discussion of this, mostly from guys that hot rod (= rice?) their Civics. You've lowered the car by a lot less than them, though. Most of the posts seem to talk about changes of 1 inch or more. For a drop of a lot less than 1 inch, they suggest you'll see no adverse effects on tire wear.
E.g. About a 1998 Civic, one guy wrote "you can get away with virtually no excesive tire wear up to 1.5 inches." Another wrote: "I guarantee that he will not need an align on a civic for only 1.5 inch drop!"
You've dropped the car a lot less than 1.5 inches. Doesn't sound like it's worth losing any sleep over.
I suppose maybe you could get an alignment check and compare your Civic's camber with its specs, assuming the fact the car isn't the design trim height doesn't mess up the alignment machine's calculations and render them meaningless. (I'm not well studied on how alignment machines work at this point. I do know making sure the car's trim height is correct is a pre-alignment requirement.)
I'd just keep an eye on tire wear at every rotation.
Agreed about the odometer, but like the other folks said, no biggie at 3%, especially given how much variation there is in fuel mileage from other effects. I guess if you want to measure traveling distance, you'd want to make the correction, though.
