Nitrogen; You gotta tip your hat to the marketing guys who came up with that one.
Speed; They always talk about setting a national speed limit, but it will never happen. Not with an economy so dependent on auto manufacturing, and a national pride of our luxury and sports cars. Also, our gas is highly taxed, and we pay a yearly car tax, a big component of which is based on engine size. The speedmongers pay for the privelege, and the state is happy to collect the extra cash. One positive effect of this, though, is that everyone is very alert on the Autobahn. People stay to the right, and everytime you move left to pass, you make damn sure it’s clear. No use for cruise control here! It’s more active and intense than driving on US interstates, but I actually find it much less stressful - and it’s fun!
I drive a BMW (safely) and never rotate my tires. In my owners manual the manufacture also makes this statement: Any questionable savings you might gain in tire life will be off set by loss of traction after rotating the tire. Each tire will ware differently and as it does traction actually improves. This is lost after you rotate the tire. I innitally questioned this until I did some simple math. If you take the cost of one tire and devide it by the number of advertised or expected miles you then get your approximate cost per mile. Then take the number of miles you expect to gain by rotating the tire (2000? Maybe more/less?) times your cost per mile (then multiply again x 4 for 4 tires) you find your savings over the life of the tires is very little especially if you are paying for tire rotations. Depending on what you are paying for rotations you may be actually spending more! Because I have high performance tires my cost per mile is high. This savings is even less for higher milage tires as your cost per mile is less. I know that we rotate tires because our fathers told us to and their fathers before them told them to and at $35.00 for a rotation it is good business for the shops to tell us to continue to rotate but just how much are we really saving VS just buying a new set of 4 when they get worn. Besides I know all of you appreciate the feel when you change from a worn set to new tires.
Back in the mid 1970s we owned a rear drive German car. We bought new Michelin X tires for it when the original Gislaved tires wore out. The literature from Michelin stated that tire rotation was not needed.
I challenge your statement about tire rotation purely on scientific grounds. Besides your owner’s manual, is there any kind of independant published test which would support this idea? I can grasp the concept that after a new tire wears in, it might actually grip better that when it was first installed, but then why wouldn’t the same be true for a used tire which is placed in a new position? You pay $35 for a tire rotation? That sounds high. There are other shops besides the BMW dealer which can competently perform this operation. Personally, I change out my winter and summer tires each half year, keeping two sets of rims, as is the norm in Germany. I simply place the best pair in front each spring and fall, and replace tires in pairs as necessary. I even buy used - as the trend is toward larger rims, there are lots of 15"ers in like new condition availabe cheap here. I drive a classic Saab at 90-100mph on the Autobahn, and find no issues with traction from rotating or running used tires as compared to when I have actually bought brand new tires.
Well, this thread was originally about rims and their ability to be moved around the car. But:
I’m only 47, so I don’t have much memory about tire wear on rear drive cars. With front drive, however, I don’t think many will challenge the statement that the front tires wear much faster than the rear ones. In my personal experience as a very aggressive driver in my youth (not anymore!) all the action is in the front, so it’s ok to run a rather worn set in the back (of a subcompact at least) but don’t skimp on the front! That means that good economics would have you move your front tires to the back when they get worn, and place a new (or slightly used) set on the front as necessary, which is what I have always done. I suppose that it doesn’t make for a huge cost difference in the end if you don’t rotate, but simply replace tires in pairs, but the downside might be running the rear tires for longer than if you rotate. Tires age in other ways than treadwear.
It sounds like your mechanic’s tire guy needs more to do. Yes, the tires can be rotated on the same rims.
Filling the tires with Nitrogen isn’t as kooky as it sounds. If I was driving regularly on one of the German Autobahnen, I would consider it. More and more U.S. shops are offering Nitrogen tire service. In my opinion, it’s a waste of money, but only because my car isn’t a high performance machine being driven at extreme speeds.