Does the way you break in a car really matter? We ‘ve been asked that question many times over the years by readers. There are two popular schools of thought. The first is that you strictly follow the manufacturers guidelines and go easy. The idea is that this allows for the various mechanicals to be properly ‘bedded in ‘ and for wear to happen gradually.
The second is that you simply drive the car how you would normally from day one. Here the idea is that you ‘re breaking in the car by treating to a heavy does of normalcy.
For us the answer has always been easy. If German engineers suggest you go easy on a car they ‘ve engineered, we suggest you follow their advice. But what about M cars? We know that M cars demand a 1,200 miles service at the close of break-in. But what else is specific to M models? We talked to a BMW about to see if there were some specifics that, while not in the manual, are good guidelines to follow. What they told us expanded on the manual and gave us a lot of the reasoning behind the rules (along with a few new ones to follow). You can see the entire list after the break.
Tires: these need 200 miles of wear before they have the full intended grip. Until then avoid unnecessary wear or heavy cornering.
Gearbox: you should always treat a manual box with respect. But none more than the first 400 miles. During that time be extra clean with your shifts and for God ‘s sake don ‘t grind anything but your teeth. Once the 400 miles are up, feel free to have at it.
The M Differential: The M Diff is a complex and special piece of mechanical goodness that requires some serious respect. That means no full acceleration – ie slamming your foot the floor. But what if you accidentally do 5-6 times? While it doesn ‘t mean expensive repairs down the road it will cause the M Diff to be noisier as it racks up the miles. So how can you feel the brunt of an M car while in the break-in period? During the first 1,200 miles M recommends that you ease on the throttle rather than slam it to the floor.
The Engine: The official line by BMW on the 1M is to keep it below 4,500 rpms until 1,200 miles. In reality, we ‘ve heard that you only need to keep it below 4,500 until it gets closer to 1,000 miles. At that point you can start to gradually increase your self-imposed redline until that magic 1,200 miles mark when you can also touch redline now and again.
The other requirement is to vary the RPMs through the range while not reaching over 100 mph. The thought here is that this will allow you to vary the load on the rings which allows them to seat properly.
Breaking in my 1M has been a test of patience given the ability of the twin-turbo inline six to generate enormous torque from the lowest depths of the rpms. With only 800 miles to go until that 1,200 mark, I may just make it without laying down black marks.