My E36 M3 has about 90k miles and about 20-30 days at the track. My original LCAB's look nearly perfect and I have no clunks and no discernable play in my LCA ball joints. Is there any rational reason to believe that the inner LCA ball joint will fail catastrophically, or will regular inspection be sufficient to diagnose any potential problems? A search turns up lots of recommendations to replace control arms as regular maintenance on track cars, but given the general durability of ball joints until they have significant play, that seems excessive. Does anyone have anecdotal or scientific evidence for replacing them beyond 'it's a good idea'? Many thanks!!

The problem first arose with the E30s. All E30s up to 1989 came with a steel control arm and non-heat treated ball joints. Then in late 89 BMW used induction-hardened balljoints in their aluminum E30 M3 control arms.

Today, the only control arms that are not heat treated are either el-cheapo POS arms or the original E30 steel arms. ALL other good brand E36, E46, and aluminum E30 M3 arms come with heat treated ball joints. The only brands you want to buy if you plan on tracking the car are Lemforder and Original BMW, which are nearly always made by Lemforder.

There have been reports of broken ball joints on E36s, but they are much more of an anomaly these days. Typically the ball joint wears out long before it will succumb to fatigue failure.

Any idea if the oem replacement e30 c-arms that are sold these days are heat-reated / induction hardened, such as meyle?

Meyle arms are a big no-no. They have been selling an all-metal E36 outer balljoint replacement for a few years now to replace the rubber-lined E36 outer balljoints. They are so bad that our wholesale parts rep cancelled an order we placed a while back and called us to tell us specifically not to order them. I dissected one a long time ago (eBay purchase) and found they are not heat treated.

Even BMW original E30 arms are not heat treated, which is why you'll find most guys running E30 M3 arms or changing their standard steel arms every season. They hold up for a while, but there's no warning before they let go.