I’ve been intentionally driving on crappy roads to test out my new Speedthane front bump stops that replaced my E36 M3 front bump stops which were way too soft and letting my Koni FSD shocks bottom out on sharp impacts. Yesterday, I underestimated a BUMP sign.

Most people with lowered E9x BMWs use the front bump stops from the E36 M3 because they are a similar OE BMW bump stop but shorter, and this gains back some shock travel before engaging the bump stops. But I’ve learned the E36 M3 front bump stops are really too soft for the heavier E9x cars, especially my awd E92, and especially with my Koni FSD shocks that have blowoff valves in them that soften the shock up in response to sharp bumps. The shocks would go soft on big bumps and then crash bang into the end of their travel because the bump stops were too soft.

Last week I replaced the front bump stops with some stiff-but-progressive Speedthane polyurethane foam ones. I started out cautiously testing the limits of the front suspension, and the initial results were very encouraging, so I’ve gotten a bit more adventurous with seeing how they handle bumps. So when I say I’ve been intentionally driving on crappy roads, I actually mean, “driving around Madison, WI like anyone else who lives here, because many of our roads suck.”

Last night I was out for a drive on some back roads, when I saw a BUMP sign. The very exact BUMP sign at the top of this post, in fact. I thought, “hey this is an opportunity to test my so-far-very-kickass new bump stops!” and slowed down a bit because I didn’t want to go nuts with this bump. As I would soon learn, it was not quite slow enough.


Ok, so it didn’t go exactly like that. For one thing, my car has like 1/4 of the ground clearance of this Audi, so the plastic undertray made a nice gentle brushing noise on the ground (but not a horrible crunching cracking “oh crap now I need to browse the parts catalog again” noise).

But really other than that, and the Z4M rear bump stops (the other common lowered E9x bump stop choice) maybe being a hair softer than I’d like, the car handled it great!

Now I just have to figure out which Speedthane bump stops to put on the rear and I’ll be flying like Colin McRae.


Time to proactively invest in some plastic undertrays. There’s only a few under the engine bay...

And then these other ones under the rest of the car...


I’m sure all of these will be nice and affordable. It’s not like they’re made by magical elves in the German forest of Plästicträyẞetrieẞeländphäliä or something.