So, lots of changes made in the last week, and today was the first shake down ride, which was simply a 31 mile commute to work. The seats sit just a little higher than the R170 Crossfire seats. This results in a slightly different seating angle. It was enough that lots of fiddling with the seat adjustments and the rear view mirror occurred. Think it is settled out, now, and I am nested Seems that the more high performance you make any car, the more finnicky all of the adjustments become. At 5'8", I'm not a tall person. My 6'3" son loves the seats, but he finds that they leave him quite a bit less room to fit in versus the stock seats. They sure are comfortable, though. I've had people tell me the R172 seats are even better. Hmmmm.....

During the drive this morning, everything did well, except for the hub centering. This presents itself as a tire shake, that feels like an unbalanced tire. It comes and goes at different speeds. This tells me that torqueing the bolts down in a pattern of small changes, allowing each bolt to find its center in the hole does help, but there's no replacement for the hub doing its job centering the wheel. This being said, it's impractical to drive the car 1200 miles this coming weekend with this issue. Tonight, it will be back to the SRT-6 front brakes.

Last night, the bed down procedures for the EBC Yellow Stuff Brake Pads in the SLK55 4-pot brakes was completed. They grab! In true apples to apples comparison, I have the equivalent Yellow Stuff pads in the SRT-6 brakes, and while the pads in the SRT-6 brakes are much larger, they do not bite down like the 4-pot calipers on the larger rotor do. I am looking forward to putting these back on the car!



So how to do it? The current setup uses a 5mm spacer so that the wheel will clear the outboard edge of the caliper. It relies on the hub being wide enough to accommodate the thicker SLK55 rotor, the 5mm spacer and still mount the wheel. We now know for certain that there's not enough hub to do that. So, the solutions could come in a few forms:

1. Machine down the offending ridge on the outboard side of the caliper. Would work, but now there would be a custom part in the car that cannot be replaced at the roadside, if there is an issue.

2. Find a different hub that has a wider hub portion. This is my preferred solution, but I do not know if, say a SLK55 hub, would do that. Dimensions are needed, if anyone has a hub around. This would have the side benefit of solving the rotor retention bolt issue.

3. Use a hub centric spacer with it's own hub flange. These are a dime a dozen, so why not use these? The required spacing is 5mm. There's not a practical way to add an attached hub surface to this thin of a spacer, as there is still a few millimeters of hub left. In other words, since there is hub material in the way, a spacer cannot have it's own hub surface in the same spot. Pics would help, but I don't have any except what you can see in this view:



If you look closely, you can see the steel hub material poking out from the spacer. There's not enough meat here to grab the wheel, but also too much for a spacer with its own hub surface to fit over.

So, the thinnest spacer found with a hub flange is 10mm, so far. Amazon has these MB specific spacers, and so I ordered a pair:



Now, 10mm is really too thick, and will present me with other fitment challenges. Preliminary estimate is that to clear the original hub and function as a spacer would be about 7-8mm. That seems like splitting hairs, but the idea is to reduce the wheel spacing as much as is possible. Measurements and a drawing will be made tonight of all the pertinent dimensions before brake removal this evening. The plan will be to take these spacers, and turn them on a lathe to thin up the spaced surface just a bit. Depending on metal thickness, it may also be possible to run a lathe up inside these, thinning the material up near the hub extension, and may be able to gain another 1-2mm. Doing that might reduce the need for the spacing thickness further, getting total thickness in the 5-7mm region again. That's optimistic, and the answer will not be clear until the hubs arrive sometime in the next 2 weeks.

Parts are on order to work with Option #3, but Option #2 is truly the better one. There doesn't seem to be a practical way to completely eliminate the spacer, but having to go to a thicker one to solve the hub center issue is like a bandaid on top of a bandaid to me. Several people have PM'd me here and on other forums (where this thread is being paralleled) to say that they have swapped these same brakes on their SLKs, Crossfires, and a few other vehicles. If you have solved this problem a different way, please shoot me a PM.

Due to time constraints tonight, there won't be much more than swapping the SRT-6 brakes back on. Tomorrow more miles will be put on. In all, there should be 150 miles further on the car before leaving Friday, bringing the total up to around 900 miles on the whole M113K setup. Not a ton for any setup, but hopefully enough to shake out the major bugs.

Missing from the formula for the Dragon event this weekend will be the Killer Chiller. After speaking with Kincaid Performance about it, we thought a system would be here in time to install before the event, but that just didn't happen. This will just added to the list of winter projects for the car. After the KC, attention will shift towards instrumentation and the interior. Some exciting stuff is going to happen there!