So, finally some progress on the car... Next race is in March and with the new front alignment (almost -4 degree camber) the rear needed adjustment. I was starting to consider to find a race shop to modify the Dedion for rear camber and toe-in, but Colin and I decided to do it ourselves since we finally had some time.

The idea is to add negative camber and widen track by 50 mm, and then trade of some of the extra rear grip with a stiffer (adjustable) rear sway bar to further reduce roll.

When Ron was here we went over how he does it on the 75Experience Ring cars, and I picked up some pointers. Though, I opted for doing the rear camber and toe-in with the Dedion in the car although he suggested to pull it out.

Anyway, some pics below. First Colin and I marked where the CV-joint of the half-shaft near the hub ends, and where the bolt heads end. You want to cut inside of those since the clearance between the CV-joint and the Dedion is minimal. To get a marking completely parallel with the zero degree camber, zero toe-in wheel, we conveniently dug up a board of proper thickness and held it against the backside of the rim/tire and marked the Dedion _all_ the way around. Getting the marking right and following it during the cutting is critical to make the job easier. For zero degree toe-in you also want to mark equal depth cutting on both sides. Since I wanted 2 mm toe-in (per wheel) we needed to cut slightly deeper on the front side than the rear side.

 

The cutting is somewhat challenging. Mostly because access isn't great. It would perhaps be slightly better, although not much, with the Dedion out of the car (we will know soon since we will probably do Colin's out of the car). To get the cutting done we used two angle grinders. A small that takes 3" blades, and a bigger that takes a 7" blade. We ended having to also put a 10" blade on it to reach the bottom part of the front cut.

From the lowest original mark we gradually cut deeper, in increments of 1/4" since we did want to cut so far that the hub would be too "loose". We used the weight of the car (by jacking up the hub-end of the Dedion) to achieved sufficient leverage to bend the tube. The final depth is shown on the closed-up picture where the gap at the top is completely closed.

 

 

Two BIG advantages of doing it with the Dedion in the car is that:
1. You can use the weight of the car as leverage to bend the Dedion.
2. You measure exactly what camber and toe-in you get before welding it up for good.

What we did next was to put a single smallish tag-weld right at top, after verifying that closing the gap completely gave the approximate negative camber I was looking for. We then put the wheel back on lowered the car down on the turn-plates and measured toe-in. It was too much toe-in - 4 mm (I want 2 mm per side for a total of 4 mm). So, we used a screw driver as a wedge and tapped it in the open slot from the front until we had exactly 2 mm. After that we added tags on front and rear side of cut, put wheel back on, lowered car, and re-checked toe-in again. It remained at 2 mm. The welding did not seem to change the alignment.

After that, Colin finished up the welding, I wire-brushed the weld and coated it with Wurth Rust Guard.

 

And some pictures with the final setting of the rear (left side) camber and toe-in. I ended up with slightly more negative camber than planned (almost -4 degrees, I was aiming for -3 degrees), but we got the toe-in spot on - 2 mm toe-in.

On these pictures I still did not put my 25 mm H&R aluminum spacers that I got from Jason to the rear (they maintain the 58.6 mm bore and 5x98 bolt pattern - TUV approved). On the front I added more than 1 cm of spacer to the lower control arms to get the negative camber. That increased the front track. On the rear we cut away material to get the negative camber, hence the reason for the 25 mm rear spacers.

So, unless I only want to run clock-wise ovals I need to find time to do the right side