In my first article I spoke about front bulkhead, front arms, C-Hubs and uprights.
Astute upper arms are bulky, massive and heavy with 4 mm rod. The hardware is also complicated and heavy with two 730 bushing each one and a lot of nuts. The only good reason to keep the Astute front upper arms is that they reduce the bending of front arms, especially if you mount Madcap lower arms.
There’s no way to have a lighter Astute upper arm if you don’t replace it. The only other solution is find the super rare Avante titanium 4 mm rods and four 730 ball bearings but you spend a lot and obtain little in terms of weight savings.
Anyway a 3 mm rod with tight 4 or 5 mm ball connectors is the correct configuration in my opinion. A double tread rod is better and easier for suspension set up on the track. With 3 mm rods and Madcap arms your car will be a little bit under steering due the bending of lower arms. In fact the ball ends on both sides of upper arms can not prevent the bending of the lower arms. Super Astute stronger lower arms don’t bend and are the best choice again.
Differences between Astute upper arms and Super Astute upper arms:
Steering links are very good on the Astute so they can remain the same. I suggest to replace the sloppy original 5 mm ball connectors with tight 4 o 5 mm ones. This will reduce weight and will give more precision to the drive. Four 850 ball connectors are also a good replacement of the heavier 850 bushings.
Steering links, the only good part on the Astute? ;-)
Battery position on the Astute is an old concept. As on the Madcap the battery is mounted transversely on the frame. There are three positions to choose from forward or backward to decide the weight balance. Obviously these regulations are not enough to have a decent weight balance so Tamiya went to longitudinally mounted battery on Super Astute. You must install Super Astute G parts to have the longitudinally battery position. In the same G parts you will find the battery stays and the very important G4 front bulkhead brace.
Different battery positions between Astute and Super Astute.
Astute and Super Astute frp chassis plates are almost identical except two more holes needed to mount the Super Astute battery stay. When you mount Super Astute G2 and G5 parts you will eliminate three aluminum columns, mechanical speed controller plate and servo stay but must drill these two more holes. You must drill a 3 mm hole and use a tool called countersink for the countersunk head of the screws. Longitudinally mounted battery will give better weight balance and quicker power pack replacement.
Position of these new two holes is explained in the picture.
Astute chassis plate plus the Super Astute battery holes in blue:
Astute and Super Astute rear shock tower stays are almost identical. Madcap rear shock tower stay is simpler and lighter. As usual there are a lot of heavy press nuts that are not present on Madcap. Anyway there’s no need to swap the Astute/Super Astute tower stay with Madcap one except for the weight saving.
On the tower stay are joined rear upper arms. I’ll speak about them later.
An handmade modification is needed on the rear tower stay, on both Madcap and Astute ones. A carbon fiber or aluminum brace is needed between right and left upper arms. If not the upper arm will strip its mount on the tower stay. This is an highly suggested modification. You can see mine in the picture. With this modification the problem is solved.
Another modification that must be done on the rear tower stay (if you replace the Astute bulky arms with normal ones) is adding two spacers at the upper arms mount. These spacers must be 4 or 5 mm thick on the Astute shock tower and 2 or 3 mm on Madcap shock tower (spacers are present on the Super Astute). Will explain the reason of these spacers later but remember this thing.
Rear upper arms are bulky as and more than front ones and they are heavy. On the rear upper arms are also joined the rear toe links. All this things must go away. They are over engineered and heavy with all this hardware and 4 mm rods. I absolutely suggest 3 mm double tread rod and 4 or 5 mm tight ball connectors. If you make this modification you also must replace Astute rear uprights and hubs with Madcap or Super Astute ones.
As per front these bulky rear upper arms avoid the rear lower arms bending. This is due they are not joined with ball connectors but with solid 3 mm shafts.
So, when you go to ball connectors nothing prevent the lower arm bending. This is a problem with rear end because this bending allows the upper arms to touch the damper springs. This problem can be solved with the spacers (point #5) plus the tower stay brace. These spacers give more clearance between rear dampers and rear upper arms. To avoid the bending Super Astute rear lower arms are the best solution again.
Astute rear end:
Madcap is simpler:
Written by TB member Massimo Kontemax Russo, TB user Kontemax