Astute guide tread.

[kontemax 1734]

Hi, as suggested by Jesse James I open here a Astute guide tread for all Astute fans. I also made a "how to" entry in my showroom. It's a work in progress so please be patient.

The Astute is a beautiful 2WD car, very fast on the track but very fragile and it's frustrating how it can break easy if you don't make some work on it to improve strength. I drove it a lot and made many mods so I can share with you my tips.

1) Front end. One of the most fragile part of the car. You absolutely must have a G4 Super Astute front brace if you wanna drive your car for more than some minutes. This part is not an optional, is a must have.

Super Astute front brace:

You can see the part in the picture.

You can also use Madcap front end that is a little bit more strong but non enough without any brace. Madcap has a front brace but needs plastic bathtub chassis to be mounted. You can avoid this problem with a couple of aluminum columns.

Madcap front bulkhead:

Madcap front brace (G3 part). As you can see it need a Madcap plastic bathtub chassis or...

The columns to adapt the Madcap front brace to a FRP or Carbon plate chassis. I made them by myself and must be 25 mm longer. You must drill two more holes in the chassis to accommodate these two columns.

Madcap and Astute front bulkheads fit very well but they are not identical. Madcap one is longer on front to accommodate the larger bumper but this is not a problem. Astute mini bumper will fit without problems. The major difference is the front arms offset that is some millimeter back on the Madcap. This is not a big problem again. If you have dampers on ball connectors the problem doesn't exist, your dampers will be a little bit more inclined. If you have dampers on bushing you will need longer bushing on top mount. The length of the car will be shorter obviously if you will use Astute uprights. With Madcap bulkhead you need also Madcap uprights to keep the same wheelbase. The Madcap bulkhead is lighter and doesn't need the 730 bushings or 730 ball bearings.

Differences between bulkheads:

2) Front arms: another modification for the Astute is the front arm swap with Madcap ones. Astute and Madcap front arms are almost identical in width and length. The only good reason to swap them is the lack of Astute spares. There are only few differences between the two arms. Damper position is different. Both arms have 3 damper holes but on Madcap they are more inner so Madcap middle hole is Astute inner hole. Another difference is the offset. On the Madcap arms the damper mount is more ahead in front of Astute one to compensate the different arm offset on the bulkhead. The result is that if you mount a Madcap front arm on the Astute bulkhead the dampers will be more inclined ahead in the lower mount and the wheelbase will remain identical. If you mount a Madcap arm on the Madcap bulkhead the dampers will be not inclined but you must use the Madcap Upright also or the wheelbase will be shorter. In fact Astute Uprights have the wheel axle some millimeter back to compensate the different C-Hub offset in the Astute and keep the same wheelbase.

Super Astute arms is another thing. Astute upright have the wheel axle back like the shopping carts. This allows to keep the straight direction of the car. After the release of the Astute Tamiya made the Madcap with different bulkhead, front arms and uprights. In the Madcap the traditional Hornet uprights have the wheel axle in the same position of the steering axle. The wheelbase is equal to Astute but the geometries of front upright are different. With the Super Astute Tamiya decided to keep the Astute bulkhead and the Madcap wheel base together. A new design is for Super Astute arms, with the correct offset for the dampers and more inner holes to increase wheel travel and car height. But the SA arm curves back to obtain the same wheelbase than the Madcap. This allows to use normal uprights without wheel axle back.

In my opinion the best choice for the Astute is the Super Astute arms that are stronger and keep the normal uprights. Madcap arms are lighter than Astute ones but are softer and flex a lot so there's no vantage to mount them.

Differences between arms shape and damper position:

Correct position of the arms on their own bulkheads:

UPDATE: This is what happen if you use the Astute or the Madcap without any sort of front brace. These parts snap in seconds of use on the track. Also the rear hubs are too fragile.

[kontemax 1734]

3) Front uprights and C-Hubs. As you can see in the pictures Astute front C-Hubs are crazy complicated and heavy with a total of twelve 730 ball bearings (or bushings). Madcap C-Hubs are the right solution but keep in mind that Astute upright have a different wheel offset. This is compensated buy the different bulkhead in the Madcap or the different shape in the Super Astute if you want to maintain the same wheel base.

The best solution in my opinion is Super Astute front arms and bulkheads with front brace, Madcap C-Hub and Super Astute/Dyna Storm uprights.

Madcap C-Hubs are lighter, simpler and allow a normal upper arm with 5 mm ball connector.

Super Astute upright have the same wheel offset than Madcap but a longer arm that allows a more precise responding in the drive.

Astute over engineered front C-Hubs and Upright:

Madcap simpler C-Hubs and Upright. These C-Hubs allow simple upper arms with 5 mm ball connectors:

Different wheel offset in the uprights. Note Astute wheel position:

Substantially the wheelbase on all cars is the same.

Astute has bulkhead arms position ahead and wheel offset back.

Madcap has bulkhead arms position back and zero wheel offset.

Super Astute has bulkhead arms position ahead and zero wheel offset. To maintain the same wheelbase the arms are curved to back.

NOTE:

If you want to fit Super Astute steering arms on Madcap C-Hubs you must file the white part of the arms. Original Madcap Steering arms are 11 millimeters height, Super Astute are 13 millimeters so no direct fit. A little bit of work is needed to bring the Super Astute pieces to 11 mm.

[Origineelreclamebord 45]

Sweet piece of documentation man! I don't have an Astute, but this is really the sort of documentation that'll keep people running and racing them! (Exactly what they're made for!)

[Jesse James 13]

hey max,

wow what a great amount of information you've put in here already!!

it would have been great if all this info was all together when i started building my astute!!

As it is, i have built mine with the madcap from bulkhead and arms with the SA front brace which needed a couple of spacers to get it right, astute shock tower, i didnt have to space the shocks out up the top too much, they are leaning back a little, im using the middle hole on the arm to mount the shock. I mainly use the mad cap arms to avoid the bushings, they do flex a lot, i felt the flex was similar to the amount in the astute arms

in the rear im running the madcap arms, hubs and the madcap bulkhead. i had to make my own rear adapter plate to make it match up to the astute mounting points. The madcap rear bulkhead had the advantage of having the turnbuckle line up better as i have seen astutes running madcap arms and hubs have the turnbuckle fowl on the shock spring, i actually dremelled the mount point for the ballstud in the rear hub flush with the rest of the hub to make the turnbuckle line up even better. The other tip here is that you can run stadium blitzer rear hubs which has a shorter axle and that allows you to run df02 universals which are much cheaper than the astute unis selling on ebay

Thats pretty much all i can think of at the moment, im writing up a bit of a build story about my astute, im using the SA battery mount and running the battery along the chassis rather than across it to try and balance it out and get better steering. Keep this thread going with all your tips guys!!

[Rockcrusher 6]

Great thread. Good info here. Will there be a section on setting up the ball diff to help make it last? I never knew there were so many subtle differences between the Astute and the Madcap besides the obvious ones. Considering many of the Astute's more fragile parts were often replaced with Madcap ones, does an Astute hold any real performance advantage over an upgraded Madcap (oil shocks, turnbuckles, bearings etc.)?

[Thommo 1241]

Bravo Max, A great thread with lots of useful info.

This one has the Astute front bulkhead, shock tower and upper arms with Madcap lower arms and C hubs and Super Astute steering uprights. The problem of the Madcap arm flexing is very easy to fix. You just have to use Astute upper arms. Because they hinge on a shaft, they simply don't allow as much twisting so this front suspension set up is tight and has very little flex. The Super Astute steering upright does have to be trimmed down to fit inside the Madcap C hubs as Max mentioned. This set up results in the longest possible wheelbase so more stable at speed but at the expense of turn in.

When using turnbuckle upper arms on the rear, both the early Astute rear arms and the Madcap arms will flex quite a bit (a reinforced Astute rear arm appeared sometime in the middle of production) and yes they will flex and twist the rear hub enough for the upper arm to clash with the rear spring under brakes. This can be rectified again, by using modified Astute rear upper arms that hinge on a stainless shaft as opposed to ball joints that allow the arm to twist. I don't see this as much of a problem (#EDIT#, I have since trimmed the front off of the Madcap rear hub to relocate the upper ball connector and upper turnbuckle away from the rear shock spring. Problem solved). I like that the Madcap rear arms are a bit foregiving under power. These ones are hanging on Madcap mounts with 10mm hex screws which is far better than the fragile Astute mounts.

Top view shows the changed steering angle at the front and how close those rear turnbuckles are with the Super Astute upper arms connected to Madcap rear hubs. An extra O'ring is required inside each axle cup with this set up to stop the dog bone from floating but the result is excellent and I've never had one pop out.

[Jesse James 13]

Great thread. Good info here. Will there be a section on setting up the ball diff to help make it last? I never knew there were so many subtle differences between the Astute and the Madcap besides the obvious ones. Considering many of the Astute's more fragile parts were often replaced with Madcap ones, does an Astute hold any real performance advantage over an upgraded Madcap (oil shocks, turnbuckles, bearings etc.)?

Good questionsyou're right, in theory with as many madcap bits as we throw on the astute you'd ask why not just run a madcap. the astute just has more flexibility because of its design, you can run the battery along the chassis which does a lot to move weight forward to get the car to turn in, also the steering bell crank arrangement is better as it doesnt use the "coathanger" wire like the madcap doesas for the diff, im not too sure, the trick with the standard gearbox is just not to put too much power through it. The diff acts as the slipper and the diff and physically its too small to efficiently transmit a heap of power without getting too hot and melting stuff but hopefully others can contribute a good building process

[Grastens 2801]

On my Astute build, I have attempted to temper the problem using a combination of standard Ball Diff Grease and Anti-Wear Grease inside the diff to slow down the parts' rotation. which should help them last a bit longer. I received it second-hand, and the previous owner appeared to have done something similar; the rebuilt diff (with both greases) feels like it did before.

[kontemax 1734]

Hey guys! Thank you for your answers, I'm writing a second part of this thread and will post it in some days. Need to make the pictures.

And yes, there's a solution for the rear diff. There will be three or four articles in my HOW TO section in my showrooms and then will be posted here. One of them is about the entire transmission.

Max

[Jesse James 13]

hey max

thanks for all your work, your first section about the front end is awesome

i followed your advice from your thread about your truck regarding using ta03 front hubs to allow me to use 4wd front rims, i've attached a couple of pics for comparison, the width looks very close as does the wheelbase, i spaced the hubs full forward in the arms

my main reason for wanting to run the 4wd front rims was so i could use the black df03 rims which look great and i think they look like a modern version of the astute rim, also when i saw these alloy gold rims, it fitted my theme perfectly (gold rims are for show only - this car is planned to be a racer 99% of the time (thanks to Jak for the great shot of it!)

This is the astute i've built for our vintage racing events including the 6 hour enduro we have coming up on sunday. i hope it lasts 6 hours of racing!!

[Percymon 2185]

The wing decal says it all about that Astute JJ - truly awesome look  

[Jesse James 13]

Thanks percymon. I think between yourself, thommo and max I learned the bulk of what I need to so I could build the car just by reading all the responses to people's questions.

[Jesse James 13]

A couple more shots from that day and jaks awesome camera

[Thommo 1241]

Great work mate, she is very impressive. Both thumbs and big toes up from me

Good luck in the big annual vintage enduro this weekend. I'm glad to see that car at last buddy, well done.

Hey what trans did you go with ?

[kontemax 1734]

That's a good job and your Astute is really awesome. You should paint the rear wing also, it seems not complete.

You can cut the internal rib in the front wheels if you wanna them more narrow.

Also you mount the Lethal Weapon 2 Tranny. This is a really good choice. I use it on my King Cab.

Max

hey max

thanks for all your work, your first section about the front end is awesome

i followed your advice from your thread about your truck regarding using ta03 front hubs to allow me to use 4wd front rims, i've attached a couple of pics for comparison, the width looks very close as does the wheelbase, i spaced the hubs full forward in the arms

my main reason for wanting to run the 4wd front rims was so i could use the black df03 rims which look great and i think they look like a modern version of the astute rim, also when i saw these alloy gold rims, it fitted my theme perfectly (gold rims are for show only - this car is planned to be a racer 99% of the time (thanks to Jak for the great shot of it!)

This is the astute i've built for our vintage racing events including the 6 hour enduro we have coming up on sunday. i hope it lasts 6 hours of racing!!

[Jesse James 13]

Hey max

Yeah the lethal weapon tranny is excellent. I'm stoked with how well it works. I've just rebuilt it and it was totally clean inside.

Has everyone found they have to run a really hard spring on the rear of these cars. I've had to switch to losi red rear springs just to keep the rear end from sagging. It must be something in the geometry, I've never had to run a spring that hard on any of my cars. I think the manta ray would be similar. Does anyone know the spring rates for the hi-cap option springs?

[Thommo 1241]

Has everyone found they have to run a really hard spring on the rear of these cars. I've had to switch to losi red rear springs just to keep the rear end from sagging. It must be something in the geometry, I've never had to run a spring that hard on any of my cars. Does anyone know the spring rates for the hi-cap option springs?

Spot on. The hardest springs you can find for the rear. I found some generic truck springs that are super hard because even the DF03 hard set were not hard enough.

I'm concerned that the Hi-Caps won't be hard enough either but I'm a long way off testing mine. I'm hoping that by running Li-Po and the S.Astute battery location that the rear will be OK with Hi-Caps. I use the highest viscosity damper oil in the rear too #1100 from memory.

[kontemax 1734]

This is the second part of my Astute Guide Thread.

How can we obtain a better performing and more affordable Astute on the track?

In my first topic 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

[Jesse James 13]

Hey guys, just thought I'd post links to a couple of vids my mate has put up

The enduro footage features some highlights of our recent 6 hour race and my black astute is in there battling with an rc10 mainly

Enduro footage

My astute vs losi jrx pro

Hope they work anyway