Probably the most tuning work is done in the chassis area. The offer in the aftermarket is almost endless, whether it is stainless steel screws or anodized gearbox or portal housing, you can beautify or improve almost everything. The TRX-4 is "bought and unpacked" certainly one of the best you can buy at the moment, but for real crawler fans that is not enough to make the vehicle optimally controllable.
The original shocks that Traxxas includes with the TRX-4 are currently not really improveable in the aftermarket. They are very sensitive and do their job almost perfectly. But of course you can still improve the response behavior. With a few small tuning rings that are screwed into the damper housing, you can make the damper even more sensitive, the breakaway torque is significantly lighter and the dampers respond much faster. Small costs with great effect, what more could you want. Also, you can still change the response with different oils.
100, 200 or 300 cst damper oil changes this already strongly. 100 oil has the thinnest viscosity and is almost like water. If the vehicle is already very heavy due to weight tuning, however, the 100 oil is not recommended. The TRX-4 is originally delivered with 350 oil.
Since some would like to make adjustments to the chassis or even have to, here is an overview of the shock absorber wheels and the associated marking at Traxxas.
The higher the rate value, the harder the spring.
The vehicles are delivered with the following springs:
8041 - Defender v, Bronco v+h, Tactical v, Kit v+h, Blazer v+h, G500 v+h, G63 v
8040 - Defender h, Tactical h
8043 - Sport v+h, Sport Kit v, G63 h
8044 - Sport Kit h
The chassis left the steel rods that are at the bottom of the vehicle. The original weight of these rods is xxx - xxx grams. To get the TRX-4 heavier this is one of the best points.
No mass that wants to be moved by a servo with extreme extra effort and also no flywheel mass that the engine has to drive while driving. The links are low down on the chassis and keep the car on the ground on inclines or slopes. Brass links here are the way to increase the weight to 250 - 270 grams.
Attention the links are different for the vehicles (wheelbase). If these links are ordered so be sure to check which TRX-4 should be tuned. The Defender and the Tactical need a set for 324mm wheelbase, the Bronco, Blazer, Kit and the Sport the for 312mm wheelbase. Also, grub screws must be ordered to connect the brass links with the original ball heads (rod ends).
In addition to the brass links, there are now also some made of stainless steel. These are probably a little lighter than their brass counterparts (the specific weight of stainless steel is slightly below that of brass), but purely visually, these make something really.
Here, too, the main links were turned to 8mm in diameter and the ends run positively conical to the rodends. The Panhard and the link of the servo are a bit thinner.
After assembly there are no gaps here, this is how modeling should be.
A special eye-catcher is the steering rod, it is not only beautifully crafted, you can also purchase it separately to significantly brighten up the front of your vehicle.
The links are highly polished and the threads were, as it makes sense with stainless steel, directly turned on. The dimensional accuracy is really extremely good with 1/10 millimeter.
The price is slightly higher than those made of brass, but this is absolutely justified in view of the material and the workmanship. Who is looking for something special for his little one, here it is!
The links are available, as well as those made of brass for the different vehicles:
For the TRX4 Defender, Bronco 2021 and Tactical with 324mm and 264 grams there are them here, the Bronco, Blazer Sport, Kit and Sportkit with 312mm and 246 grams here and the TRX6, which has yes 3 axles with 368 grams here. To this are then 15 grams for the handlebars which can be purchased separately in stainless steel here and in brass / steel hard chrome plated here.
The portals are small deflection gears that allow the vehicle to significantly increase ground clearance. The drive shafts are deflected again and the TRX-4 comes to an increase in ground clearance of 25mm. The housings are plastic from the factory. But even here there are remedies in the aftermarket. Housings made of aluminum, they are a bit heavier than the original plastic ones, or made of brass. Here one can exchange e.g. the portal cover on the wheel side which brings up to 200 grams and more per axle at weight, thus altogether about 400 grams at the vehicle. Of course, you can also replace the inner portal housing front and rear, as well as the entire steering against brass.
If you plan to replace your original portal housing with a brass one, please replace the steering servo in advance with a more powerful one, like the HD-Power, the Xpert Servo WR4401 / WR7701 or similar. The Traxxasservo will not withstand this extra load for long.
Axle weights offer a further means of making the vehicle heavier in the floor area. These are bolted between the portal housing and the wheel carrier. The weight increase is partially adjustable. Here you should consult with your dealer. When working with axle weights, the weight difference for the steering servo should not be ignored. The steering point may be pushed very far outwards, sometimes the track width changes considerably which can lead to problems with the body or the steering.
The cardan shafts can also be replaced. Traxxas has installed plastic shafts here, these can be replaced with steel ones. Of course, you can also change many other things on the original TRX-4 chassis. For almost all components there are alternatives made of aluminum or even carbon (battery holder). The possibilities are almost inexhaustible, but so is the hole in your wallet. What certainly makes sense is an underride protection on the differential and transmission. The two places suffer very much in stony terrain, these are available in stainless steel and aluminum.
Whether now gearbox housing made of aluminum really helps the vehicle to better driving characteristics is certainly debatable, but colorful anodized components look fantastic.