Complete T-Maxx Performance Guide
(Part 1)


The Complete T-Maxx Performance Guide

Part: 1

 

"Suspension Tuning"

 

 

It’s no doubt that the Traxxas T-Maxx is the most popular 4WD monster machine on the planet. Since its inception back in 1999, it has continued to astound people everywhere with its speed, power, agility, and ease of use. The T-Maxx has also proven to be the most all-around fun-to-run R/C vehicle available, {Year after year}. We receive an overwhelming number of requests each day for T-Maxx set-up information and tuning tips. So, it only makes sense to give Traxxas T-Maxx owners what they want; a complete T-Maxx set-up guide. Due to the enormous size of this T-Maxx set-up guide, I’ve separated it into three sections: suspension, chassis, and drive train. Tips on tuning your engine for maximum performance can be found here: TRX 2.5 engine tuning tips

 

The monster truck class is getting more and more competitive everyday, which means that maximizing the performance of your T-Maxx truck is becoming very important. I’ve been successfully racing the ?T? machine for nearly four years now, and have come up with a good base set-up that works great on most track conditions. The best part is, you don’t have to spend an arm and a leg to get this set-up. Many racers believe that they need to buy all of the latest trendy bolt-ons for their truck to be race-worthy. It’s just not true; Though, it may be true for some of those other companies that have tried to make their own version based on the ?T?. The Traxxas T-Maxx is an excellent performer out of the box. In this series, I will show you the hops-ups that I feel are worthy of the extra money, plus I’ll tell you what each adjustment does for your T-Maxx, and provide suggestions on what you should do with them for different driving conditions.

 

The T-Maxx in its stock "out of the box" form

For racing, I leave as much plastic on my truck as possible. This is to keep weight down for quicker response and added reliability. Heavier vehicles tend to break and wear out more quickly; not to mention the extra work that is required out of your engine to propel that extra weight. Don’t get me wrong, aluminum parts look awesome, and do a great job of holding things together, but when a lot of aluminum is used, the extra weight adds up quickly, and can end up making the truck too heavy for its own good.

 

Here’s the "T" after the transformation

In this first installment of the T-Maxx set-up guide, I’m going to cover the suspension system. The T-Maxx suspension is completely adjustable, and can be set-up to handle any type of track condition. Knowing what your truck is doing, and what you need your truck to do is the first step in determining what area you should start with, and what you should adjust to achieve desirable handling. Remember to click on the photos to enlarge the pictures.

 

 

4-shock vs. 8-shock setup

Part 2 of my Maxximum SportMaxx article, using four 1/10-scale shocks will save a decent amount of weight, and works fine for the lighter 2WD chassis. Due to the extra weight of the T-Maxx over the S-Maxx, four shocks have a fairly hard time keeping up with the dampening duties on rough sections of the track. I recommend sticking with all eight shocks on the T-Maxx for greater consistency, and better overall performance through the rough stuff. A 4-shock (1/10-scale size shock) set-up would be better suited for a smooth and flowing track.

 

The use of 1/8-scale buggy shocks is a viable option if you intend to run a 4-shock set-up. Most 1/8-scale buggy shocks will fit and work fine, but because of their larger size and shape, there is really no significant weight savings, and the prices of 1/8-scale buggy shocks are typically more expensive than 1/10-scale shocks.

I use an 8-shock set-up on my T-Maxx

One thing to keep in mind though - is the broader range of tuning possibilities that an 8-shock set-up offers. The extra four shocks and springs allow you to experiment with more oil/spring combos, providing special dampening and bump handling characteristics that a four shock set-up would have trouble duplicating.

 

Shock Springs

 

Shock springs do more than just handle the imperfections of the track. They can also reduce, or allow more chassis roll in the corners, and they play a large part in how quickly the truck reacts to steering input.

 

 

Soft Springs

Soft springs are more beneficial on slick and bumpy tracks, and give the truck more of a ?lazy? feel going into the corners. Softer springs are also a little more forgiving, allowing you a little more time to correct the chassis if it gets out of shape.

Firm Springs

You can make the T-Maxx more sensitive, and faster reacting to steering input by installing firmer springs. A track with large, high-speed jumps may require a firmer spring to help keep the chassis from slapping the ground too hard too, which can upset the handling of the truck. Keep in mind that when you change to a firmer spring, you may need to go to a thicker shock oil to keep the shock from rebounding too fast.

 

The stock T-Maxx red springs work well for most conditions, but firmer springs are usually more desirable for quicker response, and for handling the big-air jumps seen on most tracks today. There are many different companies that make aftermarket springs for the T-Maxx, and 1/8-scale buggy springs work well too. Try a medium/firm to firm spring rate all around the truck.

I use four 1/10-scale Team Losi truck blue springs (2 in the front, 2 in the rear), and four Kyosho 1/8-scale white springs (2 in the front, 2 in the rear) for excellent response and bump handling on my truck. Check with your local hobby shop for all of the different springs available for the T-Maxx.

 

Tip: Crimp the ends of the springs a little bit to fit snugly over the spring retainers. This will keep the springs attached to the retainers, which will provide more consistent suspension performance. This will also prevent the lower retainer from popping completely off of the shock.

 

 

Shock Oil / Pistons

 

A shock damper basically consists of a thin round plastic piston affixed to the end of the shock shaft (inside the shock body), and is filled with a silicone damper fluid. The exterior end of the shock shaft is connected to the lower suspension arm, and moves up and down with the arm when handling the bumps and imperfections of the track surface. The fluid inside the shock body, along with the size and quantity of holes located in the piston will dictate the resistance of the piston as it moves up and down during the compression and rebound stroke of the shock shaft. Shock fluid of different viscosities, and pistons made with different hole sizes can be changed to alter the performance of the shock shaft.

Tip: After filling the shock with oil, move the piston up and down (slowly) releasing all of the air bubbles to the top. The oil should be free of all air bubbles before installing the shock cap. Remember to allow a little room at the top for the shock bladder.

Basically, the lighter the oil in the shock, the faster the suspension can react to bumps on the track surface. Thicker oil will offer more resistance, making it harder for the piston to move back and forth within the shock body. Shock fluids are made from silicone oil, which can vary in viscosity. The thinnest shock oil that should ever be considered for the T-Maxx is 20wt. and the maxximum oil viscosity that you should find yourself using is around 80wt. Your local hobby shop should carry all of the different viscosities within this range, typically in increments of 5.

Light vs. Heavy shock oil

Lighter shock oil will react more quickly to bumps, but will allow more chassis roll in the corners, similar to using softer springs. A shock with oil that is too light for its spring rate will cause the truck to bounce excessively, and will be very difficult to drive.

 

Heavier shock oil will give the truck more response on smooth tracks, and also resist the chassis from bottoming out excessively from large jumps. If the oil is too heavy, then it will cause the truck to become very unstable on rough surfaces causing the truck to bounce and skid around. Try to find a set-up that is soft enough to handle the rough sections of the track, but not so soft that the truck is sluggish in the corners.

Alternate Pistons

There are two different piston sets that are included with the Traxxas Big Bore shock set: 2-hole, and 3-hole. The shocks come preassembled with the 2-hole pistons already installed. I believe that the 2-hole pistons deliver the best all-around performance for most racing conditions. 3-hole pistons will require thicker oil to achieve the same performance as the 2-hole pistons, but if you are limited on what oil is available to you, then going to 3-hole pistons may be beneficial.

 

Effects of Weather

Weather conditions can also have an effect on the dampening performance of the shock oil. Hotter weather typically causes the oil to feel slightly thinner, thus allowing the shocks shafts to move a little more quickly. If the temperature outside is considerably hotter than the last time that you ran, you may need to run slightly thicker oil in your shocks to get them to work the same as they did before.

 

An 8-shock set-up (with 2-hole pistons) will normally be happy with shock fluids between 30wt. and 50wt. viscosity. A 4-shock set-up will require heavier fluids typically between 60wt. to 80wt. With my 8-shock set-up, I normally use oil around 50wt. for smooth tracks, and oil around 40wt. for rough tracks. When the outside temperature cools off during wintertime, I may drop down to 30-35wt. oil in the shocks. I recommend using 2-hole pistons in all of the shocks for most all track conditions.

 

 

Shock Length / Down Travel

 

Ride Height Extended

 

Down travel is the distance that the suspension arms travel downward as you lift the chassis off of the surface it is resting on (as the photos illustrate above). The length and mounting position of the shocks will dictate how much down travel the suspension arms will have.

The most important thing to remember is that the left and right shocks need to be the same length. You can decrease the length of the shocks by placing 3.0mm I.D. spacers underneath the pistons inside the shock body. The larger the spacer, the shorter the shock will be.

 

 

Rough tracks, or tracks with large high speed jumps will require more down travel. More down travel will also increase body roll, which can slow you down in the corners, so choose just enough down travel needed to handle the rougher sections of the track.

Smooth high bite tracks will allow you to take advantage of less down travel. Less down travel will make the truck more responsive when cornering, and enable the truck to react more quickly to steering input. I try to run as little down travel as the track will allow. A good shock length for most track conditions is 110mm positioned in the #3 hole on the lower suspension arm (see shock position below).

 

 

Shock Position

 

There are four mounting positions on the lower front and rear suspension arms of T-Maxx. The inside holes are less progressive, and allow a little more chassis role in the corners. The outside holes make the suspension more progressive as it is compressed. This will give the truck a slightly firmer feel.

Keep in mind that changing the position of the shocks will also alter the down travel of the arms (see down travel above), and the ride height of the chassis, so you may need to make other changes to keep those current settings, if desired.

 

There are three upper shock mount positions. Changing the upper mounting positions to the outside holes will add a firmer spring rate feel to the wheels, but will speed up the dampening (faster compression and rebound). I normally mount the shocks in the middle location on the shock towers, and start with the #3 position (3rd from inside) on the arms for most tracks. If the track is rough and has big-air jumps, I’ll use the #2 position, which allows more down travel to absorb the landings.

 

 

Ride Height

 

The chassis should sit level, or slightly up in the back like the one in this photo. Raising the back end up a little will improve steering when entering a corner.

Ride height is adjusted by adding or taking away spring pre-load spacers. Do not use the length of the shock to determine ride height. This will make a very twitchy and unpredictable truck. Also, do not use extra pre-load spacers to give the shock a firmer feel. If you want to firm up the suspension, then use a firmer spring. Pre-load spacers are only used for adjusting ride height.

 

Front Arms Level
Rear Arms Level

Generally, it is best to run the chassis as low as you can, but still high enough to negotiate the bumps and jumps on the track. Smooth surfaces will allow lower ride height settings, and bumpy tracks will need a higher stance. Ride height is checked with the truck on a smooth flat surface. Push down on the front and rear of the truck at the same time and allow the shocks to rebound the truck to its set ride height. A good starting point is when the truck rebounds to where the front and rear suspension arms are level. You can run the rear a little higher than the front for more steering when entering corners.

 

Sway Bars

 

This sway bar is one that I had made for my "narrow" suspension E-Maxx. This set-up worked very well on smooth "blue-grooved" tracks. Most outdoor Monster truck tracks do not offer this kind of surface though, therefore I do not have this set-up on my T-Maxx.

There are not that many sway bar kits available for the T-Maxx. Some racers make their own sway bars with thick music wire and hand-made brackets (like I did in the picture above). Sway bars will give the truck a more sensitive feel, meaning turn-in will be a lot quicker. They will usually upset the handling on rougher tracks though. If you run on a very smooth, high-bite, hard-packed track that has smooth flowing jumps, then they can definitely be beneficial. I personally do not run sway bars on my T-Maxx, but I have experimented with them in the past, and they worked great on smooth tracks with small jumps.

 

 

Shock Set-up

 

Set-up: Front Shocks

Note: Both the inboard and outboard shocks are set-up the same internally. Use the outboard shocks to quickly change shock oil for different track conditions.

Dampers: Traxxas Big Bore w/ Ti. Nitride shock shafts

Pistons: 2-hole (all-around)

Oil:

inboard - Team Associated 40wt.

outboard - Team Associated 50wt.

Springs:

inboard - Team Losi 1/10-scale truck rear blue(firm)

outboard - Kyosho 1/8-scale buggy front white(firm)

Travel Limiters: no limiters

Length: 110mm (top of cap to bottom of rod end)

Location: Upper ? A (middle) Lower - #3 (3rd from inside)

 

Set-up: Rear Shocks

Note: Both the inboard and outboard shocks are set-up the same internally. Use the outboard shocks to quickly change shock oil for different track conditions.

Dampers: Traxxas Big Bore w/ Ti. Nitride shock shafts

Pistons: 2-hole (all-around)

Oil:

inboard - Team Associated 40wt.

outboard - Team Associated 50wt.

Springs:

inboard - Team Losi 1/10-scale truck rear blue(firm)

outboard - Kyosho 1/8-scale buggy front white(firm)

Travel Limiters: no limiters

Length: 110mm (top of cap to bottom of rod end)

Location: Upper ? A (middle) Lower - #3 (3rd from inside)

 

 

"Wheel Angles"

 

Camber

 

 

Camber is the angle of the wheels in relation to the surface when looking at the front or rear of the truck. If the tops of the wheels are pointing toward the inside of the chassis, then this is called negative camber. If the tops of the wheels are pointed outward then this is called positive camber, and of course if they are standing straight up, then it is set at 0-camber. Camber can easily be measured by using a "camber gauge" like the one shown here made by RPM. Check with your local hobby shop for price and availability.

 

The camber gauge (above) is set at -2.0 degrees. Adjust the upper, or lower pivot balls to achieve the desired angle. Remember to adjust the left and right sides to the same setting. Note: Toe settings will also be affected by the camber adjustment. After setting camber, double-check, and reset the toe angles to your desired settings.

Camber is measured in degrees. A good base starting point for camber is -1 to -2 degrees front and rear. Camber adjustments are made to change the contact patch of the tires in the corners. Typically, more negative camber equals more traction, to an extent. If you are looking for a little more bite in the front or the rear of the car then just dial in a little more negative camber. Be careful not to go too far. There is a window of adjustment from 0 degrees to about ?3.0 degrees of camber. Going further than that will decrease the contact patch, and traction will be lost in the corners. This is a finely tuned adjustment that should only be made no more than one degree at a time. Positive camber is never used.

 

 

Caster

 

This graphic shows the three different caster settings. The truck comes preset to 7 degrees from the factory. This is good for most applications. (click pic for larger view)

Caster is the angle of the axis that the front hub carriers pivot on when looking at the chassis from the side. More positive caster will allow the wheels to lay back a little more when they are turned one way or the other. Typically, a greater caster angle will provide more steering coming out of the corners.

To adjust front caster you simply move the caster spacers that are located on the upper suspension pin next to the upper suspension arms. By placing the spacers to the rear of the arm you are adding more caster, and you should get more steering from the truck. By placing the spacers toward the front you will reduce caster, and this will take some steering out of the truck. This setting usually makes the truck a little more driveable, and less sensitive out of the corners.

I normally run with 10 degrees of caster (arms all the way back) for better steering through the corners.

 

Toe-in / out

Toe angle is the angle that the front and rear wheels are positioned at when looking at the vehicle from above. As an easy reference, think of it as looking down at your feet. If your toes were pointing outward, then you would call that "toe-out?. If your toes were pointing inward (toward each) other, then you would call that ?toe-in?.

 

Front Toe Angle

The front wheels are normally set with 0 degrees (straight) of toe. Toe-out will give the truck more ?instant? steering. Toe-in will make the truck feel a little more stable with less ?instant? steering. The window of adjustment is from 1.0 degree of toe-in to 1.5 degrees of toe-out. I typically adjust my front toe setting from 0.5 to 1.0 degrees of toe-out.

 

Rear Toe Angle

Rear toe angle is a very important setting. This, next to the tires, is the main factor that dictates how much traction and control you have over the vehicle on and off throttle. More toe-in dialed into the rear will make the truck more stable, and will give the truck more rear traction. Do not go too far with this, or you will lose steering and response, forcing you to over-work the truck in the turns to hold a tight line. Toe-out in the rear will basically render your truck undrivable with over-steer. Toe-out should never be used. For high-bite conditions, I set the rear toe-in at 0.5 to 1.0 degrees. For loose conditions, I’ll adjust it up to 2.0 to 2.5 degrees of toe-in.

Setting Toe Angle
You can use a camber gauge to measure toe angle. Position the centerline of the chassis perpendicular with the edge of the table, and place the bottom of the camber gauge flat against the edge of the table. Set the camber gauge to the desired angle setting, then adjust the toe link until the wheel angle meets that setting.

 

"Suspension Upgrades"

 

Traxxas Big Bore shocks, 8-pack (part# 4962) -- When set-up correctly, these are some of the smoothest shocks available for your Maxx truck. Traxxas Big Bore shocks should be one of the first items purchased when building a race-ready Maxx. The bodies are hard-anodized for maximum durability, and PTFE-coated for smooth action. The 8-pack of Big Bore shocks now come built with titanium-nitride coated shock shafts. These shock shafts are very smooth and are virtually unbreakable.

 

 

 

Team Losi 1/10-scale 2.5" springs (truck-rear) Blue
(part# A-5160), and Kyosho 1/8-scale 2.75" springs (buggy-front) White
(part# IFW032W) (2-pr. of each) -- These springs are firmer than the standard T-Maxx (red) springs, and they are very close to being the same rate to each other. The reason that I went with the shorter (2.5") Team Losi Blue springs instead of running the (2.75") Kyosho springs on all eight shocks was to achieve a lower ride height that I wanted for the truck without having to cut the larger Kyosho springs.

 

Traxxas Aluminum pivot balls, 4-pack (part# 4933X) -- Like the shocks, these hi-performance pivot balls are hard-anodized and PTFE-coated. Steering response and suspension performance is noticeably improved due to the slick PTFE coating. The T-Maxx uses a total of eight pivot balls, which will add up to 1.2oz. of weight saved when switching to the aluminum ones.

 

Traxxas Titanium hinge pins (part# 4939R) -- Titanium hinge pins are considerably stronger than steel and weigh 50% less than the stock screws pins. There are a total of eight hinge pins that mount the suspension arms to the bulkheads. Replacing the heavier steel units with the super-lightweight, yet stronger titanium ones is a big step towards building a lighter race Maxx.

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