Few questions from a noob

[kainedogg]

I have had my rc's sitting on the shelf for years (Army) and finally decided to get them fixed now that I am in Tampa and near a decent shop. I burnt up my T-Maxx and 4TEC running them way to lean. I went ahead and payed for a 3.3 conversion on my Maxx and it runs great except for a bit of chatter when it's taking off (why is that?) and it no longer tracks straight, I mean it is extremely twitchy so I can never get to WOT. Anyone know what could be causing this?

Secondly I have a Revo with the 2.5R motor and a dead 4-TEC. I was going to do the 3.3 program again, but put the 2.5R in the TEC(was told it's a better car engine than it is for the heavy Revo) and put the 3.3 in the Revo or just stick the 3.3 in the 4-tec.

As I get all my vehicles off the shelf and back in running order, I am sure I will have far more questions

 

[Zdragon71]

Check your throttle linkage on the tmaxx. Take the filter off and without cranking the truck turn all electrics on and move throttle linkage while looking into carb and see if its opening all the way. If not you can adjust the linkage collets to where it is getting wide open throttle. Or you may can just center the servo horn by removing the screw while power is on and centering the horn and replacing screw. As far as the revo and 4tech. I would run the 2.5R on the 4tech and go with a 3.3 on the revo. The 4tech should be plenty powerful with the 2.5R.

 

[kainedogg]

Thanks Z.

 

[Nitro4910]

If your maxx has the black cased trany & still has reverse then the bucking at takeoff is normal.

For tracking straight, make sure the servo trim is set right, check for bent steering parts, check that the steering centered when the servo is,
if not pull the servo arm center the servo & put the arm back on.

 

[JoeMAXX]

Tracking straight is often caused by the steering trim set to far from the left or right. Ok I am going to get a little tech now. For tracking strait I like to toe out my front tires at .5 deg toe out. This can be set by just 1/8 of an inch from the front and back of the tires to the chassis. The rear tires I toe them in 2.5 deg for more traction. I measure front side and inside of the tires to the chassis to the tires to make sure each side is set equal. Hudy makes a setup board or used to for TMaxx but I just use measurements to the chassis to get each side set equal. I set my suspension to level after dropping it on the ground for the best handling. Stock a TMaxx is set for High Suspension settings and I lay the shocks down so the suspension is level too the ground after dropping it from the air 2 inches off the ground to set the weight of the truck onto the suspension and it best setting for racing and handling corners.

You can download setup sheets from Traxxas and they can explain proper setup better then I can.

The older original TMaxx tranny will buck a little bit on take off when the engine is cold and in my experience will go away once the engine warms up than tuned in for the day.

 

[kainedogg]

Thanks Nitro and Joe. The truck is indeed an older 2.5 model. I think I saw a thread on here for centering the servo so that will be my task today. Without the board how would I calculate toe angle?

 

[Snook Man]

Eyeball it. Fronts 0 to a little toe out, rears 0 to a little toe in.

Toe and camber unless drastically off from the opposite wheel usually has little to do with a Tmaxx tracking straight.

Make sure the outer toe links are attached on the bottom side of the axle carrier steering arm or you will get major bump steer when you brake/apply throttle or hit a bump.

 

[tmaxxfreek]

If its been sitting a while, the not tracking straight could be a bearing trying to seize up in the front.

 

[Mn Monster]

also if it has been sitting for a while, you may have flat spots on your tires.

 

[JoeMAXX]

Thanks Nitro and Joe. The truck is indeed an older 2.5 model. I think I saw a thread on here for centering the servo so that will be my task today. Without the board how would I calculate toe angle?

There are areas on the chassis are about the same distance apart from the inside of the front and rear of the tires. The Front skid plate and the lower chassis I like to use a tape measure and on the front it is about 1/8 of an inch longer then the rear side of the tires to get to 0.5 degrees toe out on each side. Take measurements with your radio system on so it is always centered to the servo.

On the rear suspension same thing skid plate and chassis but to get to around 2.5 toe in the rear of the tires should be about 1/4 inch longer then the front side of the tires.

It is easy to lower your suspension settings too set it level with the ground. On the front set both the upper and lower suspension to the lowest settings. On the rear set the top shock setting to most inward setting and on the lower setting it is the third lowest setting. On the rear it has four settings and the bottom shocks should on the third setting from the chassis.

I like to have my tires set level to the ground and use 90 degree Angle for my front and rear tires. I have an inexpensive tool from RPM called a Chamber gauge. Any 90 degree angle tool will work. These settings are done on the ball joints on the suspension arms. On my older T Maxx I pack them with cotton balls to keep the dirt out. Squirt a little WD40 in there for lube then pack the hex setting with a Cotton ball. You will see on the newer Traxxas 3.3 T Maxx they have a seal.

Caster settings are another thing and it is done with spacers on the front suspension. I put both spacers to the rear end of the suspension arms this will help also with handling.

I upgraded my shocks long ago to the Traxxas Big Bore shocks and have two different spring rates on the suspension and run 40W oil in them and also bought a Tool to balance the shocks from Team Losi called a Shock matching tool so each shock has the same length but not needed unless you really want to have your suspension balanced.
Hope this helps

 

[JoeMAXX]

Eyeball it. Fronts 0 to a little toe out, rears 0 to a little toe in.

Toe and camber unless drastically off from the opposite wheel usually has little to do with a Tmaxx tracking straight.

Make sure the outer toe links are attached on the bottom side of the axle carrier steering arm or you will get major bump steer when you brake/apply throttle or hit a bump.

I never eye ball and always measure

 

[kainedogg]

Thanks guys, and I see you are quite committed Joe, your attention to detail...is astonishing. I might as well start refilling my r/c tool kit.

 

[JoeMAXX]

Thanks guys, and I see you are quite committed Joe, your attention to detail...is astonishing. I might as well start refilling my r/c tool kit.

Your welcome. I like to provide enough detail most of the time so you can setup your R/C in the best way possible. Did it quit bucking on take off?

 

[kainedogg]

Sorry Joe, I took it apart so not sure about the bucking part yet.