Team Losi XXXT Forum v2.0

[cancruiser]

Thanks for the feedback. I'll tear into it tonight after work and check out the Thrust bearing assembly.

[cancruiser]

It's getting annoying!

I replaced the diff adjusting screw, nut, thrust bearing and the 8 bevelled washers and the diff gear itself as you can see from the pic, the bearings melted into the diff gear and pushed to the outer edge of the gear.

I put it all back together, tightened to what the book says and took it out. two to three minutes later it was loose again.

Help!!

http://dufferinrc.scrc209.com/images/diff.JPG

[GSMnow]

Your slipper clutch seems to have not been slipping. It also seems the diff may not have been seated well enough. The only thing that will get the balls hot enough to melt the gear is the balls slipping on the rings. Since you have the belville washer design, the adjustment is far more critical. You only have about 1 turn of the screw from way too loose to locked down.

According to a Losi tech, you really need to work up to the setting. The diff balls need to make a groove into the rings. A perfct ball pn a flat surface has only a microscopic point of contact. As the groove forms in the rings, this turns into a line contact which will hole much more torque and last far longer. But you need to run a minute, check it, run a minute, check it, etc. After about 15 to 20 minutes of driving, it should start to take a set. Even in this break in phase, you never want the balls to slip between the rings. Loosen the slipper so it really slips, and slowly tighten it as the diff can take it.

I am willing to bet you recently upgraded to a brushless system??

[cancruiser]

Thanks for the feedback. It does seem to be a tough match up to get it to work right.

No, not a brushless....just a 12 turn for now. It's plenty fast enough. Maybe I should go back to the 19 turn and see what happens. Maybe this old school setup is too much for this motor.....

[GSMnow]

You may need to replace the slipper pads, and/or plates. I had trouble with the yellow pads grabbing into the plates and locking it up. I have never seen anyone have that much diff trouble with a brush motor, you must have some really strong batteries.

[cancruiser]

I am running IB3800 and 3700's. They are still really good and take a good charge. I will see what I can do with the slipper pads....although they are relatively new too.

[buckettim]

Gearing question

I'm running a Novak GTB/SS13.5 on the Novak sight it states that I should be running a final drive of 8.5 FDR so with a 86 spur that would be a 24 pinion gear.. what if any recommendations do you guys have? The track I will be running on is tight track so I was thinking of trying 22 to 24 and see were I'm running as far as heat, I'm also using A123 batts I have a MF2, just curious if anyone has any ideas I've been away from the hobby for 1.5 years so I'm a little rusty when it comes to gearing

[GSMnow]

The SS13.5 Pro is a 3300 KV motor. Are you running just 2S A123? If so, you are at just 6.6 volts, not the 7.2 or 7.4 of NiMh or LiPo. This will change it a bit. What ever voltage you have, take off 5% or so for realistic loading. And then figure your rpm to go about 28 mph for starters with a 13.5 turn.

28 is about 41 feet per second. The tires are close to 1 foot per rev. So 41 rps, or (41 x 60) 2460 wheel rpm. X 2.55 (MF2 trans ratio) = 6273 rpm at the spur gear.

Using 7.4 x .95 = 7 volts x 3300 = 23100 rpm at the motor.
23100 / 6273 = 3.68 pinion to spur
86 / 3.68 = 23.3 tooth pinion. So a 23 is a good start. With the 6.6 2S A123 pack, you need a 26 tooth for the same speed, but it will pull more current, and may run a little hotter. As always, check your temps.

[buckettim]

Thank for the response I am running the A123 cells and I will start off with a 24 and check the temps and see how it feels at the track, and will move to a 25 if needed and I'll be checking my temps, I don't think I'll go higher than a 25 I might drop my spur gear if needed

[929rog]

Thanks for the feedback. It does seem to be a tough match up to get it to work right.

No, not a brushless....just a 12 turn for now. It's plenty fast enough. Maybe I should go back to the 19 turn and see what happens. Maybe this old school setup is too much for this motor.....

Not even close to too much motor. I don't really race and got tired of the ball diffs so I put in a locker from a speed t. It works fine for running around and its tough and no maintenance. Last night I installed a gear diff out of a desert truck. Looks like a really nice piece and its very smooth. The diff housing is diffferent and is very tight in the rear shock tower. I took a small file and barely took off any material and its in. I think the whole set up was around $24... I hate to think about how much I've spent on ball diff stuff. We'll see how it works when I get out today. Wondering how its going to hold up with the 7700 lipo.

[929rog]

Got home and ran three lipo packs through the truck with the gear diff. Beat the hell out of it and so far it has held up awesome.. In fact it works waaaay better than the ball diff. You have to run a ball diff so tight with big power, this diff when you spin the tires you would not think it would even work it spins so free. Handles so much better than the ball diff in my opinion. Real test tomorow, going to the sand pit with paddle tires. That usually would kill a ball diff in no time. Time will tell if it will hold up but if I had a brushed motor I bet it would last a very long time.

[got2bqik]

I have looked at in the past and wondered about these wheels. It states on the wheel graphite and hard anondized? This is a plastic wheel or is it graphite? and how do you anondize plastic or graphite that is process for aluminium and other alloys. The big question is are they any truer than stock plastic?
Tim

[929rog]

got a ton of packs on my xxxt with the desert truck gear diff in it with no problems. I'm sold, works awesome and its very tough.

[dogger315]

Hi everyone, new guy here. I need some help updating a XXX-T MF I put together back in '04. I assembled the car with good components at the time, then, due to other commitments, never got to race it.

Current setup includes: Novak GT7 ESC, Novak XXtra 75mhz rcvr, Trinity motor (several diferent winds), Trinity 3300 matched team spec batteries, HiTec digital servo,
titanium suspension pieces and hardware.

I know most of the components are obsolete so what type of brushless motor/speed controller, batteries, servos, etc. do you recommend for ROAR sanctioned racing today?

Any help is appreciated.

dogger

[GSMnow]

I have not driven it myselkf, but I am very close to ordering a Losi excelorin sensored system. Specifically, their 13.5 for running in the new Super Stock (ex 19 turn) class. On our local track (Hot Rod Hobbies, home of the 2008 ROAR Nats) the fastest trucks tend to be the Super Stocks because you just can't put down mod power reliably on the tighter courses. A true master driver like Jesse Robbers does a great job, but even he was just one lap faster in mod vs Super Stock. I tried running my Mamba Max 5700 (not Roar legal) in my XXX-T MF2 and it was just frustrating to be the fastest thing out of corners and down the straight, only to be eaten alive in the tight infield or back flipping half way down the straight when the front tires lift off from the torque. The Sensored systems did seem a little smoother on track, and the 6.5's didn't have enough power to back flip, they could just mash it on the straight, I could not. One guy drove mine and said "This is like driving a Viper on ice!" With 2WD, don't try to run anything less than a 5.5, I would personally opt for the L series motors for mod. I moved my Mamba Max to a XXX-4 and now I can use all of the power, which is why I am looking into the 13.5 setup for the truck.

[dogger315]

Thanks for the input. How does the Xcelorin 6.5 system compare with a Novak GTB/Velociti 6.5? I was thinking of going with Losi or maybe a Novak
5.5. The dirt here is loamy with high traction compared to the blue groove I raced on in NorCal so I could probably use the power from a 5.5.

Next I have to upgrade my batteries. My 3300s are woefully out of date so I was thinking about some 4600s if I stick with Nimh or switch to LiPo which
means buying another charger.

I also noticed Losi has included an motor cooling fan mount on the CR. I know these brushless motors can run hot, so does anyone actually use
a cooling fan?

So many questions. I have a lot to learn to get back up to speed.

Thanks again.

dogger

[929rog]

Guys, I enjoy reading this daily and have really learned alot here. I've had my XXXT RTR2 (NOTHING RTR left) for over a year now and went to my first race last week. Not too bad, ran 2nd, 2nd, and 3rd in the main. I changed a bunch of stuff on my truck and now I'm a little confused. The track... pretty loose on top, goes from wet to dry pretty quick. Two big jumps, you can get 3 feet+ of air with a flat landing. One set of triples if I hit right I can tripple it. 1/8 scales run the track and dig it up some.

Seems everyone hits the big jumps pretty hard as one is near the end of the straight and one is in the middle. Problem... Practicing the thing would slam HARD. I tried to slow down, keep it low then nail it but seemed to be faster to just nail the jump. The truck would bottom out VERY hard and upset it. I was running red springs up front 37.5 oil, yellow in back 37.5 middle hole on the bottom arms front and rear. Front tower and rear second from inside hole.

Sooo... I decided to stiffen it up. Changed to 50 oil, blue springs front, yellow rear. Same holes on the arms, moved front to inside.. reaer second to outside. Added (you guys are probably going to flip on this one) small pieces of real soft vacuume hose about 1/4 long, the top cut at an angle at the top on the bottom of the shock shafts. The angle makes it progessive. It just starts to stiffen a little as it bottoms on the chassis.

It handled the jumps alot better but other problems came up. It became rear loose out of turns and I had to be pretty carefull. I had to wait on it quite a bit. I'd actually like just a little push.. it turns pretty quick.

To handle the jumps I'd like to go a little stiffer, maybe 60w oil. I'm thinking though at some point here its going to start bouncing around and loose traction.

Am I way too stiff? Should I soften it up and keep working on rolling the big jumps? Or, should I go stiffer? What should I change to get it not so loose.

Truck had brand new proline lugnut T on the rear and Losi ribs on the front. 4800 Excelorin, 2s lipo. Truck set level toe and camber set to xxxt set up specs.

The guy that won's XXXT looked like it was on rails.. I crashed some because of being loose. Any help on what direction I should go would be appreciated!! Thanks guys.

[GSMnow]

It does sound like you are too stiff, especially in the rear. I use Green springs up front and Pink springs out back. I think my final setup is 37.5 oil all around, but I have changed it a few times. I tried as high as 45, but it was just too bouncy. I found it better to just let the chassis slap a bit on the big jumps.

To get it to push you need it a bit stiffer in front and softer in the rear. I actually went to just a front sway bar to get the desired balance (some push). The Losi front sway ber setup sucks. It uses a plastic plate in place of the aluminum across the front arm pins. Instead, I am using a slightly modified rear sway bar package on the front. I bent a small "V" on the bar to narrow it as needed. The mounts bolt flat onto the shock tower. I then used ball studs in the holes on the a-arms.

The other thing that helped quite a bit was to install slightly longer dropp limiters inside the front shocks. This way I could run less pre-load on the springs and they would still stay under tension, and in very tight turns, it will lift the inside front and pushed a tick instead of looping.

The surface here is pretty well groomed, but we are in hot So Cal so it does dry out very fast, and can get quite dusty between wet downs, so we have extreme changing conditions. I found the best tire to be Pro Line Hole Shot T's, get the R3 compound if you can find them (They may not be made any more). M3's have great grip, but only last 3 packs or so. M2 lasts a litle longer, but the R3 just seems like a better compromise between grip and life. For the front, I like eith the Losi Directionals, or Pro Line EDGE tires. Both work well, and the harder compounds will last longer and give some push. I also stumbled on a ribbed directional style front tire from Panther that I like. I forgot the name. They are a little smaller in Dia. so it gave a little more tuning room with front ride height.

For power I was using a Mamba Max 5700 system on 2S LiPo. It should be pretty close to your system. Speed is never an issue, but pulling a wheelie half way down the straight is. Careful setup of the slipper does help. I also found that switching to an Associated T4 spur gear and slipper pads holds a more consistent setting than the Losi slipper gear.

Your mileage may vary. Only change one thing at a time. See what it does, and if it hurts, go back.

[929rog]

So I'll try softening up the rear and going back to thinner oil. How about ride height? Mine's same height front and rear...

[929rog]

I'm not familiar with the drop limiters... Do you have a part number?

[GSMnow]

For ride height I have the rear dog bones level and the chassis level front to rear.

The MF2 kit I have came with droop limiters about 0.1 inch long. They are just little plastic tubes you put on the shock shafts betwee the cartridge and piston. I made my own a little over 1/8 inch long 0.130 inch or so.

I have also messed with bump limiters like you did with the tubing, but it didn't really seem to help much for me. I just found it better to let the chassis slap a little. We have had jumps that put us over 8 feet in the air, so it is going to slap, no option.

[929rog]

Thanks. I'll let you know how I make out. I already changed the shocks and springs around.

[GSMnow]

I just raced my XXX-T MF2 for the first time in over 6 months last night. I put a 19 turn brush motor in it to try it out, and boy do I miss having the Mamba Max power in it. I ran fairly old worn Losi Step Pins in the back and even more worn Pro Line EDGE tires up front. Grip was not great, but with the limited torque of the 19 turn, it held full trigger as long as it was close to straight. I was only a tick off the speed of the front runners on the straight, so I think my gearing was close. When I got alone on the track, I did turn laps within 1 sec of the top lap times for a 19 turn truck. The 13.5 brushless guys blew us away in the tight infield where torque rules. I tried a smaller pinion, and it was much better in the infield, but then I got left behind big time on the straight. It was able to clear all of the doubles, and cornering balance was good, but overall cornering grip was down with my worn tires. Switching classes from the 4WD to the truck was a bit too big of an adjustment. I found myself going in way too deep in the truck, and then slowing too much in the 4WD. I think I will have to stick to a single class when there is only 6 heats total. I was driving or working course for 4 heats, only 2 heats to work on the cars and take a rest. I did finish both mains, but my times were way off from my normal. After over 2 months without racing and first time out on the new course, and first time trying 2 classes, I bit off too much.

[929rog]

ran mine today. I ended up going down to 37.5 oil.. much better. The problem I had was the Losi system. The card just does not adjust enough. I ordered the programming disc over a week ago and it did not come in. Way to abrupt out of the corners and made it want to spin. Not bad though, got second in the A really having to be carefull and spending plenty of time on the roof. I wish I had my Mamba ESC back... Two more weeks.

[929rog]

GSM... thanks for the help

[GSMnow]

929rog
Yu are now the second person I have seen report that the Losi sensorless systems are just rough and abrupt at startup. The Mamba Max might not be the total smooth silk of a sensored, but I have yet to see any other sensorless even come close. I have totally beat the snot out of my poor Mamba Max 5700 system, and it just keeps going. I tore the end bell out of the motor, drilled new mounting holes to bolt it together, ripped wires off of the ESC, and dragged it in the dirt for more than a lap, and after all that, it still out pulls the nitros.

I need to get another brushless system for my truck. Since the Mamba Max went into my 4WD, I only have the one race day on it. Running it with a brushed 19 turn just plain sucks. Thought it was easy to control amd handled very well.

[Needler56]

gsm, do you know what size fan you're supposed to use for the motor fan mount?

[929rog]

I called Horizon today on the excelorin and they said something is definately wrong. When I get my Mamba back I'll send it in. Are you talking about the fan you put on the ESC? I have a small Novak on mine.

[Needler56]

no, there's a fan mount for the motor, it's this thing: http://images.amainhobbies.com/images/small/losa4151.jpg

[GSMnow]

I made my own fan mout to hold a 25 mm square fan. I saw the mount on the CR's and it looks the same size. I think any 25 mm square fane should fit without a problem. I found a few surplus ones at All Electronics. They have a web site, but they usually have even more stuff on the shelves. Their stock is always changing.

[929rog]

I have one in my box, It is a Losi piece off a speed t or CR I believe. It was cheap just check out the part manuals on the losi site and you'll find it.

[fritzzz]

Hi There,
One of my kids drove my stock XXX-T into a curb and the chassis broke up the front in the normal spot.

I want to just get the standard length chassis as I don't want to replace the body, so two Q's:-

(1) does anyone make a stronger chassis or should I just get another one like the one that was on it

(2) does anyone make a brace bar that could span the weak area on top of the chassis? Anything to strengthen the area would be great.

Thanks

[929rog]

You won't need a new body with the CR chassis. Just move the holes. Other than that try not to hit curbs.

[fritzzz]

What's the difference with the CR chassis (apart from the length)?
- different design?
- different material?
- stronger?

Our kids are 6 and 4 and so far they've done pretty well - they were mortified when they did it!

[fritzzz]

Bump:-)

[GSMnow]

The CR chassis is made from the new EA3 material. It is almost as strong and stiff as the graphite on my MF2, but it will flex before it cracks, unlike the graphite. I will switch to the CR chassis, if mine gets any more messed up. I have 2 minor cracks now, but they are not effecting driving it. I braced the areas by CA gluing a carbon firbe piece across the cracks. The 1/4 inch more length is barely noticeable, we swapped bodies without even moving the holes, but you can tell they are off.

[dukefan99]

hey i need help when igot to goldsboro i took out my mini-t put batteries in it
and it wouldnt go do you have soulotion for me

[lscrisp]

I have been racing my stock Slash for a while, but recently bought a used XXX-T and need to find a comptetitive motor to race with.

It's gonna be an indoor carpet racer, but might be converted to indoor dirt when our local track gets finished.

For now, I'd like to get something to be competitive on the indoor carpet track.

I'm looking at a Mamba Max Pro esc, and maybe a Tekin Redline 10.5T, but I'm a bit confused over the numbers on the motors. Would a 10.5T be too much or not enough motor to be cometitive? (I'm not sure if the lower the numbers, the faster the truck would be, or the other way around)

I've seen some trucks that the drivers seem to have a hard time keeping the front wheels on the ground with and they just seem to be handful to drive, I don't need that much torque. I've also seen some that seem to be really fast, once they get up and moving, but have no low end grunt to get them off the line very quickly.

Or, if anyone likes a particular brand or system better than another, let me know what you like and why it's good.

Any help is surely appreciated.

Thanks!!!

[GSMnow]

There are many options when it comes to a motor and ESC for this truck. I have run mine with a Mamba Max 5700 system and a Losi Exelorin 13.5 setup. Huge difference there.

To answer your question we need to know a few things about the track and the rules. First off, do they have spec classes? Many tracks have a Stock and a Super Stock class that have specific motor limits. With a XXX-T, I highly recomend running in the 13.5 Super Stock class as that is about as much power as the chassis can take without becoming a huge handful on all but the best large tracks. A truly great driver did turn some silly fast laps with my Mamba Max, but even he was not very consistent. The power made it very hard to place coming out of turns. When I went to about 1.3 the power with the 13.5, my lap times averaged about the same. Sure I had the rare faster one with the insane mod power, but I could not hold on to it for a whole race. The Losi Excelorin is a nice system, but it is lacking in power to some of the other class legal 13.5 systems. I just could not hang with the main pack in a big race. The Mamba Max Pro is an EXCELLENT choice for an ESC. it will make more power out of a spec class sensored motor than any other ESC. I ran my Losi 13.5 motor on my old Mamba Max and the power was great, but it just could not start worth a crap without the sensors. THe MM Pro has the sensor port just for starting those things. It was hard to believe it was the same motor and that just an ESC could bring out so much more power. It was still very controllable without the silly wheelies all over, but it had so much more authority down the straight and seemed to actually runa tick cooler while going faster. I will be changing both my cars (XXX-T and XXX-4) over the the MM Pro ESC's as money allows. The "spec" motors are very close in performance. All the 13.5's will do okay, but I have to admit, the Murf Dogg ones sure have more kick on a normal ESC like a Novak. I have not had a chance to try one on a MM Pro or my Loisi ESC for that matter, but when a 17.5 stock buggie out ran my 13.5 Super Stock truck on both acceleration and top end, I knew there was something different about those motors. Murf does not charge much more than a normal spec motor at the hobby shop, but you do get more.

If your track does not run spec classes, and it is an anything goes affair, you have a tougher choice. Everyone wants as much power as they can get, but you do need to keep reality in the equation. As much as I love flinging my truck with the Mamba Max 5700, it is way too much motor. The 4600 is a much tamer beast while still able to out run any normal sensored system out there. If you need more delicate control for a tight track, stick with the Mamba Max Pro ESC and go with a lower turn sensored motor. I was thinking about a 7.5 turn for my driving skill and the track at Hot Rod Hobbies. A bigger track might handle down to a 6.5 or 5.5 if you have the grip to use it and the reaction time to drive it. The 10.5 is a lame duck motor. Very few tracks have a class for it, which is why they are cheaper now. It was going to be the replacement for the 19 turn brushed motors, but it proved too powerful, so they went down to the 13.5 in that class, now called Super Stock. If your track is tight, the 10.5 may prove to be a great choice for excellent delicate control coming out of tight corners etc. At my local track though, I would have to run it right up against the open class mods, and it just is not quite enough on this track.

Whichever motor you end up going with, you want to gear it so you can hit full trigger and hold it for a bit on the longest straight. If the truck does not top out before the end fo the strtaight, gear it a bit slower and try again. It if winds out and is at topo speed befor 3/4 down the long straight, then gear it up a little but be carfeul if the track has some very tight stuff, you may have to trade a little top end to keep the motor temp in check. As always with electric and great batteries, let your motor temp be your main gearing guide. If the motor is over 185F at the end of a 5 min run, then you need to gear it slower. In that temp range, the heat will start to demagnatize the Neo rotor making the motor become less efficient, which makes it run hotter the next time. The cycle justs gets worse and worse once a motor has been cooked. As long as you catch it soon enough, most motor makers do sell the rotor separate, so as long as you stop before the windings smoke, you can usually save them. Brushless is great, they will run forever with little care. Knock off the dirt, oil the bearings and don't fry it with over gearing. Brushes are dead

[lscrisp]

Well I finally got a motor for my XXXT, I went with a 17.5T Novak Ballistic and a Mamba Max Pro esc, but am having a problem with the diff.

I bought the truck used and disassembled the diff to clean the old grease out and check it over. I reassembled it and the center gear (the plastic one) melted after a few minutes of running. I replaced it and went through the instructions and put it together exactly like it said and it lasted a couple of trips around the track, only to melt the gear again.

In the instructions it says that the wheels should be "very difficult" to turn when one is held. I tightened the screw until the diff was basically locked and the tires would barely turn when one was held. To me, that didn't seem right, as that would defeat the purpose of the diff, but I did it anyway.

The only part that I did not replace was the spring that the long adjuster screw goes through.

If the diff gear melts where the carbide balls sit, is that a sign that the diff is too tight or too loose? Could the spring be worn out that adjusts the tension on the diff?

Thanks

[st_dragn_wagen]

my experience with melted dif gears is that its to loose. mine happened because of overly worn out parts.
here's what id do. try rebuilding the dif with new internals (cause if its melted im betting parts even if new are now worn) build everything as per the instructions. drive the car around easily for a few minutes and and let work itself in and then readjust the diff. then loosed up the slipper clutch. you might just be putting to much power through the diff and causing it to slip when its not supposed to. the clutch needs to soak up and dissipate that energy before it hits the dif and causes it to slip. dif's are mint to spin not slip. id bet money that most ball dif problems out there are caused by improperly adjusted slipper clutches

[GSMnow]

A melted diff gear is caused by the diff balls slipping on the rings. In most cases it is just too loose, or the slipper is locked too tight and the truck got bound up or something.

When a diff is built with fresh rings and balls, there is a break in procedure that you need to do if you want it to live a long time. I also have not had the best luck using the Losi diff lube, the Associated lube seems to work much better. They look and feel almost the same, but for some reason, the Associated stuff just gives a smoother longer lasting diff.

Once you have the diff assembled correctly, all the springs and shims in the correct places etc., you need to start with it set fairly tight, but not locked. Run the motor with the wheels in the air but holding one tire still. Roll on the power smooth and let it run for a minute or so. Then hold the other tire and run it again. After doing this, check the diff screw and you will likely find it has loosened quite a bit. Dial it back in tight. Turning one tire should feel smooth, if it is gritty, the diff is not right. With some brushless motors, you may need to hold the spur gear to make the diff turn side to side, that is fine. Also with the rear tires on a smooth surface, you should be able to lift the nose off the ground and move it side to side with the tires just rolling in opposite directions. If the tires slide on the surface, you are probably too tight. Now that you tightened it up a bit, it is time to drive, but still easy on the throttle. Drive in tight circles, slow enough so the tires don't spin or skid. Go one way for a minute and then the other way. I know this all sounds really boring, but if done right, the diff will last a good long time. After all the circles, adjust the diff one more time, it will probably take a half turn to tighten it back up.

What all this running at light load is doing is making a track in the ring for the ball to ride. If the ring and ball were both perfect and diamond hard, the contact would be a microscopic dot. The balls are very hard, the rings have a little give to them, this causes the ball to actually make a slot into the ring that now makes the ball have a much larger contact line. This greater contact will now hold much more torque at less pressure without slipping. It will still wear in a little for the first few packs, so it is a good idea to run it hard for just one minute, and check it. Tighten the diff to where it is still smooth side to side, but you feel a little drag. Do the test again with the rear tires n a table and move the nose side to side. As long as the tires are not sliding on the surface, you are not too tight. It is safer to err a little tight than loose, especially if you have a high power brushless motor. Now that the diff is working right, be sure the slipper clutch is not too tight. I did not like the Losi yellow slipper pads. I changed to an Associated spur gear and their white pads. They seem to hold a setting better when pushed hard. The Losi pads had to be set fairly loose to work at all, and then it would get hot and either slip too much and not pull out of turns, or if you started a little tighter, it would just plain lock when hot and you have no slipper and the diff get's beat up. If you hold the tires and pull the trigger, the slipper should do all the slipping. The slipper makes a smooth high pitched sound, if you hear a bark from the diff, it is too loose, or the slipper is just too tight.

I hope this helps. I have run a full race eason on my diff without even looking at it and I run a Mamba Max 5700 system that will pull wheelies down the straight if I get on it too quick. This diff can take it if built right and properly seated and set.

[SuburbnHooligan]

iv got an old XXXT (and i mean old. it was bought less than a year after the truck had been released). it needs front suspension arms. the instructions list part number A-1116 but im having trouble finding that part number at hobby shops. i did find it on horizonhobby.com but they want $5 for shipping and im not spending $5 to ship a $8 part.
what parts i have found at local tracks is part number A-1117. which is the arms off the current XXXT CR.
iv been told that there have been some minor suspension changes on the XXXT over the years which has me wondering will the A-1117 parts for the current XXXT CR work as a replacement on my old school standard XXXT?