Originally Posted by Cain

need some advice on gearing. I am planning to use either a 8.5 motor or 10.5 motor.

Anything you guys recommend for starting point?

will be using Avid slipper setup, have a wide range of spurs.

Originally Posted by Cain

need some advice on gearing. I am planning to use either a 8.5 motor or 10.5 motor.

Anything you guys recommend for starting point?

will be using Avid slipper setup, have a wide range of spurs.

Originally Posted by Cain

Thanks!

The track is very small, so a bigger spur may be the ticket.

the only thing that really sucks with this avid setup other than the durability of the included spur gear cover is that it seems to slip alot during assembly. A real pain to get it seated. Once its seated thought its great. Its like you need to get it threaded to a certain point before it "sticks" if that makes sense.

Right now I got 76 tooth on there.

Originally Posted by Dino_D

I run the avid on the mid motor car I have. The cover is more protected in MM config and less likely to crack. Also I run 1 Red pad in the middle with 2 whites using a 8.5T

For rear motor (RM) I run the Exotek metal gear cover with AE B4 slipper pads. The gear cover is bullet proof, and also on my truck.

Originally Posted by fredswain

I've always found "rear grip" to be a misnomer. Most people interpret it to mean forward grip. However another important aspect of rear grip is rear end grip under braking going into a corner. This is side grip. MM in general has less side grip due to less weight on the rear wheels which is most noticeable on lower grip surfaces. Due to less weight on the wheels, the artificial weight transfer of MM4 helps with forward grip during acceleration. That much is true. Keep in mind that I add weight to the rear half of the buggy to account for a static weight redistribution from going to MM. The difference is that the weight is not way behind the rear wheels anymore.

Think about artificial weight transfer this way. Let's make up some numbers first of all. Let's say our buggy weighs 4 lbs. Let's also say that 60% of that weight is on the rear wheels in MM. That's 2.4 lbs on the rear end. Lets say that in rear motor there's 70% weight on the rear wheels. That's 2.8 lbs on the wheels. You can already see a .4 lb difference. Most people run RM3 which opposes an artificial weight transfer from the motor. Most people also run 3° rear kick which also further reduces weight transfer to the rear.

In MM4, the motor rotation assists in shifting weight bias to the rear. It does this by taking it away from the front. MM4 cars have been known to wheelie even on tracks that RM cars don't. If it wheelies, that's 4 lbs of weight on the rear wheels so good forward grip. However that's also 0 weight on the front wheels which is useless for on power cornering. You've got to baby it. To compensate people run rear kick and add weight up front. That certainly helps but doesn't change the fact that under hard braking during turn in, weight is shifted forwards which is less side grip on the rear. That's why many MM cars spin out easier going into looser track corners than RM cars do.

You may be saying that MM3 isn't going to do any better going into a corner. That's true but only if you leave the weight distribution the same. I add some weight. I just don't add it up front. I add it in back. I increase the weight on drive wheels. I also run no rear kick which also helps a bit with rear weight transfer under acceleration. I may not get 4 lbs of weight on the wheels under hard acceleration but if you don't need that much, why have it? The added weight on my rear wheels is also an aid in corner turn in off power. When I get on the throttle, I keep more grip on the wheels that steer.

Have I ever run MM4? Yes. We had one track layout that had berms for corners that you had to ride like a skateboard and no sweeping corners. That was a point and shoot layout. MM4 worked better there. Then again RM3 worked better yet since it was more controllable. If I can't make MM3 work, I'll go back to RM3. I don't ever like the motor rotating in the same direction as the wheels. It's much more twitchy to drive.

If you just run MM3 on a low grip track but you don't take the time to pay attention to weight or a balanced spring setup, you will be disappointed. Most people don't, and are.

Originally Posted by Wanderer77

@keepitsteel - I stole an idea from someone else many pages ago in this thread and am using lead sinker fishing weights tucked against the very rear of the car. They are attached via long screws that come up through the rear of the gear box. I would take a pic and post it, but I just changed my diff oil weight last night and haven't rebuilt the back of my car yet. Am planning on racing tomorrow night, so I will post a few pics in the next few days. If you google dex210 rear weight, you'll also find a spiffy brass weight available. My lead weights are ~10g each, for 21g total. The brass weight is 50g.