Rig kit is a supposed MM coming about by merely inverting the rear end of the car to place the transmission in backwards and throwing the rear suspension assembly further back. If you look at the Schumacher KF, THAT is a purpose engineered and built MM vehicle. The 22, RB65, and every other similar kit, thought they might function ok, they're all rig kits.

X-ray is now producing a 2WD kit that is basically the XB4 with the front drivetrain removed. And while that's a rig kit of sorts, the base from which they are working is already a MM design so from inception, it's still a true MM vehicle.

The B5M was purposely intended as Associated's MM vehicle but they simply took what already existed and further refined it and are now producing it. If they had thrown out the ideology of the now traditional Rig Kit and designed something from scratch with a low slung drive train where the motor and electronics are better centered, I'm sure the car would have looked more the part.

Having said that, the B5M looks to be one of the better thought out "Rig Kit" designs to date and I'm sure it will perform quite well. I've heard from several people that of all the Rig Kits, the PRS1 is one of the best thus far, once the few weak points are addressed. For sure though, it'll be interesting to see how well the B5M compares to all of the MM cars.

Almost have all the funds for my RM B5. Can't wait.

We run outdoors at both my local tracks and the KF has been improving each week. It's thus far impressing the hell out of me and it's still one of the top MM contenders in my mind.

As for the Motor getting all bashed up, I TOTALLY AGREE!!!!!

My LRP and SP motors were both all nicked up and it sucks. So, on my new SP motor I got creating and since I have so much stuff in my garage, I remembered something I had in a drawer for a few years so I cut it up and used it to protect my new motor. I ran it hard yesterday for the first time and took some major spills and the motor looked flawless when the day was over.

This is what I used. i cut 2 discs in half and then placed it with the straight edge butted up to the end of the Motor's can on both ends and then for the section that resides at the very back and bottom I took a 3rd disc and cut the sides off to create a strip that would fit in between the pieces on the end, making sure not to cover any vent holes. Worked like a charm and I will be doing this to all my cars from now on.

http://www.homedepot.com/p/Shepherd-...971/202514361#


I'll try to remember to snap a few pics for you sometime this week.

Id like to share my opinion and experience about RM, MM and FM (front motor) chassis.

On any track with a certain layout and certain tyre, there will be an optimal weight balance for a 2wd vehicle that achieves the fastest lap time. For some tracks (eg low traction point and shoot or high traction flowing) the optimal weight bias will be quite clear. For some tracks (eg med traction) different weight bias will be faster in some sections but the overall lap time will be similar.

The different layouts all have a different 'natural' weight bias (ie without using ballast weights). For RM its about 33%, for MM about 37%, for FM about 40%. You can add ballast to change the weight balance, but as you are generally adding a large amount of ballast to one end you will also dramatically increase the yaw inertia of the car. Generally the lowest yaw inertia will give the most responsive feeling vehicle.

So depending on your track, there will be an optimal layout that gives the best performance with minimal ballast. To say a MM is a 'rig kit' (ie cobbled together compromise) is a little unfair as in many conditions they are clearly fast. The FM cars are very quick on high traction tracks but in low traction they suffer a lot with poor forward traction. RM cars are great on low traction but become evil on high traction. If anything the MM are the most versatile right now as they are great on medium tracks and can be made to work on high and low traction.

You will read people say that they can make 'this chassis work on a low traction surface' etc but without doing true back-back comparisons its hard to read too much into this on rctech. And what some think is low traction is very different to what others think is low traction!

Most 'big' events are on med to high traction dirt nowadays so the MM cars are very popular now. if AE had come out with an FM car it would have been a big risk. The Team C style (inline motor with shorty) looks interesting but isnt legal for ROAR so there is no way they would release that and alienate the market. However with the way the Euro market is headed (with FM) I wouldnt be surprised to see either AE or Centro make a FM conversion at some stage.

Anyway not wanting to argue, just sharing my thoughts.

Ray

W3 has plenty of traction if you run the tire of choice (Ions or Beams) but I would still not consider it a high traction clay/sugar track which is what the mid motor was designed for. There are people trying to get them to work in 17.5 it's just too heavy and the rear motor is dialed. I don't see any reason to convert other than trying to follow the newest trend

If I was running mod where the weight was not such an issue I might try it but 17.5 is plenty for me

What tuning can i do to get more air on a jump but not go further because currently there is a jump at our track and I feel the lip isn't steep enough. Every time I go off it I have to go pretty fast where I cant downside the jump or I don't clear it.

A few options. Read this
http://users.telenet.be/elvo/15/1.html

Thankyou, I think it is my springs because they are the softest one brown front and black rear. I see most setup sheets have white rear and green/black front

My centro is at 1500 grams ready to run with body and tires and transponder. I am not heavy at all for 17.5 racing. 1499 is the minimum.

Springs. the stiffer the spring, the more lift off the jumps you get. Try green springs up front and white springs in rear. also, if you have little or no antisquat, put the 2* shim back in. Running little to no antisquat will hinder jumping as well.

I currently run a full size pack in my B4.2. I am going to buy new batteries soon and want to try a Shorty in my B4.2. What foam spacers do I need to get? I am thinking of buying a few foam spacers for a SC10 2WD. Where in the tray is a good place to start to place the Shorty? Do shock springs and oil need to be changed around as well?

It honestly depends on how it feels on the track and very track dependent. As for foams any stiff foam will work if you have it. If you don't there are a couple companies that make shorty specific foams. As for a starting point, I'd say shorty in the middle, and dont change suspension till you try it.

I cut the sc10 foams to fit, they are cheap.

Thanks Guys !

Hideeho
When I 1st went to the shorty I use 2 medium pads & a BUNCH of thin pads so I could play around with exactly where I wanted the lipo to sit. Once I found where I wanted it, I cut an sc10 pad in 2. This fits in, but doesn't hold a shorty tight. To tighten everything in the tray up I add in a thin pad. This also gives the benefit of an easy way to adjust the weight balance at a moments notice by moving the thin pad to the back or front. I run a t4 chassis, so the sc10 pad cut in half will be 7mm to long to be able to use the small pad the way I do. If you want to, you can cut a small part (7mm) off one of the pads to fit in the thin pad.

Where you end up setting the shorty is a matter of taste. If you have your electronics in the side pods (standard config), you will probably end up with the back of the shorty around the front of the "U" brace (I set mine about 5mm forward, t4 chassis ). If you end up with the electronics in line, you will probably end up with the lipo all the way, or close to it, forward (I put 1 thin pad in front).

Going to a shorty can be a good move if you are looking for a quicker responding car. If you are on low traction it can be a handful. My local track I would describe as low to medium traction. Several guys tried it & they all went back to stick packs because it was too twitchy. I stuck with it because of the t4 chassis. The longer chassis slowes everything down & makes it more stable. The lighter shorty pack adds back in some edgyness.

If you are switching to shorty, you should also think about putting the ESC in the back of the battery tray and run inline. The person I bought my 4.2 from had used a toe block to mod in a little wall to separate the tray into two sections. I run a 1/2" foam in the front of the battery tray. Then I added 7grams to each of the rear triangles. The buggy felt GREAT with that setup. Alternately you could run the ESC shelf, but that raises the center of gravity slightly.