Really? Hard on the rear and soft in the front?

Please help. My front diff in my MRS4 is blown. I need a whole new diff not just the diff frame and I can't seem to find a complete diff anywhere. Does anyone have any idea where I can get me a whole new diff? Thanks

Forget it I found 'em.

As long as I've been running the mRS4, I hate asking this newbie question...

but what is the difference between these 2 chassis:

HPI Chassis Micro RS4 (PN 72332) (http://www3.towerhobbies.com/cgi-bin...?&I=LXAYS5&P=Z)

and this one:

HPI Chassis Type B Micro RS4 (PN 72333) (http://www3.towerhobbies.com/cgi-bin...?&I=LXNYL1&P=Z)

I've run either a Ratzas or ExoTech chassis for so long, I didn't even know HPI did another stock chassis

I need help and I hope someone here can help me out. I recently installed a Penguin 3500 LM chassis in my MRS4 and replaced the belt along with it. I'm running a ball diff in the rear w/ a stock diff in the front (until I can get my hands on a one-way), team orion micro modified motor, w/ a Novak spy esc and a Team Orion 1600 6 cell pack. My problem comes while running. The car runs fine for a few seconds then seems to bind up and freeze. When I pick it up and put it on the bench while its bound up the rear wheels will spin nice and free but the fronts seem to be locked up. I though it was the front diff so I pulled it apart and inspected it. The plastic gears seemed all right except for one tooth that seemed nicked. After reassembly the car rolled smooth as glass. Then once I put the motor back in and put power to it the same thing happened. I just placed an order for new gears and I hoping that will do it. Anyone have any other ideas? Plus does anyone know where I can get a front one way for this little guy. I need to get this thing running because all of the M18 and RC18 guys at my local track talk a lot of smack and I need to show them what my little HPI can do. Also is there a way to put some tension on the belt? I have the chassis set to 150 w/ a 150 belt but it is real loose and I think part of the problem is the belt slipping off of the front spool.

Did you check the rear-end of you car?? It kind of sounds like your rear is too tight...there should be some play (side-to-side) in the rear axel...this will help with the play in the car some...

also if you over tighten the rear wheels to tight, the car will bind - you need to tighten the rear wheels until they are snug against the inner hubs, not super tight...

I'd check there first, then move to the gear mesh...If that's too tight, you'll bind as well...you will need to adjust the gear mesh - there's all kinds of theories about the best way to set up gear mesh, so pick you favorite

I normally slide the pinion into the spur, then back it off so that I can freely rock the spur gear in the pinion - not super loose, just enough to rock a little...

try looking there and see what happens...

Looks to me like the "B" chassis was meant for the Drift version of the car, & according to the Tower listings, the "B" version is a couple of mm longer(180mm vs. 178mm) & uses thinner material(1.78mm thick for the "B" version vs. 2mm for the original), so the "B" version might make the car a tick longer(but not sure on that) & should flex more than the original....

I've checked the rear of the car and it seems fine. When the car is binding it's the fronts that seem to be stuck because the back spins freely. I also noticed that the belt seems to come off of the front pulley when its bound up. I'm thinking that could be the problem also which leads me to the question of tightening up the belt. The chassis is set at 150 and its a 150 belt but it seems real loose and I have no idea how to tighten it.

I got a Micro RS4 with the Exotek EXO-150 chassis. Everything is running great but I get traction roll once in a while when I make a hard right (hairpin turn). I'm running soft tires in the rear and I think hard in the front. Any suggestions on eliminating the traction roll?

Comparing Team Orion's Big Block to the Micro Modified, which one is fast or better overall? Any other motor suggestion without going to brushless?

Hey Kbo,

Like Grizz said, the type "B" chassis came with the drift version cars... it also came with the ARR cars (assembled but no electronics... exc motor). Its the same lenght as the original and can be ran 140mm or 150mm.

Without them here in front of me... one could be thicker than the other. Difference I can see is the cutout has a different shape. One is longer front to back and norrower. The other is shorter and fatter. So basically the rear frame rails are wider on one.

I've ran them both... and can't say I notice any difference.

One thing I noticed on replacements is... on the original "versions" the screw holes arn't counter sunk enough... and the screws stick out. The type "B", they are fine.

the binding will happen if the belt slips off the front pulley, to fix that i bought the alloy pulley for the front,. also on the old 1:18th.com site some guy made a mod for a belt tenisoner, but the site is gone so i doubt you would ever find it. CHECK yourmicro.com go to the micro rs4 mods section might be sumtin in there.

The Graupner Speed 300 6v, this is the same exact motor as the team orion big block without the hefty price tag. BTW between the motors u have above the big block is better i know because i own them both in addition to the Speed 300 6v

Well I see the Big Block fairly cheap now, like $13. How much is the Speed 300?

no one having traction roll problem? How to solve this (it's not like my 1/10 which I can do more adjustments).

OH snap if the big block is $13 go get that cause the speed 300 6v is $13.90

As far as traction roll i just threw a vcs shock on the rear and added the gpm front shocks, also put a little CA glue on the sidewall of your tires if your running foams.