Cooked mmm, well done of course
 

My new mmm just went up in smoke. I was running a 4s lipo 2200kv neu-castle motor and my gearing was 19-46 on a Cen genesis. I was running a center diff alone and was getting a lot of cogging when starting out. Will the warranty cover it?

As long as you didn't mod the case or solder to the internal PCB, I don't see why not. Although gearing is a little high IMO. 5s lipo on that motor geared down to ~14T would be easier on it.

Well I was in the process of testing gear ratio I did not run it very much. I did not do anything as far as modding the esc, everything was original.

Here is a pic of the aftermath

Just curious, what version is this, and what firmware version were you running?

its a v3 and I was using the latest version available for download

like I said it was brand new, only had it running like 3 times

I guess you were one of the unlucky ones then.

To help keep this from happening again, I'd drop gearing. The more I think about it, the more I think that it was geared too high on too heavy a truck (especially with those tires!), for 4s IMO. It's probably a simple matter of drawing too much current.

Of course, gearing down will lose top speed, but then you can run 5s or 6s lipo to get it back. Although, on 6s, I'd drop down to 12T pinion and get a bigger spur if there's one available.

right brian... at the weight of the truck and the gearing im not surprised to see that kind of failure but the monster can take a huge amount of amp ...mine melt exactly the same way....in my e-revo and this is a light set-up(18/68,2200kv 6 cell)...the v3 is solid i know what im talking about:lol:anybody can have a badluck...


93firebird..call castle they take care of you

Okay, running the numbers...
CEN Genesis has 9/26 diff ratio, correct? And let's say 7" tall tires (even if they are taller than that). 2200kv, 14.8v, 19/46 spur/pinion gearing.

Assuming the numbers I listed are correct, you were geared for a solid 90+mph. No wonder the MMM died.

Even if you could fit a 10t pinion, you would still be overgeared at 50mph.

Poor MMM never had a chance.

shouldnt the batteries have taken a beating 1st ?

There should be a sticky telling people to stop trying to get their vehicle(s) going when it stutters badly, it will always damage the ESC and things can be sometimes ugly. I saw a guy with the same problem at my LHS and I told him to stop as that would cause the ESC to burn, well he didn't listen and in about 10 sec. the ESC started smoking and the cause of this is like others mentioned, geared to the moon or a very high Kv motors geared to the moon as well. I would love to see people do this to their real vehicles.

Well since there are no conversion kits for this truck yet gearing can be hit or miss. No one has a set ratio to use, but it looks like what I was using was too much.

Your set up is basically similar as most 1/8 scale conversions. I go by BrianG's calculator and if you're not using the transmission it would have saved your MMM.

Well I got my new esc today and I dropped the gear down to the smallest gear I could use that would still reach the spur, which was a 14t gear. I am using the RCM matrix mount for the motor. I still feel like it is cogging an awful lot. I have a pair of 3s lipos on order should I wait till they come in to see if the extra voltage helps. When I ran it in my basement the battery and esc got hot pretty fast. The motor jumped up to about 120.

Esc
 

I have this happen to me about three years ago with FD motors. When the motor gets hot real fast that means it is no good and will take out the ESC.

Yep. I'd not run the truck until you modify the mount so you can drop to a 9 or 10t gear, and/or get smaller tires.

You'll need a very big spur gear.

+1. That'll not only get your ratio closer to where it should be with your current gears but it'll allow you to fit a smaller pinion. That Genesis is a big, heavy truck and I'd personally gear it for about 40 MPH and go from there (watch those temps!)

When the bigger CC motors come out, I'd look into one of those if I were you. They should be able to handle the load of the larger truck better.

maybe a bk45-8xl motor would suit your needs. it is meant for 6s lipo and it is much bigger than the cc/neu motor. the neu motor is 40x75 while the kb is 45x77. the extra diameter and bigger rotor should help get that massive truck moving well.

edit: a fiegao 580 motor would be even batter than the kb motor. it is 45x76 and it is more efficient than the kb and it mounts like neu motor. the kb has a bigger shaft that will need to be grounded down and the screws are 30mm apart instead of the standard 25mm.

With the gearing he has now, he needs a 4 or 6 pole low Kv motor which will have the torque needed for the job.

Still way over geared. Use the calculator and don't expect that setup to work reliably until it's geared for around 40 mph, maybe even less for 4s in a truck that big. At the moment your geared for around 70mph (if you are running a center diff with no trans and the 7.5" tires). The last thing I would do is try and use that setup on 6s, you'll be geared for 100mph and will have a similar result to the first time.
Will this spur work in your truck? http://www.amainhobbies.com/product_...ducts_id/11243 If it does, you should be able to fit smaller pinions. With that spur a 10t pinion will give around 36mph and an 11t around 40mph. I'd start with the 10t and see how it goes. May even need to go down to 9t not sure...it's a big truck.

http://www.cenracing.com/cars/gst/pic/gst4.jpg

Like some of the other guys said, the best setup would be to go for a slightly bigger motor with lower kv and use 6s, while still gearing in the 40mph area. Smaller tires will help as well, but I guess it would kind off defeat the purpose of the truck.

The only problem with that is space. There is not a whole lot of room to mount a bigger spur gear there.

here is a link to the post where I have a pic of the set up

http://www.rc-monster.com/forum/show...?t=5513&page=9

What is the space between the frames?

You can always ditch the tall tires and go with what most truggies use. You can try and see how it will run with the transmision in there like aqwut and jzemaxx has in his set up. If you do stick with the set up you have, your best option is a long motor with a low Kv.

Now here is what can work with your set up:

Neu 1527/1.5Y (825Kv)
6S lipos
14T pinion
46T spur

That should give you a speed of around 42MPH without tire ballooning.

If you go with a 5.6" truggy tire, then you'll have more options to play with the pinion with the following set up:

Neu 1527/2.5D (925Kv)
6S lipos
14T (36MPH), 15T (38MPH), 16T (41MPH) and 17T (44MPH)
46T spur

I have my tryggies geared for 34-36MPH and they usually go much faster when the tires start to balloon.

i cant reist!
http://www.youtube.com/watch?v=rNQRf...eature=related
:lol:

indeed, a other one bites the dust!!
me!!

i just hope mine doesn't bite the dust

Does anybody know what gearing the hpi flux uses. I know they used a 2200kv motor with 6s lipo to reach 62mph. It looks like they use a 44t spur but what pinion do they use?

hpi said 20t pion 44t spur for 4s,but for 6s it 25t pion 44t spur!!

And the tire size?

they are gt2 from hpi dont know the size

I was under the impression that was a Typo HPI made, but if it wasn't it just goes to show that some companies don't know jack S:whistle::gasp:T.

Well the replacement seems to be cooked as well. I re-geared the truck to a 66t spur and an 11t pinion. and ran with a dual 3s setup for the battery. At first the Batteries had a connection between the cell go. I reconnected them thinking that it was just a bad connection job. So then I hook them back up the unit turned on, armed, and then when I tried to hit the throttle it cogged a little then started to take off then suddenly stopped. I noticed the lights were not on so I checked the batteries and they were fine. I tried my 4s battery and the esc would not turn back on. There was no smoke or noise when this all happened. It just quit working and will not turn back on. I pulled the esc and tried to hook it up to the data link and it would not recognize it either. I am so frustrated right now.

Contact tech support, and let them know exactly what happened -- a bad battery connection can damage the ESC. We'll make sure we take care of you.

Patrick

You need to get a data logger to get an idea of how many AMPs your set up is asking for.