m1kie

hi all, i have a fg monster truck and after an hours bashing session with it, i noticed that the plastic spur 48t gear has all the outside edge of the teeth worn (aprox 45 deg angle) but the center to inside edge is fine. this has now happened on 2 spur gears back to back. any ideas what may cause this?

thanks

bigmodman

you gear mesh i would think.

Dave ESPI

Motor mounts may have shifted, and are chewing the drive gear as a result of it if you hit anythign or slammed hard a few times.

PAPE

Its the rear susp arm that hits the gear, need to get alloy rear uper arms

cyclops1970

My Feedback: (5)

Yes Pape is correct .. Push down the rear suspension and see how close it come .. and once it lands on the rear your can imagine the flexing the arms give and see where they rub ..

Pigsmightfly

That couldn't happen. The plastic gears are attached to the gear plate and have a fixed mesh.

RC_chaos

PAPE and Cyclops are correct. This happened to mine. Sloppy rear plastic arms will kill the spur gear.

Dave ESPI

It could if the mount shifted (AND WAS RUBBING ON THE REAR ARM)........ I learned about that one and luckily my truck came with the previous owner having upgraded the gear to metal aswell as the upper arm, so no worries UNLESS the mounts move... this can still cause an issue. Also, that pinion can loosen up and slide out a bit and the set screw can chew gears also if it backs out too far

ScooterTrash

He, Pape is right on the money[sm=thumbup.gif], it is the Suspension arm!

TheFgMan01

Also be carefull of the bearing in the large motor mount. when it goes bad it will cause the layshaft to move. spur gear will then be out of alignment. Happened to me. Just something to keep an eye out on

Pigsmightfly

It's easy to appear knowledgable when others have given the correct answer

Dave ESPI

Yeah, because my comment was totaly not even close to plauseable ........

Considering I was the second reply, and the accepted "answer" came AFTER my first post you are questioning and is still related to the topic as a possible cause. I don't have all the exact correct answers based upon speculation. All I have is personal experiece and that which I have read in the past from other FG MT owners. I'm saying it was a possability, lets not nitpick over split hairs here. The only thing preventing the spur from making contact with the arm is a small silver screw on the bracket of the rear hub case and the motor mount and the screws (which can and do move, bend or shear off) on the motor if you hit anything really hard.

How do I know this ? because when I slammed a light pole at 45 mph it did just that. Luckily I sustained no damages to the gear as I have the metal gear and the upgraded upper link arm, but it definately stopped the gear from turning at that point in time. The OP mentioned an "Hour worth of Bashing". I can do a lot of tweeking to my truck with how I consider "bashing for an hour" as opposed to just driving it around and rolling it over a few times is "Bashing " to some other people. Not sure how hard Mike was driving, or if somethign just came loose and moved, but one would think that FG engineered a truck that would not have issues with a drive gear rubbing on an arm without tweeking the truck in some fashion with negative results.


No worries, All is well,

D-

m1kie

thanks for all the advice on the spur problem. my bashing session consistes if quite a few jumps 2-3 ft high, flat out racing on bumpy grass till my tank runs low of fuel.... i have recentley upgraded to alloy engine mounts and have red thread locked them into place and as far as i can tell the engine hasnt moved and all bolts are tight. The reply ref the spur catching on the upper arm is intresting , but to prove this im going put some tipex on the arm and then i can see if the spur is catching as the tipex wil rub off on contact.

thanks all

PAPE

Mike if you want a cheap fix this is what I did, buy the firehammer rear uper arms http://www2.towerhobbies.com/cgi-bin...?&I=LXHTP2&P=7 only 4.49 and currently out of stock. install them and adjust your toe-in toe-out to 0 degrees or 1 degree out in the rear wheels, this will move the top arm away from the spur gear, and if you whant it a little further you can adjust the caster with wasshers on the lower arms too.