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Discussion Starter · #1 ·
RE: Stripped Bevel Gear in the front diff</span>



I was wondering if anyone has experienced stripped gears in the diff
before. Usually the symptoms are clicking noise during braking and a
loss of diff action. Is this thing common, like stripped spur gears, I
ask this because then I can stock up on this part, damn gear costs 3
times as much as a spur gear, $10 US.



It looks like this and is in the diff connecting to the centre dog bones.







milknbutter
 

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Hey milk n butter,



I have mashed around 10 bevel gears now, quite common for me but they
are quite cheap , only 13 bucks australian. I usually have 3 on me at
all times. I think they are around the same price as a spur, if not
only a few buck more expensive.







Edited by: Dan
 

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Yeah mate they are pretty common... for some people more than others also. I think if you are hard on the brakes then you will also be hard on the bevel gears. Like Dan, I always carry a few spares with me.
 

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Skidd said:
Yeah mate they are pretty common... for some people more
than others also. I think if you are hard on the brakes then you
will also be hard on the bevel gears. Like Dan, I always carry a
few spares with me.


few? LOL!..
 

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Fire said:
Skidd said:
Yeah mate they are pretty common... for some people more than others also. I think if you are hard on the brakes then you will also be hard on the bevel gears. Like Dan, I always carry a few spares with me.
few? LOL!..

LOL... OK, yeah you've had the benefit of seeing inside my 'spares' box. The truth is that I carry a few of most things.
 

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Discussion Starter · #6 ·
Well, MRC had the bevel gear for $15au + postage. Pretty costly
for something that looks like a metal screw if you ask me. Alas...need
the Savage up and running.



Skidd - "I think if you are hard on the brakes you also will be hard on the bevel gear...."



Good God, I just did a dual disk mod.




milknbutter
 

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milknbutter said:
Pretty costly
for something that looks like a metal screw
Ask your LHS for a quote on the same part!
milknbutter said:
Good God, I just did a dual disk mod.
I
don't believe you'll be much worse off - it's largely dependent on how
you actuate the brakes - i.e. if you slam them on whilst in a carpark
locking the tyres it'll be bad, but if you were on loose dirt it
wouldn't be so bad. If you change the throw on your brake linkage so it
engages later you won't be yanking it on as hard, or if you lower
the 86101d rod in the pivot so that the throttle servo has less
leverage upon the brakes you will reduce the yank effect. Just imagine
the 13tooth pinion being slammed into the ring gear at 30000rpm and
effectively having the diff trying to rotate as the front tyres are
fighting for grip, and the tranmission locked from the brakes on the
other end.
 

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Discussion Starter · #8 ·
Jerrah - "Just imagine
the 13tooth pinion being slammed into the ring gear at 30000rpm and
effectively having the diff trying to rotate as the front tyres are
fighting for grip, and the tranmission locked from the brakes on the
other end."



That really made me think.......are there any other manufacturers that
sell stronger diff parts especially bevel gears? Gonna do a search
today, maybe titanium would do it.



milknbutter
 

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milknbutter said:
That really made me think.......are there any other manufacturers that sell stronger diff parts especially bevel gears? Gonna do a search today, maybe titanium would do it.

milknbutter

Mate I think that Jeerah makes the point quite well... not so much what braking parts you have but rather how you use them. If you were racing competatively and so were using the brakes a lot (and hard) than I imagine the pinions would suffer... casual back yard bashing with stopping to suit should prove less stressfull on the parts concerned.


As has already been pointed out... there's a lot of momentun in a Savage to stop and it all goes through those 2 13 teeth pinions... most of it infact through the front one. FWIW... I can't imagine why a twin disc conversion would be needed... but that's just me.
 

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Discussion Starter · #10 ·
Yea I guess a revised driving attitude is on the plate.



milknbutter
 

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milknbutter said:
That really made me think.......are there any other manufacturers that sell stronger diff parts especially bevel gears? Gonna do a search today, maybe titanium would do it.

milknbutter

No other manufactures make the same part, but if you got lots of $$$ you can go the kanai TCD diffs. The kyosho pinion gear is much harder but its a pricey set up. I still believe that HPI havnt got it right. I have seen 3 different shaped teeth on these gears .
 

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Discussion Starter · #12 ·
I just ordered the 4 spider diff parts, 1000 and 3000 weight Ofna
silicon oil. Hopefully they do the trick, make the diff's more
durable.



Anyone done this mod recently? Was it worth the wack in the wallet? I
know I could visit the yankee website and read the forums but was
wondering if anyone has recently done this mod in AUSRC.



Also thanks for the advice regarding the bevel gear. Cannot wait for the diff mod.



milknbutter.
 

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Most people on this list with Savages I would imagine would have done the 4 spider gear mod.



AUSRC's essential Hopups and Mods.



Don't forget to look in the Savage tech section of this site.



Having the cross axles insides the diffs is a prevention of the spider
gear axles from chewing a hole through the plastic of the diffs.



NOTE: The spider gear mod will not help save your bevel gear.</span>


Edited by: jerrah
 

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Do the 4 spider gear diff mod just out of cause. You have you truck in bits - do it now!


I was supprised at my 13t gear as I did exactly the same thing as yours. Updated the brakes and busted the gear. Now all I do is set the brakes on my transmitter so that they are just working enough to slow the car to a stop in a few meters, but not able to lock the wheels. Since then I have had no trouble with the 13t and I expect it to last a long time...
 

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4 spider mod is definatly worth doing, but as others have said wont help the 13t bevel gear. The plactic diff cups do flex alot and as a resilt the bevel cears can skip across eachother and cause premature wear or rounding of the gears. If teeth have broken off your brakes are on too strong or i find that when landing a jump with the throttle on you will also strip teeth
 

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Some TXes (afraid not the basic ones) have facility to adjust the endpoint of the brake travel, without affecting neutral and max-throttle points.


I like to set it so that I can adjust the strength of the braking from the TX. Set the car so that you get wheel-lock at max throw, then use the TX's knobto reduce the throw to temper your brakes.


After that, the only time you have to muck with the linkages is to re-adjust the brake bias between F & R.
 

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mate savages don't have a brake bias. Its just a gearbox brake.


Whatever you do, don't lock the wheels and you should be fine.
 

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Discussion Starter · #18 ·
Man I was locking up the wheels willy nilly like a rally car going around corners, no wonder.



milknbutter
 

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That would do it.... Damn HPI for making a dual disk kit and then not telling us its going to break stuff!
 

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Fair enough.


Guess if the bevels didn't give way, the dogbones would get twisted.


Those big tyres give a lot of leverage on the poor drivetrain!
 
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