Differential cases
08-06-2003, 11:26 PM
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Differential cases
Please tell me why they are made of plastic (besides the obvious weight aspect).
I hadn’t payed any attention to this until the aftermath but I’m looking at this thing and going “well that’s just stupid to begin with”.
My stadium truck (Duratrax Overdrive ST) and many, many like it, has the rear shock tower (made of aluminum) attached to the top half of the differential case (which is plastic) with 4 screws. Now these screws are roughly 5/16 of an inch apart. The mounts atop of the case are narrow, very narrow, with no beef. So basically, when doing jumps and landing, the weight of the truck and the force of the bounce has to be absorbed and supported through these two tiny little mounts.
Yeah, they broke off. The axles flew here and there (I found it all) but from examining the “point of breakage”, there are 4 points of approximately 1/6" thick plastic taking on all that abuse.
If you’re gonna design it that way, how ‘bout some beef man! Under Duratrax’s warranty, I can get it replaced for free under their “Stress-Tech” part warranty but I’m not going to go through the hassle and the wait.
I’ll spot glue the little pathetic supports in their original positions, plastic weld them and add beef (I have a plastic welding system at work). Then I’ll make support rods tying the shock tower to the chassis just like it should have been done from the factory.
I hate design flaws.
I hadn’t payed any attention to this until the aftermath but I’m looking at this thing and going “well that’s just stupid to begin with”.
My stadium truck (Duratrax Overdrive ST) and many, many like it, has the rear shock tower (made of aluminum) attached to the top half of the differential case (which is plastic) with 4 screws. Now these screws are roughly 5/16 of an inch apart. The mounts atop of the case are narrow, very narrow, with no beef. So basically, when doing jumps and landing, the weight of the truck and the force of the bounce has to be absorbed and supported through these two tiny little mounts.
Yeah, they broke off. The axles flew here and there (I found it all) but from examining the “point of breakage”, there are 4 points of approximately 1/6" thick plastic taking on all that abuse.
If you’re gonna design it that way, how ‘bout some beef man! Under Duratrax’s warranty, I can get it replaced for free under their “Stress-Tech” part warranty but I’m not going to go through the hassle and the wait.
I’ll spot glue the little pathetic supports in their original positions, plastic weld them and add beef (I have a plastic welding system at work). Then I’ll make support rods tying the shock tower to the chassis just like it should have been done from the factory.
I hate design flaws.
08-07-2003, 05:15 AM
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Differential cases
The Duratrax overdrive diff is the weakest piece of crap I have ever dealt with. Overall, I think the whole truck is a piece of crap.
I just got through rebuilding one for a friend because his diff went belly up and I came to the above conclusion.
I looked all over for a metal case hop-up to replace the plastic but couldn't find one. There is one pictured on tower hobbies but it's misleading. The photo shows a standard diff with metal case but what you get is some kind of center diff instead that doesn't work.
I just got through rebuilding one for a friend because his diff went belly up and I came to the above conclusion.
I looked all over for a metal case hop-up to replace the plastic but couldn't find one. There is one pictured on tower hobbies but it's misleading. The photo shows a standard diff with metal case but what you get is some kind of center diff instead that doesn't work.
08-07-2003, 06:17 AM
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i feel your pain, the overdrive was my first rc car, that was nothing but problems, every day i used it a a arm would brak, and the dog bones fell out. finnaly i replaced them with cv joints.( the front ones work in the rear also.) but i finaly sold it, you should too.
