wheel axle breaks easy?

[Ruffy]

The front/rear wheel axle has broke on mine. Looks like a some what poor design with a hole drilled through and a small metal pin to hold it into the gearbox. Much like some of my older RC cars I had they did the same thing to the tires.


Is there other people out there that are breaking them easy? And is there a upgraded version?

 

[Guest]

Are you talking about the dog bones?

I have not broke one yet. Knock on wood.

 

[RampageHopUps]

He is talking about the diff cups. Yes, they are a weak point. There is a new style that is harder material:

http://rampagehopups.com/product.sc?productId=817&categoryId=-1

 

[Ruffy]

There is 2 different things that looks the same but named different.

http://www.redcatracing.com/RC-Cars/Redcat-Parts/50032

http://www.redcatracing.com/RC-Cars/Redcat-Parts/50031

I think I am looking for part# 50032 to be honest. Its where the dog bone/axle goes into the front it rear gearbox.

 

[RampageHopUps]

Not sure what one you are looking for. Can you take a picture?

 

[Guest]

No,50032 is at the wheels the dif cups are the ones going into differential or gear box.

You need 50031.

 

[Deluge]

50031 goes into the diff. 50032 goes into the wheel hub.

 

[Ruffy]

31 must be the ones I need then. Where that pin goes it holds it into the gearbox. That's where it broke. Not from the wheel to the a arm.

 

[Deluge]

Try tempering them before you install them.

[ame]

[/ame]

 

[RampageHopUps]

He is talking about the diff cups. Yes, they are a weak point. There is a new style that is harder material:http://rampagehopups.com/product.sc?productId=817&categoryId=-1

Here you go.

 

[RAMJET]

Try tempering them before you install them.

this process will just take the temper out of the metal , to temper you need to bring the metal to a blueish color and keep it at that temp with out getting any hotter, then you need to quench it .

the best way to get uniform heat is to hang the piece in a section of steel tubing and put the torch in the bottom of the tube ,adjust the torch until you get the metal the correct color(bring it up slowly) ,on a piece that small keep it there for 10 min , then quench in water ,there are better fluids for quenching but water works OK.

a tempered piece will be stronger but brittle ,look at the piece that broke if it twisted off and you can see the metal was twisted then broke ,it's not tempered . If it's a clean break and you can put the pieces back together cleanly ,there is nothing wrong with the temper the part was just over stressed.

Hope this helps .Roger

 

[Deluge]

Mine were tempered using that method. I haven't snapped a diff shaft since then.

 

[RAMJET]

Mine were tempered using that method. I haven't snapped a diff shaft since then.

It may have been because you took some temper out ,the axle may have been tempered so hard that they became brittle,causing them to fracture. if you want to machine a tempered piece of metal you heat it first and let it cool slowly . This will take the temper out of the metal.this is also why when sharpening tool steel you cant get it too hot ,it looses it's temper, you have to keep quenching it to keep it cool . I am not doubting that you fix your problem doing this ,you got the results you needed .but reducing the temper is likely what fixed your problem.

 

[Deluge]

That was thought to be one of the issues early on. Either the temper was off, or the material was sketchy. Once everybody started tempering the shafts themselves, the issue went away.

 

[IVIayheIVI]

Diff cups are my major malfunction right now. I have a full set in transit, hopefully arriving before the weekend. These cups are brittle. Plenty of stress at those little pins in the middle. I'm seeing a little bit of compression but for the most part it's cracks or even little chunks snapping off at the edge of the hole where that pin goes. Also, I've split a cup in half on an outer cup (at the wheel) from a sideways landing off a jump. I have that on video, just need to figure out why I can't upload to youtube... grrr.

So it looks like I'll be (de-?) tempering my cups before I put them in. My MT runs pretty strong so we'll see how they hold up.

On a related note, I found a thread on a baja forum, the guy has an MT too. He has a set of these:

http://www.davesmotors.com/s.nl/c.885035/n.1/it.A/id.5177/.f

He explained how he used different pins in his dogbones and was able to use the outer cups. He was going to try to install the inner cups and post his results but never did.

Well, I decided to try this myself. The outer cups may work, but will have a lot of slop. The ball at the end of our dogbone is a lot smaller than the baja's. The diff cups don't fit at all. You would have to mill the shaft down to get it into the diff and the hole doesn't line up either. Would have to mill the back of the cup down a bit to line that up, and the hole is a different size as well, HPI uses a larger pin. This set went into a bag and got thrown into the spare parts box. I might try the outer cups if I'm waiting on parts.

If this design was based on baja tech, why did they decide to make it weaker than baja's on a heavier rig? That's a big fat fail in my opinion.

 

[Guest]

If this design was based on baja tech, why did they decide to make it weaker than baja's on a heavier rig? That's a big fat fail in my opinion.

The Redcats were not designed after any other platform.

 

[IVIayheIVI]

The Redcats were not designed after any other platform.

If I were to ask redcat directly, I'm sure this would be the official answer. Realistically though, I have to assume this design is based off the baja, or at least, they were both based off a similar design. They are so similar in design that some parts are interchangeable such as the outer cups/axles. The diff cups are only different in shaft and pin sizes, the design is the same.

**Edit --> I just re-read what I typed above... not entirely clear but I hope you understand what I'm trying to say.

Whatever the case, the original Redcat design was not meant for tuned motors and pipes. In this respect, it's my own fault for these shafts breaking as I'm running after-market options increasing power on a power-train designed for less.

My mission is then to strengthen my rig so I can bash without so much breaking. Only once this season has it come home without breaking and that's running it in a sand pit. I'm scared to take it on grass at this point. I wish this weren't the case.

Another assumption I have is that if I put smaller wheels/tires on it, I won't be so prone to breaking stuff. I really like those big tires tho.

 

[IVIayheIVI]

Have people had this problem with a stock MT? I bought mine used with a done up motor and Jetpro already installed.

 

[IVIayheIVI]

I read in another thread that this has been a problem for people running stock (or at least one person). So I still call it a fail. In any case, I still need to bulletproof this rig. Hopefully my new cups arrive today.

 

[IVIayheIVI]

Got the diff cups, hit them with some heat, and they've held up to about 2.5 tanks so far. Good stuff!