Hybrid Diff Instructions for Review
 

Please find some instructions for review / comment.

Shaun - Thanks for use of the pics

Cheers

Having never used these how much is required (if any) in reference to shimming?

Other than that it's a really nice write up. Simple and clean with good pictures, sentences short and to the point. I like it!

I've neve built one of these either, but I've done stockers.

1) I have no idea how to shim a diff, or what parts to buy to do this shimming. Some instructions on this would be nice.
2) "Assemble the differential according to the manufacturer’s instructions." Ummm....in this case, RCM is the manufacture isn't it? If a customer has a problem, they should and would call RCM first. So the instructions should be included with the diffs.
3) You reference some parts in your instructions by their street name. But in the diagrams and pictures they have part numbers, but no names. You should be consistent with this. Example - "flange bearings" must be the C8020's in the diagram?

Just some thoughts so far....

See comments below:

Thanks for feedback - v0.2

I for one am glad you wrote this up. Came back from bashing this afternoon with what I believe to be a blown rear diff. TIme to upgrade I guess (but that's a tough 250 bucks to swallow).
Has anyone ever blown a front diff? It seems to me that the rear takes most of the load and abuse. And at the cost of this, it would be nice, I think, to just be able to replace the rear.

I do have a aluminum cup already (golden horizons brand?), maybe I'll just try that for now and see how that holds up.

You have to do both, as the ratio is different to the traxxas diffs..

Try the al cup and shim the stock diff properly. A good diff shimming write up would be good. I will have to take pics next time I do one. I did find a good writeup once for a tmaxx diff, can't remember where.

I have my old diffs that I removed - Front and rear both with aluminum inner and outer cups if you are interested...

In the diff selection section, I think in the table you should have "Top Speed with stock pinion" or something to that effect. I think it could be a little confusing to some people.

I'm also not a huge fan of the layout and how you reference the pictures... but I also proof read mathematics journal articles half my waking hours, so I'm trying not to be too pedantic. It did take me a second to figure out that table though.

I'm just trying to nitpick though, to give feedback. I think it would be fine released how it is, and I've seen worse written manuals released with products.

The info mentions that the HB diffs use hardened spiral cut gears. The truggy are spiral, but the buggy are not spiral cut. Unless HB has changed them recently.

The D8 uses the spiral cut diff gears. At least the hot bodies site lead me to believe such a thing. I bought a Lightning buggy just before release of the D8 and it has straight cut.

Ok, I have the buggy and truggy gears, and only the truggy are spiral cut. From what Sikeston found the spiral cut tends to place addl thrust on the inner pinion bearing, potentially causing failure. I would generally stick to the buggy gearing.

On a side note, the lst diffs incorporate a spacer between the inner and outer pinion bearings. This is handy for multiple reasons, as you can assmeble the bearings,spacer and the drivecup on the pinion and then just drop it into the diff case. Plus the spacer will spead any thrust load across both of the bearings, which should help the races survive.

I am not that good with electronics theory, but I can sure see mechanical failures before they happen. No real need to mess with the truggy gears.

I am not wild about the teflon shims as stated in that link. I tried this and had wobble that was unacceptable so I stick with metal shims. Any size shim rings you need can easily be found at www.McMaster.com. I got the original instructions I used for shimming diffs years ago from someone on the TRX forums. It also had notes about shimming the pinion gear which helps a lot as well. Sometimes there is a lot of front/back play in the pinion gear against the ring.

Here's the instructions for assembling and shimming the diffs from UE. I used them for my 6 and 8 spider diffs:

8 spiders:
http://www.unlimitedengineering.com/...nsV1.1-Web.pdf

6 spiders:
http://www.unlimitedengineering.com/...ctions-WEB.pdf

WOW what a great thread..:gasp: Extremely well written,:yes: it should help out many of the newcomers for many years to come..

Great Job Sir..:party:

[QUOTE=Sammus;219662]In the diff selection section, I think in the table you should have "Top Speed with stock pinion" or something to that effect. I think it could be a little confusing to some people.



There is no such thing as a stock pinion really ( i quoted the setup I based it on) - The only other thing I could do it is show it was a % that you need to gear up and then include some examples ie. 9T now needs to be 12T etc

Not sure I will change it but any preference for next time?

Shaun - Thank you very much for the pics

Thanks Linc - I'm sure mike isn't doing anything special except I think they are the hardened gears... will update to reflect

George16 - Thanks for the shimming lincs I will reference those - i couldn't find a good one searching on google - the tmaxx one is all I found - The process on Tmaxx one looked correct but agree that telfon's not going to work too well on buggy/truggy diffs.

Well stock may not have been the right word to use. Looking at the page as if I wanted to build the diffs (which I eventuall will), I did as I do with many manuals - scan over the text until I see something that stands out as important or interesting. A lot of the writing is (and this is no exception, and is not a bad thing at all) standard description and other formalities that not everyone will read in the excitement.

At first glance, I saw the table. I saw "diff ratio, top speed, pinion required for 41mph" and it took me a few seconds to realise the 'top speed' column was the top speed with the "standard" gearing (ie the gearing in your example setup). It's far from major issue though, and I doubt anyone would be seriously hung up on it.

I guess the point is there should be some qualifier next to top speed, because unless you read it thoroughly (which of course you're meant to, but unfortunately most people don't) it is initially confusing having a top speed written next a column suggesting pinion choice for a particular top speed.

Again nothing overly important, more aesthetics than anything. What drew my initial attention was on the second page you say "The following picture shows the layout for the....differentials included..." and I wasn't sure which picture you were referring to. 'The following picture' I think could mean the one next to it or the one beneath it. It doesn't really change the meaning of anything, but it made me stop and think about the layout.

Final Version unless anyone spots anything very wrong...

Cool. Except where does one find a 26t or 33t pinion? :smile:

It may be a good idea to add something about the pinion/spur ratio, and that you can also choose a smaller spur and not such an enormous (impossible in this case) leap in pinion size.

I guess this is hardly a gear selection tutorial sheet, but if you say its good to change the gearing if swapping in a lower ratio diff, then recommending a pinion size that's near impossible to get, it may be a good idea to put a word in about it. Or am I being pedantic?

Also you need to change the link to the rc-monster forum to
www.rc-monster.com/forum/

Leaving out the last back slash causes an invalid link.

Tough crowd! you can get a 25T - the 33T was to show that the gearing gets silly - The next paragraph says truggy diffs only for a novak HV setup...

Link fixed - It was case sensitive...



That is kind of the point...

Great job Arct1k, but just one thing missing, is for the front diff, when you reinstall the bulckhead on the frame, the little black plastic goodies who hold the stock diff in place have to be triming a little bit with a Dremel to give room for the new and bigger Hybrid alloy diff case.

Other than that, all is OK:wink:

Nice Arct1c!

Question: why do you say to make note of which diff is front or rear? Is it simply because of the oil differences? If that is it, you can always feel the difference in stiffness...

For the oil - I guess you can feel it but doesn't hurt to make a note...

question:
if I have the truggy diffs? can I just purchase the Hot Bodies 13T BEVEL GEAR? to make them buggie diffs? or is it not that simple?

sorry for my ignorance, I just purchased a G3R and it came these 1/8 truggy diffs but would prefer the buggy.

http://www.hpishop.de/images/product...es/HBC8030.jpg

Yes but make sure the pinion and ring gear have the same cut. Some truggy gears are spiral cut. What brand are your current diffs?

hot bodies 43/10 truggy diffs

Then you're good to go.

thanks for the super fast response. cheers

sorry I'm still confussed,
Wouldn't the 13T be larger than the 10T? if this is the case then I wouldn't mesh up to the ring gear when it goes case?
do i need the ring gear too?

It's bigger but it will fit.

Kool got myself worried for a bit then. So i just need to by hot boddies part number C8030 and off I go?

Yes. Might as well get some shims too.

cheers