Helical cut or Straight cut Diff Gears?

[STINKYBOY13]

Lookin to buy new gears for my diffs. Helical or Straight which is best? Anyone

[jhautz]

I say the answer is 7






How about a little more info. Hard to answer a question like that without some specifics.

Whats it going in, what is the rest of the setup, etc....

[STINKYBOY13]

OK XTM Mammoth with too much slop in the diffs. I am going through pretty much everything and the diffs are pretty shot. Also converting it to BL.With things I had layin around MM,4s lipo,feigao, ect. Just don't want to mess with it when I,m finished. Unless I break it. Thanks

[jhautz]

Well if you can get either then Helical is typically smoother and possibly a little stronger. The only real thing to worry about is what the gearing is. Typically the truggies run the lower ratio diffs with helical cut and the buggies have a higher gear ratio whit straight gears.

[Serum]

Helical gears produce less noise.

Both are good, unless shimmed right. Shimming is the key to strong diffs.

[Mike_D]

Serum is right shimming is the most important part of good strong diffs. Althougth since i have replaced my Twin force with helical diffs i have not had any problems. And this is using the same shims as i had with the straight cut diffs. The point is you just need to get rid of any slop but at the same time not too tight that it will cause any binding.

[STINKYBOY13]

Thanks Guys! I thought serum would have some beta. I have been workin with the shimming part. Yes it is very important I have found through trial and error. Ok gear shoppin time. Thanks agin!!!!

[mwry13]

Good luck finding some diffs that work... i work for Global Hobbies (aka xtm) and i dont know of any that will work because XTM's method for mounting the diffs is quite uncoventional... and you have no idea how many diffs ive seen blown up on those things... NIGHTMARES!

what oil are you running in the car for the diffs... i usually of course make sure the diffs are shimmed properly but also make sure on new diffs to recheck the shimming after a run or two because they do move a bit... I usually recomend 8-10k front diff oil with about 10-15 in the center and 3-5 in the rear.

[STINKYBOY13]

Hey Thanks mwry13 I will go with your oil recomendation. Also you say you work for Global Hobbies. I was wondering if you could help me with some info on aluminum rear wheel hubs. The guy I bought the truck from got all the alum arms and so on but still runnin plastic wheel hubs. The arms say XTM on them. So I'm guessin they came from Global? Thanks Agin

[Sammus]

What cars run helical diff gears? I've never seen them before? And which gears are they? the ring/pinion or the internals? Something I've been meaning to ask someone , sorry bout the hijack :P

[STINKYBOY13]

Ring & Pinion. From what I understand you can find helical cut gears for most diffs. I dug around and found these in a parts list. http://globalservices.globalhobby.com/part/145621.asp
I think they will work for my application. XTM Mammoth.

[MetalMan]

Originally Posted by STINKYBOY13

Hey Thanks mwry13 I will go with your oil recomendation. Also you say you work for Global Hobbies. I was wondering if you could help me with some info on aluminum rear wheel hubs. The guy I bought the truck from got all the alum arms and so on but still runnin plastic wheel hubs. The arms say XTM on them. So I'm guessin they came from Global? Thanks Agin

XTM makes a lot of aluminum hop ups for their 1/8 vehicles. In aluminum they make arms, hinge pin plates, knuckles, c-hubs, rear uprights, arms (for the Mammoth trucks), and that's all I can think of off the top of my head.

[DrKnow65]

helical cut gears are mechanically stronger, they have mure surface area for tooth contact. shimming is more crotical though as you have the usual depth concern but now you also have to account for heel/toe depth too.

Go helical, get some gear setting paste from the local auto parts house, or perssian blue paste if they don't have the yellow gear setting paste (the blue is harder to see). You'll have to move the pinion in and out, the ring gear side to side. Lots of working back and forth to get the pattern just right (paste wiped away from the center of the tooth on the ring gear, center top to bottom and center heel to toe).

[mwry13]

i dont remember ever seeing some aluminum rear hubs... ill check my stock next time im at work for ya... piviot blocks, arms, front spindles, and some carbon fiber are all that come to mind.