spiral (Helical) cut diff gears?

[B-Woo]

I’ve found helical gears that will fit a savage, however how do they fare to the bullet proof gears? Is there any advantage to the spiral cut over the straight cut?

Basically hpi #102692 vs. Kyosho #KYOIS102 & #KYOIS101

And if anyone wouldn't mind sharing their choice of diff gasket, I think the Hpi ones suck.

Thank you for sharing your knowledge

 

[redneck]

helical gears are used in automotive applications to ruduce noise,and much stronger than straight cut gears (more contact area) but are much more costly to manufacture.Not sure what they are like in RC use, ( have built many "rear ends" for full sized 4x4`s and sport trucks, but have only been into rc for about a year or so) I thought about going with helical gear sets but decided to use CEN diffs in one of my XL`s, and HPI BULLET PROOF`s in the other (time and bashing will tell which set is better) Two things that have done to improve these mods were, on the CEN mod was to "dimple" a spot on the pinion gear for the set screw to get a better grip, then shim it on both sides of it so it cannot move back into the carrier. With the HPI`s i machined the "diff cup" to accecpt an 8x16x5 bearing (pinion / wheel bearing) Not really an answer to your question,but might help.

 

[CTDpower]

I think the main reason helical (spiral bevel) gears were made was to reduce noise and vibration. However, it MAY be safe to say that on a set of straight cut vs spiral cut that are about the same size, there MAY be more contact area between the teek on the spiral cut, which may increase the life span or make them slightly stronger? Not sure, but most likely the bullet proof ones will fair better. Can't imagine any 1/8 buggy diffs out lasting ones called "bullet proof", made for a much heavier brushless vehicle.

Here is the D8T ring gear (incase people don't know what we are talkig about), they look nice, but prolly won't cut it.

How do you know the kyosho 777's will fit?

 

[CTDpower]

Holy crap, you beat me to it, oh well 🙂 It seems that we at least agree on the topic, haha.

 

[BIGDAN89]

helicial gears have been used in savages with the same result they are weak in a savage . due to the weight and the stress loads the diffs are out threw. they work great in truggies cause there light and have 3 diffs at one speed.

 

[frddyj]

helicial gears have been used in savages with the same result they are weak in a savage . due to the weight and the stress loads the diffs are out threw. they work great in truggies cause there light and have 3 diffs at one speed.

+1 on this post. in addition, the buggs & truggs have the advantage of a flat chassis-tray which wont flex the bulk & affect gear mesh like the tvps on a savage.

bankrupter & allanq both run the hotbodies conical gears in their hellfires; I'm pretty sure br is going for the hpi bulletproofs in his flux.

 

[Bankrupter]

then actual contact patch of those gears is very narrow.. don't work in a savage and ive done it ...

Kevlar gaskets Hot racing

 

[B-Woo]

on a very old savage-central post a guy put them in his savage with no problem other then shimming, he never went on about how long they lasted but he said they gave him no trouble.
This was like a year before the bulletproof ones came out.

However about the comment about the hot bodies’s gears, I’ve only heard negative things about them in anything.

 

[Bankrupter]

on a very old savage-central post a guy put them in his savage with no problem other then shimming, he never went on about how long they lasted but he said they gave him no trouble.
This was like a year before the bulletproof ones came out.

However about the comment about the hot bodies’s gears, I’ve only heard negative things about them in anything.

Cool get them and let us know! I have BPs so I don't have to worry about diffs anymore

 

[AllanQ]

Yeah I would like to know how this turns out. I went to put some helical's in my savage and changed my mind after everything was installed. the helicals I used just looked to thin and weak and did not feel like blowing up a set of diffs for the heck of it.

I do have them in my HF, they work great with no issues and they have taken an extreme beating.

 

[B-Woo]

the main reason i thought about them was for a change in gear ratio, closer to a truggy for my racer

 

[BIGDAN89]

theres a older savage central post of a guy using the kyasho helical gears and had the same objection didn't last too weak. then there was another guy who used crt diffs on irc diff cups and had the same thing happend imo helical don't do good in a savages platform.

 

[redneck]

The ratio of BULLETT PROOF`s and CEN are slightly higher than stock gears, if thats what your looking for.

 

[B-Woo]

ok well maybe i'll just play it safe then, how about a good Differential Gasket, i hate to one's from hpi.

 

[Bankrupter]

check my post above post # 7