Bevel gears (diff)

[Shogun1122]

Is anyone else having problems with the differential bevel gears? I have already gone through several sets of them. I know about the spider upgrade. however since i have learned about the upgrade there has been some sort of shortage of this part. I can't find it anywhere. I have used other makers bevel gear sets with no avail. I am blowing them out with some regularity (like about an hours worth of run time).

I asked at my LHS they suggested that i may have had my spur gear too tight, so i loosend the SG and put a set of kyosho (sp?) gears(Rear only, I had already bought all the sets they had) in and they broke too. I can't figure it out. Should i just wait till MID MARCH!!! to get the HPI gears or is something else my problem?

 

[Çh®i§tiªñ]

I dont think its the gears at this point.

More like a housing or cup(s) thats bad.

If the parts dont fit snug and have too much play, they can blow faster than it takes to install a new one.

 

[SunnyD]

"I can't figure it out. Should i just wait till MID MARCH!!! to get the HPI gears or is something else my problem?"

Is Hpi is coming out with a spider gear diff mod? or are they coming out with a stonger then stock replacement? cause i blew out my front diff also and i didnt over tighten the SG either

 

[Shogun1122]

No there not coming out with anything new. That just the date that places like tower hobbies are expecting to see a shipment of the bevel gears (part # 86032) Look it up. No one i can find has them.

 

[Çh®i§tiªñ]

Still, dont overlook the diff casing itself. As well as the diff cups. Proper shimming can play a major role as well.

It just seems odd that you are blowing through so many so fast. If they were that bad, the Savage forum would be LOADED with nothing but complaints about it. Dont get me wrong, there is a reason people add the additional spider gears (OFNA Spider gear mod), but, there are a LOT of people who run their Savages to the hilt on this site without problems. Correction: Without blowing diffs that often.

It is normal to blow diffs on all nitro R.C.'s. Sooner or later, they just plain give. Especially for the individuals who drop MASSIVE power plants and setup a gear ratio for low end (wheelies and so on). The rate at which you replace them could be an indicator of something else wrong. Too much power, too low of gearing, too many landings with the brakes on etc..

If they are blowing every hour worth of run time, I can bet its not the diff gears alone.

 

[newnitrofan]

I think most people at this point who aren't blowing diffs in the savage are finding that before the 4 spider mod is done. Well I think they are finding that the pin that the two spider gears ride on get tweaked in the diff casing and actually bury themselves in some plastic and are hard as hell to get out. I found my set like this with just the 21BB running in it. This was my main reason for doing the diff mod. I had no idea that one day I would be running a picco 26 in it.

 

[Darnit26]

You think thats bad, try finding a the 13 tooth small bevel that comes from the dogbone to the diff (86031). You simply won't find it. I know 5 Savage owners that have blown this gear and believe me it is nowhere to be found (and yes, I do have spider mod). I had to buy a Kyosho bevel and send it to a shop to have it drilled.

So here's my diff setup:
1. Spider Mod - HPI bevels on Kyosho shafts.
2. 5000 wt front oil
3. 3000 wt rear oil
4. Kyosho 7.5 MP 13 tooth hardened small bevel with custom drill hole.

So far so good, I hope I get better run time now.

I enjoy the heck out of my Savage but I feel that everything involved with the diffs needs to be improved.

 

[badbronco]

ofna bevel gears??

Can you use the OFNA bevel gears in place of the hpi's bevel gears?? The ofna set comes with some washers to put behind the little gears, would these little shims help or hurt matters. I have a couple packs of both and am going to do the MOD to my Son's and my Brothers savage's. But I really want to know if I can use the ofna bevel gear set?? They look identical and I also counted the teeth and thier the same, so in my opinion this should work. BUt don't really want to experiment if someone knows the answers already, that what were here four, right??? I also am going to use the Kyosho 4mm cross pins.:smoke:

 

[Darnit26]

The Ofna bevels will work just fine. I'm not aware of anyone using the washers but my MBX Pro has them, so I guess they will work just fine too.

 

[NCNitro]

My rear diff completely grenaded after only the tenth tank, and six of those were break in. The pin twisted inside the weak ass cup, the bearing disintigrated, both bevels are missing teeth, totally destroyed the rear diff. HPIs customer service SUCKS! I waited on hold for 50 min before I finally gave up, called back and used their option to leave my phone number and they would have a representative call me back, well that never happened. So I too have been trying to find replacement parts for over a month now. I am so disgusted with this whole thing I am actually considering getting rid of the Savage. Yes parts have broken on my maxx but getting replacements, either stock or aftermarket has never been a problem for me, and Traxxas customer service was far better than HPI's.

 

[badbronco]

customer service

They were very prompt with me. I left my number and they called me back in no time. I sent all kinds of stuff in like steering servos and other servos , 13 final bevel gear, roto start and more. Everything came back brand new in the package. When I called a couple of times , I found it rather easy to get a voice on the line. If you don't get through , always try at first thing in the morning or right after lunch. Morning works best for me. Same with HITEC and OFNA, great service, with no problems. And I'm sending in a 40 series rim to PROLINE right now and thier sending me back 2 brand new ones, and I think I talked her into sending 3 so that it would give me a full set extra to mount sum 40 series bowties. :dancin: Just call me luckey I guess. I also am going to try my luck with HITEC again and send in a second servo of the same as before (645mg ) cause the motor seems weak and see if I can get a new one. The last one did not work at all , so of course they sent me a brand new one with real quick time. I think its in all how you talk to them and persuade them. Also , RATEK sent me a brand new laser temp gun just cause I called-in and said that I had mine for a little over a 1yr. ,and it went on the blink out of the blue. All the figures on the LED screen showed-up all the time and the temp was unreadable. (WOW, that was awsome) since I actually bought it for $20 from some guy and it broke on me the 2nd day I had it. JUST a HINT, talk real nice to the ladies that answer the phone at any company and they seem to wanna help you out a little more, especially when you tell them they have a very , very nice phone voice and that the other end of the phone is probally beautiful. Women love that word to the extreme. Well sorry for such a long post and hope this helps sum of you young bucks out, and the pain meds just make me feel like ramblin. I'm a ramblin man tonight haahha Watch-out wife here I come!! :fro: :flamer: :doc: :trout: :trout: Sorry, just found all the images hahaa

 

[Mugen-Racer]

Gee, I thought it was only me that had the diff problem. Mine's been sitting in the garage since December. I just ordered the gear last week. They were expecting shipments in but said they were on back order. I went in last week and they said that they could special order them now. I ordered 2. hehehe.