U4 gearing...front to back!

[r6cj69]

I have searched through the first 25 pages of this forum gathering ideas and info but still have few questions regarding gearing. I plan to use my Yeti (rtr version) for U4 racing. Currently my yeti is in stock form with the exception of the aluminum steering rack, knuckles, carriers, camber & steering links and the MIP rear shaft.
I've noticed gears grinding on sudden stop and hard acceleration. I pulled the front diff apart and the ring and pinion gears are worn. The diff gasket is also torn. The bearing looked to be in good shape and I have already repacked the bearings with grease. I may still replace them but while I had them apart I went ahead and greased them.

I have read may different reviews and opinions about the HD gear set as well as the spider gears in the diff cup itself and have some questions.
Are the HPI gears better than the Axial ones? I've seen people offer those as a replacement. The cost is about the same but the HPI pack comes with two sets of gears as opposed to one set with the Axial.

Next I've read about the Dlux housing. It's aluminum and stronger to help hold bearing fit to my understanding. My stock diff case seems to be fine.
I tend to understand the older cases may have been a problem but the newer ones not so much. So, is the Dlux case more of a "nice to have" or a highly recommended item?

Next is the Avid thrust bearing for the inner rear pinion gear. I've read that the gear mesh on the stock units need a good amount of shimming and that the Avid bearing helps to remove the need for shims. Also this varied from stock gears to the HD gears? Does it matter.

Finally I'll get to the HD gears themselves. I've seen two different sets relating to ratio. I want to make sure I get the right set for my application.
My current set up has a Tekin RX8 Gen2 with a Pro4 (not HD) 4600kv motor. I'm running 2s only and with a 13t pinion and stock spur.
I'd really like to get one simple straight forward answer for suggestions on gears, ratio and shimming/thrust bearing and all for a U4 specific yeti.

[DTB1]

I have found that the under drive gears front and rear have reduced torque twist and improved handling. I run locked front and rear so I can't help with the spider gears in the front diff.

[trig n tahoe]

Thrust Bering for sure , axial spider gears suck go for the hip, hd gears from axial are super tough. Eric dlux makes super sic stuff, depends on budget. Have fun!!

[binaryterror]

The Thurst bearings or Dlux housings are required in my opinion. Which you do depends on you though. Both will greatly increase life of the ring and pinion.

Another good option is running the 43/13 gearing, the under drive. It has the best contact area and therefore lasts better. It does slow you down a hair, but that can be fixed at the motor pinion or spur.

Finally, the HPI gears are better and worth the extra. The Axial work, but are made of a cheaper metal and a lot less cleanly made.

[rob4607]

So this thrust bearing, for a noob does anyone have a photo of one and where we are talking about? I am assuming that we are talking about a bearing with one side having the raised lip on it but I am probably wrong. Sorry, my kit arrives today thanks to a bunch of amazon gift cards that I found buried in the center console of my truck so I will have 2 builds going at one time, the Yeti and the Yeti XL.

[ninja turtle]

Originally Posted by rob4607

So this thrust bearing, for a noob does anyone have a photo of one and where we are talking about? I am assuming that we are talking about a bearing with one side having the raised lip on it but I am probably wrong. Sorry, my kit arrives today thanks to a bunch of amazon gift cards that I found buried in the center console of my truck so I will have 2 builds going at one time, the Yeti and the Yeti XL.

Avid thrust bearing 5x11 Bearing 5x11x4.5 Thrust Bearing Bearing F5-11M

[r6cj69]

Thanks guys. That's a lot of great information. I'll be ordering the required parts today.

[binaryterror]

If you go thrust bearing you need 2. One for the front housing and one for the rear.

The thrust bearing goes inside (closest to the teeth on the pinion gear). You still use a regular bearing 5x11x4 on the side where the driveshaft/dog bone cup goes.

[r6cj69]

Thanks again for the info.
What is you guys opinion on tires? I've read that the VooDoo U4 are nice.
I'd also like to keep the plastic wheels from a cost standpoint. Whats a good wheel for the Yeti? And are the closed cell foams that are talked so highly about a real difference maker? I can't remember the name of the foams but I think it was crawler innovations?

[KellyC]

Originally Posted by r6cj69

Thanks again for the info.
What is you guys opinion on tires? I've read that the VooDoo U4 are nice.
I'd also like to keep the plastic wheels from a cost standpoint. Whats a good wheel for the Yeti? And are the closed cell foams that are talked so highly about a real difference maker? I can't remember the name of the foams but I think it was crawler innovations?

I'm new to RC and am using my Yeti for U4 stuff. I've got a track in my yard.
I've got the RTR tires, the Falkens that came with the kit, and a set of VooDoo U4s that came with a Yeti I bought for parts.

So far I like the Falkens the best. They seem to hook up better on my track and don't want to roll like the VooDoos. However, I don't know enough about foams to know if the previous owner put too stiff of foams in the VooDoos, so I'm withholding judgement until I try some softer foams in them. They seem like they have too much sidewall and are too stiff. The truck bounces and smashes through rock sections but wants to roll over a lot easier and doesn't see to "crawl" over some of the rocky uphill sections of my track.

Regarding wheels, if you want to stay with plastic, look at the new Proline U4 wheels. They are plastic with a metal deadlock. They will likely be what I get, I'm just waiting for others in the forum to post up reviews/impressions. I broke the Methods that came with my kit Yeti, so I'm gun shy about spending more money on wheels until I see how the Prolines hold up.

[KellyC]

Take a look at Teenracer's Yeti build thread:
Marc's Yeti Kit Build

Towards the end of the thread he says he just bought the Proline wheels. I think he's the first on the forum to have them.
He said he'd post up impressions in his thread soon.

[binaryterror]

I pay way less in wheels. Crawler Innovations plastic 6 bolt. Easy to glue on. Lighter which means less drag too.

Tires, I'm using cut Voodoo U4's, really like them. Also with the good Foams from Crawler Innovations.