GPM rear ball diff.

[xxtcrgp]

How come I hear so many complaints about these? is it just because the axel bends? I want to hear all of the pros and cons please, Also whats the diff between 1/8 and 1/16 and which is better

TIA

[xxtcrgp]

TTT

[juan23]

Trip out on that!!!!! No replies WOW.

From a physics stand point, I would choose the 1/16" bearing, it most likely will be a lot smoother than the 1/8".

I dont remeber but I think the peice your talking about uses an aluminum shaft. If it does, well, aluminum is good but I would think that in that part of the car its probibly best to use the stock steel shaft for durability issues.

Hope this helps:D

I used the HPI upgrade.........it worked out perfect.

[xxtcrgp]

thanks alot. But I heard issues with adjusting it. Is this true? because I want to make an order for some parts soon!:D

[juan23]

Not sure on that, but I have to adjust the HPI diff every few runs.

I would think its normal sence the nut is so small. The nylon in that thing barely hangs on.:confused:

If it were me I would probibly base the decision on the price.

[xxtcrgp]

well its 36 dollars on sale for 16. As for your hpi ball diff, try putting 2 nuts on so the changes will be less frequent

[gotspeed_2000]

I bought one of those GPM rear ball diffs. It sucked! I bent the axle without really banging anything! And the worst part is that the axle they use is a specialized part from GPM! I just went out and bought the Team Hommies rear ball diff. It's exactly like the HPI brand but better, the diff gear is made out of delrin instead of plastic like the HPI one. Good luck

[Mykroe]

Does the Team Homies use the stock axle?

[TFRMicro]

Team Homies one is like the HPI ball diff..

[xxtcrgp]

so the answer is yes

[HO502cid]

You might deduce that.

[xxtcrgp]

what? lol

[J Smith]

I love all my GPM parts I use the current:

GPM Front One-Way
GPM Steering Arm
GPM Upper Bulk
GPM Rear Diff
GPM Adjustable Motor Mount

My car rolls super smooth and I had the HPI front one-way and the HPi rear ball diff but I like the GPM better, it rolls smoother and the spur gear from what I heard is made out of Derlin or better plastic.

[T Man]

You can get a titanium shaft for the GPM diff.:D ;)

[gotspeed_2000]

Most other companies use delrin for thier gears, unlike HPI which molds them out of the standard plastic. And yes the titanium shaft is avaliable, but how much and how long will it last? I've seen them from someone on ebay, but how easy will it to get them here and then you have to stock more than one unless your lhs keeps them instock. It's also a matter of how you set the gear mesh on these cars too. I've seen a few micros super tight due to incorrect gear mesh, but on mines, it's super smooth. The parts on my car are:

GPM main, upper and rear (modified to use VCS) chassis plates
Jet motor pod
Team Hommies rear ball diff(had GPM, but took it out.)
GPM front universals
GPM front shocks
GPM front knuckles
HPI Belt tensioner for rs4 nitro modified to fit micro
Hitec 81 mg servo
Tekin G 12CIII speed control
Futaba 133 receiver
VCS rear shock
Orion 6 cell battery
Orion soft tires

[ZeroSanity]

The 1/16" and the 1/8" refers to the size of the balls. I have a powerline diff. I like it alot. Same as HPI but with derlin spur.

[TGRupert]

What's better big balls or small balls?

[xxtcrgp]

hahaha:p

[Downwardspiral9]

I own the 1/16 size GPM ball diff..

I opted to go with the smaller balls becuase i figured that it would probably have more balls than the 1/8th... and i think i was right... (a buddy of mine ((brave_Sir_Robin)) uses the HPI ball diff and its 1/8 and has really really big balls. more balls = smoother diff.

I did notice that the stupid think has to be adjusted by taking the whole rear end out and adjusting the nut inside of the pulley. REAL BIG HASSLE!!! AAAAAHHHH!!!

not to mention that i lost the friggin E-clip that hold the whold diff together...and could run the car for a week or 2... untill i finally got sooo pissed that i took apart a RC10 buggy and found the same E-clip on the fron A-Arm.

OVERALL... im happy... but in the future... im never reccomending the GPM ball diff to anyone....

-Jason

[TGRupert]

Originally posted by xxtcrgp
hahaha:p

I was serious

[T Man]

I think peopoel have a lot of trouble with the GPM diff because the shaft is hollow, not solid.:(

[TGRupert]

hollow shafts are stronger than solid shafts. I saw it on mr.Wizard so it must be true.

[T Man]

rofl. How can that possibly be true?

[TGRupert]

sorry, let me make it more clear. A hollow shaft of the same diameter is weaker, but a hollow shaft of the same weight is stronger. so a slid shaft is less efficient

[T Man]

............................

[xxtcrgp]

Originally posted by TGRupert


I was serious

I know, thats the funny part.

[TGRupert]

After I talk about what size balls are best then I start comparing the diameter of different shafts.

[T Man]

Don't start with that!:rolleyes:

[xxtcrgp]

ah this forum cracks me up:)