Diff cups from the factory

[Lizardking]

any video of the 30.5 in action?

 

[mooman007uk]

Guys just to let it be known I am not bashing the rampage diffs.....if we don't talk about it and then try and fix whatever may be wrong then we will scare people off.


It's R & D...hell FG still sell their cars with the shit plastic rear diff housing...it's an item that needs replacing before you run it and they're sneaky and sell it after market and don't fit it as standard equipment. been like that for 15yrs.


Everything has it's weaknesses, however i don't believe now it's big motors or diff lube causing the rampage problem, I'll know more shortly after another attempt to break the cups I tempered, i whacked every wheel prior to breakage where it was brought to a sudden stop from speeed, throttle on landings will be a good cause too.


The truck is more prone than the buggy it seems cos of the big tires but the rest of the truck is now near bulletproof with a few mods....I don't think it'll be long before this current minor problem is fixed, no other seller/manufacturer comes close to supporting their customers like redcat, they have addressed every issue because we talk about it openly, they see and they do do fixing pretty damn quick.


My hat goes off to redcat and rampage hopups for their ongoing customer support and for building a great truck.

 

[basher]

keep bashin da hell outa that truuk. let me know if you need co signer to back up your results. I'll pm my address. what clutc spring r u running?

 

[str8jailbird]

Guys just to let it be known I am not bashing the rampage diffs.....if we don't talk about it and then try and fix whatever may be wrong then we will scare people off.
It's R & D...hell FG still sell their cars with the shit plastic rear diff housing...it's an item that needs replacing before you run it and they're sneaky and sell it after market and don't fit it as standard equipment. been like that for 15yrs.


Everything has it's weaknesses, however i don't believe now it's big motors or diff lube causing the rampage problem, I'll know more shortly after another attempt to break the cups I tempered, i whacked every wheel prior to breakage where it was brought to a sudden stop from speeed, throttle on landings will be a good cause too.


The truck is more prone than the buggy it seems cos of the big tires but the rest of the truck is now near bulletproof with a few mods....I don't think it'll be long before this current minor problem is fixed, no other seller/manufacturer comes close to supporting their customers like redcat, they have addressed every issue because we talk about it openly, they see and they do do fixing pretty damn quick.


My hat goes off to redcat and rampage hopups for their ongoing customer support and for building a great truck.

I couldn't agree more Moo. Rob has been nothing but helpful especially with the diff cups that I have broken. Redcat racing support were pretty quick to respond and think VERY highly of Rob and Rampage Hop Ups. I think that should be a feather in his cap after they told me that Rob would have more thoghts on solving the problem and alternative parts that may work (yes Redcat Racing Support deferred to Rob, that is quite a compliment in my book!). The minor breaks and issues are like everyone said. Every RC out there has a few bugs, this just happens to be the Ramp's. In all honesty I would rather have to replace a diff cup vs drive pins. I had a similar issue when my LST2 was new. It kept snapping drive pins in the tranny. A very big PITA that was solved with a piece of coat hanger that is still there and working beautifully after a year of abuse. I think it is a good thing that these mechanical failures are talked about openly not to scare away noobs but to get other ideas for a fix. I am still debating whether or not to have some diff cups milled out of titanium. I found titanium round stock and am waiting on my buddy's dad (he's a machinist) to get the time to do it. I am still considering 4140 steel as well. Regardless my tempered cups are still holding up and I have 6 spares if they fail.

 

[mooman007uk]

just changed 8000 hpi for 7500 ddm much less snappy take off.

 

[speedyd]

i will get some up soon, i took it back out and broke a steering servo , out with gws and in with hitec.

 

[str8jailbird]

just changed 8000 hpi for 7500 ddm much less snappy take off.

Hey Moo, I am running the 8000 HPI. I just did the clutch reversal to lower the clutch engage point. I did the same thing to my 5B SS to make the take offs a little more controllable.

 

[mooman007uk]

I don't think titanium it the right material in a drivetrain, it isn't as strong in that application as a hardened alloy steel and will probably stretch and fracture. pound for pound titanium is stronger but size for size in high stress drivetrain appplication it isn't...sprint should be able to give us the skinny as he's an aircraft engineer.


I believe the dimensions of the existing cups is fine just the metallurgy needs a slight tweak is all. A high alloy steel like 4140 hardened and tempered correctly will probably work but just a different temper on the existing ones may be all that's required.


the ddm is still up there in rpm but just seems way smoother

 

[RampageHopUps]

I will be taking 10 sets over to a heat treater on Tuesday, and we can see if a new hardenss specification will fix the problem for good.


If anyone wants samples, let me know. You have to be an active member with at least 100 posts.

 

[Ron E]

i'm building my mt as we speak, 28.5, sprint77 rear dom, etc... i'd like to put treated ones in while it's apart. so i'm in. let me know how much and i'd like to pre pay for phat dad shock shafts at the same time to make sure I get some asap. I want this thing done. i'm ready to play.

 

[Sprint 77]

I don't think titanium it the right material in a drivetrain, it isn't as strong in that application as a hardened alloy steel and will probably stretch and fracture. pound for pound titanium is stronger but size for size in high stress drivetrain appplication it isn't...sprint should be able to give us the skinny as he's an aircraft engineer.
I believe the dimensions of the existing cups is fine just the metallurgy needs a slight tweak is all. A high alloy steel like 4140 hardened and tempered correctly will probably work but just a different temper on the existing ones may be all that's required.


the ddm is still up there in rpm but just seems way smoother

You give me to much credit Moo I am a aircraft mechanic not an engineer, Although I do agree with you fully the 4140 steel would be better than the titanium for this application, Heat treating the ones we got may help as you said.

 

[Clubin]

I'd volunteer to be a guinee pig. I am sure once the snow is gone I will need more part's.

 

[mooman007uk]

Rob can you send me a sample when you send my other bits...you know they'll get a thorough test in my truck.


Hats off to you again Rob...which other brand name has the backing that we do, I just bought beachthrottles tt he had for sale and am parting out my fg, I can get parts in 2 days, they're cheap, my trucks tough and spends more time running than on the bench and we have the best aftersales commitment with redcat and rampage hopups, and the best community of forum members here.

 

[str8jailbird]

I will be taking 10 sets over to a heat treater on Tuesday, and we can see if a new hardenss specification will fix the problem for good.
If anyone wants samples, let me know. You have to be an active member with at least 100 posts.

Hey Rob, Count me in. So far my Dremeled tempered cups are holding up. I'd like to be a guinea pig! I'd be curious to see if the fix works! I think it will!

 

[Sprint 77]

Rob Put me on the list . I need some to do some more porting work am afraid to make to much power right now.

 

[str8jailbird]

Mooman, I have over 4 tanks through the tempered cups as of today. Still holding up beautifully. I am going to tear down the rear end this weekend, probably Friday to see if there are any cracks, twisting or stretching on the cups. Amazing that this may be the problem, i thought it was the dimensions of the shaft with the larger hole for the new pins at first. This is a much easier fix (and a hell of a lot cheaper!) than having cups made or purchasing aftermarkets. On another note I tried the pinion (A) spur(B) swap to see the top speed. Made one pass and changed it back. Way too much clutch slippage! Granted the top speed was really nice but the stress on the clutch isn't worth it. Maybe just a set of 27/33 for a little more. With the 27/33 how much low end will I be losing? If I do that I just may reverse the clutch shoes back to their original spots.

 

[Piranha2]

I tried the 33/27 and it was "ok" on the street but not great in the dirt, went to 27/33 and when the 77DOM came on it was too fast for our little area we run in so we are back to 25/35 till we go to Foxboro Stadium

 

[yolonda21]

There is no such thing as TOO FAST in Canada....

 

[Piranha2]

Yeah Clubin's got a whole state to run in right out his front door.......I have to drive to find a spot the size of a baseball diamond

 

[basher]

with no diff cups to spare i would love to get my hands on those treated ones. rampage rob put me down for a set pleeeeeeeeeeeeeeeeeeeeeeeeese.