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Front Axles Chromoly VS. RCV Axle

JoeLopezTexas

New Member
Joined
Jun 22, 2014
Messages
4
Loc.
Austin, Texas
Y'all! Seeking Front Axle Knowledge

Which route would you choose?

Trying to figure out which route to take with my front axles. Have a 77 bronco, 4.88 gears,locker in front and back, 37" tires, 3.5" suspension, 3" body to fit tires, 302 with c4 3 speed...

I want the strongest most durable wheeler and not concerned with street performance.

1. Regular Chromoly axles (i.e. Yukon, 4340 ChroMo Wildhorses) both inner and outer with CTM u joints

2. Moser Chromoly Axles both inner and outer with CTM u joints

or

3. RCV CV axle set with RCV Drive Flanges


Thanks in advance...
 

bronconut73

Contributor
Bronco Guru
Joined
Aug 7, 2012
Messages
9,908
RCV CV axle is the strongest thing out there right now.
Just real expensive and you need to use '78 or '79 Bronco or F-150 knuckles so you will have a big enough hole to slide that CV through.
 

bmc69

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Jun 11, 2004
Messages
11,449
I have snapped like matchsticks literally every aftermarket axle made in the last decade. I'm installing the RCVs now...(I shoulda done that years ago..I've been an RCV OEM account since 1999....%))

From everything I've seen, those CV axles should be the ones that hold up. We'll see soon enough.
 

Broncobowsher

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Jun 4, 2002
Messages
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I take it you are just asking to confirm that the RCV is what you already decided on.
 

stlo

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Mar 1, 2011
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Loc.
tulsa
They can be installed if u have the chevy breaks as well.... But u have to put the inside in with the boot and then put the knuckle and outer shaft on at the same time....it's a pain but it will work.....not something I would want to do all the time......
 

mp

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Dec 22, 2001
Messages
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I was on the fence in the same position after snapping my stock full width D44's at an event--RCV's or cro-mo with top shelf joints? Actually witnessed a guy blow up an RCV at the same event. Did some cost comparisons and looked at warranties. Wound up cheating out with a set of Yukon cro-mo's with the 300m Superjoints. Wheeled them hard once since install at Clayton, OK. Followed a guy with RCV's, watched him blow one up, and took same line. Yukon's held up--no breakage. Pretty happy with my decision.
 

67EB_in_619

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Mar 6, 2003
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San Diego
The RCV shafts arent any stronger than a chromoly shaft.. the magic they have is the elimination of the ujoint in favor of the spherical. Ujoints and the ears they attach to on the shafts are the weak point... if you CTMs or similar, your weakpoint is now the ears of the shafts. I have grenaded two of those in the last two years... both times I warrantied the Yukon shafts and rebuilt the joints and was good to go. I am tired of breaking ears and spending hours fixing shit on the ever more rare wheeling weekend. I pulled the trigger on "worry free wheeling" and bought RCVs. I have to swap knuckles out because I know nothing is bulletproof and dont want to have to take the knuckle off to put in a spare.

I will bet you the guy who broke the RCV on that same line you took either had more HP, heavier truck, less finesse, heavier right foot or all of the above.

RCVs are as strong when turned as they are when straight... NO ujoint axle can say the same thing. Period. End of story.
 

brewchief

Sr. Member
Joined
Feb 11, 2007
Messages
833
Before I dropped the coin on RCVs I think I would have to seriously consider going to a dana 60 front, if you find that the RCVs aren't enough your pretty much maxed out, 60 with decent shafts could still be upgraded.
 

bmc69

Contributor
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Messages
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Were I to do it over again, my '69 would definitely have a D60 front axle.

But I'm not going to do that one over again...so I'm trying the RCVs now. ;)
 

pbwcr

Sr. Member
Joined
Jul 11, 2007
Messages
617
The alloy axles that use forged 4340 are less strong than the 300M RCV axles. However the yoke on the 4340 axles is defiantly not as strong as the RCV CV joint. Both are a huge improvement over other axles.
Before RCV we had Superior axles made from Forged 4340 that company folded due to bad business practices. The employees have now created a new company called Revolution gear & Axle. The sell the same product as Superior sold.
Now we have a new standard in the RCV axles. They use 300m material and that has always been the choice for the highest strength. Trouble is that material costs more and the extra machining for the CV just adds more cost.
Its always about cost vs benefit. If one does not care about cost for a small increase in strength over the strongest non CV setup then for sure get the RCV

If I did it all over I would choose RCV if I could be sure it had no fitment issues.
PaulW
 

KyleQ

Bronco Guru
Joined
Apr 24, 2008
Messages
5,480
IIRC D44 RCV's are about as strong as stock D60 stuff without the extra expense and weight of a D60.

That being said - I've killed a lot of D60 stuff, and due to the cost I'm running Yukon 4340 shafts and joints.

If I were to do it all over again I would have at least tried the RCV stuff before going D60, it didn't exist when I was building.
 

Skiddy

Bronco Guru
Joined
Oct 8, 2003
Messages
11,543
I was on the fence in the same position after snapping my stock full width D44's at an event--RCV's or cro-mo with top shelf joints? Actually witnessed a guy blow up an RCV at the same event. Did some cost comparisons and looked at warranties. Wound up cheating out with a set of Yukon cro-mo's with the 300m Superjoints. Wheeled them hard once since install at Clayton, OK. Followed a guy with RCV's, watched him blow one up, and took same line. Yukon's held up--no breakage. Pretty happy with my decision.

i just got some cro-mo, i hope they will hold up pretty good. will see in a couple more months
 

welndmn

Bronco Guru
Joined
Nov 12, 2001
Messages
2,112
I'm still not sold on the RCV, too many ultra 4 guys took them out because of "strange issues". I'm still a fan of the factory 10 shafts with CTMs.
 

bronconut73

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Aug 7, 2012
Messages
9,908
In my experience a little finesse goes a long way.
I have seen more front lockers break more shafts than anything.
Once you bend the shaft at the u-joint your fun is done that day.
RCV's are just too expensive for me right now.
I went to WH for their chromoly front with Yukon Super Joints and 1541 rear axles.
Detroit locker in the back with a Detroit Tru Trac in the front to hopefully reduce front axle breakage over a locker.
If I break my front axle shaft and have to go RCV's I will come back to this thread to let ya'll know I am saving my money for RCV's.
 

ransil

Contributor
Bronco Guru
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Sep 6, 2003
Messages
8,092
whats the cost of of good axles & u-joints vs RCV's i have not looked them up in a long time.
 

xcntrk

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Jan 12, 2012
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2,473
Loc.
NOVA
One of the downsides of going with a solid body and cap style joint, such as the Yukon Superjjoint or CTM, is that without any needle bearings the trunion & cap require a lining of grease in order to rotate and retain proper movement. These joints are greased directly through the caps. Also as they spin, they consume the grease and therefore it’s necessary to lubricate them nearly every single trip (aka grease 8 caps everytime you go wheeling). Sort of a PITA. Also they don’t recommend any high-speed rotation (aka 4-Hi) due to this nature to sling the grease out.

I don’t know what the maint req are for the RCV joints, but if I had to do it again I’d look at them to overcome these two issues.
 

snipes243

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Oct 12, 2006
Messages
1,241
Loc.
Huntersville, NC
I run the RCVs on 76 disk knuckles. All I had to do was grind the ball joint studs down to clearance the cv boot. I went with lockouts for 2 reasons first they were cheaper, second it provided a fuse so i would risk breaking a ring gear.
 
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