Custom Bomber keeps snapping front axle shafts

[Zka17]

Hello! I am new here and need some help...

I have recently built a custom Axial RR-10 Bomber. I am an amateur, but very enthusiastic builder. Have some experience in general rc building, this is my second truck (the first is a D110 Defender). It is intended for general driving, mostly trailing when I am hiking.

The problem is that this thing keeps snapping the front axle shafts!

I have tried the Integy Billet Machined Front Drive Shaft Set for Axial 1/10 Wraith & Bomber (part #C26988RED), and a Heavy Duty Steel Front CVD Drive Shaft Set for 1/10 Axial Wraith 90018 RC Truck from Amazon. Both sets were broken within one hour of mild running (no jumping, no rock crawling).

I am using the following relevant parts (please ask if you need more info):
1. Vanquish Currie F9 axle
2. Vanquish Axial Wraith Stage One Kit - the pieces for the front part
3. The above-mentioned axle shafts
4. Axial Racing Heavy Duty Bevel Gear Set 43T/13T
5. Two speed transmission and transfer case with steel gears
6. Axial Racing Pinion Gear 32P 12T Steel
7. Robinson Racing Yeti Gen3 Slip Unit 64T Spur gear
8. Dynamite Tazer 4000kV 6-pole motor
9. 6-cell NiMh 5000mAh battery

I have ordered the Vanquish VXD Universal axle shafts, but until waiting, I would be interested in some opinions about what could I do to prevent breaking them.

I am planning to step up to 2s LiPo batteries and I am afraid that I will have even more power to break things...

Thanks in advance for your help!

[slowmethinks]

I used the Hot Racing CVDs on my Wraith and busted them in a week. They look to be about the same as the Integy.

I fixed mine going with Axial universals. They held up for over a year. And I'm HARD on my Wraith. That said, I think the Vanquish ones you ordered will be plenty.

[Ninomaniac]

Both seem to be shitty products. Vanquish this and that and then you throw in Integy shafts... whyyy?

[MasteroFlego]

Have you set the steering endpoints properly? Improper EPA can eat front shafts (and servos).

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[Zka17]

slowmethinks: Thanks for the input! Could you give me a part number for the axial universals?

Ninomaniac: Because my Vanquish shaft had not arrived yet... I am not a very patient person, I wanted to drive this truck! I agree, the shafts I used were weak. Any idea on different ones or settings?

MasteroFlego: Thanks - the question is, what is "properly"? I have set my servo, yes - do I need to set something else too? The tires are not rubbing...

[altd896]

Originally Posted by Zka17

the question is, what is "properly"? I have set my servo, yes - do I need to set something else too? The tires are not rubbing...

Tires may not be rubbing but that doesn't mean your not beyond the usable range of the shaft joint, the stage 1 VP knuckles & C-hub have no stops built in like the scale versions do so it's easily possible to steer too far.



I'd drop the front drive shaft off, then while turning the steering via the radio manually rotate a wheel, if it feels at all notchy/binding back off the end point till it feels smooth.

With the VP scale stuff I just turn full lock (knucle hits the stop on the C-hub) & then back the end point off till the servo stops growling from being loaded, then back off another couple of % for good measure.

[Zka17]

Thanks, altd896, will try that!

[durok]

Here are the Axial Universals:

https://www.rpphobby.com/product_p/ax30780.htm

And here's a slightly more expensive & heavier-duty option - Incision VDI Universal for Axial AR60 Axles:

https://www.rpphobby.com/product_p/irc00022.htm

And - if you also break rear axles, try these - Locked Up RC OT Shaft - AR60:

https://www.rpphobby.com/product_p/loc0823-ar60.htm

Or the Vanquish Products AR60 Rear Axle Shafts:

https://www.rpphobby.com/product_p/vps08081.htm

[Zka17]

Hm... increased to 50 degrees (the axial ones)? I really need to measure mines... Thanks durok!

[Ninomaniac]

Originally Posted by Zka17

I am not a very patient person, I wanted to drive this truck! I agree, the shafts I used were weak. Any idea on different ones or settings?

Oh, I can understand that. If I got a kit with a wheel missing I'd probably go run it on three

Dunno, my Wraith came w Axial CVDs stock and they'rere still in good shape, but I run mostly 3s brushed. I did break some stuff while on brushless power but the axles are fine, if a bit sloppy.

[Zka17]

OK, I have measured the angle my front wheels can turn: approx. 40 degrees without the servo. For some reason it felt way more than that...
Anyway, that should be handled by the Axial universals! But will manually test them too as alt896 suggested...

[altd896]

Even Axial universal shafts benefit from a little extra clearancing, at tight angles you'll feel the slight bind, just a touch with a file or dremel (I actually use a linish belt on a bench grinder) on the end of the yoke will take off enough to smooth out.
You can just see the shiny bare metal spot in this pic where I did some XR10 unis in my 1.9 Wraith

[Zka17]

I think, I figured out how to attach pictures...

Here is my first set of front axle shafts:



As said, this happened in less than one hour mild driving. Then I've got an another set, cheaper - and guess what? That broke too...

Again, I just wanted to drive and used what I could get fast.

Then I've got two recommendations from the nice people of this Forum (thanks again!), and both the Axial and Vanquish shafts came in:



I am just comparing the longer side of the two kits here. The Vanquish seems beefier and better made (it should for that price!). I am still deciding which one to build in first... the other will be a backup.

And here is a comparison of the new Vanquish and the broken Integy shafts:



There is a clear difference at the neck (sorry, don't know the correct term), where the Integy let go...

Please, don't get me wrong, I am not saying that the Integy shafts are bad - they just didn't worked out for my setup. Maybe for a stock setup (motor + gears) they would work, they certainly look nice.

[altd896]

Just note that with the VP shafts you'll likely have to clearance the link mount screws slightly for the shaft to not bind on them.

[Zka17]

Thanks for the tip!

[Runfrcover]

Dluxfab.com

If you break these.... you won't break these



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[durok]

Originally Posted by Zka17

I think, I figured out how to attach pictures...

Here is my first set of front axle shafts:

As said, this happened in less than one hour mild driving. Then I've got an another set, cheaper - and guess what? That broke too...

Again, I just wanted to drive and used what I could get fast.

Then I've got two recommendations from the nice people of this Forum (thanks again!), and both the Axial and Vanquish shafts came in:

I am just comparing the longer side of the two kits here. The Vanquish seems beefier and better made (it should for that price!). I am still deciding which one to build in first... the other will be a backup.

And here is a comparison of the new Vanquish and the broken Integy shafts:

There is a clear difference at the neck (sorry, don't know the correct term), where the Integy let go...

Please, don't get me wrong, I am not saying that the Integy shafts are bad - they just didn't worked out for my setup. Maybe for a stock setup (motor + gears) they would work, they certainly look nice.

Integy shafts ARE bad, but it's not your fault you got caught up in the advertising.

Integy parts are really best avoided unless they are just for show, not in an area where strength is required.

There are several manufacturers that don't use the properly heat-treated steel, or the right alloy of steel for their axles.

It takes some time and word of mouth for the lack of quality to be made known to everyone...

[slowmethinks]

I finally got around to replacing my busted Axial Uni tonight. I just went ahead and swapped them with new Axials. They've held up for over a year of hard abuse.

Enjoy the carnage.

[Zka17]

Finally I've got some time for my front axle! I thought that I will change the axle shaft in few minutes, then I will be ready to ride. Well it was a wishful thinking... there are always surprises!

First of all, here is the last broken shaft:



As said, I've got it from Amazon, very cheap, until my Vanquish ones would arrive. I was prepared to see something similar to what I have found with the Integy shafts, but this is different... Do you see that brass ring (green arrow)? Now that suppose to all the way to the right and cover that hole... in which suppose to be a pin to hold together the two parts... well that ring is moving left-right freely! Simply I just lost the pin and the front wheels disengaged! If/when I figure out how to hold that ring in place, these axles will be still usable.

Then I went ahead to insert the Vanquis VXD shaft... and something is wrong... Can you see what's wrong on the picture?



How about now?



Yeah, I could not insert them completely... I had to disassemble the whole front axle! That's where my ride time went...

These spools are different:



Both are from Vanquish, but the new one which came with the VXD shafts has a square hole (left side). Yeah, I know, if I would have read before the description... Just to note, the new spool fits only the VXD shafts, no Axial or nonane shafts from Amazon...

With the new spool, the shafts fit perfectly:



Magnified:



Then I went ahead and mounted the knuckles and the tie rod. Very slowly was turning the differential's input shaft while moving the steering from one side to another and tried to find an angle where it would bind. No binding even if forcing the steering to the max (the servo won't do that, it is slightly reduced). So, I hope it will work...

[durok]

BTW - I finally built up my Bomber axles - I'm using the Incision VDI Universal for Axial AR60 Axles parts in these - I'll let you know if I break them! :