Boom Racing XR Axle Review

[OSRC]

I've been happy with my standard "Phat" axles from Boom, and after having my Full Metal Deadbolt get shown up a few weeks ago by an Ascender (in the steering department anyway), I decided to try out their new XR conversion phat axles.

Box arrived, 2 days later after ordering from Asiatees. Strangely, the 2 day shipping was the same price as standard shipping. (expensive, but it sure was fast!)I picked up Boom's knuckles and hubs while I was at it since all I have are some stock beat up plastic leftovers around.


The axles come in 3 parts, a front, rear, and diff cover. All are the same cast metal as the standard phat axles, and feel pretty hefty. Also included are stainless axles and steering links.


View of the axles front and rear before bolting everything together.



I had to tap in the outer pinion bearing, but otherwise fit and finish was good.
Stock gears dropped right in and spin fine, but my HR overdrive gears were very tight/notchy. I tossed in some UD gears and they were the same.... odd. So then I tried a few combos with different lockers and gear combos and found that the stock gears spun true no matter what locker they were bolted to. It was notchy only with OD or UD gears. I can say there was very little play with the stock gears - no shims needed at all, so I suspect the tolerances are just that tight. Or maybe it was HR gears - I don't have Axials here to try. In any case, something to be aware of. For this axle, I used a file and a drill press and turned down the pinion just a hair and my OD gearset then spun smoothly.


Finished up - the fit and finish of the Boom parts overall was very precise. No play with any of the parts, and the entire assembly is very solid. I didn't realize that the axle is a "wide XR" width - it's about 30mm wider than the stock SCX10 axle total. I took some comparison pics next to the hot mess Integy/STRC axle that was on there originally.



And back on my Deadbolt. I forget to weigh the axle, but it's heavy when all assembled. The steering links I'm not sure about design-wise, though the stainless is nice, and the rod ends are aluminum. Feels strong enough. Time will tell. Steering is WAY improved for sure...45 degrees + I'd say. I'll have to swap on some wheels and play with offset front and rear though - it's enough of a difference that it bothers me.




All in all, I'm happy with this axle, and looking forward to trying it out.

[JDMRX-7]

Im thinking of buying the boom racing complete differentials for both front and rear for my wraith. Busted a topcad cvd last week and looking at replacement cost thinking maybe worth the extra dollars to just go alloy. And remove the back lash in front diff and excess play in everything else. Im glad to see this post as i feel more confident in their product.

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[OSRC]

I've had petty good luck with their parts so far. Just waiting on some offset hubs at this point for an offroad test.

[redemon]

I just ordered the axles and the steering links to put into a stock housing with beeftubes.
Hopefully it will work. Lol
If not I might just order this axle housing.

[JatoTheRipper]

Nice write up. Cool axles for sure. Boom makes great stuff. Everything I've gotten from them is awesome. I love the Boom is innovating.

[Natedog]

Yes, nice write up OSRC, love to see the innovation too, steel slides over rocks better than aluminum and plastic. Good to hear the press fit bearings, XR width is what lots of peeps want, I like stock narrow myself, looking forward to your long term test.

[letthebombsfall]

It's funny to think, the more "high-end" companies have CNC milled aluminum everything, which is light and clean and pretty and all.

But for crawling, a cast-metal axle is genius! Cheap, easy to manufacture, puts weight down low.

Great write up! Do they make it in any other colors or just black?

[OSRC]

Yes, I think they come in silver/black as well.

Quick update - I was not happy with the width on my Deadbolt, it just looked off to me. I ended up moving the axle over to my 1.9 Wraith and it is much more at home there. There's not a lot of clearance between the shock and the tires up front - a wider axle solves all of that.

Since my Wraith is CMS/panhard, I needed a new bracket of sorts since the pivot point moved out past the built in mounts with the additional width.


Mounted up and right at home!


Played with the hubs/offset on my Gearheads and got within about 3/4in difference front to back - I can totally live with that.



Clearance issues solved!


Of course, since the rear axle is silver and black, I should have gotten the other color combo to match, but oh well.

On a separate note, while I had the wheels off, I added Prolines new dual stage foams - the tires feel SO much better. I think with the better steering, Front OD, and new foams this rig will totally come to life!

[grunt95]

kinda bad timing but if it would be possible could you measure the thickness of the bottom portion of the case? Where the rocks will most likely rub. They look pretty damn good honestly. Always love your builds keep it up!

[Johan_Eriksson]

I am buying this axle. I'm just wondering what exactly you did to the pinion to make it fit. I have boom racings od gears in my axle today.


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[OSRC]

Originally Posted by grunt95

kinda bad timing but if it would be possible could you measure the thickness of the bottom portion of the case? Where the rocks will most likely rub. They look pretty damn good honestly. Always love your builds keep it up!

I'd be glad to next time I have them apart.

Originally Posted by Johan_Eriksson

I am buying this axle. I'm just wondering what exactly you did to the pinion to make it fit. I have boom racings od gears in my axle today.

It seemed to stick out too far and mesh really tight with the ring gear. I put in in my drill press and used a file to take off some of the metal where it is stepped in size to let it sit in a little further. Didn't take much. Kinda hard to explain..but if you have it all in front of you, it makes sense. If you have trouble, post up and I'll see what i can do to get a pic that would help.

I will again say the stock Axial gears fit perfectly, and maybe the Axial HD or OD gears fit fine - I just did not have them to test. I think mine were Hot Racing, but I'm not 100% sure. Yours might drop right in without issue, who knows?

[Johan_Eriksson]

I just orderd 1 axle.


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[redneck crawler]

I could not get the axial O/D gears to fit in mine. Hell still cant get the c hubs and knuckles on either. Did you have to file down the "tang" where it goes into the locker? mine seem to be holding it out just enough that the knuckles will not go on all the way.
I am hoping it is just installer error.
Has anyone else had any issues?
Thanks

[OSRC]

Mine fit right in, no issues...stock locker?

[JokersWild]

So what's the point of a removable different cover if you can't get the gears out? This has alluded me ever since this axle housing release

[OSRC]

What does that concept have to do with this axle? AR60, Ascender, RC$WD and many other axles use the same basic design.

[Johan_Eriksson]

You dont have to dissasemble the entire axle. You can most likley losen the c hubs and just pull the axles out an it to remove the gears. Also you can inspect the gears without having to do a lot of work.


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[redneck crawler]

Originally Posted by OSRC

Mine fit right in, no issues...stock locker?

Yeah, stock locker.
It seems there are little nipples on the ends of the shafts keeping them from going all the way into the locker. When i force the knuckle onto the C it pushes the locker into the side of the housing where it cannot spin freely. I am going to do a little dremel work and see if it helps.

[JokersWild]

Are we on drugs here?

You cannot pull the locker or gears out of this by just removing the cover. Ar60 is totally opposite. ..... you CAN pull gears from it with cover off.

Only plus I can see is that if you have those "no slop " style lockers you can tighten the screws...... but that's it. Not hard to mod and plug the case like we did years ago when grip fab and vp came out with those style lockers.

I still see zero point in making a axle housing 3 pc if really it act's like a 2 pc.

Also....... no one's really out just " checking out their gear's " randomly lol

[dittohead]

Ive been looking at these axles since they came out and until someone has done some serious durability testing on them I can't see myself running them. The axle shafts are my main concern. Looking forward to hearing about how they hold up