Boom racing Phat axle xr mod

[Johan_Eriksson]

Anyone have this front axle? I am planing on buying one but I want to make sure od fits the housing. Also if you have it, did you find any issues with the axle?


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[jDtheBEAR]

Yeh I got one and the normal PHAT axle for the rear. Very heavy and strong axles and the turning radius is increased significantly which is what they are designed to do. Issue I found was my front axle gears aren't running as free as the rear putting significant and unnecessary strain on the motor. Still to figure this out-the gears ran free before I put axle together but when secured both halves together they became a little tight and appear to stick slightly every half turn. The gears aren't missing any teeth and aren't slipping. I can only conclude that one of the bearings may be at fault but cant be sure till I go back in and test it out. Either way I don't think it's the axles themselves. Gonna try to turn the gears when axle secured together without the bearings to see if they run free. Make sure you have a decent motor to run it with plenty of torque as they are heavy. Any thoughts on my issue would be appreciated.

[Johan_Eriksson]

Must be a bearing if they are shimed correctly if you ask me.


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[andy551]

I have one I just installed. All stock internals went in with no issue. I then installed an overdrive ring and pinion set. Gear mesh was tight with both axle halves bolted together. Installed one extra ring gear gasket and now seems to be about perfect. Tolerances seem to be pretty good on the axle for being cast and from china. Bearings were all nice and snug and the 4 link mount fit perfect. The only thing I may swap out is the steering tie rod and drag link that came with the kit.

[jDtheBEAR]

Originally Posted by andy551

I have one I just installed. All stock internals went in with no issue. I then installed an overdrive ring and pinion set. Gear mesh was tight with both axle halves bolted together. Installed one extra ring gear gasket and now seems to be about perfect. Tolerances seem to be pretty good on the axle for being cast and from china. Bearings were all nice and snug and the 4 link mount fit perfect. The only thing I may swap out is the steering tie rod and drag link that came with the kit.

Hi andy551, I have just installed Axial overdrive ring and pinion and have found same issue. You say you installed an extra ring gear gasket? which one did you use? and am assuming this moved ring gear slightly to the side to help with mesh issue? I put the axial underdrive ring and pinion in the rear with same issue (tight mesh) but found using a larger bearing to hold pinion rather than standard smaller bearing helped but the ring gear gasket may work better.

[jDtheBEAR]

It seems to be an issue with all underdrive and overdrive gear sets from axial. Tried em in a stock axial axle housing and same issue. They spin freely then 3/4 way round the mesh gets tight as if it's gonna bind. Brand new bearings so not a bearing issue and gears all OK (no missing teeth etc) so not a gear issue although it is odd that it just seems to be in one spot on the gears that they bind a little. Gonna try putting a ring gear gasket between locker and ring gear to see if that helps any as suggested above.