XRAY - Model racing cars

XRAY will be releasing these new pinion gears that use 3 bearings as a new part number, but we have yet to receive them.

I know this goes against my sponsorship, but I feel setting up the car for longevity is more important than sales on a couple part numbers...

I run the avid 13x20 which have a larger outer lip keeping the inner race as small as possible (which is the best situation (I will bore you with the explanation if you would like)). I also ream out the new 'dust cover' extension on the back of the bulkhead, as this just keeps dirt in, decreasing the life of the joint and the bearings.

To recap, run the Avid 13x20mm bearings, take the rubber shields out and point the metal shields to the outside (one facing the driveshaft/center diff and one facing the drive differential). Ream bulkhead to remove the little dust cover as well.

John & Gany:

Below is a picture of 3 bearings (obviously)...
Top: XRAY 13x19
Bottom left:XRAY 13x20
Bottom right: Avid 13x20

See the difference in the outer race of the Avid bearing (bottom right) and the XRAY 13x20 (bottom left)?

Avid kept the inner race the same size as the 13x19 and only changed the outer race to take up the gap in the new bulkhead.

This is also why everybody asking for bigger bearings over the last couple years doesn't understand a bigger bearing is not always better...

When you have a finite space to put the bearing in, you have to keep the size of the balls and the cage that bears them the same size and can only adjust the races to accommodate the bigger space.

When you increase the size of the inner race, you create a longer distance for the balls in the bearing to travel. So if you have the XRAY 13x19 and the XRAY 13x20 and each complete 1 exact revolution, the balls in the XRAY 13x20 will have to travel father by a factor of the change in diameter of the race and 3.14(pi). And when you introduce time in the equation: Say the the XRAY 13x19 and XRAY 13x20 both complete exactly 5 complete revolutions in 2 seconds, the balls in the XRAY 13x20, have to travel at a faster rate to complete those 5 revolutions in the same time as the 13x19.

What Avid did is only change the outer race, minimizing the size of the inner race, thus minimizing the speed and total distance the balls in the bearing travel.


John, more specifically, you should pop those rubber seals out of the Avid bearings and face the metal shields out.

i know you guys are talking about the 2010 808 but for the first time in YEARS i broke some parts on my 808. last weekend my rear bulkhead bearing went out. i replaced them and it did it again. my rear tranny has some wear but i notice that i didnt have the collar in between my bearing. i got my buggy use so i take it that it was the first 808 or a non updated 808.

that is a possiblity. RCamerica has the rings or Im sure Jon over at Carolinas RC can get them for you.

leon

These bearings should be checked quite often. I check them before each race and so far I've only had one failure and that includes the time we didn't even have the collar available (countless hours of driving)! So the key is to check those bearings often. Few times I've found very worn bearings that needed replacing asap! If I wouldn't have checked them they would have failed on me. Usually only cleaning and relubing them is needed.

808 is a high performance racing car and some maintanance is needed. If you race your 808 then check those bearings as often as you can. If you only bash then you shouldn't care if they fail - just replace them after failure

ill get extra bearing and put the collar in. i might get new bulkheads to. my local track got a face lift and with the big air jumps and the sx style whoop section. my car took a beating last weekend. i was lucky to have another 808 racer that had extra bearings to help me out.

Hi Rocco,

I do exactly the same as you, but I put the Avid bearings with the metal side facing the collar and the rubber outside.

Luis Vieira

XRA352076 or XRA352075

which one do i need for my bulk head? not sure why the same part has different part number.

352075 with #355111 pinion gear and 13x19mm bearings
352076 with #355113 pinion gear and 13x20mm bearings

ok, thanks.

so would the 13x20 with collar be a better set up or would it matter.

If you have a 2010 car, you would need the 352076 collars, any other car you would need the 352075.

If you are using the 13x19 setup there isn't a reason to change.

I took aparat one Xray 13x20 and one Avid 13x20 bearing and have to correct Rocco's statment a bit. So here is what I measured with a caliper:

Xray 13x20 vs Avid 13x20
Ball size: 2.0mm vs 1.5mm (huge difference in favor of Xray bearing)
Ball count: 13 vs 13
Inner race diameter: 14.25mm vs 14.0mm (only minimal difference!)

On paper Xray bearing looks a lot better. It has bigger balls (2.0mm vs 1.5mm Avid) and only slightly bigger inner race (14.25mm vs 14.0mm).

I've ran both on my 808 2010 and so far neither has failed. One AVID bearing had HUGE play when I changed it. All Xray bearings have had acceptable play. I do change the bearings often. Clean and check old ones and if they are smooth and with little play relube and use them again.

Hola a todos!!

Solo queria enseñaros una foto de mi XB808 antes de empezar a dar guerra.

Un saludo from SPAIN