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R/C Tech Forums Thread Wiki: Xray XB2 2WD Buggy Thread
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Last edit by: dgrobe2112
Instruction manuals: (C/O BentKa)

Xray XB2 Carpet Edition Instruction Manual

Xray XB2 Dirt Edition Instruction Manual

BentKa: Carpet Edition 4 gear to 3 gear laydown conversion parts:
  • Gearbox #323014
  • Motorplate #324012
  • 36T idler gear #324236
  • Brace for waterfall #324031

Socket: Bodies Available:

Xray has two OEM bodies, the .75mm and the .50mm light weight:
light weight: https://www.amainhobbies.com/xray-xb...329701/p492942

OEM .75mm: https://www.amainhobbies.com/xray-0....329700/p477762

Also, I've fitted the yz2 body, both the light and regular fit fine, just make your own cut lines:

[i] J Concepts S2 Body [i]

Penguin Racing makes a high grip body that fits the DE and CE:

Socket: Wheel fitment:

According to some, you'll require different offset rear hexes to use B5M wheels. According to my Hudy setup board, B5M wheels are the same offset. I measured the overall width of the car with XB2 wheels, and then again with B5M wheels, same measurement.

On the front, B5M wheels were 1.5mm wider. Xray offers hexes to reduce width -.75 on each side, or you could spend 3-5 minutes and sand your OEM hexes down .75mm.

edit by dgrobe2112
here are the hubs for losi and AE

for AE Front 365354 -0.75
for Losi rear 365358 +3.00 (4 stripe)
for AE rear 365359 +3.75 (5 stripe)

Socket: Flex and the XB2:

Flex screws are as follows:

Plastic bulkhead between motor and waterfall. Can remove screw in chassis, or remove bulkhead altogether.

Waterfall has 4 screws, can remove the inner two or outer two. IIRC, removing the inner two provides more flex, and thus more bite.

Removing the battery brace. This gives a tremendous amount of flex on the middle of the car, and can sometimes be inconsistent. I do this for outdoor racing on low bite. I like the feel over the 4 gear in 17.5 racing, since the 4 gear will take some snap away off the corner.

Rear C block - has inner and outer screws. I haven't played with this, as it's a crucial pivot point of the car.

Medium arms and towers -> I don't believe the carpet car has the rear medium tower available, however the DE DOES have an optional hard part. I think the hard parts are more consistent, especially when it gets hot (90+ degrees F). However, the medium parts do NOT break unless you're severely talented. They also don't wear out.

Socket: Avid/Schelle Slipper mod:

Credit to WillS, Matt Trimmings, and myself for figuring this out months ago.

Parts you'll need:

B5M V2 3gear compatible top shaft.
TKO Special 5x13x5 bear OR 5x13x6 bearing Either can work. This replaces the spur side bearing on the top shaft.
5mm shims, same shims used in 1/8th scale clutch bells. Look for protek .1mm and .2mm kit.
Avid or Schelle b5m top shaft kit, with spur gears of your choosing. (DE can't handle a 69, the CE can)

Shimming: You'll need to install the bearing in the front portion of the removable piece for the shaft. Make sure the bearing is pushed all the way in. With the TKO bearing, you'll need to shim approximately 1.4mm on the front side of the top shaft. Roughly .3-.5mm with the other bearing. This is a "feel" and tolerance setting. I urge you to watch videos about setting clutch bell play in 1/8th scale to get an idea of what yield you want for end play. Too tight, it'll eat bearings.

Outside of trans case: Use Avid/Schelle top shaft spacer plus .2mm shim to offset slipper from motor plate perfectly. Install slipper as instructed, and use Avid/Schelle spring and XB2 slipper nut.

- NEW - Schelle now sells Xb2 Topshafts. They include a spacer, so no need for shims in gearbox, and comes with the smaller bearing. Both methods work.

Socket: Yokomo Differential or MIP pucks:

Credit to: WillS for figuring out pucks, and as well fitting the Losi 22 diff with the same mods.

Parts needed: Yokomo Bmax2 or YZ2 complete diff OR Mip PUCKS outdrives
Xb2 diff gear
Bmax2 V3 Worlds rear dog bones, or Bmax 2 pucks dog bones
You'll use XB2 axles, and will require no other mods for the axles or dog bones.
You'll need .2mm outdrive/diff shims. Shim approximately .5mm on each side of the diff, behind the bearings. The top portion of the transmission is what "sets" the diff in place, not the bottom half. A little play back and forth is fine, the stock diff has some play from the factory.

dgrobe2112: CE to DE conversion:
along with the parts needed.. you MUST have these following hardware, or it wont work


(3) XRAY 902340 M3x40 button head screws. these are the screws that mount the motor mount to the tranny
(4) XRAY 903322 M3x22 counter sunk screws. these are for the rear diff case, to mount to the chassis. i think i used some M3x18 and they worked ok.

Socket: Best method for setting up the XB2 ball diff:

The XB2 diff is stellar when setup correctly. The spring is too short and soft, allowing the diff to slip. You'll need to glue the rings to the outdrives with just a drop of CA, then add a 1mm shim between the spring and the outdrive. This preloads the spring and stops the diff from slipping so easily.

OR, you can run the AE diff spring, which is both slightly longer, and stiffer. The overwhelming issue is the stock spring allows the nut to bottom out on the outdrive before the diff is tight enough.

This shim:

This diff spring (don't need a shim, then.)


Functional Aftermarket parts: (Not just bling!)

Servo Horn: (The B5M sized horns are too short to get full throw)

Socket: Exotek has a full suite of parts, some bling, some not. Here's a list (all fit DE and CE, unless otherwise noted):

Titanium front axles: http://www.exotekracing.com/xb2-titanium-front-axles-2/

Rear Hanger, HD (Adds 4 grams): http://www.exotekracing.com/xb2-rear...75-heavy-duty/

Brass C block, 18 grams added: http://www.exotekracing.com/xb2-rear...-brass-weight/

Alloy front camber mount: http://www.exotekracing.com/xb2-fron...er-mount-7075/

Carbon Fiber Chassis: http://www.exotekracing.com/xb2-carb...m-plate-2-5mm/

Alloy rear hubs:http://www.exotekracing.com/xb2-allo...ub-set-2-7075/

Alloy servo mounts, allow for use of LP servo:http://www.exotekracing.com/xb2-xb4-...-alloy-1-pair/

Titanium shock mounts: http://www.exotekracing.com/xb2-xb4-...shock-posts-2/

Slipper Eliminator: http://www.exotekracing.com/xb2-direct-spur-mount/
Xray eliminator is #324100

dgrobe2112: 2016-2017 new 3 gear laydown
Gearbox #323014
Motor plate #324012
36T idler gear #324236
Brace for waterfall #324031

dgrobe2112: Xray Spring Rate Conversion:
front C WHT
368174 2 str 0.65-0.85 3.71-4.85

358184 2 dot 0.65 3.71
368185 3 dot 0.72 4.11
368186 4 dot 0.80 4.57

368273 2 str 0.35-0.45 2.00-2.57

368284 1 Dot 0.35 2.00
368285 2 Dot 0.40 2.28
368286 3 Dot 0.45 2.57
368287 4 Dot 0.50 2.86

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Old 02-10-2016, 06:47 PM   #1396
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Originally Posted by suby723 View Post
That's pretty cool I enjoy looking at that picture now haha. Both those hanger screws where always tight and regularly checked and also ran with a chassis protector. It's just crazy that I was literally going down a straight away when it broke. A few pro's also looked at the car and all said it looks like a weak design and should be reinforced better. The car is amazing though and it is the fastest and easiest to drive 2wd buggy I have ever owned.
thats cool you have pros where you run. What manufacturers do they run for? Do you get to see any prototypes?
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Old 02-10-2016, 08:30 PM   #1397
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Inspired by another xb2 user on this thread I've modeled a weight for the rear end of the car that should fit under 5the gearbox. I had a friend print it up for me so I can see how it fits. According to the model properties if made of brass it should weigh approx 80 grams. I could make it in 3 pieces so you can add or remove weigh if desired. If it fits in may have some machined.

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Old 02-10-2016, 09:02 PM   #1398
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Aluminum 7075 T6 is a great alloy. We use it where we can in aircraft. It can be a bit brittle depending on the machine operations and heat treatment/stress relief that is used on the parts. It can also suffer from surface corrosion issues if you don't treat it correctly, but Xray looks to use Cerakote on their parts which is a great coating.

In serious applications you always run finite element stress analysis to know exactly where your margins to failure are. I have no idea if Xray is this sophisticated in their engineering methods. Nor do we know exactly what operations are performed on their parts before they are kitted.

Again, there are lots of possibilities in tracing the root cause of a failure. Manufacturing defect that could affect a whole lot of parts. Like a defective mill bit that leaves stress risers in the part. Substandard material from the supplier that has voids or precipitates, again affecting an entire lot of parts. Or insufficient margin to failure, which could affect every part. We don't want Xray throwing material at everything, otherwise you would end up with a car that weights 1550 grams out of the box. Sometimes you just make a part too thin and need to revise the design to take care of load cases that you hadn't understood at the time of the original design. Hell oxygen embrittlement could even be an issue with this part!

We just don't know enough to trace the root cause, and frankly that is the job of the manufacturer and not the user. I would be happy to offer engineering services, as that is my profession, but I am sure they don't need it.

Based on the thorough nature of the design of the XB2 and XB4, which is exactly what attracted me to them...I would bet that Xray will determine a cause and come up with a corrective action.
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Old 02-10-2016, 09:12 PM   #1399
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I'm sure XRAY does runs FEA on their models...
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Old 02-11-2016, 01:39 AM   #1400
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Well im 99.9% sure I will be getting the XB2 Carpet Edition. I was gonna wait for the Dirt Edition since 90% of the time I run on a medium to loose track but I figure with a ball diff and a few other Dirt Edition parts I should be a happy camper.
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Old 02-11-2016, 02:23 AM   #1401
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If a loose screw breaks the toe block it should still be loose after failure, easy to check.

not having the car and thus going by the pictures the part does look really thin.
A racecar is only as good as the mechanic who build it.
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Old 02-11-2016, 02:54 AM   #1402
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Ahh I remember when xray had issues with their touring car pulling the screws for the ff hinge pin holder through the chassis when released.

Me and a friend questioned it on their forum with picture evidence. Got shot down saying it didn't happen and got banned pretty instantly.

Them eastern Europeans don't like it up em
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Old 02-11-2016, 06:24 AM   #1403
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OK guys, can we move on from the hing pin block? Several have broken one, many have not.
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Old 02-11-2016, 06:28 AM   #1404
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Can we move past this example of one thing breaking. You have an avenue to report it to the people who can help. Nobody on this forum can do anything about it. I hate to say it, but everything can break. We have no idea how he assembled it or used it, except for what he tells us. He is upset, and I understand this. However, trying to get others to join him in bashing the car is wrong. If you are not happy, move on. You were given an option to get the part cheap to help out, that should really be the end of it. The did not help you out so that you can be a d/ck about it. I had a car with the wrong hanger, i did exactly as they said to do and got a new hanger. I provided SN for the 4wd and 2wd models and received hangers for both. If a problem is identified, it will be resolved.
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Old 02-11-2016, 07:54 AM   #1405
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How the heck do you figure im bashing the car!? Read my posts about this car throughout this thread! This car is absolutely amazing BUT the RR hanger sucks. End of story.
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Old 02-11-2016, 09:37 AM   #1406
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Even though the ball diff comes factory pre-assembled I recommend to open it up and add black grease to the thrust bearing and clear ball diff grease to the diff rings and balls before breaking it in


XB2 Ball Adjustable Differential - Set - HUDY Spring Steel™

• For very-low to medium traction tracks
• Increases traction
• Externally adjustable
• HUDY Spring Steel™
• Additionally hardened
• Extra durable
• Long lifespan
• Ultra-smooth operation
• Factory pre-assembled

The XB2 ball differential is recommended for all XB2 configurations when used on very-low to medium-traction dirt or clay surfaces to increase traction. The externally-adjustable ball differential is machined from HUDY Spring Steel™ and is additionally hardened for extra durability and long lifespan. A high-quality carbide thrustbearing and carbide balls are included for ultra-smooth operation. The ball differential comes factory pre-assembled.

#325000 Ball Adjustable Differential - Set - HUDY Spring Steel™ - http://bit.ly/1SKbtRG

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Old 02-11-2016, 10:50 AM   #1407
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And on a positive note Rc America just received the brass front bulk head(26 degrees) and also the battery weight.
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Old 02-11-2016, 11:09 AM   #1408
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Originally Posted by WesRaven View Post
I pre-apologize if this is a question that has been asked before, I don't have a lot of time at the moment to read through this entire thread (although I will soon). I'm seriously considering pre-ordering the dirt XB2 (about 90% there, was about to get a Schumacher KF2 but I reconsidered when I saw this car) and would like to pick up some basic replacement parts since I don't have any X-Ray stuff whatsoever. I'm primarily an on-road guy, and just wanting to play with off-road occasionally, so I'm not looking to go super insane with every hop-up, I just want to avoid ending a race-day early if I break something basic. Or if people have experienced issues with a part included with the car, I'd rather avoid issues and just buy the better part right off the bat.

Anyone have a list of recommended parts when starting off with this platform brand new? I will be running primarily 17.5 on a relatively large outdoor hard packed dirt track.

Edit: One specific question I have at the moment is what alloy servo arm works the best for this car? I assume it comes with a plastic horn, or none at all. Also, is there a preferred servo that easily drops into this car? I was considering a shorty to gain some space for the electronics. The last time I drove an off-road buggy was the RC10 when chassis space was plentiful and pretty much anything fit.
I just broke my front roll center hard plastic last night with a devastating head on with another x-Ray xb2. It was my fault, hit the jump crooked and landed in the straight. His xb2 kept racing, it was fine and I only broke that piece. Luckily the carpet addition came with extra plastics and I was on my way again in the next qualifier and for the a-main. This is a super durable buggy. I've had many cart wheel crashes and other high speed crashes with cars stopped in the straights and last night was my first broken part in the course of two months or so. i will probably be ordering an aluminum one but it's not necessary. I am in the sportsman class because I am still learning to be more competitive and was becoming more competitive until they reversed the layout and change up the jumps. Anyways very durable car and with the extra plastics I wouldn't worry too much about extra parts.
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Old 02-11-2016, 02:42 PM   #1409
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Originally Posted by suby723 View Post
And on a positive note Rc America just received the brass front bulk head(26 degrees) and also the battery weight.
do you know the part numbers for these?
i googled the weight.. is this it?

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Old 02-11-2016, 03:03 PM   #1410
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Originally Posted by BentKa View Post
The solution is to use Loctite on the screws to make sure they don't come loose and protrude through the chassis.

However I'm not saying that for a future release there could be a revised version of the hinge pin holder to make it withstand the stress from a screw coming loose.

But for the moment the solution is to use Loctite to make sure they stay in place.

Thanks Bent.. yes, using loctite on any metal screw going into aluminum is definitely required... both so the screws don't back out, and also so you don't strip out the alu threads by over-torquing.

I'm sure it will get worked out without issue.
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