CreationFab Ultra-Lightweight XR Build

[Chris_The_Battery_Man]

I knew it wasnt going to be long before I started another XR. I started to look through all the parts I had, and I nearly had a complete set of axles in my parts pile. Picked up a couple hop up goodies from a buddy, and here we begin.


First things first, were starting with a set of RC4WD gears front and rear. I was able to machine quite a bit out.

The most weight was lost in the lockers. They dont have any holes drilled in em, and are massive.

Figured I would post a few pics, of the weights, of the stock stuff for comparison. I was able to machine out 11g from this bad boy!

Locker machined!


Stock:


RC4WD:


RC4WD Machined weight:




Now on to the 36t gears. 3g lost per gear!

Machined!


Stock gear:


RC4WD before:


RC4WD after:



The attached 36t gear before and after.

Before:


After:



Now on to the shafts. Later I learned that I took too much off the outside, and it hardly sits on the bearing. I guess we will see how long it will last. I drilled out the center some, then lathed down the outside.





Before:


After:



Now the small gears. Drilled the centers out partially. It was good for a gram savings, even with a 1/16" bit partially broken off into one of the gears.

Before:


After:



Now the grand totals for all the gear train.

Stock:


RC4wd Before:


RC4WD after:





Now that the gear train is done. It was on to the universals. They got clearanced some, as well as some drilling. It ended up only being good for a gram per shaft, but hey!... it all adds up!

Dis-assembly:


Drilling the centers of the shaft and stub some:


Before:


After:





On to the housing and such. After comparing the VP upper link mount, and the stock one, the lower most hole on the VP is nearly the same on the XR stock. Thats where I plan to run my front upper link anyhow, so no sense in running the extra weight, or spending the extra coin.

VP mount:


XR:




Now I have heard of folks using the stock center section, the VP trans case, and bearing cap to save weight. I have some stock housings coming to me, but was able to find one to get some comparisons and get at least one axle assembled.

VP:


Stock:



Now for some axle housing shaving. Cut the rubs out of the middle, shaved off the stock little steering link "tunnel", and pressed in some brass inserts.

Before:


After:



On to the assembly... mostly. I had to make a servo mount, get the gears to roll smooth, make a tie rod(6061 hard anodized AL), and make a CF servo mount. Used 99% AL hardware, stock XR trans center, stock upper link mount, VP bearing caps, VP motor mount, VP knuckles, stock chubs....





Thats all for now. I need to grab a couple more bearings, and wait for a few small parts to show up in the mail. Once I start on the rear axle, I am planning on making a set of 7075 shafts. Hopefully that will save some weight. Then once that is assembled, It will be on to the chassis and links.

Stay tuned...

[MitchellY]

Another one of those gram counter threads...... haha JK bro! Looks great and the machining is amazing!

[TSK]

You've been a busy bee!

What chassis you gonna run? The bodied Minimal is tipping the scales at 45g

[Oz Bruiser]

Looking good. After my own weight loss challange on my new build i was happy and seeing what someone can do with all the cool tools etc and save only a little bit more weight saving than someone without all the cool tools encourages me that i did ok lol.

Thanks for posting the detail before and after pics up.

[JeremyH]

Nice work Chris!

[63comet]

Coming along great!

[Charlie-III]

Diet Time!!



Nice machining.

On the hubs, you could use a center drill to make a "cone" to save a little more weight.
How about a little larger bit for some of the other holes? Looks to be enough meat there.

How hard are the RC4WD gears to drill? Thought about drilling mine next time it's apart (I'm a little over due now....).

[now stop drilling gears and get my CBP packs out!.... LOL]

[Chris_The_Battery_Man]

Originally Posted by TheSCorpionKing

You've been a busy bee!

What chassis you gonna run? The bodied Minimal is tipping the scales at 45g

Im sticking with an RT my friend. I love that chassis, and know how to drive it. Got a couple more comps this season and am only a few points out of qualifying for nats. So I cant take any chances trying new stuff I dont know

Originally Posted by Charlie-III

Diet Time!!



Nice machining.

On the hubs, you could use a center drill to make a "cone" to save a little more weight.
How about a little larger bit for some of the other holes? Looks to be enough meat there.

How hard are the RC4WD gears to drill? Thought about drilling mine next time it's apart (I'm a little over due now....).

[now stop drilling gears and get my CBP packs out!.... LOL]

Yeah.... I am not going to waste my time to taper any of the holes lol. Considering it took 2 1/8" holes per small gear to yield a gram....

The gears were actually easy to drill out. I just used a 1/8" dewalt bit I had, and put a little 90wt shock oil on the gear about every other hole to keep the bit from heating up too much. Pretty easy to do in a drill press with a pretty high RPM if you have a nice way to hold it, and use a punch to mark all your holes so they turn out even.

[Frankenwheely]

Things just got interesting.

[TSK]

10-4 good buddy. But...

No lightening of the motor plates or did I just miss it?

And yeah, the rc4wd gears are just case hardened so once you crack through the surfaces, it's just like drilling regular steel.

[Chris_The_Battery_Man]

No drilling of the motor plates. I have found that it takes ALOT of material loss to yield anything significant. I would likely only save a gram or 2 per plate. There are some areas that its not worth it to do that to.

My last rig was sitting at 4 flat with no major lightening. This will have more lightening, so I am hoping to be around 3 lbs 12oz, to 3 lbs 14oz. Time will tell though.

[filotr14lsdude]

Originally Posted by Chris_The_Battery_Man

No drilling of the motor plates. I have found that it takes ALOT of material loss to yield anything significant. I would likely only save a gram or 2 per plate. There are some areas that its not worth it to do that to.

My last rig was sitting at 4 flat with no major lightening. This will have more lightening, so I am hoping to be around 3 lbs 12oz, to 3 lbs 14oz. Time will tell though.

If this is the case,why did you drill the small gear shafts? And the universals?

You only saved 1gr on these. I'd imagine the motor plate wouldn't be as hard to mod.

[Chris_The_Battery_Man]

Mainly because I already had everything setup. Also, I didnt know at the time how much weight I would save. Now that I have something to go by, I know what to expect. On the uni's, I was hoping for more than a gram per shaft, but wouldnt have known until I did it.

[adamargue]

I'm not into comping. My xr10 is siting in a box in pieces but these are my favorite threads. I like seeing what u guys can do to save as much weight as you can. Keep up the good work:thumbup:

Sent from my SAMSUNG-SGH-I717 using Tapatalk 2

[winnerone23]

Originally Posted by Chris_The_Battery_Man

No drilling of the motor plates. I have found that it takes ALOT of material loss to yield anything significant. I would likely only save a gram or 2 per plate. There are some areas that its not worth it to do that to.

My last rig was sitting at 4 flat with no major lightening. This will have more lightening, so I am hoping to be around 3 lbs 12oz, to 3 lbs 14oz. Time will tell though.

It's 3-4 grams a plate.. VP plates down to 6.23 grams.. Started out over 10 grams.. Just for heads up.

[ash38]

Can't wait to see this build progress, I'm about to do a full tear down and do similar to what you've done, looks great,


Sssshhhh

[OFFROADRCKOREA]

Sweet Chris, I saved a bit more on my halls build on the gears i drilled the RC4WD as well, Didnt go as far as lathing the shafts though, respect haha.

LIK

[Chris_The_Battery_Man]

Well, while I am waiting for a few small detail parts for the rear axle, I decided to get the front axle, and empty rear housing hung on a chassis. Pulled the egressor SCX10 shocks off my sporty, and made some links up.

After it was all assembled... I found the wheel base to be 3/4" too short. So I will have to slap on some jato ends on the rear links, and crank the links out a whisker to compensate. The links are all made of hard anodized 6061 aluminum. Pretty stout.

Once I get the rear axle assembled, there should be only some minor detail work, then plumb in some electronics. Trying to get her ready for our next comp which is next weekend.

[slowride1]

looks killer man . I always dig your builds

[Chris_The_Battery_Man]

Thanks man. I think I am just going to use blitz wheels. Shooting for around 3 lbs 12 oz or so, Hard to say where I will end up for sure. I have seen some stupid light XR's. Del Montes RT I saw was around 3.5 lbs at some point. Hoping I can be there also since I have taken every measure to lighten her. But time will tell.