thats a sweet truggy brian its pritty small once you compared it to the jato. I never had any good clarification, but does a normal kyosho plastic spure fit on these small center diffs? and the HB 10's?(Talking about the crt.5 and lightning 10 buggy?)

I *think* it fits. The spur looks like the same size (diameter) and gear pitch as the metal spur from my Hyper 8. The only difference I can see is that the diff cup is much shallower on the .5. I ordered a 44T and 46T plastic spur from Mike so we'll see. I also ordered a couple of Ofna gaskets from Tower in case I need them to space it a little since I needed to do that to the Hyper 8 diff. Tower lists this same gasket for the Hyper 8 and the CRT .5 so I'm guessing everything will work.

It looks and feels like a solid little truggy, so it should be quite tough. And since it has a typical b/truggy layout, working on it is a breeze. The only thing lacking is battery room, so I'll probably mount the lipos on edge instead.

Overall, I'm pretty excited about getting it done!

Brian you are killing me! Mine is still on backorder. I've seen a couple pop up on ebay so looks like they're slowly being distributed. I'll be keeping my eye on your build and taking notes!

lol, sorry. :)

I thought mine wouldn't be available for a while either the way the store was jerking me around. That's OK though, this will give me a chance to make a mess of my setup. :)

@BP-Revo - Here are your measurements:

http://scriptasylum.com/forumpics/crt5measurebi6.jpg

All measurements are in mm (in case in wasn't obvious ;)) and are pretty accurate +/- 1mm (mostly they are spot-on).

The extra 32mm measurement is how much room between the largest part of the spur to the edge of the chassis. Actually, it is really 33mm, but I figure an extra 1mm for safety is in order. You didn't ask for this, but I assume you would want to know how much battery clearance you have. It looks like it's further out from the spur, but that's just because of the angle of the pic.

The motor mount is all done... except for the adjustment slot (like the stock emaxx mesh adjustment scheme). That's the part I hate because if I slip, the slot is too big, uneven, or just ugly and I have to start all over.

that thing is soo sweet, It MUST handle like a dream!

I can't beleive that chassis is 152ft long - thats huge! Where'd you get a measuring tape that size? :D

lol just kidding - Thanks Brian! :)

Whoa...that IS pretty narrow though. I think I'll be mounting my packs verticle just like you are.

Could you actually do the same measurement on the otherside of the center diff/spur? I'd like to know how much clearance I have there now that you mention it.

I was going to mount one pack on each side in a saddle arangement, but now that you mention it, I may be mounting just one large on on the left side...

Hmm....this brings up alot of new things I have to think about.

@Mike L: Well, it does handle pretty good, but it's tough to drive and push it at the same time. ;)

@BP-Revo: lol. It would take one heck of a motor to push a 153ft buggy. What would that be; 0.1 scale? ;)

Well, the CD is actually perfectly centered, so the same measurement works on the other side. If you do a saddle pack, the motor would have to sit in front/side or on top, and there's not much room for the motor unless you put it in front and move the diff further back. But then the brace would need modding. The truck body may interfere if you try to mount the motor on top. Of course, I'm thinking of an S size motor. You might have more options with a smaller motor.

I'm going to use a 1525 or 1530 motor (or maybe the new 1535 motor). I was originally thinking of a 1525 since the 1530 is pretty long, but seeing how the buggy is still pretty heavy despite its size, I'm thinking of opting for the longer motor for the torque. I'm not worried about the current since the Mamba Max can push any current these motors require.

I was originally going to mount it up top over the rear dogbone, but I think I will now be mounting it behind the servo, with the can toward the rear. Then, I think I should be able to easily squeeze the Mamba Max ESC behind it. This way, I'll also be able to easily take advantage of both brake linkages in stock form, which is what I wanted to do.

I will mount my receiver wherever room appears on the chassis (its a Spektrum Micro SR3500, so its really tiny anyway).

I'm actually thinking of running a 3S now so I don't have to deal with a UBEC. This is kind of bad...I've gone from 8S to 4S to 3S... So much for a High Voltage project lol.

I'm going to go look at the FlightPower size charts now lol...

I think some saddle packs, like the ones Maxamps has would be a decent choice. Then put the motor opposite the servos and you should still have room to leave the throttle servo...

Well, finished the motor mount. Came out pretty good. I "machined" the slot using this Dremel bit. It's a little smaller than the 1/8" I need, but that gives me a little room for error. Then it's just a matter of slowly and carefully grinding away.

The MM motor is from the Jato so don't mind the condition. It's just for test purposes. :)

http://scriptasylum.com/forumpics/crtp5_test1.jpg

http://scriptasylum.com/forumpics/crtp5_test2.jpg

it looks nice! where are you going to mount the mamba?

Thanks! Probably on top somewhere. I'm thinking of making an integrated top plate/ESC mount/Rx mount. Might even connect it to the battery tray to make everything sturdy.

Nice job! That motor mount looks like it was made by a pro - and nice idea using the brake caliper mounts for extra support.

I have another favor to ask though - could you get a picture of the servo and how it mounts? I saw the little extension tab there and was wondering if a larger servo would fit in the same spot. Or you could just measure the distance in between the servo mounts (which would be easier, and better).

Thanks Brian! :)

I think I've found my setup though. I'm going to run a 4S 3300mah Flightpower Pack on one side, and try to mount everything else on the otherside.

Lol, I don't know if it looks that good, but I'm happy with my Dremel work. :) The little "extension tab" you see in the pic is so you can use a Futaba servo. There are apparently two different sizes of "mini servos", one 3mm longer than the other. I didn't measure, but I can say with confidence that a standard servo will not fit there unless substantial mods and changes to layout are made. A full size servo looks like a monster in comparison. Just think of the little shifting servo that comes in a stock Revo and you get the idea.

4s on this little thing?! :dft002: You want to make it literally fly or something? :) I think I'll stick to a lower voltage setup because 2s of those 5Ah Maxamp cells will fit nicely in there. And I won't need a UBEC either, which makes it simpler.

Looks really good Brian! How thick is the mount, 3mm? Is there any flex?

Bye:018:

Well, I'll think about it. I want to do 4S, but I don't want to deal with the UBEC...its quite a decision.

That thing looks very nice! Sorry if you said this already, but how much was the CRT .5? Was it a roller, or a whole kit?

That was the ARTR kit, which consisted of everything except motor, electronics, etc. Basically just a rolling chassis. It goes for ~275-280.

There is also a RTR kit which is due to come out sometime in the near future.

I think I've got my CRT .5 setup nearly figured out. I'm going with the MM ESC and LMT 1530.

For batteries, I'm thinking of using my current Maxamps 8K 2S2P's if they don't sell. They are a bit heavy, but I'll get some MAJOR runtime and they will easily supply enough current.

@cemetary: It's actually ~3.5mm thick. I use the same material and setup in the Jato and am still using the same spur as when I got it and I've run it dozens and dozens of times with no issues. So, if there is any flex, it's very minimal. Besides, the motor is shorter (less hanging off the back) and lighter, so there are far fewer stresses on the mount, even when landing from a jump.

@BP-Revo: Don't let the UBEC sway your decision! Sure, it adds a little extra wiring, but not too bad if routed right. Besides, you could get a high turn motor on 4s and have tons of runtime even with only a 1p setup. I'm going 2s mainly for the size of the cells and the weight. The BEC part is secondary really.

@green24: BP is right, ~$275 for the "pro" kit which comes with the F/R ends assembled. You just have to assemble the shocks and servo area. It doesn't come with any electrics (servo, receiver, etc) and no motor. Perfect for BL conversion! :) The RTR will come with just about everything to run, but will have fewer of the hop-up parts pre-installed - like the CF servo area, upgraded chassis, etc. Only the pro kit is out right now and even then they seem to be a bit hard to get a hold of. My LHS said that Ofna should be shipping the next batch if they haven't already.

BP: let me know how that LMT works for you. I am just using the MM 4600 for now to see how it runs and how much power it has/needs. It should run quite cool since this will weigh about the same as the Jato (using the same motor/ESC/voltage) but not go as fast.

I'll let you know how the LMT works - but take note I won't have it for a while. I really want to get the CRT.5 in my hands so I figure out my setup and order the motor (since the motor will take ages to get here).

I guess I'll go with 4S. I wanted to from the beginning - I'm going to go post a thread on UBEC's now...since I can't find any that suit my need.

If Mike's UBEC won't work for you (it is kinda big), I've used this UBEC with good results so far (just the BEC in the link, not the ESC :)). I took off the heatshrink and studied the circuit. The IC it uses is a nice chip and the circuit design is pretty much verbatum from the IC datasheet suggested circuit setup. Very simple circuit too. I put on longer wire and re-heatshrinked it and it has worked great. However, I always use a capacitor on the AUX channel on the RX to help filter any switching noise.

These UBECs appear on eBay from time to time for about $10-$15 shipped. I have seen them at other online stores, but can't recall which at the moment.

Don't get me wrong; I'm not trying to steer business away from Mike, it's just that the Koolflight UBEC is kinda large for such a small vehicle.

Thats the one I have as well, Brian. I added different wires and reshrunk it as well (didn't like the red). BP, check the other thread. I suggest you use the ParkBEC from Dimension Engineering. Its super small...

The mount looks great Brian. Its hard to tell from the pictures how big it is, but it seems as if you will have a pretty close fit withe the rest of the electronics. Anyways, good luck finishing it, and can't wait to finally see it run!! :027:

The mount is exactly the height of the CD mounts, and it goes almost to the edge of the chassis (actually, it goes to where the edge starts bending up). The batts are going to go on the other side and the electrics are going to go on top of a custom top plate. Actually, I did notice there is a little flex in the chassis (no more than normal for buggies really), so I think I'm going to make a top plate that hooks to the front and rear diff areas to stiffen it up. This will also give me plenty of room to mount the MM ESC and Spektrum Rx.

sweet man!

lol but ur not the first ;D

a guy at my local track has a converted crt.5, its sweet, i still would of dumped it for my cyclone, but its awsome! hes using a mm 5700kv, and a 2 cell lipo

he isnt on the fourms but i need to get him here so u guys can see it! buts its sweet!


jw, sorry if u already said this but what motor are u going to keep running?

Thanks! I didn't didn't intend nor think I would be the first to convert a CRT.5, so that's no biggie. Actually, I like to look at other conversions to see how things could have been done differently/better/etc.

I'm planning on using the 4600 on 2s lipo. I like the slower motors. :)

And yes, you MUST get him here. That's not a request... ;)

I like it so far!

I bet it will be a fun ride!

Why didn't you made the motormount of perfect 90 degree stock aluminum (without the round corner) so the motor sits on the bottom of the lower plate? it gives it a nice stability.

Allthough you would need two straight slots to move the motor instead of 1 round slot with 1 hole.

Three reasons: 1) I already had the stock, 2) when I ordered the angle, the only thing available in 6061-T6 at onlinemetals was the one with the rounded corner, and 3) I wouldn't be able to use stock screw locations to tie down the mount to the chassis because the motor would hit the screw ends.

And yes, I would have to "machine" two slots instead of one (and one was bad enough!). Even so, there is virtually no flex in the mount, so I think I should be fine.

yeh his pulls wheelies with a center diff:004: :018: :017: :028: and she just flat out huals!!!!!!!!!!!!! urs looks alot cleaner tho, lol u did the motor mount very well, i guess after u have done so many they get simple a? lol it looks almost perfect

Lol, never simple, but they are getting easier since I've done a couple of them. My conversions are usually clean becauseI figure if I'm gonna go through the trouble of doign it, why not do it right. :)

Brian;

point three; doable; flush the screws to the top, and use red loctite. Nitro engines are held down the same way.. And they shake like crazy..

1 and 2 are not arguable.. :)

Actually...I've never locktighted a single part around my engine assembly...(knock on wood) - nothing has happened...

I don't have much luck with tapping threads into aluminum for some reason. Plus, being only 3.5mm 6061, I'm concerned about the threads holding up. At any rate, I don't want to rebuild the mount simply to have tapped holes. :) The top of the motor doesn't even go as high as the top of the diff mount so it shouldn't be too bad. If anything, I'm more worried about my batteries because they are going to have to sit in there edgewise to fit, which will make them quite tall...

thats looks awesome. looks like you will have just enough room for the 5000mah cells too. I just saw one of these in person yesterday for the first time(test for rcdriver). First thought was converting, but didn't know if there would be enough room for the battery.

I would like to stay with 2s so that way I can use the same pack as my MF2. I will definetly be checking to see how the mamba works for you and if the kyosho gears will work. If they do then I think this will be my next car.....

Brian i like what i see .

OK, bad news. :007: The Kyosho spur physically fits, but is quite a bit too thick to fit the diff holder. The steel spur is formed differently to be as thin as possible - way thinner than the Hyper 8 spur for example. Not only that, but the existing diff doesn't use your typical sized bearings. The stock bearings are 15x10x4 (OD/ID/W) compared to whatever size the typical diffs are. So, my choices are:

1. Try to find bearings that will fit the stock mount with the Kyosho diff. I would need 15x8x4 (od/id/w) bearings, which I cannot find for some reason, not even at Avid. If I go with this plan, the diff mount has to be moved back a little (not a big deal) and I'd have to modify the Kyosho spur since the diff outdrive is too short to go all the way through the Kyosho spur and still be able to use the retaining pin (inside the diff).
   
   
2. Keep using the existing diff with the steel spur, get a steel pinion, and take my chances with the wear. However, 1/8" bore Mod1 pinions are not available anywhere.
   
   
3. Get a regular center diff with mount (although I think I can use the stock mount from my Hyper 8), install the Kyosho spur, and remake the motor mount.

Neither of these options is very appealing, but #3 sounds like the best bet from a part availability standpoint. Option #2 sounds like the easiest, but the pinion is not available and I'm not sure on the steel-on-steel idea.

Any suggestions or other alternatives?

Brian try looking here.

http://bocabearings.com/main1.aspx?p...esearchbearing

Sadly, niether Boca nor Avid has the size bearings I need.

I spoke with glassdoctor a little while ago and he wanted some pics, so here they are:

This image shows the insides of the various spurs. From top left: CRT.5, Kyosho, and Hyper 8. Right away you can see the CRT spur is shaped differently and has less depth.

http://scriptasylum.com/forumspics/crtp5_diff_1.jpg

This image shows the top view and you can see the bumped out part of the CRT diff that makes it so low profile.

http://scriptasylum.com/forumspics/crtp5_diff_3.jpg

This one shows the difference in collar size/depth.

http://scriptasylum.com/forumspics/crtp5_diff_4.jpg

This one shows one of the outdrives and how short it is. This is why it won't fit on the Kyosho spur. If I shave enough off the Kyosho collar for the outdrive end to reach the other side, there isn't enough room for the bearing. I can't use a regular 1/8th scale outdrive since those are made for much larger dogbones.

http://scriptasylum.com/forumspics/crtp5_diff_5.jpg

There is no O-ring in the diff, just this plasticy gasket. Maybe this is why there are reports of leaks? I replaced it with 2 of the Ofna paper gaskets.

http://scriptasylum.com/forumspics/crtp5_diff_6.jpg

This one shows that even when the collar of the Kyosho spur is shaved down, the other end of the outdrive is still too short. Any more shaving and the bearing on the collar won't fit.

http://scriptasylum.com/forumspics/crtp5_diff_7.jpg

This one just shows the stock bearing on the Kyosho. Doesn't fit well obviously. :)

http://scriptasylum.com/forumspics/crtp5_diff_8.jpg

Hope this helps you visualize what I was talking about glassdoctor...

OK, how about this for thinking outside the box. I trimmed out the inside of a 44T spur and press fitted it on the diff case. I just don't know what to use the secure it there without it slipping. Maybe drill some pins into both spurs? I want to be able to replace the spur if needed...

http://scriptasylum.com/forumspics/crtp5_diff_2.jpg

http://scriptasylum.com/forumspics/crtp5_diff_9.jpg