Help! My u-joints are cursed!

[rkcrawlr]

I recently bought a Losi mini rock crawler to see if I liked the hobby. I LOVE crawling, but I keep having the same problem with my u-joints. They keep breaking. I broke one, bought more stock ones, broke two replacement stock, and one more original stock. So I upgraded to some hop up u-joints, and broke three new upgraded joints in one night.

My car is cursed.

This seems like it has to be a problem with my car, I'm not driving it hard, and every u-joint out there cant be bad...right?


thanks for your help,
rkcrwlr

[conejo]

This is fairly common when using an upgraded motor. The extra torque can be a bit much for the stock driveshafts. It's less common with the stock motor. If you're using the stock motor, this is a sign that you're a bit heavy with the throttle. Back off a bit when it's bound up, it's either gonna break loose or break something.

There are a few solutions for strengthening the driveshafts.

1. Use female shafts on both ends. Join them in the middle with the male spliney bit. You'll have to shorten the female ends, but keep them as long as possible to minimize the exposed amount of the spliney bit. I ran this for a while after I got my HH motor, and it worked well. There is a thread on here somewhere with pics.

2. Buy MIP driveshafts. They are machined out of steel, with hex slidey-bits. They are _extremely_ strong, and work better at extreme pinion angles. I have these now, and they rock! I'll break something in the transmission or axles before these break.


There are other solutions out there, but these are the 2 I know about.

HTH,

Rich C.

[stomper4x4.com]

I just got a set of the RC4WD Punisher Shafts as they call them. Looks like they are probably indestructable. I ordered them right off the rc4wd.com website and got them in two days.

[sddill]

Originally Posted by rkcrawlr

I recently bought a Losi mini rock crawler to see if I liked the hobby. I LOVE crawling, but I keep having the same problem with my u-joints. They keep breaking. I broke one, bought more stock ones, broke two replacement stock, and one more original stock. So I upgraded to some hop up u-joints, and broke three new upgraded joints in one night.

My car is cursed.

This seems like it has to be a problem with my car, I'm not driving it hard, and every u-joint out there cant be bad...right?


thanks for your help,
rkcrwlr

Do you have any pics of your set up ?? ..Is it all stock ??

[Kamikaze]

Thats what the slipper is for. Use it, its free.

[soundcolor]

I doubt you are breaking the U-joints themselves. Your most likely breaking the driveshafts. If thats the case and when you broke your stock ones and replaced them with either the Integy, or HotRacing shafts then thats a huge problem right there as they make some pretty crappy shafts. The new punisher shafts should hold up to all the abuse you can throw at them. You may also want to seriously consider adjusting that slipper clutch. Much better to wear out a clutch or gear face than to replace motors, gears, shafts and lockers.

[goodoldlevi]

One of the other members posted these joints
http://www3.towerhobbies.com/cgi-bin...&I=LXGBH2&P=SM

Use them with traxxas shafts and they work great! I used them on my mrc scaler to extend the rear wheelbase.

Here is the link from the member I got the idea from.

Pede Shaft Conversion (w/ PICS)

Hope this helps

[rkcrawlr]

Thanks for all your help, Ive since replaced the losi mini with a axial ax10 and love the bigger size. the guys at the hobby store said it was just bad luck that I broke 7 u joints, I think my slipper was defective, since I never saw it actually slip. anyway, love working on the new crawler, and will probably post some pics of my homemade mods.

[Kamikaze]

Originally Posted by rkcrawlr

I think my slipper was defective, since I never saw it actually slip.

I was just screwing with you........

[QuicherKryan]

Originally Posted by conejo

This is fairly common when using an upgraded motor. The extra torque can be a bit much for the stock driveshafts. It's less common with the stock motor. If you're using the stock motor, this is a sign that you're a bit heavy with the throttle. Back off a bit when it's bound up, it's either gonna break loose or break something.

There are a few solutions for strengthening the driveshafts.

1. Use female shafts on both ends. Join them in the middle with the male spliney bit. You'll have to shorten the female ends, but keep them as long as possible to minimize the exposed amount of the spliney bit. I ran this for a while after I got my HH motor, and it worked well. There is a thread on here somewhere with pics.

2. Buy MIP driveshafts. They are machined out of steel, with hex slidey-bits. They are _extremely_ strong, and work better at extreme pinion angles. I have these now, and they rock! I'll break something in the transmission or axles before these break.


There are other solutions out there, but these are the 2 I know about.

HTH,

Rich C.

I did an internet search. I found MIP driveshafts but not for the Losi MRC.

[joesbruiser]

Is teshaft breaking or the Joint?

My new rig I just built had a set of faulty joints.They were not breaking but the pin that holds the joints together fell out of every Joint.

[binaryterror]

I use Traxxas Stampede shafts....never gonna break.

Use these for the pinion and trans: http://www3.towerhobbies.com/cgi-bin...?&I=LXGBH2&P=7

You will need to clearance the motor plate some and the trans just a touch.

[xzk7nr]

MIP does make Center drive shafts for the MRC. They are sweet!

[rcjunky3]

you can go right to mips website and get them