RC-Monster Forums - Hot bodies 1/8 diffs

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- - Hot bodies 1/8 diffs (https://www.rc-monster.com/forum/showthread.php?t=30169)

Quote:

Originally Posted by RC-Monster Mike (Post 413915)

Even 50K in the center will allow wheelies at will, Mike - I can wheelie my truggy with 10K from a standing start on grass. 50k will allow some give while feeling largely like a locked diff. 300K is totally defeating the center diff - I don't think this is the root cause of the problem, though. The servo saver would be a primary candidate, along with linkages and bearings. A plastic rod end could be cracked but not broken, for instance - you wouldn't see the problem, but it would pull away/flex under stress when in use. A stuck bearing could also create the pull - there should be signs of this if it is the case(scars on the shaft it rides on, for instance). If you are using 1/8 diffs with diff outdrives, it could be as simple as a loose set screw on one of the drive cups(would send power to only one wheel and eventually diff out to the wheel not receiving power). The truck should accelerate nice and straight without the D-box.

Mike I am using a dual servo saver setup, and they are all metal (from Golden Horizon) The bearings are brand new. Very little on this truck is old. In fact the only "used" things on the truck would be the MM motor and ESC. All bearings on the truck are brand new. Do you think the dual servo saver setup might be too stiff? I'm using dual black springs with this set up.

If you are using servo mounted servo savers then that is most likely the problem - they don't make those things stiff enough to handle the torque load your setup dishes out. I suggest finding a UE servo saver or even the Proline version(I have a couple around if you need one) - the bellcrank saver design is far superior to the old school 1/10 servo mounted pieces of crap. To verify whether or not the savers are the problem, simply remove them and replace with solid servo horns(try not to hit anything when testing). If the truck suddenly drives straight, then search for the savers mentioned above. :)

Mike I have dual bellcranks (all metal from Golden Horizon). Do you think the Proponents or UE designs offer better performance?

Metal bellcranks aren't directly the problem - soft servo savers are the likely culprit. The UE servo saver is part of the bellcranks and is superior to anything else made(it is a typical 1/8 buggy style servo saver setup). The Proline setup mentioned has been out of production(like the UE) for some time, but is also a bellcrank 1/8 style servo saver setup. Your truck is deserving of the UE saver if you can find one - servo mounted savers won't get it done for your beast. I have 4 UE savers, but they are each on different trucks and not for sale.

Can you use dual servos with the UE servo savers? I think I will wait till someone puts a UE servo saver up for sale on ebay. I had the chance to buy two or three as I was putting this truck together, and I'm now kicking myself for not getting one of them. I will just have to wait as usual.

Dual servos is accomplished with linkage - the bellcrank setup is largely the same as stock so it is no problem to use dual servos(although dual servos is not necessary - 1 good servo is the ideal setup).

Thanks Mike, as soon as I can get my hands on a UE servo saver I will install and I'm sure it will fix the problem. On to my next build. I just got my pair of Hot bodies 43t 8028 ring gears and that completes my parts list. I can now start my build. I will not do another complete build thread, but I will post pictures when I can.

Well I just bought a gen 4 UE servo saver and can't wait to install it:yes:

Congrats, those are to come by. How much did you pay for it if you don't mind me asking?

$95.00 US. I also got the spring pack from UE $12.00 on the way.
http://www.ebay.com/itm/160688343760...84.m1439.l2649

I have not heard back from UE on my spring package, is this common procedure? They took my money though. This is the first time I have ordered from them directly.

Yup, that's common. There is no more email or anything after Sam left the place and let Robin do everything. You'll get it though.

Quote:

Originally Posted by George16 (Post 414674)

Yup, that's common. There is no more email or anything after Sam left the place and let Robin do everything. You'll get it though.

Thanks that's good to know.

Ok, I just got the time to swap out the steering linkage for the UE (gen 4) servo saver,and took the truck out for a spin. I still have the severe pull to the right. I now don't think it's the saver that is the problem. I am now thinking it's the 300k diff oil and locked slipper. At first I tried to run the truck with two servos, but I am now going to give in and just go with one. I know I'm stubborn, but when all the senior members in here keep saying just use one.........( I can here you guys saying I told you so). I just think all the torque is forcing the truck to the right under full acceleration. I'm really glad that I got the UE servo saver it just really looks great and you can tell what craftsmanship when into the design. So, guys what diff oil should I try to use? Remember I still want to be able to pop the front wheels up off the ground at will.
Thanks,
Mike.

Since you are running a thick diff oil, have you thought about the tires.
Is one side growing more then another?
Does it pull to one side at a low speed or just high speed?