Hot bodies 1/8 diffs - Page 26 - RC-Monster Forums

JERRY2KONE · **Unfortunately -** 12.10.2011, 01:54 PM

Unfortunately a lot of this hobby is trial and error. Even with the best advice from some of the most experienced hobbiests you have to try different things to find what will work best for your vehicle and your style of driving. With your severe pull under acceleration I would try going on the low end of things and work your way up. Losen your slipper just a tad, and put some low weight diff oil in your diffs and see if it all goes away. Even though the advice given to check your steering linkage did not resolve your problem it did give you a better look into exactly how well or not so well your steering was working. The UE Gen4 servo saver is the best one ever made for sure, and you are lucky to have one for your truck. It sounds like you have worked your way pretty much through all of the possible problems that your steering could have been giving you.

So I would go back to what I started telling you a while back. Your getting torque steer from your drivetrain because of the power your truck has in it. It could be a fault in your setup (sticky bearing, of bad toe adjustment, Etc), but I really do believe that you just have to play with your diffs until you get it where you want it to be. Are your tires taped and balanced? Are you using beadlock rims or just gluing your tires? If you have your tires taped and you are not seeing any ballooning, than that leaves your drivetrain itself as your culprit.

I think I remember asking you to try disconnecting your front driveshaft and just running it with rear drive and see what happens. Then try running it with just front wheel drive and see how that works out. That will give you a good idea how the front and rear wheel drive works independently so you can figure out if further adjustment is needed to run them together.

cmac · 12.10.2011, 02:50 PM

Quote:

Originally Posted by coolhandcountry

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?

No it happens the moment I pull on the throttle. I have the tires double gorilla taped so they don't balloon at all.

coolhandcountry · 12.10.2011, 03:07 PM

Can you switch sides with tires for a test run and see what happens?

cmac · 12.10.2011, 08:03 PM

I'm willing to give anything a try.

cmac · 12.11.2011, 10:25 AM

I don't know why I didn't think of this but my tires are directional. I can't swap them for the other side.

JERRY2KONE · **Anything is possible -** 12.11.2011, 11:17 AM

Quote:

Originally Posted by cmac

I don't know why I didn't think of this but my tires are directional. I can't swap them for the other side.

Well anything is possible, but honestly unless one tire is totally different from the rest I doubt that it would make much of a change for your particular problem. And even though the tread is directional you can still try swapping them around for a test. Even so as long as they are all the same size, and the weights do not differ more than an ounce or two I would find it hard to believe that it would change your driving experience to swap them around. The only way tires would affect steering would be if they were different sizes like they do with some oval track racing. They put small diameter tires on the left side to make the vehicle naturally want to turn left making it easier to steer through the turns.

What you have been describing as your torque steer issue would not be affected by the tires unless one side is balooning drastically. Alignment maybe, but this seems more like a diff issue where one side is receiving more power (rotation) than the other. You have to try whatever comes to mind after you do a little knowledge based elimination. Eliminate what you know for sure is not your problem, and make a list of what you do suspect, and then test that theory one by one until you have tried everything that you can think of, or the problem disapears.

Steering issues under power can only be caused by a few things. The servo is always the first place to look. Second would be the steering linkages to make sure that there is no slack or binding of any kind. If it operates smoothly by hand than it should do the same under servo power as long as you have the right servo for your setup. Next is the drivetrain itself. Closely examine each axle for any unusual binding due to a bad bearing or improper installation. The diffs are next in the line. Diff slipage is an individual descresion and you have to set yours up to match your expectations, but you still have to make sure that they are smooth as silk and have no binding what so ever. The last thing in the drive line is the transimission or center diff including whatever slipper you might be using. Make sure that everything is operating smoothly and easily as it should. I cannot think of anything else that will effect your vehicle in the way that you have described.

coolhandcountry · 12.11.2011, 01:33 PM

Have you noticed if it dog tracks any?
I looked back but no video to see.
Maybe something out of line in rear of truck as well.
Just things to look for that is simple.

cmac · 12.12.2011, 07:26 AM

Quote:

Originally Posted by coolhandcountry

Have you noticed if it dog tracks any?
I looked back but no video to see.

I'm not sure what "dog tracking" is. Yes I still have not had the chance to get the video camera out to film this running.

coolhandcountry · 12.12.2011, 08:49 PM

Dog tracking is where the rear is out of whack.
The back of the truck runs out further on one side then the other.
It can cause all kinds of weird steering issues.

cmac · 03:41 PM

I have a question not related to my metal maxx. I am putting together my stock brushless emaxx (3908) and I am going to use dog bones for center drive shafts does anyone know what length the front and rear shafts are? I am using the stock plastic chassis and the stock transmission.

suicideneil · 12.14.2011, 12:49 PM

I don't know the actual lengths, but if you are looking for bones to use that will definitely fit:

http://204.186.93.64/NewE-Maxx-CenterDogBone.htm

Saves a job- Mike can custom make dogbones too, though he'd need the dimensions before he started, so...

cmac · 12.14.2011, 11:25 PM

Thanks Neil,
I found out that I needed a 60mm pin to pin for the front, and a 120mm pin to pin for the rear. I have both on the way. I already bought them before you posted, but as always thanks again.....
Mike.

mothman · 12.15.2011, 12:31 AM

Quote:

Originally Posted by cmac

Thanks Neil,
I found out that I needed a 60mm pin to pin for the front, and a 120mm pin to pin for the rear. I have both on the way. I already bought them before you posted, but as always thanks again.....
Mike.

Did you get the 120mm from kershaw design as well? I have been trying to find 120mm pin to pin dogbone for quite some time..

cmac · 12.15.2011, 07:40 AM

No I actually got a Ofna 40710 120mm dogbone.
http://www.ofna.com/parts.php?start=3600

mothman · 12.15.2011, 11:53 AM

Quote:

Originally Posted by cmac

No I actually got a Ofna 40710 120mm dogbone.
http://www.ofna.com/parts.php?start=3600

I was told that Ofna measures their dogbones according to the overall length, not pin-to-pin. I might be wrong. Please let me know once you get the parts.

And as for the link on Kershaw Design, the dogbone is not 120mm.. it is only 114mm, according to Dan, the owner.