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Old 08-19-2013, 02:55 AM   #11911
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Ordered a ball diff for the car but cant get it together now The spring and nut seem to be much to long to fit in the out drive and interfere with the axle once installed (the axle cant plunge).

Edit: guess I just didnt have it "tight." Sure felt tight enough but I kept cranking on it and wasnt getting anymore friction on the diff. It sucked the T-nut most of the way into the outdrive (couple mm from bottoming out on the outdrive). Diff is nice and tight now but still doesnt seem like there is a whole lot of room in the outdrive.
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Old 08-19-2013, 07:39 AM   #11912
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Mid motor setups aren't about getting as much weight on the front tires as possible. It's about getting all the weight inside the wheelbase in order to reduce the pendulum effect that happens when the motor sits behind the wheelbase.

What makes RM work so well in lower traction is the static weight distribution. It has more weight on the rear. I'm not shocking anyone by saying this. They usually have at least 65% and up to 70% of their weight on the rear tires. The dex210 in mid motor with the battery the whole way back has about 62% on the rear. It's never going to generate as much reach bite like that. Other companies have identified a solution, as vr6cj has pointed out. Turn the battery sideways and get as much freaking weight on the back without putting it outside the wheelbase as possible. My goal is to get at least 65% on the rear without having to add weight. I was up to about 64% with the battery a 1/4" from the motor. With my new configuration, the battery is as close as it can get. That 1/4" will help quite a bit. Also, now I can move my ESC a little off center and 1/4 further back to optimize it's placement and reduce the wire length to help my weight distribution even more.
This looks awfully familiar. In fact much of it is nearly word for word familiar.
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Old 08-19-2013, 07:43 AM   #11913
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I'm trying to understand what are you trying to accomplish by moving the battery in that direction especially with a mid motor setup?

You're shifting more weight to the back and oddly still have a mid motor setup... AND you're also adding more weight to the outer edges of the car which would make it less nimble. All road race car designers out there aim to get the center of gravity as close to the center line of the car as much as possible and then play with the weight distribution front/back as they see fit.

So by putting more weight to the outer edges of the car, you're making the car want to "lean more" as it's turning. But at the same time, it would be less nimble when you want to change directions. And then by moving the battery to the back (and keeping mid motor setup), you've reduced the amount of weight in the front which would have a tendency to give you less steering...

So, I'm confused with what you're trying to accomplish. But maybe I missed something so I'm open to the thought process. Certainly not trying to insult anyone as I'm just trying to understand.
Actually all things being equal weight shifted rearwards increases steering and weight shifted forwards decreases it. There are lots of very technical articles written about it. Many rc people seem to think opposite of reality because they aren't thinking about the effect that shifting weight without making any other changes is having on front and rear roll stiffness.
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Old 08-19-2013, 11:55 AM   #11914
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Quote:
Originally Posted by madweazl View Post
Ordered a ball diff for the car but cant get it together now The spring and nut seem to be much to long to fit in the out drive and interfere with the axle once installed (the axle cant plunge).

Edit: guess I just didnt have it "tight." Sure felt tight enough but I kept cranking on it and wasnt getting anymore friction on the diff. It sucked the T-nut most of the way into the outdrive (couple mm from bottoming out on the outdrive). Diff is nice and tight now but still doesnt seem like there is a whole lot of room in the outdrive.
If you go to the Durango website they have a video on how to build their diff. I checked it out before I built mine because I heard so much about the c clip and making sure it was in right. I put mine together like the video showed and it has worked great from the very first battery til now a few months later. Never once has it come loose. It is a vid worth watching.
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Old 08-19-2013, 11:57 AM   #11915
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Anyone mess around with moving the front axles forward to make the inline steering setup? Did you run the spacers all in the front when you ran inlines or all in the back. I think it shows all in the front if you run inlines. Want to mess with it the next time I go racing.
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Old 08-19-2013, 12:06 PM   #11916
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This looks awfully familiar. In fact much of it is nearly word for word familiar.
I learned everything I know about tuning from a very smart member here. I owe this member a great deal of gratitude as following his posts have made me much faster.
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Last edited by RC10Nick; 08-19-2013 at 12:19 PM.
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Old 08-19-2013, 01:44 PM   #11917
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Does anyone have a good base setup for running 17.5 on a small carpet track? All of the ones on petit are for mod and i don't know how well they will translate.
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Old 08-19-2013, 01:57 PM   #11918
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Does anyone have a good base setup for running 17.5 on a small carpet track? All of the ones on petit are for mod and i don't know how well they will translate.
Not a bad idea to start out with the mod setup, as 17.5t on carpet is still VERY fast. At least on my local "outdoor" offroad carpet track, I found this setup: http://www.petitrc.com/setup/durango...ce20121229.pdf to be easy to drive. I do have the brass nose weight.. If your car has to much steering I found the new proline tires (http://prolineracing.com/tires/wedge...y-front-tires/) to be the ticket! no inserts, score the inner rib with a hobby knife and peel.. don't cut your finders off. Also, you'll have to fix your shock length as the lower tires will effect droop. Take out any droop limiters inside the shock and unscrew each shock eyelet out about 1mm until the front and rear have the same equal droop..
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Old 08-19-2013, 03:39 PM   #11919
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Any ideas where to get good pliers for the diff?
I got some cheap ones from ebay, but they were too big and after modifying they didn't really work too good any more.
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Old 08-19-2013, 03:45 PM   #11920
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Originally Posted by wyd View Post
If you go to the Durango website they have a video on how to build their diff. I checked it out before I built mine because I heard so much about the c clip and making sure it was in right. I put mine together like the video showed and it has worked great from the very first battery til now a few months later. Never once has it come loose. It is a vid worth watching.
I watched the vid before assembly, didnt notice anything out of the norm. Didnt have any issues with the snap right, just the spring/t-nut initially. Never built a diff that had so much initial bite but so much more room for adjustment. After initial feel of pressure on the diff, it took another 5 to 10 full turns to get the bite I was after.
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Old 08-19-2013, 03:52 PM   #11921
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Any ideas where to get good pliers for the diff?
I got some cheap ones from ebay, but they were too big and after modifying they didn't really work too good any more.
Sears was the cheapest I found.
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Old 08-19-2013, 04:02 PM   #11922
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I'm not in the US so looking for an online option.
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Old 08-19-2013, 06:34 PM   #11923
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I believe the holes in the snap ring are 1.1mm so you can use that as a reference. I took a cheap pair of wire cutters and used a Dremel and cutoff wheel to shape them since my snap ring pliers were also to large. Worked just fine
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Old 08-19-2013, 06:43 PM   #11924
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yeah my snap ring pliers have the right sized "posts" but do not come close enough to be able to compress the snap ring enough to remove...guess I have to keep hunting.
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Old 08-19-2013, 06:47 PM   #11925
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OK best way to eliminate bump steer?
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