S400 Differential Problems
 

I just finished putting together my S400 yesterday and ran it a little. It seems like it has some unusual handling characteristics compared to what i'm used to, and I believe it's because of the front spool. After running it for awhile, I tightened up the diff a bit since it is breaking in. But, when I inspected everything, I found out the thrust bearing for the rear diff is shot, wasn't very smooth either.
Since i'll be running on a pretty technical track this summer for racing, and the spool doesn't seem to help, what do most of you guys run as far as differentials go? I was thinking the rear gear diff, but i'm not sure what to run up front. Should I still run the spool? Or a oneway with the spool? Keep in mind its a technical track..

Thanks,
steve

I'm not sure but you shouldn't have a gear diff but a ball diff for the rear. Running a diff up front may be better for you. I run a spool almost all the time but a diff will help get around a technical track.

Rod

The gear diff is the best option ever. Just fill and forget and it'll perform perfect for a loong time

What are the advantages of a spool up front then? Also would softer tires up front compensate for the spool as regards for steering?

Even for technical asphalt track, the fastest option is to use front spool. You get better rip out of corners. The S400 has tons of steering with the front spool. The rear ball diff thrust bearing, just remove it the cage, and use the thrust bearing plates, and instead of the cage just use 1.5mm balls. You'll need about six of those, and rebuild the diff and you're set.

You might want to post on the S400 thread here on Rctech as S400 team drivers are always there to help you with tips and updates, etc...

regards

Yohan

get the gear diff for the rear and it will solve all your diff issues. If you want to continue running the ball diff then do as yyhayim suggested with the thrust bearing. The initial design was not that great and Serpent has since gone away from that design and released a new thrust bearing setup.

Front spool is the favorite option among most drivers for technical tracks, however you need to find what is going to work best for you. Serpent has released a front diff for the s400 as well as a one way. There are a few threads that go into pretty good discussion on spool vs one way vs diff. Just do a search and you should be able to fine one or two.

And there is a S400 thread, post your questions in there for more support with the car. You may also want to look through there for some answers.

I'd lok more at diff screw #40179, and nut nylock #401096. What you got in the kit, if it was preassembled, the screw and nut probably stripped. I ordered 2 set of each for spares. And it worked out. Ordered myself a geared diff also, for more traction. Front spool is good for technical tracks.. Ordered the one-way axle for the frt. Frt one-way been on BO list and expected this week. Since it was BO'd I had the one-way pulley installed.It's cheaper to use the pulley, it works the same way as the one-way axle frt.

I'd like to get the gear diff, but I can't find anywhere to purchase it. How much is it? Our first parking lot race is this Wed. so i'm not so sure if i can get one by then. i'll probably have to run the ball diff for the first race, unless somehow a gear diff shows up in my car.

Thanks for all the help guys I really appreciate it!!

Conner and I will be at the track about 430 on Wednesday. I ran the front spool in my first S400 at the Duluth carpet track in December '07. Box stock setup and took 4th place in the A Main.

I have since changed to the ball diff for my first car and Conner's S400. My third S400 chassis has the original spool and I ran it at the Carpet Nats in Omaha running the 13/5 rubber tire class. Did pretty well with it. I also ran that spool chassis at the WOW race for the Trans Am class.

This Wednesday will be our first endeavor on asphalt with nitro shoes. So, the experimenting begins.

My point is that any front axle combo will work with the right tweaking of the suspension. And, if Andrew runs a car, there will be 4 - S400s on the track to try different things with to see how the car is going to handle on the asphalt vs carpet. I plan to run exactly what I have for setup and change after that. Remember, the S400 is designed for asphalt. The carpet version has a different chassis and upper deck. So, we're half way there with the correct setup out of the box.

See you Wednesday,

Allan

I will be down there around 5:30 or 6 maybe. I will try my best to make down down there.

PM me with your number and I can find out from andrew if he has any gear diffs.

Most of the guys down there like Allan, Andrew, Sandy, or myself can help you out adjusting your car to the track conditions. It'll take a couple of meets to hone in a setup for HT.

Hope to see you down there.
-Brian

Thank you local guys for chiming in!

Hopefully i'll make it by 430, I haven't really driven this thing anywhere close to competively yet so I got to be there early for practice.


Looking forward to HT.


-steve

Try stripping down the ball diff and relubing it first (including the thrust race) if you can't get parts in time, then consider getting the gear diff.

The gear diff should also need a lot less maintanence and is well suited to brushless motors for this very reason :)

We definatly have the parts. I probably have a couple of diffs in my box, but I am sure I can build the diff in just a couple minutes at the track for you.

I followed what yyhayyim said and the diff works fine now with the 1.5mm thrust balls. It will defiantly hold up for a few races at the very least, so don't worry about throwing a diff together for me i've got it taken care of. Thank you for offering though..If your selling the gear diffs for $20 or under i'll take one, just low on cash right now lol.