Diff Issues

[Welshy40]

Guys,

Has anyone had any issues with the rear diff?

I feel that the diff screw is way to thin and have done a rebuild using Kyosho diff parts (I have loads of spares still).

This now utilises a much thicker screw and different bigger thrust ball races and plates. Also a better nut that hides the screw end totally.

The only thing I didnt change was the spring, which I think may be the real problem with the diff, as its not strong enough to give a totally slip free diff as it could snap the original thin screw, hence why there is still slip.

I will test and update what I have done. Let us all know what issues you have had and what was done. Cheers.

[mole2k]

I've always thought the diff screw and nut was far to small. I've stripped the threads of one screw already and I know other people at the club have had issues with the small nut.

[DCM]

There is nothing wrong with the diff screw, nut or spring, but if the diff keeps backing off, you either got them in wrong way round or the nut and screw needs replacing (they sell them in packs you know). Only thing you have to watch, is which way up the thrust washer goes, as one side is rounded and the other is square, the rounded side goes facing the screw head.

I have run this type of diff for 2 1/2 years no problems.

[Garry Driffill]

When my dad had a Tamiya 501X he had issues with the rear diff screw and nut.

[DCM]

the temptation is to over tighten it, which isn't needed, I got 4 DB-01's and the same amount of TA05's and never had an issue....

[Welshy40]

Well compared to all the other cars out there the screw is almost half as thin.

Some tracks need a tight diff and the standard design doesnt give you much of an option, hence why I done the rebuild and replaced these weak items, giving me all the options if I require them. Its simple and no diff rebuilds.

I will see if any slacking happens, and if so will come up with a solution (I already have an idea) if needed.

[501X Driver]

I can tighten the screw enough to strip the nut and break the screw.
BUT I DONT!
The diff doesn't need to be anywhere near that tight to work proberly.
I have been running the 501X since Jan-08 and I am using the same diff halves, screw, nut, plastic holder, Front and Rear. The halves do have some play and now need to replaced, the rings have been changed once and I run Acer Ceramic Nitrade Diff Balls. I rebuild the diff about every 2 months if it needs it or not and I use Niftech grease. My lap times are within .5-.9 seconds of the fastest racers at my track and we have 4-5 sponcered guys there. So I'm not a backyard racer with my car barely holding together.
Look at how you are building the diff before you claim that the parts are crap. Tamiya has sent out probably ten of thousands of this diff setup and you have found a problem. Why are you so much smarter then the previous racers?
Maybe it is your driving style?
But don't trash a company. If you don't like it get rid of the car.
Good Luck

[A.J. Gee]

I have had some issues with the diff as well. I ended up stripping the head off of both my diff screws. My problems probably have a bit to do with user error but Tamiya could have done a better job supplying better bits for such a crucial part of any R/C car. Glad to hear that you haven't had any problems with all the Diffs that you have had DCM. You must be real careful and precise with them

[DCM]

A.J. I just throw them together, the thing with the rear diff is to not over tighten it, and have the front a tad tighter. They are really good diffs, but they need far less tightening than you think.

The best way, is to build it, tighten it so you can't slip it by hand, then bed the diff in, and re-tighten.

[mole2k]

When I stripped the screw it was just user error on my behalf. I went to re-tighten it in a hurry as I was just after bedding it in and was a bit over-enthusiastic. Never had an issue with them apart from that and they've lasted quite a long time.

[A.J. Gee]

Originally Posted by DCM

A.J. I just throw them together, the thing with the rear diff is to not over tighten it, and have the front a tad tighter. They are really good diffs, but they need far less tightening than you think.

The best way, is to build it, tighten it so you can't slip it by hand, then bed the diff in, and re-tighten.

I dont believe i have my diffs over tightened at the moment but i have just ran into another Diff issue as i type right now. i ran the buggy woth no problems at all yesterday. It was running real sweet, but i just noticed that when i spin the right rear wheel by hand that the left wheel doesn't want to spin. It kind of just stutters. I then put a battery to and see if it is doing what i mentioned when i do it by hand. Both wheels start off strong and then the left wheel dies out leaving the right wheel to spin by itself. My question is: Do i have the diff too tight or too loose, or is it something else?

[DCM]

sounds like the 'something else' or the diff is too loose.

If you are struggling, where to are you?

[A.J. Gee]

I think my problem might be the Diff being too loose. I need to get a new diff screw as i have stripped the head off of the one i have now. I can't tighten it anymore because of this problem. I am hoping that i can get the screw out since it's stripped. I'm sorry DCM, was your question asking me where i am located? I am in the states. Boston to be exact.

[DCM]

ah, no point you sending me your diff then lol

[501X Driver]

Originally Posted by DCM

A.J. I just throw them together, the thing with the rear diff is to not over tighten it, and have the front a tad tighter. They are really good diffs, but they need far less tightening than you think.

The best way, is to build it, tighten it so you can't slip it by hand, then bed the diff in, and re-tighten.

I build mine just as you described but I don't mess with it after it is in the car. I have maybe twice in my 10 yrs of running car messed with it in the car and that was to tighten it so I did have to rebuild it then I had one race and wasn't doing so well anyways.
The #1 killer is if you start just a little to loose it slips and you get trash in the grease and it snow balls from that point.
And it is so important to the handling on a slick track.

[Welshy40]

A.J.Gee - Have you checked the UJ pin, as the same thing happened to me, the pin cam slightly out and stopped the wheel, then slotted back in etc etc. I ended up taking the pin out and dremelling a flat spot in the centre so the screw locks it in permanently. I have not had that problem again.

If it isnt then your ghoing to have to do a rebuild and possibly the thust race could have been damaged.

501X Driver - you seem to misunderstand, you appear to race on dirt, dust and basically surfaces that are not high traction. Yes skill is a big part, especially the surfaces you race on, and great to hear how competitive you are - keep it up.

We in the UK race on high grip surfaces where torque is needed and no slip on the diff is required (well im my case anyway). We even race a lot on carpet and for the most torque/accelaration you cant afford to have a slipping diff, possibly just a fraction on the slipper, but hardly any.

I like yourself have plenty of racing experience as well and have always built my diffs by following a simple principle (associated and kyosho use this) - Tighten all the way up and then loosen off as this will bed in the spring and then you can tighten or lose off whilst tuning the car for its first run.

However the standard diff doesnt totally stop slipping, as you can tighten it all the way, hold the spur and other wheel and turn the free wheel and there is still a lot of slip. I am not dissing Tamiya, but this car was never sold in this country so kindof guess no feed back was given into the cars design from here.

I solved this problem by putting in a kyosho thrust race (bigger balls and a bigger screw hole on the plates) and also a bigger screw (almost twice the size)with the appropriate metal associated lookalike diff nut.

This now seems to be resolved but until my next run I may do one more thing. However I can now run twice the amount of balls in the diff, making it far smoother. However I have not yet tried the Kyosho diff spring which may be my next trial, as I do feel that the part that is causing the problem may be just that, a weak spring. Hence why a few people have snapped the screw, maybe due to the springs that they have being a tad stronger. Its a work in progress, and hope that this information helps someone else out.

[DCM]

James, if you can bottom the screw out and still get the diff to slip, you are doing something majorly wrong.

1. compress a new spring with pliers if needs must (never have with Tamiya ball diffs)
2. as little grease as you can get away with
3. never run a slipping diff
4. erm.... thats it really

Seriously guys, if you run the diff and it starts to slip, tighten it ASAP as all you will do is screw the diff up.

James, have you glued the diff rings to the diff halves as that might stop your diff slipping, tightening it harder will just gouge your diff plates. I know Millzy blew my rear diff on the weekend, but I had just rebuilt it and not had a chance to bed it in, he run it without adjusting it, it slipped and blew the pulley. Simple really.

[B44&501xRacerEX]

One of my diffs melted because I tried making my own covers
and super glue got down in the diff.

After inspection the front diff survived but the rear diff was gone.
I bought a front-one-way to put in the front of the car, and
I could re-use the front diff and put it in the rear end of the car.
Another note I built the diffs wrong, forgot the little spacer and the bearings
that's why my front diff came loose everytime I took it out on the track.
Due to this error I made now I can enjoy this car by building them
the way they are supposed to be, and follow the directions.

[RcRob]

Originally Posted by Welshy40

We in the UK race on high grip surfaces where torque is needed and no slip on the diff is required (well im my case anyway). We even race a lot on carpet and for the most torque/accelaration you cant afford to have a slipping diff, possibly just a fraction on the slipper, but hardly any.

Strange that, this weekend at the National, which was possibly the highest grip track of the national series this year, I saw nearly all of the top (best in the country) drivers (of which you were not one of them) adjusting there slipper so that it SLIPPED!!!!!!

Have you noticed that for everything that is wrong with this car you are the common factor and nobody else has the problems, maybe the problem is you? I've also noticed that everything that is wrong with the Tamiya is better'd (is that a real word? ) by the mighty Kyoshos (that you have since re-designed) from 1362, why not race that? It will be cheaper to as the belts last 48 years and still don't have any wear

[DCM]

hee hee... now now, play nice guys!!!

The slipper is a tuning tool in the end, and on high traction can be used to make the car a little more settled coming out of turns and on landings.... but James is white and we know white men can't jump lol, sorry, just HAD TO...