Adjust Differential?

lnfjn · #1 07-14-2009, 12:43 AM

Hi, I'm new to Dnanos. I bought a Enzo Ferrari and a Lamborghini Murcielago. I drove the Enzo on the Hobbytown Corona track. It was a blast! I was into Mini-Z's about 4 years ago and then got busy. I thought the Mini-Z's were great but these cars are really more refined in their design.
I'm having a slight problem with the Lamborghini Murcielago. One rear wheel is slipping causing the car to pull. I looked at the technical manual and it's not very clear on how the differential is made on the standard Dnano. Is there a way to tighten it up?

Pierro · #2 07-14-2009, 08:16 AM

Hello!

The standart diff is a gear dif. So, the same as on the mini-z. It can perhaps need a little practice to free up a little bit. Or you can even try to some lube to help (but be carefull for the dust that will come).
Personnaly I went to the ball dif after a few runs and really love it much than the gear dif.

Hope you enjoy your new rides.

lornecherry · #3 07-14-2009, 11:36 AM

...agree with the poster above ...the stock diff will loosen up after a while, but the ball diff is adjustable for a variety of surfaces and is much smoother.

That said, if the car originally ran straight and now pulls, it may be that the front wheels are not turning freely, thus causing the car to pull to one side. Spin the fronts with your hand and see if they both turn very freely. If one turns slower, then that is your problem and not the diff; you'll need to take the front axle off and clean out the debris wound around it ...this is by far the most common cause of left or right "pulling". Hope you like working really tiny screws

lnfjn · #4 07-14-2009, 06:55 PM

Actually, my problem is opposite from what everyone is thinking. The differential is not too tight but it's too loose. When holding the car upside down only one rear wheel (the sprocket side) is spinning. There doesn't seemed to be a way to tighten it up. It was this way out of the box.

Pierro · #5 07-15-2009, 10:20 AM

Hello!

Unfortunately I don't know what you means by sprocket side...

But if this means the wheel on the dif side, perhaps is it a binding of the axle in the pod. Check the plastic bushings to see if it's well free.

I believe the pod bearings are the same size as wheel bearings of mini-z, so you can also try with some bearings.

edhchoe · #6 07-15-2009, 10:39 PM

I'd make sure the screw is tight on the hub carrier of the loose side. If it is loose the axle will spin freely.

MrNanoTrax · #7 07-15-2009, 11:22 PM

the stock differential is loose out of the box. its horrible and that's probably intentional. forget the stock diff, pick up a ball diff & call it a day

fraz · #8 08-01-2009, 05:53 AM

I said it once before, my fastest car is my stock Murci with gear diff well broken in. If there was a national or world level event that I had to race tomorrow, I would throw this car down without thinking twice.

We have like 7 Kyosho ball diffs between the two of us and we have found they are all very different out of the box. These ball diffs require solid cleaning and consistent LIGHT lube and regular maintenance to be really good and predictable.

As for tension setting, the diffs have 2 spacers and one c-clip keeper stock. This is way too much tension. One spacer and the keeper is plenty for the torque put out but the little stock motor. I woud even say it is enough for the xspeed too but we decided the xspeed was a bit ridiculous speed for our track and shelved them.

The comment about fuzz in one of the front wheels should always be the first thing you check if your car is tweaked on power.

MrNanoTrax · #9 08-01-2009, 12:09 PM

one can't determine what setting is best for the diff until you consider the track surface. i've noticed the stock (gear) diff binds occasionally, but this problem disappears with the ball diff. i think it's benefits are more apparent on our rubber track surface. this hobby isn't for the lazy... the dnano is a model that requires constant maintenance so keeping the diff in top condition should be a given.

Zach.Type/RS · #10 08-22-2009, 09:50 PM

I use three spacers on my ball diff now.Your making me worry now that I have it too tight!

I was using the out of the box set up on my ball diff and that was too loose and I eventually went to one and I didn't like that at all. I was tinkering with mine before I actually read the setting sheet.

With the three I am doing good.

Fraz, are you working at a HobbyTownUSA if so do you have the 3P Infield track at your store? If not what are you running on? Its bound to be RCP right?

Quote:

Originally Posted by fraz

I said it once before, my fastest car is my stock Murci with gear diff well broken in. If there was a national or world level event that I had to race tomorrow, I would throw this car down without thinking twice.

We have like 7 Kyosho ball diffs between the two of us and we have found they are all very different out of the box. These ball diffs require solid cleaning and consistent LIGHT lube and regular maintenance to be really good and predictable.

As for tension setting, the diffs have 2 spacers and one c-clip keeper stock. This is way too much tension. One spacer and the keeper is plenty for the torque put out but the little stock motor. I woud even say it is enough for the xspeed too but we decided the xspeed was a bit ridiculous speed for our track and shelved them.

The comment about fuzz in one of the front wheels should always be the first thing you check if your car is tweaked on power.

fraz · #11 08-29-2009, 05:36 AM

Quote:

Originally Posted by Zach.Type/RS

I use three spacers on my ball diff now.Your making me worry now that I have it too tight!

I was using the out of the box set up on my ball diff and that was too loose and I eventually went to one and I didn't like that at all. I was tinkering with mine before I actually read the setting sheet.

With the three I am doing good.

Wow, you must be on xspeed with tiny gear or something. First let's be clear on the count cause it is easy to mess up. The plastic piece that goes next to the little white clip looks just like the spacers but has a ridge. Do not count this as a spacer. The stock ball diff comes with the middle setting and it is 2 spacers and is too tight (except may be good for very high traction with xspeed motor and/or lower gearing). We finally figured out that the motors lack so much torque that even one spacer _can_ be heavy. But one spacer seems pretty dialed and we are on RCP and it is quite tacky. Another thing that happens is ballooning tires causing weird diff action. We have started gluing our tires on the wheels too. TIP: if you want to get Kyosho metal shim set you can totally fine tune the spring tension. They come .1mm, .2mm, and .3mm in the kit and the stock plastic spacers are roughly 1mm thick.

Now even with all of the fine tuning hours, we ended up sticking with 1 spacer always and we do all of our diff tuning with various lubes. The rotating mass of a dNano is sooo lightweight, the diff lube and even the dirt have a greater effect on the action than anything else. Sanding the diff rings down with like 1200 grit and using different shock oils does absolute wonders for this diff!!!

Don't believe me, give it a try. Forgetting ring sanding for the quick experiment, disassemble and clean diff pieces, balls, spur. Now put a very light amount of standard diff lube (I have tried AE red, AE black, Losi, CRC, Tamiya, and a couple others). Now reassemble with 1 spacer and test. Now take it all apart again and clean. Rebuild with light coat of 20wt shock oil (AE oil is heavier so like 10wt if using AE). Now reassemble with one spacer again and try it. Night and day, eh? Then if you throw some spiffy polished rings at the shock oil setup, it will start feeling like a ball diff should.

Quote:

Originally Posted by Zach.Type/RS

Fraz, are you working at a HobbyTownUSA if so do you have the 3P Infield track at your store? If not what are you running on? Its bound to be RCP right?

Yeah I don't work or run at HT and primarily run RCP. The folks running the track up there all know me though as we have raced together lots over the years. However, my main dNano race buddy races with pretty much the same setup on the carpet track in Hong Kong on a regular basis as he travels there for business a lot. We are both accomplished racers of various scales so we bring a lot of tuning experience to the table. We bounce lots of ideas off each other and have some cars that really work well... but like NanoTrax said, it takes a good amount of effort. If you have specific behaviors or questions, post 'em up. I am sure we can figure it out.

Btw Zach, I have raced a few nitro onroad races out in your neck of the woods with http://www.rcrcnt.com/ a number of years ago. Of course this was before they got their permanent track built. Would love to come run again someday. Nice group of people if ya ever want get into nitro.

quarterpound · #12 10-01-2009, 12:34 AM

Wow. I've had my dNano less than a week, and already run into both of the original problems laid out here. It took me all of an hour to try running my dNano on the floor and pull up enough fuzz and hair to gum up one of the front steering knuckles. However, even after addressing this problem, the diff started slipping excessively and I would have to go in and tighten the hubs over and over. Afterward, I first got 15 minutes, then less and less race time before the rear wheel power would diminish into nothing. At this point my diff will start slipping in about 30 seconds of racing on carpet. And the hub never actually seems loose or anything when I check it. We tried bearing oil on it and it made it spin a little more freely, but not slip less. So I'm getting the ball diff once they're in stock here. I probably abused it the first couple of days, crashing so often and occasionally revving against the barrier to try to get unstuck. I do wish Atomic's ball diff had been better, so I wouldn't have to buy yet another Kyosho part...

nitrojunkie · #13 10-01-2009, 05:05 PM

Don't knock the Kyosho diff.It is a bummer to buy one and then end up buying another one.I have a friend that has replaced all of his Atomic diffs with the Kyosho one it is alot better.But it does have to be serviced regularly and the polishing with a minimum 1200 grit wet or dry paper is a must.As for shimms I run on the HT USA carpet track exclusively my car has never seen the floor of my house.I am set with 1 plastic spacer and 1, .005 thousandths slotcar armature shimm with the stock motor and it still from time to time spins the rear tires.I have also weakened the spring in the diff a little bit.The car is really turning good now I just need to get consistent with my line and then start working on my lap times.A wise man once told me you have to go slow before you go fast.

quarterpound · #14 10-02-2009, 05:58 AM

thanks for the tips, nitrojunkie. I'll put those to good use when our shop gets K ball diffs in stock.

nalves · #15 10-07-2009, 02:45 PM

Quote:

Originally Posted by fraz

Now put a very light amount of standard diff lube (I have tried AE red, AE black, Losi, CRC, Tamiya, and a couple others). Now reassemble with 1 spacer and test.

The standart diff lube is 5.000? That's what i have from Kyosho...

Quote:

Originally Posted by fraz

Now take it all apart again and clean. Rebuild with light coat of 20wt shock oil (AE oil is heavier so like 10wt if using AE). Now reassemble with one spacer again and try it. Night and day, eh?

20wt shock oil? Well, that's way different from the Kyosho 5.000...so, lighter the better...

I have to try...

Nuno