Diff Putty?

[Nobbi1977 1793]

I have done a search and did not find a specific topic but I am sure this must have been covered many times.

I got a pot of TFT diff putty today. My intention is to make the doffs on my Dt-01 and WT-01 less open. The DT-01 has holes in the plates so stiff oil is out.

Has anyone used the putty and if so how much and how? I was expecting a tub full rather than a strip so I am a bit confused now.

[waterbok 1282]

If I read it correctly on Seidels website it states that the putty is an additive to the oils if these don't work enough in the diff. It says add pieces of putty to the oil till you reach desired hardness.

Kind of sound like a piece of bubba gum would work just as well.

[Backlash 481]

Nobbi,

When I wanted to "tighten" or make a limited slip diff out of the stock gear diff in my M03 Mini, all I did was cut a shim out of a piece of plastic (body shell offcuts work well) and placed it on the side gear in addition to the stock metal washer that is there.. By altering the thickness of the shim, you can adjust how tight or loose the differential action will be..

Alternatively, you could just add some more of the stock washers if you have them..

[speedy_w_beans 4272]

A good dollop of Tamiya Anti-Wear Grease instead of ceramic grease will also tighten the diff; it's really tacky stuff and won't leak out.

[oz-trash-cowboy 63]

Or a good tight pack with white grease, like you get in a tube a bicycle shops!!

[Nobbi1977 1793]

Nobbi,

 

When I wanted to "tighten" or make a limited slip diff out of the stock gear diff in my M03 Mini, all I did was cut a shim out of a piece of plastic (body shell offcuts work well) and placed it on the side gear in addition to the stock metal washer that is there.. By altering the thickness of the shim, you can adjust how tight or loose the differential action will be..

 

Alternatively, you could just add some more of the stock washers if you have them..

I tightened the Hornet diff with O rings but increased friction in this way also increases wear so I was looking to avoid it.

I thought the putty being a Tamiya product would have a how to guide some where but I am at a loss to find it. Grease is a good plan in a diff but they all vary weight based on heat so a couple of packs on a hot day and their effect could disappear completely.

[InsaneJim69 1584]

A good dollop of Tamiya Anti-Wear Grease instead of ceramic grease will also tighten the diff; it's really tacky stuff and won't leak out.

This is what i use in gear diffs, works an absolute treat. A little goes along way.

James

[OoALEJOoO 3127]

Resurrecting this thread as I am about to build a differential for a TT01E car. According to Tamiya's webpage:

"Gear differential putty is used to control the differential action of gear diff units used in R/C cars that have sealed gear diff systems. When high viscosity oils are not enough to achieve the desired differential action, the use of putty can become quite handy. The material in this package comes in a roll which can be removed easily from the plastic case, cut into 3mm pieces with scissors and inserted into the differential"

Does somebody have experience using the putty on a non-sealed geared differentail such as the one in the TT01E?

I've tried using a glob of AW grease before, which works great for perhaps a battery pack or two, after which it seems to settle away from the gears and the differential becomes a lot looser. I'm hoping using the putty would have a more permanent effect. Planning to do some light racing on medium-grip concrete.

[alvinlwh 5895]

This is what I found on an Amazon review. Translated from Japanese.

"This time, I tried using TXT-1 and CC-01. This item, compared to kneading eraser, etc., is quite soft, it is necessary to fill the eye full to the full lock, but in my case, in order to protect the gear cup and bevel gear, try to adjust to the degree of turning heavily did. It adheres to the hands because it is quite viscous. Also, since it has the property to dissolve in the grease, it is strongly recommended to spread the grease on the gear cup. As it is, there is a possibility that the gear cup will not be removed when incorporated. It is easy to adjust, simply pack it into the gear def, assemble the def, stab the gear cup to secure the def, and turn it with a flat-blade screwdriver or hex wrench to adjust it to the desired stiffness. However, if it protrudes from the differential case, wipe it with grease and do not adhere to the gear and drive becomes heavy, drive loss, of course, or the worst motor burns, you need to be careful because the amplifier burns .

Finally, it is expensive compared to kneading eraser, etc., but since it can be finely adjusted so that the gear does not break, I think there is no loss to have for those who enjoy the cross country. Also, it is quite viscous, so you need to pay attention to the sticking to the hands or to the drive gear."

[Willy iine 18806]

On 1/8/2015 at 6:38 PM, Backlash said:

Nobbi,

When I wanted to "tighten" or make a limited slip diff out of the stock gear diff in my M03 Mini, all I did was cut a shim out of a piece of plastic (body shell offcuts work well) and placed it on the side gear in addition to the stock metal washer that is there.. By altering the thickness of the shim, you can adjust how tight or loose the differential action will be..

Alternatively, you could just add some more of the stock washers if you have them..

I too just added extra shims in the diff to stiffen.   Diff putty can be a mess too and if setup for only minor resistance, it will leak out rather quickly and you’d need to repeat the process often.  

[OoALEJOoO 3127]

4 hours ago, Willy iine said:

I too just added extra shims in the diff to stiffen.   Diff putty can be a mess too and if setup for only minor resistance, it will leak out rather quickly and you’d need to repeat the process often.  

My concern from that method is that the diff resistance seems to be coming from increased contact pressure between the gears, caused by the shims. Wouldn't this indeed create more wear? I think this was Nobbi1977's point above.

[taffer 948]

The tamiya diff putty is like chewing gum, it shouldn't and hasn't leaked out on my three diffs in my g6-01....

One 15mm length strip rolled into a ball will create a good resistance, less for a more slippy diff

[Willy iine 18806]

49 minutes ago, OoALEJOoO said:

My concern from that method is that the diff resistance seems to be coming from increased contact pressure between the gears, caused by the shims. Wouldn't this indeed create more wear? I think this was Nobbi1977's point above.

I have not seen excessive wear.   Mine is not set up super stiff.  

Regarding diff putty, if you use a lot of putty like near lock, it will last longer.  If you used it like me with only some resistance, it will soften up rather quickly.  I know because my GF01TR I recently built uses it and it’s pretty loose now only with maybe 15 or so battery cycles (3600mAh).. 

And it is a mess to clean if you want to disassemble your diff.   It’s all up to you, I am just posting my experience and knowledge so that you can make the right decisions for you.   

[sosidge 624]

You have to pack the diff with the putty otherwise it just gets pushed away from the gear faces.

But its ideal for almost-locking an unsealed diff.

[SlideWRX 785]

9 hours ago, OoALEJOoO said:

I've tried using a glob of AW grease before, which works great for perhaps a battery pack or two, after which it seems to settle away from the gears and the differential becomes a lot looser. I'm hoping using the putty would have a more permanent effect. Planning to do some light racing on medium-grip concrete.

That is the same experience I had.  I put a lot in, closed it up an ran.  Eventually some squeezed out.  After 3-4 packs most of the effect was gone, and the grease managed to get all the way to the pinion.

[OoALEJOoO 3127]

Thanks for all the comments. From what I can gather, everyone's experience is consistent with:

AW Grease can get you a midly stiffened diff, but it will only last a few packs.

Diff putty will work similary to AW if used only a little bit, looseing after a few packs. If used to fully or almost-fully lock the diff, it will remain in place for long term. I guess this makes sense, given that progressive loosening is a function of movement (which creates heat and therefore a positive feedback loop). If you use a little it will move a lot more, thus loosening much faster. If you largely lock it, there is little movement, thus it will take very long to loosen (if at all).

I'll go ahead and build the differential to a near full lock and report back.

[Juggular 4964]

There is something between Diff Clay and AW grease. 

"3 Racing Ultra High Viscosity gear diff oil" is like caramel.  Terribly sticky stuff that will make your hand sticky for days.  If your diff is sealed type, it works better than AW.  I use the clay on my Konghead too, but this stuff isn't as hard as the clay.  (What I didn't like about the clay is how it could clump in one spot and make it uneven at the beginning.)  

 

[OoALEJOoO 3127]

Just completed the build of a TT02 casual concrete racer. Used the following:

Front differential: Diff Putty

• Four (4) bits of 5x12mm. The diff putty comes as a tape, therefore cut 5mm pieces x4. Made a sandwhich: large bevel gear / 2 diff putty pieces / 4 small bevel gears / 2 diff putty pieces / large bevel gears.
• Also spread a bit of AW grease on all moving surfaces (behind large bevel gears and the star-shaft).
• After assembly the differential is VERY stiff. It needs a good level of effort to manually turn the tires in opposite direction. If you hold one tire with your hand, the motor cannot turn. I'm using a Super Stock TZ with 5.74 ratio. I'm begining to think I overdid it but let's see how it performs once I get a chance to race it a bit.

Rear differential: A blob of AW grease.

• Spread a little bit of grease on all moving surfaces and a blob between the large and small bevel gears.
• After assembly the differential provides some resistance. The motor can easily turn the other tire if you hold one.

I decided to go this route after racing a TT01 with both open diffs and experiencing extreme oversteer.

Of course I remembered to take pictures! The problem is that I remembered to take them only after everything was done!

[rich_f 233]

On 9/23/2021 at 4:40 PM, OoALEJOoO said:

My concern from that method is that the diff resistance seems to be coming from increased contact pressure between the gears, caused by the shims. Wouldn't this indeed create more wear? I think this was Nobbi1977's point above.

I think you have to remember that the gears inside the diff don't move anywhere near as fast as the rest of the gears in the drivetrain. They only move during cornering, and even then only very slowly, at a rate proportional to the difference in path length of the inside and outside tyres around the corner, which is probably why no appreciable additional wear is being reported. I have also used this method with no extra wear. 

[OoALEJOoO 3127]

6 hours ago, rich_f said:

I think you have to remember that the gears inside the diff don't move anywhere near as fast as the rest of the gears in the drivetrain. They only move during cornering, and even then only very slowly, at a rate proportional to the difference in path length of the inside and outside tyres around the corner, which is probably why no appreciable additional wear is being reported. I have also used this method with no extra wear. 

Very true, I missed that detail.

I guess there are situations where one wheel looses ground contact and fully spins, while the other one is almost static, but indeed these are quite infrequent compared to the regular rolling time. Further, this only really happens with a fully open diff, once there is some resistance it should happen even less frequently.