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View Full Version : Mini-Z Slower after Spur gear bearing istall.


Evil_Sephiroth
2016.11.25, 07:31 AM
I have an MA-020VE pro chassis.

The only bearing this chassis miss as OEM is a spur gear bearing

This one.

https://s12.postimg.org/k9dqqscz1/AWD223_E_l.jpg

I bought a spur gear bearing BRG002 and istalled it in the rear part of the chassis, where the spur gear go to the differential.

After this my car is slower...when i release the throttle the braking affect is incredibly bigger.

Am i missing something? I can't feel the presence of grease on the bearing but have i to degrease it?

Mike Keely
2016.11.26, 08:09 AM
Can you show a picture of the true bearing that you installed? I am wondering if it is a shielded bearing or a sealed bearing? You really do want it to be a shielded bearing with out grease in it. Put it on the shaft that it goes on and spin it. If it does not spin around a few revolutions free it has grease or dirt in it. If you have a PN bearing cleaner bottle you can put some motor spray in it to clean it out. If it is a sealed bearing you will want to get another bearing that is shielded. Hope this helps.

Evil_Sephiroth
2016.11.26, 08:19 AM
https://www.rocousa.com/kyosho/KYBRG002.jpg

shield bearing.

i have already cleared it with isopropylic alchool and then a little lubrificant..

it's better now but still slower.

mleemor60
2016.11.26, 09:06 AM
When using alcohol to clean bearings it is best to use de-natured alcohol since it has no water in it like Isopropyl does.

Evil_Sephiroth
2016.11.26, 09:13 AM
btw even after clearing really not even a single turn if i spin them, even with a little crc on them no spin..maybe i got a set of bad bearing..any idea of what i can buy?

Another set of kyosho? other one?

mleemor60
2016.11.26, 04:32 PM
Unable to tell from the photo if the bearings are rubber shielded or metal. if they are rubber you can just pick the seal(s) out of it.

Evil_Sephiroth
2016.11.27, 05:14 AM
Unable to tell from the photo if the bearings are rubber shielded or metal. if they are rubber you can just pick the seal(s) out of it.

Metal.

Kyo-BRG002

mleemor60
2016.11.27, 07:58 AM
If the bearings are from Kyosho then it is highly unlikely that you could purchase anything that is in fact a better product so I don't think your issue is mechanical with the product. How long did you soak the bearings in the alcohol? If overnight then I would suggest something stronger like lacquer thinner for the same overnight period. Allow them to air dry(it won't take long if using thinner) then apply a semi liberal application of WD-40(or local equivalent but WD is the best) and again allow to air dry. That "should" do the trick. It is very difficult to spin up a bearing that size with just your fingers since it lacks mass so just make sure it is positioned and seated properly and test it out. To see how free it is you should remove the pinion gear so that you are not bringing the motor into the mix. With the pinion removed the car should roll like a "Hot Wheels" car.

Evil_Sephiroth
2016.11.27, 04:02 PM
If the bearings are from Kyosho then it is highly unlikely that you could purchase anything that is in fact a better product so I don't think your issue is mechanical with the product. How long did you soak the bearings in the alcohol? If overnight then I would suggest something stronger like lacquer thinner for the same overnight period. Allow them to air dry(it won't take long if using thinner) then apply a semi liberal application of WD-40(or local equivalent but WD is the best) and again allow to air dry. That "should" do the trick. It is very difficult to spin up a bearing that size with just your fingers since it lacks mass so just make sure it is positioned and seated properly and test it out. To see how free it is you should remove the pinion gear so that you are not bringing the motor into the mix. With the pinion removed the car should roll like a "Hot Wheels" car.

It roll lesser then without bearing.

can it be a coupling problem?

Maybe with bearing istalled i have too much contact beetween spur gear and differential...

The problem is that the differentian don't have possibility to be relocated and it's really firm in it's slot

mleemor60
2016.11.27, 05:23 PM
Clearances are something that needs to be checked at each step in the process. Does the bearing seat properly with the spur and so on until you reach the step where it starts to bind.

Evil_Sephiroth
2016.11.27, 06:22 PM
Clearances are something that needs to be checked at each step in the process. Does the bearing seat properly with the spur and so on until you reach the step where it starts to bind.

Apparently yes.

if you just move the car with hand (even without pinion) you can feel more friction and the car is slower even when you use the engine...

the bearing is pretty tight on the spur gear and sit very well in the rear part of the chassis.

My only tought is that when you have all istalled: spur gear to main driveshaft, bearin in the bearing slot and chassis fully istalled you can have tension due to misalignment beetween spur and bearing...

but if this is the problem i don't know what to do...cause it can only be linked to a bearing slot badly done from kyosho

mleemor60
2016.11.27, 09:33 PM
How did everything work with the stock bushing? Is it in fact the correct bearing? I have no idea if the bearing is the same for an 020 as it is for the older 010. Does Kyosho have a technical support number where you are located? You can get a lot of great info here but waning interest for the last few years has thinned the knowledge pool.

Evil_Sephiroth
2016.11.28, 04:35 AM
How did everything work with the stock bushing? Is it in fact the correct bearing? I have no idea if the bearing is the same for an 020 as it is for the older 010. Does Kyosho have a technical support number where you are located? You can get a lot of great info here but waning interest for the last few years has thinned the knowledge pool.


no support here...

Btw ma 020 ve arrive with full bearing..only where you see the bearing in the photo in first post here you have nothing..only an hole where spur reach rear diff.

The bearing is thw correct one..in mini z manual they write down the correct type of bearing

EMU
2016.11.30, 06:06 PM
What wheelbase is the chassis set to?

Does the spur slide easily into the bearing, or do you have to push hard to seat the bearing?

is the bearing aligned perpendicular to the shaft? Was there a bushing in the place of the bearing before you installed the bearing?

Evil_Sephiroth
2016.12.01, 04:49 AM
What wheelbase is the chassis set to?

Does the spur slide easily into the bearing, or do you have to push hard to seat the bearing?

is the bearing aligned perpendicular to the shaft? Was there a bushing in the place of the bearing before you installed the bearing?

Chassis ia set to 98 mm wheelbase

The spur is not to hard to push inside the bearing but i still Need to Press a Little to put it inside.

It's perpendicolare.

No bushing pre bearing, only an hole bigger then spur gear

Minizorro
2016.12.02, 08:30 PM
I remember having the same problem.
Car seemed faster before I added that missing bearing.
Without the bearing I though the gear was wobbling around too much, so I looked for that missing bearing thinking it would make things better.. but it didn't.
I remember I had to adjust the spacers on each side of the differential so that the meshing of the perpendicular gear/differential is a bit looser.
I guess the bearing centres the gear in place more rigidly so that the meshing needs to be tuned more carefully, without the bearing the central shaft gear can move a bit and that probably helps create less friction.
Anyway the AWD gears create a lot of friction in general so anything slightly not right will lead to a slower car.
I also found metal gears slowing the car down, again that could have been down to more friction or me not adjusting the meshing correctly.
A bit of a nightmare of a car to tune!

Evil_Sephiroth
2016.12.03, 06:42 AM
I remember having the same problem.
Car seemed faster before I added that missing bearing.
Without the bearing I though the gear was wobbling around too much, so I looked for that missing bearing thinking it would make things better.. but it didn't.
I remember I had to adjust the spacers on each side of the differential so that the meshing of the perpendicular gear/differential is a bit looser.
I guess the bearing centres the gear in place more rigidly so that the meshing needs to be tuned more carefully, without the bearing the central shaft gear can move a bit and that probably helps create less friction.
Anyway the AWD gears create a lot of friction in general so anything slightly not right will lead to a slower car.
I also found metal gears slowing the car down, again that could have been down to more friction or me not adjusting the meshing correctly.
A bit of a nightmare of a car to tune!
Today i received bearing from x Ray and marka.

I'll try then and then i see.

Maybe i remove a Little materiale from the bearing slot or i male the spur Gear smaller where the bearing touch

Evil_Sephiroth
2016.12.05, 09:12 AM
tested with Marka and X-Ray shielded bearing...still the same...

Definitivly a mesh problem beetween spur and differential..

Probably i have to istall a 0.1 shims to make the mesh a little more lose

EMU
2016.12.05, 10:58 AM
it does sound like there is a tight mesh between the spur and the rear diff. If you remove the rear differential, with rear end installed with bearing, is the drivetrain free? If so, then it is definitely the mesh between the spur and the rear differential.

If that is the case, a differential shim set may be needed, now that the spur cannot move away from the diff gear as it is retained by the rear bearing. A couple shims on the longer side of the diff may help move the diff gear away from the spur pinion and free up the drivetrain.

Evil_Sephiroth
2016.12.05, 06:25 PM
Houston we have a problem.

I've tried to push the car with my hands.

The car is without differential and without pinion.

With ball bearing on the spur Gear the car roll way less then without.

Then it's not the mesh beetween diff and spur i think.

The problem then is what Can lead to this problem or what i Can do to dmfix this?

Sanding down the part of the spur that go into the bearing?

EMU
2016.12.05, 07:18 PM
According to the first post... The rear end pictured, is not Kyosho. It is atomic. http://www.rcatomic.com/atomic/index.php?main_page=product_info&cPath=3_4_16&products_id=5547

Could this be the wrong rear end in the picture? I would assume so, since the Kyosho DWS rear end comes stock with the VE pro.

It does sound like binding between the bearing and the spur... Hard to evaluate without holding the car.

Couple questions... Is the driveshaft original? Has it been removed before? With rear removed, does the driveshaft move fore/aft? is there much space between the spur and the chassis? When you install the rear end, does the spur bearing press Hard against the spur?

What could have happened, is the pinion on the front of the driveshaft could have slid off a little, causing the shaft to stick further out the rear... Just speculating here. Also, maybe the driveshaft isn't fully installed into the spur gear (note the notch on the shaft and spur gear). If the spur is inserted into the bearing alone in the rear end, does it spin free?

If you have the rear diff removed, you cannot evaluate by rolling the chassis, as the dogbones in the rear end will bind. Just spin the front wheels, or rotate the spur. You should be able to feel the resistance there.

Again, hard to evaluate without seeing it. I also have never seen an ma020, only ma010... Although I have used every rear end on the car that was available. Never had an issue with bearing at 98mm with DWS rear end. This is definitely an odd issue.

Evil_Sephiroth
2016.12.06, 02:19 AM
I have a stock rear end... I postes the Atomic One only becouse i can't find a photo pf the kyosho with the bearing istalled

Evil_Sephiroth
2016.12.06, 02:22 AM
And never removed the driveshaft.

Front wheels are a Little more difficult to move with bearing on

Yeah the spur alone in the bearing on the rear end turn free.

It Can be the mainshaft not in linea with rear end.

But this Can be only a production problem and i rrally don't know how to fix

EMU
2016.12.06, 02:31 AM
I have a stock rear end... I postes the Atomic One only becouse i can't find a photo pf the kyosho with the bearing istalled

Thanks, was just trying to clarify.

The alternate bearings that you received, were they the same size? Perhaps a slightly thinner bearing may work better? Maybe bind less...

It's been some time since I have worked on my awd, not sure which bearing I used... In its latest setup it was 94mm (my preferred wheelbase for awd), and not sure if I have the bearing installed anymore.

Evil_Sephiroth
2016.12.06, 04:39 AM
The bearing are 5x8x2.5 like kyosho say in the manuale.

Which size do you suggest?

EMU
2016.12.06, 05:16 AM
Maybe try a 5x8x2mm bearing instead?

Do you have a local hobby shop near you? Should be able to source them somewhat easily for helicopter, blade 180 cfx

if you insert the spur alone into the rear end, does it still bind if you try to spin it?

Evil_Sephiroth
2016.12.06, 05:52 AM
Maybe try a 5x8x2mm bearing instead?

Do you have a local hobby shop near you? Should be able to source them somewhat easily for helicopter, blade 180 cfx

if you insert the spur alone into the rear end, does it still bind if you try to spin it?

Nope..

It work well.

The problem is only when i have the car fully assembled with bearing on.

With or without differential change nothing.

I never removed the main shaft. And It comes with bearing preistalled.



No shop here i have to buy online

Evil_Sephiroth
2016.12.06, 05:56 AM
I'm starting to think about putting my spur Gear under a cnc milling machine and removing 0,05 mm of material where the spur touch the bearing...

Evil_Sephiroth
2016.12.06, 08:08 AM
Probably i solved something..

I sanded a little the spur gear, istalled the rear end with all the screw lose, and after the spur gear went in the bearing i tighted all the screw...seems to go better



I think i have to 3d print my own 98mm spur gear with less diameter.

EMU
2016.12.06, 03:54 PM
Sounds good...

3d printing gears does not work very well at this small of a scale. Machined gears work best, and molded gears work ok. 3d printed gears have too low resolution to be fully accurate, and depending on process, they lack the durability. 3d printing is good for many applications, however, gears is not one of them. I tried 3d printing wheels, and the tolerances were not high enough for them to be good enough to use. Depending on orientation in the printer, you could have slightly oval wheels. That in a gear, would not be good.

Evil_Sephiroth
2016.12.06, 05:47 PM
Sounds good...

3d printing gears does not work very well at this small of a scale. Machined gears work best, and molded gears work ok. 3d printed gears have too low resolution to be fully accurate, and depending on process, they lack the durability. 3d printing is good for many applications, however, gears is not one of them. I tried 3d printing wheels, and the tolerances were not high enough for them to be good enough to use. Depending on orientation in the printer, you could have slightly oval wheels. That in a gear, would not be good.

I have access to a SLA 3D printer then we are at 0.01mm resolution if i use the max setting

With the fused deposit one is impossible, I know.

Evil_Sephiroth
2016.12.06, 05:53 PM
ok then...i'll do a final question.

I've made a test again..

Without spur gear and pinion the car is like an hotwheels, it run forever if i slightly push it

With spur gear istalled (then with AWD connected) and no pinion the car move a little less but it'ss till smooth.

Is this ok? I mean i think that like in real car the driveshaft and the connection beetween the 2 differential produce a little friction

EMU
2016.12.06, 06:58 PM
Realistically, there should be almost no difference between having the rear spur installed or not. As long as it's not a considerable difference, it should be ok. It may need a little run in to break it in...

Run it for a few minutes, and check motor temps. If the motor is getting hot, then it may cause issues.

I wish I had access to a printer like that! I would have to learn more 3d design... But it would be fun to make some prototype parts.

Evil_Sephiroth
2016.12.09, 07:51 AM
Ok i machined away another 0.02 mm from the spur gear where it touch the bearing..now all work perfect

I think i have a partially faulty chassis with a little wrong alignement beetween main driveshaft and the hole where the bearing go.

Probably my spur gear is a little more fragile atm, but with the bearing on i don't have movement then i think all is going to work fine.

Let's see in the future

EMU
2016.12.09, 12:56 PM
Glad to hear that you have found resolution with the binding. Let us know how it is down the road. On the negative, modifying spur gears to fix it means that any change in gear ratio by spur will be a pain since you need to machine it...

Evil_Sephiroth
2016.12.09, 01:59 PM
Glad to hear that you have found resolution with the binding. Let us know how it is down the road. On the negative, modifying spur gears to fix it means that any change in gear ratio by spur will be a pain since you need to machine it...

I simply have to buy a set of spur for various gear ratio and machining it one time XD

also still have to see if the problem is only with 98mm wheelbase or also on other wheelbase setp