BB priority

[nospam]

Hello,

If you have a limited amount of ball bearings,
where would you put them?

On the axes that go from the motor to the front
and back gears or on the axes that go from the
diff gears to the tires?

Why?

I have the impression that there are more energy
on the motor-front/back gear axes.
I would be tempted to put priority on this.
But as I am quite new I need a few advices.

Thanks,

[Bubba]

On Wed, 19 Feb 2003 10:57:28 +0100, nospam <nospam@antispam.com>
wrote:

>Hello,
>
>If you have a limited amount of ball bearings,
>where would you put them?
>
>On the axes that go from the motor to the front
>and back gears or on the axes that go from the
>diff gears to the tires?
>
>Why?
>
>I have the impression that there are more energy
>on the motor-front/back gear axes.
>I would be tempted to put priority on this.
>But as I am quite new I need a few advices.

In the hubs. The bearings nearest the wheels carry the highest loads
and need the best support. Inboard driveshafts have very little radial
load (unless they're bent) and can live with well greased bushings
perfectly fine.

Bubba
Losi XXXS- http://home.swbell.net/lt1_z28/xxxs.html
HPI Micro RS4- For sale
AE RC10LSS- Also for sale:
http://home.swbell.net/lt1_z28/rc10lss_for_sale.htm

[Justin Mahn]

The hubs weren't in the question, but they do need the bearings first. As
to the choices, I'd say put them in the input shafts to the diff boxes. I
assume you're driving a TC3 or other shaft driven car from your description.
The input gears operate faster than the output hubs, and therefore will
benifit more from reduced friction. Also the output hubs have more
diameter, and so will last longer with less wear until you can afford
bearings for them, too.


"Bubba" <bubba@beer.com> wrote in message
news:3e535b1e.112887287@news.dallas.sbcglobal.net. ..
> On Wed, 19 Feb 2003 10:57:28 +0100, nospam <nospam@antispam.com>
> wrote:
>
> >Hello,
> >
> >If you have a limited amount of ball bearings,
> >where would you put them?
> >
> >On the axes that go from the motor to the front
> >and back gears or on the axes that go from the
> >diff gears to the tires?
> >
> >Why?
> >
> >I have the impression that there are more energy
> >on the motor-front/back gear axes.
> >I would be tempted to put priority on this.
> >But as I am quite new I need a few advices.
>
> In the hubs. The bearings nearest the wheels carry the highest loads
> and need the best support. Inboard driveshafts have very little radial
> load (unless they're bent) and can live with well greased bushings
> perfectly fine.
>
> Bubba
> Losi XXXS- http://home.swbell.net/lt1_z28/xxxs.html
> HPI Micro RS4- For sale
> AE RC10LSS- Also for sale:
> http://home.swbell.net/lt1_z28/rc10lss_for_sale.htm

[nospam]

Hello,

Justin Mahn wrote:
> The hubs weren't in the question, but they do need the bearings first. As
> to the choices, I'd say put them in the input shafts to the diff boxes. I
> assume you're driving a TC3 or other shaft driven car from your description.
> The input gears operate faster than the output hubs, and therefore will
> benifit more from reduced friction. Also the output hubs have more
> diameter, and so will last longer with less wear until you can afford
> bearings for them, too.
>

For the people that are not very familiar with RC Car,
what does delimit the hubs?

I wanted to make sure that I understand well and my native
language is not english.

Thanks

[Bubba]

On Thu, 20 Feb 2003 10:13:52 +0100, nospam <nospam@antispam.com>
wrote:

>For the people that are not very familiar with RC Car,
>what does delimit the hubs?
>
>I wanted to make sure that I understand well and my native
>language is not english.

The parts at the ends of the suspension arms that hold the outboard
ends of the driveshafts/halfshafts/dogbones/CVDs/whatever you want to
call them.

For reference, the parts with the highest radial loads need bearings
most.

High radial loads:
Wheels
Differentials in belt driven cars

Moderate radial loads:
belt tensioners
diffs in shaft driven cars
steering arms

Low radial loads:
driveshafts
differential center bearings

Oilite, bronze, and lead bushings, properly lubricated, are perfectly
fine for high RPM parts with low radial loads like driveshafts.
There's a good chance that they'll actually have less friction than
the small (ok, bloody tiny!) ball bearings we use. The more radial
load, however, the less suitable bushings are since the force tends to
squeeze the lubricant out of the bushing.

Think about it this way. Full scale car engines have bushings
(properly called bearings, even in RC cars) on the crankshaft, conn
rods, camshaft(s), etc. and they work fine. Sure, they have a high
pressure oiling system, but they also experience loads thousands of
times greater than we have to worry about.

Personally I have exactly zero bushings in my XXXS. Everything has a
ball bearing on it. Wait, that's not true. The steering drag link has
a pair of very small steel bushings, but those are going away shortly
when I replace the drag link with an adjustable one :)

Bubba
Losi XXXS- http://home.swbell.net/lt1_z28/xxxs.html
HPI Micro RS4- For sale
AE RC10LSS- Also for sale:
http://home.swbell.net/lt1_z28/rc10lss_for_sale.htm

[MikeF]

The hubs, or in this case 'hub carriers', are what connect the wheels to the
suspension.
They do have the most load and should be replaced with only top quality
bearings. If this is for an off-road car, then they must be rubber or teflon
sealed bearings. 'Shielded' bearings are no good for off road.
Tower's duratrax bearings are not good enough to be off-road wheel bearings.


> For the people that are not very familiar with RC Car,
> what does delimit the hubs?
>
> I wanted to make sure that I understand well and my native
> language is not english.
>
> Thanks
>

[nospam]

What are the major difference between good and classical ball bearings?

MikeF wrote:
> The hubs, or in this case 'hub carriers', are what connect the wheels to the
> suspension.
> They do have the most load and should be replaced with only top quality
> bearings. If this is for an off-road car, then they must be rubber or teflon
> sealed bearings. 'Shielded' bearings are no good for off road.
> Tower's duratrax bearings are not good enough to be off-road wheel bearings.
>
>
>
>>For the people that are not very familiar with RC Car,
>>what does delimit the hubs?
>>
>>I wanted to make sure that I understand well and my native
>>language is not english.
>>
>>Thanks
>>
>
>
>

[MikeF]

Classical?
wrong word. Your thinking "affordable"
The differences between good and cheap bearings are the quality of the steel
used, the tolerances, and the seal.
In my opinion, duratrax 5x10 bearings are very weak. I have blown apart 7
bearings so far - 5 on the wheel hubs and 2 on the pinion gear support in
the rear differential.



"nospam" <nospam@antispam.com> wrote in message
news:3E54CBF5.5040306@antispam.com...
> What are the major difference between good and classical ball bearings?
>

[Corwin]

> Classical?
> wrong word. Your thinking "affordable"
> The differences between good and cheap bearings are the quality of the
steel
> used, the tolerances, and the seal.
> In my opinion, duratrax 5x10 bearings are very weak. I have blown apart 7
> bearings so far - 5 on the wheel hubs and 2 on the pinion gear support in
> the rear differential.

for budget bearings I've had good results from "Yeah Racing! Dinball For
Sure!" (hehe funny name) bearings on ebay as well as Team Blue Star
bearings... the Yeah Racing ones performed extremely well for $11 for 22
bearings.. way cheaper than the duratrax ones and they haven't broke. The
only bearings I've ever broke are metal shielded no name ones that i bought
on ebay which i've replaced with Yeah racing ones.

neL

[Justin Mahn]

Sorry, Bub, you know a lot of stuff, but comparing liquid dynamic bearings
in engines to static bushings in rc cars is completely wrong. A better
match would be the conn rod bottom bushing in most .15 or .21 size nitro
engines. There is a hole in the rod wich FORCES new lubricant into the
bushing with each revolution, and there is NO dirt or dust to speak of (with
proper air and fuel filters).

When you say radial load, I guess that means force needed to turn the shaft.
I just didn't have a good way to explain it. I was guessing that since the
diameter of the shaft was smaller than the output cups, and that it had to
push a much larger ring gear, the input shafts would have a higher load than
the output cups. Niether have to deal with the pressures of suspension,
like the axle bearings do.

So my choice would be

1) axle bearings (SEALED fer sure, DUDE!)
2) input shafts
3) output cups


Justin


"Bubba" <bubba@beer.com> wrote in message
news:3e54a50e.197363246@news.dallas.sbcglobal.net. ..
> On Thu, 20 Feb 2003 10:13:52 +0100, nospam <nospam@antispam.com>
> wrote:
>
> >For the people that are not very familiar with RC Car,
> >what does delimit the hubs?
> >
> >I wanted to make sure that I understand well and my native
> >language is not english.
>
> The parts at the ends of the suspension arms that hold the outboard
> ends of the driveshafts/halfshafts/dogbones/CVDs/whatever you want to
> call them.
>
> For reference, the parts with the highest radial loads need bearings
> most.
>
> High radial loads:
> Wheels
> Differentials in belt driven cars
>
> Moderate radial loads:
> belt tensioners
> diffs in shaft driven cars
> steering arms
>
> Low radial loads:
> driveshafts
> differential center bearings
>
> Oilite, bronze, and lead bushings, properly lubricated, are perfectly
> fine for high RPM parts with low radial loads like driveshafts.
> There's a good chance that they'll actually have less friction than
> the small (ok, bloody tiny!) ball bearings we use. The more radial
> load, however, the less suitable bushings are since the force tends to
> squeeze the lubricant out of the bushing.
>
> Think about it this way. Full scale car engines have bushings
> (properly called bearings, even in RC cars) on the crankshaft, conn
> rods, camshaft(s), etc. and they work fine. Sure, they have a high
> pressure oiling system, but they also experience loads thousands of
> times greater than we have to worry about.
>
> Personally I have exactly zero bushings in my XXXS. Everything has a
> ball bearing on it. Wait, that's not true. The steering drag link has
> a pair of very small steel bushings, but those are going away shortly
> when I replace the drag link with an adjustable one :)
>
> Bubba
> Losi XXXS- http://home.swbell.net/lt1_z28/xxxs.html
> HPI Micro RS4- For sale
> AE RC10LSS- Also for sale:
> http://home.swbell.net/lt1_z28/rc10lss_for_sale.htm

[Tempestnightmare]

My personal opinion is if you are going to use ball bearings, use double
seal aircraft grade bearings. A little more expensive but tighter
tolerances. teflon seal is best, as rubber breaks down with dirt build up.
For the Engine and diff bearings, remove the seal on the inboard side so
they get lubed.
You can find them at www.mcmastercarr.com
Jon

"Bubba" <bubba@beer.com> wrote in message
news:3e54a50e.197363246@news.dallas.sbcglobal.net. ..
> On Thu, 20 Feb 2003 10:13:52 +0100, nospam <nospam@antispam.com>
> wrote:
>
> >For the people that are not very familiar with RC Car,
> >what does delimit the hubs?
> >
> >I wanted to make sure that I understand well and my native
> >language is not english.
>
> The parts at the ends of the suspension arms that hold the outboard
> ends of the driveshafts/halfshafts/dogbones/CVDs/whatever you want to
> call them.
>
> For reference, the parts with the highest radial loads need bearings
> most.
>
> High radial loads:
> Wheels
> Differentials in belt driven cars
>
> Moderate radial loads:
> belt tensioners
> diffs in shaft driven cars
> steering arms
>
> Low radial loads:
> driveshafts
> differential center bearings
>
> Oilite, bronze, and lead bushings, properly lubricated, are perfectly
> fine for high RPM parts with low radial loads like driveshafts.
> There's a good chance that they'll actually have less friction than
> the small (ok, bloody tiny!) ball bearings we use. The more radial
> load, however, the less suitable bushings are since the force tends to
> squeeze the lubricant out of the bushing.
>
> Think about it this way. Full scale car engines have bushings
> (properly called bearings, even in RC cars) on the crankshaft, conn
> rods, camshaft(s), etc. and they work fine. Sure, they have a high
> pressure oiling system, but they also experience loads thousands of
> times greater than we have to worry about.
>
> Personally I have exactly zero bushings in my XXXS. Everything has a
> ball bearing on it. Wait, that's not true. The steering drag link has
> a pair of very small steel bushings, but those are going away shortly
> when I replace the drag link with an adjustable one :)
>
> Bubba
> Losi XXXS- http://home.swbell.net/lt1_z28/xxxs.html
> HPI Micro RS4- For sale
> AE RC10LSS- Also for sale:
> http://home.swbell.net/lt1_z28/rc10lss_for_sale.htm

[Bubba]

On Thu, 20 Feb 2003 19:26:00 -0600, "Justin Mahn"
<gabril-sp@m-blocker-at.tcainternet.com> wrote:

>Sorry, Bub, you know a lot of stuff, but comparing liquid dynamic bearings
>in engines to static bushings in rc cars is completely wrong. A better
>match would be the conn rod bottom bushing in most .15 or .21 size nitro
>engines. There is a hole in the rod wich FORCES new lubricant into the
>bushing with each revolution, and there is NO dirt or dust to speak of (with
>proper air and fuel filters).

Good point, but I was tired, so it's all good ;)

>When you say radial load, I guess that means force needed to turn the shaft.
>I just didn't have a good way to explain it. I was guessing that since the
>diameter of the shaft was smaller than the output cups, and that it had to
>push a much larger ring gear, the input shafts would have a higher load than
>the output cups. Niether have to deal with the pressures of suspension,
>like the axle bearings do.

Radial is perpendicular to the axis of the bearing, axial is along the
axis, torsional is what makes it turn. Torsional could also be called
tangental (I think that's it) in which case torsional could be used to
describe a load where the axle is being used as a lever so the bearing
sees opposing axial forces on either side of the race. But I'm not a
mechanical engineer, I just play one in front of a TV ;) The output
bearings on the differential might not see any force from the
suspension through the wheels, but when the CVDs are off axis the
bearings "think" the differential is off balance. If the CVDs weren't
supported on the outboard end the diff bearings wouldn't last 10
minutes.

Bubba
Losi XXXS- http://home.swbell.net/lt1_z28/xxxs.html
HPI Micro RS4- For sale
AE RC10LSS- Also for sale:
http://home.swbell.net/lt1_z28/rc10lss_for_sale.htm

[Paul - xxx]

Tempestnightmare deftly scribbled:

> My personal opinion is if you are going to use ball bearings, use
> double seal aircraft grade bearings. A little more expensive but
> tighter tolerances. teflon seal is best, as rubber breaks down with
> dirt build up. For the Engine and diff bearings, remove the seal on
> the inboard side so they get lubed.
> You can find them at www.mcmastercarr.com
> Jon

Actually I generally use cheap bearings .. but tear the hubs etc down
after each meeting and clean, re-lube everything .. ;) I also replace
them regularly. I've found little difference in the longevity between
cheaper to 'aircraft grade' bearings. Maintenance is all .. ;)

--
....................................Paul-xxx
Seti 1428 wu in 10426 hours
http://setiathome.ssl.berkeley.edu/
http://graffiti.virgin.net/ar.sole/Index.htm

[MikeF]

Your right up to the last point - which i didnt understand. Clarify
please...
BTW, dont forget thrust! That, which is only slightly different from
torsional stress, is what kills these little bearings.

I speak with some expertise because im a designer for a construction company
specializing in movable bridges.
I have details for a 5foot diameter x 18" wide spherical roller thrust
bearing on my desk now....
Rated capacity = 5million pounds.


>> Radial is perpendicular to the axis of the bearing, axial is along the
> axis, torsional is what makes it turn. Torsional could also be called
> tangental (I think that's it) in which case torsional could be used to
> describe a load where the axle is being used as a lever so the bearing
> sees opposing axial forces on either side of the race. But I'm not a
> mechanical engineer, I just play one in front of a TV ;) The output
> bearings on the differential might not see any force from the
> suspension through the wheels, but when the CVDs are off axis the
> bearings "think" the differential is off balance. If the CVDs weren't
> supported on the outboard end the diff bearings wouldn't last 10
> minutes.
>

[Tempestnightmare]

Well there is the point...with aircraft grade bearings you do not have to
tear down after every meet and clean them..unless you like to..
Jon

"Paul - xxx" <notcheckedever@hotmail.com> wrote in message
news:b34p9b$1ifrup$1@ID-137265.news.dfncis.de...
> Tempestnightmare deftly scribbled:
>
> > My personal opinion is if you are going to use ball bearings, use
> > double seal aircraft grade bearings. A little more expensive but
> > tighter tolerances. teflon seal is best, as rubber breaks down with
> > dirt build up. For the Engine and diff bearings, remove the seal on
> > the inboard side so they get lubed.
> > You can find them at www.mcmastercarr.com
> > Jon
>
> Actually I generally use cheap bearings .. but tear the hubs etc down
> after each meeting and clean, re-lube everything .. ;) I also replace
> them regularly. I've found little difference in the longevity between
> cheaper to 'aircraft grade' bearings. Maintenance is all .. ;)
>
> --
> ...................................Paul-xxx
> Seti 1428 wu in 10426 hours
> http://setiathome.ssl.berkeley.edu/
> http://graffiti.virgin.net/ar.sole/Index.htm
>
>

[Bubba]

On Fri, 21 Feb 2003 17:26:13 -0500, "MikeF" <vanning@comcast.net>
wrote:

>Your right up to the last point - which i didnt understand. Clarify
>please...

Chuck a piece of string up in a drill and spin it. You'll see what I
mean. Instead of just staying in line with the axis of the drill,
it'll fly off to one side. Same thing with a CVD, kinda.

>BTW, dont forget thrust! That, which is only slightly different from
>torsional stress, is what kills these little bearings.

Duh, forgot about that one. I was actually thinking about it and
intended to add it last, then forgot. Oops.

>I speak with some expertise because im a designer for a construction company
>specializing in movable bridges.
>I have details for a 5foot diameter x 18" wide spherical roller thrust
>bearing on my desk now....
>Rated capacity = 5million pounds.

Think it'll fit in a XXXS differential? ;)

Bubba
Losi XXXS- http://home.swbell.net/lt1_z28/xxxs.html
HPI Micro RS4- For sale
AE RC10LSS- Also for sale:
http://home.swbell.net/lt1_z28/rc10lss_for_sale.htm

[Paul - xxx]

I see the tear down as a pre-requisite for racing. I always did it when
I raced bikes and stuff, I do it as a matter of course. I rarely get
breakdowns on the track .. ;)

Tempestnightmare deftly scribbled:

> Well there is the point...with aircraft grade bearings you do not
> have to tear down after every meet and clean them..unless you like
> to.. Jon
>
> "Paul - xxx" <notcheckedever@hotmail.com> wrote in message
> news:b34p9b$1ifrup$1@ID-137265.news.dfncis.de...
>> Tempestnightmare deftly scribbled:
>>
>>> My personal opinion is if you are going to use ball bearings, use
>>> double seal aircraft grade bearings. A little more expensive but
>>> tighter tolerances. teflon seal is best, as rubber breaks down with
>>> dirt build up. For the Engine and diff bearings, remove the seal on
>>> the inboard side so they get lubed.
>>> You can find them at www.mcmastercarr.com
>>> Jon
>>
>> Actually I generally use cheap bearings .. but tear the hubs etc down
>> after each meeting and clean, re-lube everything .. ;) I also
>> replace them regularly. I've found little difference in the
>> longevity between cheaper to 'aircraft grade' bearings. Maintenance
>> is all .. ;)


--
....................................Paul-xxx
Seti 1428 wu in 10426 hours
http://setiathome.ssl.berkeley.edu/
http://graffiti.virgin.net/ar.sole/Index.htm

[Bubba]

On Sat, 22 Feb 2003 09:26:07 -0000, "Paul - xxx"
<notcheckedever@hotmail.com> wrote:

>I see the tear down as a pre-requisite for racing. I always did it when
>I raced bikes and stuff, I do it as a matter of course. I rarely get
>breakdowns on the track .. ;)

But did you know that the MTBF on a bearing drops to a fraction of the
previous value as soon as you pop the seal? This assumes good quality
bearings, of course. I prefer to just soak the bearings in silicone
oil after cleaning them off with a toothbrush. I've had bearings last
over a decade that way. Just remember that I'm an on-road/touring car
guy, but the streets I play on are rather dirty.

Now back to designing the world's easiest discharger. If it works out
right it'll discharge a battery to 5 volts every time with no
interaction from me :)

Bubba
Losi XXXS- http://home.swbell.net/lt1_z28/xxxs.html
HPI Micro RS4- For sale
AE RC10LSS- Also for sale:
http://home.swbell.net/lt1_z28/rc10lss_for_sale.htm