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-   -   Ceramic bearings (https://www.rctech.net/forum/electric-road/103820-ceramic-bearings.html)

THE DARKSIDE 03-04-2006 08:22 AM

Also try RC4Less.com for ceramic bearings

HB 03-04-2006 01:20 PM

SO WHITS IS BETTER?
rubber or matel shild?

koabich 03-04-2006 01:59 PM


Originally Posted by HB
SO WHITS IS BETTER?
rubber or matel shild?

For dirt or anything gas, rubber.

For anything else metal

Best for everything is PLASTIC!! Protection of rubber sealed bearings and less friction than metal sealed bearings ONCE BROKEN IN!!

HB 03-04-2006 04:44 PM

what do u mean dirty?
onroad outdoor???

koabich 03-04-2006 07:15 PM


Originally Posted by HB
what do u mean dirty?
onroad outdoor???

I didn't say dirty, I said DIRT (meaning off-road). For on road ashpalt metal or plastic would be fine as rubber would cause too much rolling resistance to make it worth while to run.

Plastic seals, in my experience, will keep the bearings almost as clean as rubber sheilds but once plastic sheilds are broken in, they will provide almost zero rolling resistance.

My Acer ceramics are better now after 3 years than they were when they were new...the more you run them the better they get! They spin forever and show absolutly zero wear. I also have very little time as far as maintenance goes into them. I ran them for over three years in my TC3. They lasted 3 race seasons practicing of 1-2 days per week in the off season and I probably cleaned them less than 4 times a year...and this is after running on a carpet track that isn't too well maintained!

corradopsi 03-04-2006 09:49 PM


Originally Posted by nnick
I'm reading the whole thread with much interest but still haven't decided to buy or not ceramic bearings!!

Does the investment worth?

Also, what do you think about ceramic bearings on the motor?? What size are they I'm trying to find them at boca site but can't

Nick


do you want less maintainance? if so, get them. if you plan to run the same car for a few years, they will pay for themselves after the first year. as for in the motor, check for legality under roar rules if your track abides by them. ceramics weren't legal for nitro for a while after they were first out, i have no idea about electrics.

as for performance wise, you probibly wont see an ontrack difference unless your running 5 minutes without hitting anything. if so, then your times may come down after thier seals break in.

Guo Chean 03-05-2006 11:49 PM

hey guy may i know where can i buy ceremic bearing for 540 motor can? thanks

warlord385 03-22-2006 03:08 PM

Ceramics vs. Metal
 
The answer to this question is rooted in simple physics. You must first understand that the bearings due offer resistance or friction. There are two kinds of friction of course: static and kinetic. We only care about kinetic friction because that is the friction of motion. Friction in the bearings must be overcome by the "power of the engine". Therefore using bearings with less kinetic friction will allow for you to put more power to the ground (thats in a nut shell). The real question is "How much kinetic friction is there in metal bearings version ceramic". Somebody mentioned that acer says they "free up 30%". This is an aribitrary statement. I agree with someone mentioning that 30% of 1% of the total friction is nothing, but this statement is out of context. The context being how much of the total friction of the drivetrain is in the bearings. Now this i don't know hte answer to. Because, if the bearings constitute only 10% of the drivetrain(belts and diffs, cause pulleys are on bearings), a 30 percent change in this would only affect your total by 3.3333333%. The best way to test if ceramics are better than metal shielded bearings is to test on a dyno, because if you decrease the kinetic friction you should increase power to the wheels (i wouldn't suggest a drum dyno, but a dyno that connects to individual wheels). But because there aren't any r/c dynos you can do a timed test. You would first need enough space to get the car up to full speed, 2/3, 1/3. You need to also know the exact position of throttle on the car. No lets say you have a 300 foot straight.

test 1: time how long the car gets from 290 to 300 ft at full throttle
test 2: Use 2/3 throttle (you have to measure this)
test 3: Use 1/3 throttle
Remember to always time the last two feet

Now switch the metal bearings out for ceramic and perform the same test while maintaing the exact throttle open postions.

Once complete the difference in times can be averaged to give you the percent change the bearings made. there you go
Also you if you know hte Hp rating of your engine and average speed over the last 10 feet you can calculate you hp loss to drivetrain as well as the percent effect bearings have. Anybody want to give this a shot?

warlord385 03-22-2006 03:13 PM

i just realized that you can calculate your speed becaue you know the distance and you know the time and speed is d/t. All you need to know to calculate the total loss or gain is the engine crank Hp


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