Monday, January 20, 2014

RE-Xtreme RC Drift Bible - Why Maintenance?


So... Why do you need maintenance?  Cause stuff breaks or rattles loose. Just making sure things are secure is a good starting point.







correct use of thread lock is important. overuse and underuse both cause issues.

but ...

Sometimes things just wear out. 

20000RPM motor is a rough ballpark.

20000 revolutions per minute on the pinion. 20000 / 4 = 5000 rpm = Revolutions per minute on the spur, and the centre shaft bearings .

each tooth on the pinion hits each other with impact... start stop.

So this all sounds reasonable. but when you translate these in to hours of run time the numbers get scary.

20000rpm x 60 minutes.  Hmmm.  Immediately... thats 1.2million revolutions on the motor / pinion!
and 240000 on the spur and main bearings. wheels bearings are similarly rotating less but rotating none the less.


Now lets take this to a month. twice a week 2.5 hours run time. = 5 x 4 weeks = 20 hours a week.

20 x 1.2million (yes remember that!) =  24Million revolutions on the pinion. take it out to a couple of months and the numbers play tricks.

So that said... think about what moves.

anything that moves... is a target.


Here is a common target. CVD constant velocity drive shafts. they have a few things that can make your day bad.

1. don't assume they are ready to install when you buy them.

you need to lubricate with black grease. you need to make sure the 'grub' screw is tight and thread locked in.



Check your steering end points. And steering angle. you can see that the yokomo cvd above has slight wear as the shaft rubs on the stub axle. It's obviously been running at too much angle.   


If the pin is not locked in place or eventually rattles loose. You may end up with this. you don't notice this stuff right away, because the pin starts to slide out slowly. Eventually the pin will come out of the CVD and something mad will happen, but you are left with a damaged CVD and whatever was surrounding it.  


Drive cups are another issue.

Where (Alloy vs Steel) or (Steel vs Plastic) there's always trouble. 

In this case all three are at work. New Yokomo setups use a steel pin surrounded by a tight fitting plastic item (that is meant to be replaced regularly) that rides inside a pretty alloy cup.


The steel pin wears inside the holes a little, but the outside rubs against the drive cup.
revolution after revolution... remember those numbers.


 you can end up with this very quickly and when that happens,

the pretty and expensive alloy parts have to be replaced also. for a 30 cent part avery week can save you $60 easily.




Here is the reason why you don't buy "copied" parts that make a lot of revolutions.

I bought this eagle racing drive gear for my TA-06. within 2 hours there was soo much play in the rear that it was seriously worrying. The HARDENED STEEL pins had started to destroy the holes in the WEAK CHEAP GRADE "ALLOY" and the weak plastic cups that were on the out drives were also cracked.



It was basically poor design coupled with and poor materials , so I bought the expensive Overdose item and some replacement outdrive consumable cups which not only eliminated play but also made the maintenance easier. I made sure it was all lubricated and never had an issue after that.

 
Think about how your maintenance plays out as part of your upgrades. If you buy the cheaper C hub carriers without the ball bearings where parts move... there are wear issues.

steel vs alloy again at work. steel on steel is a much better option.



Belt drive fans are often cursing the belt... but it's not the belts fault.

Everyone WILL create the RC handbag effect eventually.

Tension too tight is the main culprit.

The side of a misaligned pulley rubbing on the belt is another.

Worn pulleys. especially plastic ones... need to be replaced.
Alloy items will sharpen up over time and start cutting belts too.

So inspect your pulleys, inspect your belts and ALWAYS carry a spare. 

Wider belts can be better but only if your pulleys are perfectly aligned.


 Because stuff like this always happens when you don't want it to. 


Dampers... how many times will that shaft go up and down. Thats why there's titanium shaft upgrades, but those rub on plastic and rubber, so which will last longer? probably not a little o-ring.

Those pistons will rub on the inside of the shock casing.
Everything becomes less tollerant over time.  

Buying second hand has it's pros and cons.

Dirt is the killer.

Clean your chassis,
Clean your bearings,

take things apart, inspect replace repair.

thats part of the fun.



For competition runners.

Maintenance and parts replacement is where sponsors come in.

For real cars and real race cars and drift cars at the top level.
The car is basically rebuilt for each event.

That's the big budget teams. For RC, If you want to be the best, you have to invest, but you can invest in a good chassis once.

If you maintain the low cost items like belts, pulleys, bearings and drive shafts cups ball caps etc. You will spend so much less than not maintaining it at all.

Enjoy your RC






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