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Old 01-17-2003, 04:26 AM   #76
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I would not recomend driving with a overdrive bigger than 1,0. Again if you do that your car whill be FWD and because there is no oneway in the rear the rear tires will act like a break. In a 1/8 car that usually means a broken front belt... Adapt your setup/diving style so your tires wear evenly (or as close as possible)
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Old 01-17-2003, 04:54 AM   #77
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Originally posted by modellor
Right. So by increasing the RPM this in effect alters the overdrive because you can run a smaller percentage to obtain the same effect.

How? The internal ratio, over driven front or not, can not change due to rpm.... its all connected to each other...

if you forget tire size, the axles front and rear, will turn at the same ratio to the engine, no matter how fast its going...
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Old 01-17-2003, 07:01 AM   #78
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boomer underdrive isnt more stable at least not in touring car overdrive is much easier to drive as you have already seen

sparsky i agree 100% if internal ratio of car isnt already overdriving the front the wheel itself spins at exatly the same rate as the rear only the outer circumfrence is spinning further on track due to its increased foam

when i start a main with same size tires after a few laps my car will drive easier as the overdrive of front increases due to my rear tire wear thus allowing me to get faster as the race progresses

i think the 1/8 cars use it much differently even the 235mm mugen advance uses a deviation of tire size to balance the internal ratio of the car

at one point i was thinking about using advance gearing in my mtx-2 but once i learned what the gears were i couldnt figure out how they worked eventually i found that his manual and setups all included tire diameter to rebalance the drive train which i believe was severly overdriven and his rear tires had to be much larger (5mm or so) larger to compinsate

if you overdrive or underdrive too much you effectively drag one end of you car making handling horrible

as far as rotating mass i think the belt/pulley system negates all that being as how they are completely connected
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Old 01-17-2003, 02:48 PM   #79
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Ok, I am going to put it all done in simple mathematics for you to see if you can understand where I am coming from.

For arguements sake we will use a simple format to keep it simple.

Engine RPM = 20,000
Rear wheel = 1 revolution
Front wheels doing 2 revolutions for 1 rev. of rear wheel (twice as fast)

Say for this (arguements sake only) overdrive is at 2% to keep it nice.

Now you increase the RPM to 40,000
Rear wheel will now increase to 2 Revolutions
Front wheel will double also to 4 revolutions (rotation speed increase by 4 times against increasing the RPM by 2 times)

But we want the front wheels rotating at twice the speed of the rear wheels so we can reduce the overdrive ratio to 1% to enable this.

Now do you see why I say the engine RPM can effect the overdrive percentage. It doesn't alter the overall percentage directly. We have to alter it manually.
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