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Old 10-18-2009, 05:21 PM   #1
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Default Question on Weight Distribution for Touring Cars

Why are batteries off to one side seem to be the common and prevalent chassis layout for touring?

I'm a newb in on-road, but in off-road 4wd, having saddle or the battery down or closer to the center was an advantage in balance...

Why are there more TC cars with batteries on one side rather then something like the JRX-S where the battery is down the center?

in 2WD RWD foam cars (like the RC10L), saddle was the way to balance it. Batteries on one side was only for LTO (left-turn-only) cars...
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Old 10-18-2009, 05:47 PM   #2
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Don't quote me on this, but the one side battery configuration is perhaps better than the saddle for front to back weight distribution. The other reason is because of maintainability. I recall seeing someone with a JRX-S, and boy, did it look complicated to put the battery into the car (versus just one piece of tape). If the battery was in the center, the CG of the car may have to be shifted upwards. (since the placement of the electronics would be more difficult). I am really not to sure about this one... but I think keeping all rotating parts close to the center line of the car, also helps to balance the car dynamically, while the car is under power, making it easier to drive (This is why most drive shafts and drive belts of cars today are located on the center line). And since the rotating parts are put on the center line, the batter must be placed elsewhere.

That's my 2cents anyways. Happy Racing!

Feel free to correct me! I am also a newb to rc still and would like to learn what the pros here have to say.
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Old 10-19-2009, 10:33 PM   #3
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Ahh, I figured the battery on the JRX-S is harder to load then other tourers similar to the DF-03 chassis, but there must be some advantage right? Keeping things closer to the COG, especially the battery, which is the most dominant weight?
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Old 10-19-2009, 11:05 PM   #4
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I've had both of the JRXS sedans, and the battery is very easy to get into and out of the car. Two screws and the battery litterally falls out the bottom. The Type-R is the only touring car (maybe the Magic, too) that doesn't need to be rebalanced when swapping between different weight batteries, as the pack is always centered between the front and rear axles, as well as being centered across the width of the car. Even the F/R bias of the original mid-motor JRXS is affected by running batteries of varying weight. As for why that car didn't take off, it was partially due to the short arms which narrowed the setup window beyond what most racers could manage. I hacked my way into the B-main at Snowbirds with one, so with a better driver it was definitely worthy of an A-main appearance. However, just as soon as the car was released, the factory team began running protoype rear motor cars, the aforementioned Type-R. That complete lack of confindence from the team drivers (mainly in mod class) was surely a big reason many club racers didn't bother buying the mid-motor car.

As for why most touring cars evolved into having the batteries on the right side.... going back to the dawn of competitive touring car racing, the most successful cars had saddle packs. The packs were a pain to load into discharge trays and newer chassis designs like the Losi Street Weapon and AE TC3 proved that running the batteries all on one side or the other could be properly balanced, left to right. Once shaft drive cars lost favor, the now obligatory dual belt design was continually "optimized" (get used to hearing that word, I probably owe Xray $6.99 for typing it) with an ever lower center of gravity. The top decks were constantly being lowered right up to the point in history were Lipo batteries gained favor. Since Lipo dimensions were essentially fixed and were too tall to fit under the top decks of even recent designs (-2008), most manufacturers began seperating the top deck from the other myriad bulkheads in an effort to fit Lipo packs and begin allowing racers the option of adjusting the flex characteristics of the chassis itself.

Here's a better question which I don't have even a foggy clue of an answer; why are most if not all C-hubs and spindles geometric copies of one another?
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Old 10-20-2009, 04:04 AM   #5
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Quote:
Originally Posted by Greg Sharpe View Post

As for why most touring cars evolved into having the batteries on the right side.... going back to the dawn of competitive touring car racing, the most successful cars had saddle packs.

Here's a better question which I don't have even a foggy clue of an answer; why are most if not all C-hubs and spindles geometric copies of one another?
Motors need to be on the left in belt driven cars otherwise rotation direction needs to be reversed. Most TCs have one center pulley two belts and diffs. Rotation direction is therefore the same for all of them. If you were runnning a mini car (as those from tamiya where the motor is on the left) you would need to reverse the throttle control on the radio.

Shaft cars have the batteries on either side.

As for C hubs and spindles they simply have evolved to reach the best setup and that's why they up looking more or less the same. They're not exactly copies of each other but are very close. Likewise shocks, bulkheads, rear hub carriers and suspension arms, etc.
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