Motor gear ratio question
 

We are using currently for the robot a modified version of the Toughbox (Different housing, same gear ratio) in a 4X4 drive that is than geared by a 15 tooth gear to a 60 tooth one. However we are currently facing a huge weight problem, our robot is about 2 pounds overweight, and we still have parts to add. We thought about lowering the gear ratio of the gears after the Toughbox in order to save weight in both the size of the gear and in chain. We already tried holing the gears but to no avail, it didn't solve the problem and we don't have any metal plates or the likes from which weight can be taken. Our question is whether we would still be competitive after lowering the gear ratio?

BTW, any other weight saving tips will be very much appreciated :)

~Kenneth
Team #2212 The Spikes

Re: Motor gear ratio question
 

Without knowing more it is hard to answer.

• What is your total ratio from the motor to the wheels?
• How big are the wheels? What type of wheels are they (kit, grippy, smooth, plaction, etc.)?
• What motors are you using to drive?
• What is the width and centerline distance between the wheels?
• and so on.

Changing ratio is a big decision. I would generally find another area to save weight than have my drive system compromised.

When I need to save weight (basically every time I build a robot), I look for big things I can live with out. Toss something overboard so you have the weight to bring something else you like more onboard.

By the way, you have to check your ego at the door. The last thing you want is to have a system on board eating up your weight budget just because you were too proud of it to allow a more important system get ahead of it in line.

Think about priorities and start cleaning house.

Joe J.

P.S. Did I use enough mixed metaphors for you? Because I can use more... ...no really, I can... JJ

Re: Motor gear ratio question
 

You could also think about using the aluminum gears from AndyMark
http://www.andymark.biz/am-0143.html
http://www.andymark.biz/am-0521.html
And the spacers
http://store.andymark.biz/am-0156.html

This would save about 0.85 pounds per transmission according to AndyMark.


I have never used these products, but I have heard that they are the same great quality as everything else AndyMark.

Re: Motor gear ratio question
 

Try looking at this presentation for other ways to save weight. http://www.chiefdelphi.com/media/papers/2220

Re: Motor gear ratio question
 

Weight savings Ideas and examples:

http://www.chiefdelphi.com/forums/sh...eight+watchers

Re: Motor gear ratio question
 

Thank you very much for your input. The presentation had been a very useful one. However we found out that we had miscalculated our weight and so our weight problem is summed up at 70 grams and not 2.07 kg. In the end we decided to keep the gear ratio the way it is at something along the lines of 1:48.