pic: Basic chassis done

[falconmaster]

loading photo ...

[AdamHeard]

I'm just curious as to why you are running dual wheels in the back.

There is no additional traction gained, the load is more spread out but a single wheel is plenty strong.

[Bill_Hancoc]

Originally Posted by AdamHeard

I'm just curious as to why you are running dual wheels in the back.

There is no additional traction gained, the load is more spread out but a single wheel is plenty strong.

Actually you have less traction because there is less ground pressure.
Looks nice and clean
How much does it weigh..it looks heavy

[cinderblock]

Originally Posted by Bill_Hancoc

Actually you have less traction because there is less ground pressure.

Less pressure over a greater area. Friction force calculations go as the normal force times the coefficient of friction. Area is not used in the calculation of friction.

So why extra wide wheels in the back?

[RogerR]

Originally Posted by cinderblock

...So why extra wide wheels in the back?

one upside of having a large surface area is that the traction material will wear more slowly than a narrower wheel; more surface area means the forces are more widely distributed.

Also, while friction is not dependant on surface area, traction can be, under the right circumstances. for example, back in 2002 when you where allowed to lift 180# goals, teams would often tear up carpet fibers; the teams with narrow, high traction tires more than those with larger surface areas. by increasing the contact area, you spread the force around, so an individual carpet fiber is less likely to fail. more surface area, more carpet fibers sharing a given load.

[falconmaster]

Originally Posted by RogerR

one upside of having a large surface area is that the traction material will wear more slowly than a narrower wheel; more surface area means the forces are more widely distributed.

Also, while friction is not dependant on surface area, traction can be, under the right circumstances. for example, back in 2002 when you where allowed to lift 180# goals, teams would often tear up carpet fibers; the teams with narrow, high traction tires more than those with larger surface areas. by increasing the contact area, you spread the force around, so an individual carpet fiber is less likely to fail. more surface area, more carpet fibers sharing a given load.

You guessed it! It keeps us from having to repair the treads on the IFI wheels, we saw teams having to fix them frequently, last year we used this setup and never repaired one! Even though calculations show we loose some traction, we have not had a problem pushing everybody around. Plus it just plain looks cool!

[falconmaster]

Originally Posted by Bill_Hancoc

Actually you have less traction because there is less ground pressure.
Looks nice and clean
How much does it weigh..it looks heavy

Right now it weighs 45lbs but have yet to "cheese" it

[Pavan Dave]

I like the smooth look. What are you going to cover your wheels with?

Pavan.

[ChuckDickerson]

It really looks nice as usual guys! It looks like it has a pretty low ground clearance. With all the talk of ramps on robots this year do you have a plan to clear any ramp peaks so that you don't "high center"?

[NoSkaOnTheRadio]

i like that a lot. 4 back wheels is an interesting choice, but i'll defer to the designers on this one as to how useful they'll be.

[falconmaster]

Originally Posted by Pavan

I like the smooth look. What are you going to cover your wheels with?

Pavan.

IFI roughtop tread