Page Comparison

beach tires 

• can purchase commercially
• cost is under $100

• have to design within constraints of COTS wheel hubs

• similarly to Stanford, nylon chains and grips can be added to the surface of the wheels for more traction
• 8-12" diameter for a 6 wheel design (from old research
• can adapt
• Can adapt to a 6” diameter hub motor
• Width exceeding 4” (by experience, can analyze for more detail, too narrow tires can significantly increase ground pressure)
• Any 2 tires in design must be able to handle entire rover load without rupturing

ATV sand tires

• tried and tested to be efficient in sand dunes 

• would have to emulate the design ourselves/cannot buy commercially because regular ATV sand tires are too big

• can change pressure within tires, when tires are deflated to 10-20 psi, better for sandy terrain

cast with molds

• customizable 
• can use with custom hubs

• prototyping time that could  be spent working elsewhere
• need to learn how to use molds and casting 

• refer to Ryerson Rams design

Aluminum (curiosity rover)

• more similar to current tech used on Mars (air tires cannot be used due to Mars' atmosphere)

• depending on thickness of wheel/design, similarly to Curiosity Rover, the aluminum wheels could experience some damage 

• has been approved by NASA
• would be more suitable for real Mars conditions

• difficult and expensive to imitate 
• deformations can occur if shape memory alloys are not used

3D Printed

(use thermoplastic elastomers)

white NinjaFlex (very soft, therefore harder to print)

• customizability 
• compliant wheel internal design (with soft thermoplastics)
• Can rapidly prototype various wheel designs 
• custom hubs can be used which is easier for mounting motors on wheels
• With custom hub design as well, possibility of swapping tires
• FEA justified

• printing/prototyping time that could  be spent working elsewhere
• less reliable than commercially designed tires

*referenced this report which used small scale wheels https://www.sciencedirect.com/science/article/pii/S2212827117300793

(μ measured on aluminum)

• another material option is elastomer latex, but that is not commercially available

clear generic TPE90A

black SemiFlex

• can be used for glass, metals, plastics
• water resistant, flexible
• can be removed with exacto knife and acetone (for excess remaining)
• any cuts made by exacto knife on wheel can be fixed with soldering iron
• equipment: caulking gun

• non crystalline adhesives that stay flexible and tacky
• good adhesion
• long open times
• can be used for woodworking, automotive assembly
• remove with rubbing alcohol, hot gun, scraper
• equipment: hot melt gun (glorified glue gun)

• https://www.hotmelt.com/products/high-performance-product-assembly-apao-hot-melt-300-second-open-time
• requires a quote?

• can be removed with heat and force: heat gun and scraping
• good long term option, used for outdoors (bike tire repairs)
• acetone can be used to remove any excess remaining
  • note: acetone supposedly beads up on/does not affect polyurethane
• equipment: brush for application
  • does suggest scuffing up the area first for better adhesion

~$9 for 8oz container

mcmaster carr:

plastic cement

https://www.mcmaster.com/adhesives/for-use-on~polyurethane-rubber/cement-for-plastic/

• stanford used zip ties to attach the treads to their wheels
  • would only use for prototyping

• thick groove patterns, wear down evenly over time 

• move in a single direction, most common type of tire tread

• highest level of traction, control
• designed to roll in only one direction

• highest SAR Score
• scored well in 2019 competition
• greatest diameter along center of wheel
• angled ridges/small paddles

• 4th place for SAR
• video shows strong traction on snow 
• contact about material type?

• additional rubber (??) strips added, horizontal lines
• 10th place SAR

• 8th place SAR
• horizontal ridges

• paddle like ridging to dig into sand
• generally smoother than traditional (car) tires
• printing time may be very long
• bc they stick out more, they could be harder to attach/could fall off

• reduced weight
• maintains turning ability
• printing time may be very long
• bc they stick out more, they could be harder to attach/could fall off