Traction Measures for Different Tread Materials
Net Thrust Over Static Drag (pounds force)
............................................ Carpet (with slider) ....Vinyl Kitchen Flooring
Neato's Original tread ................... 3.25 lbs ........................ 4 lbs
Mouse Pad Foam Dense Rubber ........ 3.5 lbs ......................... 6 lbs*
Velcro Self-Stick Strapping (hook) ..... 3.5 lbs ......................... 0.5 lbs
Ruggies carpet gripper .................. 5.5 lbs ......................... 6 lbs*
Rubber Band .............................. 3.25 lbs ........................ 5.25 lbs (see later post on mounting)
Gold Watch Chain ........................ (for hockey rinks only)
* postal scale stops at 6lbs, could exceed
(Only mounting velcro with deeper hooks apparently grips carpet well. Nothing with Ultramate, though.)
(The slippery carpet slider probably renders this measure equivalent to a more tacky carpet. Carpets vary in consistency and effect.)
Speed: no effect, about 6 in/sec spot cleaning, but varies over program phases. Consistent with feedback control of driver motor RPM, speeds settable in USB commands. The increased friction did not overcome Neato's drive. Highest speeds, though, were not tested.  later no observed difference.
 Motor load measurements show very slight increases with higher traction mouse pad treads amounting to a couple minutes run time. Motor load increase on carpet 100ma on 625ma, hard floors 50ma on 250ma (where the problem moldings are located). Sliders are still needed on carpet to reduce drag instead of using more motor power to overcome drag.
"Ruggies" non-adhesive carpet sticking material seems coated both sides with some tacky stuff to which dirt will cling, removable only with acetone, not alcohol. $2.50 per Neato vs 50 cents for mouse pad foam rubber. May not stick to crazy glue. Advanced silicone rubber very elastic, tacky consistency.
The 50 per cent increase in traction with mouse pad material is consistent with successfully climbing a problem 1/2" quarter round metal carpet edging which Neato could not previously climb, with wheels slipping on the metal.
Quarter round moldings are the most difficult because the sharp curvature limits wheel contact area to a single tangent point, at an angle to the weight pressure as well, reducing traction. The polished metal here is also slippery. Theoretically the softer mouse pad material maintains a larger contact area; the pad surface is not especially more tacky than Neato's original tread. The pad is cross hatch patterned on the bottom for surface gripping. I don't think rubber bands are especially different than Neato's tread, either. More on moldings in their own section below. Like higher traction softer car tires, the softer Neato material will wear faster, but should be easily replaced. How well it works in the end requires observing long term usage. One possible problem would be dirt accumulation on the surface reducing effectiveness. That can be corrected by dusting off fairly easily.Tread Construction
Custom wheels were made just for testing, and can be improved for permanent use. I did not want to risk destroying a Neato wheel removing its tread. I suspect ProTech's "tread" item is the entire wheel, as the larger unit is the whole motor assembly. Couldn't get an answer from them by email, guess would have to phone. Neato's wheel has thin blades extruded into the tread holding it in place -- compared to the slipping rubber bands reported. Ideally the mouse pad material would be installed on Neato's wheel hub discarding the original silicone tread. What's involved in removing the tread and configuring the replacement to fit I don't know yet.  Attempting to obtain some extra wheels, uncertain. Or express an interest to persuade the more qualified members with some business in parts it would be worth offering some replacement treads ready to slip on.Hand-made Wheel Details
For regular wooden wheel use I would tack the material down with counter sunk thin, #19 I think, brads or sewing pins (both needing a sub-1/16 drill on hardwood not to split it). (Softwood will work initially but loosen the grip on the drive shaft over time. Plastic is available but much more expensive in 1/2 inch thickness. Small 2 ft red oak boards pre-cut are at Lowes building supply in the U.S.
There was some confusion with the wheel measurements. The Neato diameter is 3". With a 2.5" hole saw cutting a 2 3/8" wheel I ended up matching adding a 1/4" layer of several parts: one mounting tape layer and two mouse pad layers separated by self-stick scotch tape. Ends of strips are crazy glued together. A 3" hole saw should make a wheel taking a single layer of mouse pad. I extended the pad inwards of the flat wheel edge matching thickness of Neato's tread.
Using the flat wheel a 1/16" nylon washer 5/16-3/8" I.D. is used between the wheel and the motor assembly.
The wheel wobbles slightly. A 1 7/8" or 1.75" hole saw or both, will cut a groove in the wheel (before cutting it out) fitting over the raised flange on the motor assembly same as Neato's own wheel, eliminating the washer. Greese is used on the inside surface. It seems the outer flange is used to stabilize the wheel. could be more a dust seal, and the shaft fit is the issue. Surface inside the groove perimeter must be reduced sanding not to rub, just like the original wheel. Better use a slice of hard wood dowel in place of the washer, glued as protrusion. Or bolting the disk into a drill, spin to sand selected part.
 On second thought the washer surface may be needed for bearing, so a 1/4" I.D. washer can be countersunk in the wood before cutting and filed out with the wood. Some of the wobble might be due to the gap in fitting the drive shaft, hard to tell. A Dremel cutter bit could speed hole shaping, but not sure how easily controlled, very powerful. A regular drill cutting bit 1/4" did not cut hard wood. Maybe there are others.
Initially filed washer might serve as a tool guide for the wood.
The shaft screw must be counter sunk in the outer wheel surface to the level of the inserted drive shaft end, with a 7/16 or 1/2" bit.
Adjustable hole saws with a point cutter on a radial arm need a drill press to hold straight cutting. Others can be used on hand drills, requiring separate sized entire cylinders, more expensive.Molding Height Transitions
Neato cannot climb too high a molding without a ramping approach or the top edge can grab the bottom tight enough to trap the vacuum. It is not a matter of traction per se; there are limits to the mechanics of the unit size, in turn limited by the need to navigate between obstacles. The whole business is a delicate balance of factors not readily apparent. Some high moldings are wide enough to provide a ramping slope, but others have a sort of quarter round finish at the top -- those problem curves. Neato needs to bump off moldings it cannot climb, but without modifying the bumper, mag strips must be used.  When climbing, weight rests on the front and back, diminishing pressure and friction on the wheels. So better traction will help.
One solution for too high or poorly shaped moldings is to add to the molding a thin step of 1/8" hobby wood, basswood, available in narrow strips at craft stores and online suppliers. This creates a stairway Neato can climb, a series of more easily handled transitions. Whether such things are suitable for the architecture of a house is a matter of taste and circumstance. The strip must be fastened with tacks or self-stick tape. Paint and stain pens can be used.
An excellent tape approach might be the new 3M Command Adhesive strips, for hanging fixtures, which do not damage finishes, and remove by stretching them; fairly expensive. Regular self-stick mounting things have very hard to remove glue in some cases, when left on long periods, requiring acetone (nail polish remover) ruining any painted or varnished surface. Rental properties advise tenants to use only tack fittings for hangings instead of glued hangers damaging sheet rock surfacing.Other Mods
Links to all mods for utility cleaning at http://www.robotreviews.com/chat/viewtopic.php?f=20&t=16475
glnc222, mentat, reporting.
Last edited by glnc222
on November 1st, 2013, 2:20 pm, edited 13 times in total.