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Using "Hard" tires with the Parallax wheel kit? — Parallax Forums

Using "Hard" tires with the Parallax wheel kit?

vanmunchvanmunch Posts: 568
edited 2011-11-14 17:53 in General Discussion
Hello,

I've used the Parallax wheel kit in the past for some outdoor projects where the pneumatic tires worked great and I didn't mind having to refill the one tire every couple of days. However, my new project is only going to run on concrete and it's going to run autonomously for a couple of weeks so the slow air leak in the one tire will be a major problem. I'd like to replace the pneumatic tires with a hard rubber to both solve the leak problem and to reduce the coefficient of friction of the wheels. I'd like to keep the aluminum rims because they look great and I bought a pair of lawnmower wheels, but they look so.... Has anyone done this before? Any suggestions? A way to fill the pneumatic tires with hard foam? Thanks!

Dave

The wheel kit:
http://www.parallax.com/Store/Accessories/MotorServos/tabid/163/CategoryID/57/List/0/SortField/0/Level/a/ProductID/507/Default.aspx

Comments

  • RobotWorkshopRobotWorkshop Posts: 2,307
    edited 2011-11-05 19:03
    Hello Dave,

    Although I do like the inflatable tires for some projects as well I have suggested that the solid tires be offered as an option. The best wheels I have seen as a replacement would be the colson caster wheels. They are available with a non marring gray rubber that is perfect for indoor robots or even on concrete. These were used on many battlebot robots (one of mine included) and are very durable. I have some that were used on robots from the 80's that are still in great shape. No flats.

    All it would take is an adapter for the hub with a hole/slot the same dimension as the current parallax wheel to fit the larger colson hub. If these adapters/wheels were available I would switch to them in a minute on my large robot that is primarily used indoors. I believe you saw it at the UPENE. The tires went flat once and it is a PITA to add air to them. I did add some short valve extensions so I can get more air in if I have too but it still isn't easy. For that application a solid wheel would be a much better option for me.

    For an outdoor robot and some other indoor one the inflatable tires may still work well. I'd just like to see the option of using either style.

    http://www.colsoncaster.com/

    Some options:

    http://www.colsoncaster.com/products/productdetails/default.aspx?productid=44

    http://www.colsoncaster.com/products/productdetails/default.aspx?productid=47

    http://www.colsoncaster.com/products/productdetails/default.aspx?productid=109

    Robert
  • WhitWhit Posts: 4,191
    edited 2011-11-05 19:07
    There was an article in Nuts and Volts or Servo by the Editor. He used some foam donut inserts in the tires for this purpose, but I don't remember much else.

    I think it was something like this - http://www.airfreetires.com/shopping/c-35-6-inch.aspx
  • Phil Pilgrim (PhiPi)Phil Pilgrim (PhiPi) Posts: 23,514
    edited 2011-11-05 19:10
    Maybe, instead of filling the tires with air, you could fill them with some sort of expanding foam. ('Just thinking out loud here. Not sure how you'd actually do it.)

    -Phil

    Edit: I think Whit's idea is better, since it's reversible.
  • W9GFOW9GFO Posts: 4,010
    edited 2011-11-05 22:34
    The expanding foam tends to be quite hard and "crunchy". If I were to use foam in a tire like that I would try using a closed cell rubbery foam.
  • bill190bill190 Posts: 769
    edited 2011-11-05 22:46
    Would that "tire leak stopper" sold at automotive stores stop the air leak?

    Like this...
    http://www.simsupply.com/p-60775-tire-leak-stopinflator.aspx

    Also we have a really good automotive tire shop around here and I see people bringing in all sorts of small tires to have leaks fixed. Wheelbarrow, hand truck, garden trailer, whatever. Although this is a rural farming area. I don't know if a "big city" tire shop would do that?
  • $WMc%$WMc% Posts: 1,884
    edited 2011-11-05 22:53
    Most modern tire shops offer a soft foam fill for tires in use at land fills and recycling centers where punctures are often.
    '
    We use this at work and the tires are soft like on air but never go flat.
    '
    This is for low speed tires and not highway use.
    '
    At work: I wrote a REQ for two 13" tires to be foam filled, It cost the company $10.65 for the two so your little tires shouldn't be much
  • LoopyBytelooseLoopyByteloose Posts: 12,537
    edited 2011-11-05 23:14
    Inflatable tires leak at the rims and in the valves. It might just be easiest to reseat the tires by using a solution of some sort - like anti-freeze or glycerin. Or it could be that tire valves are not properly seated. Disassemble, clean and reseat. Automotive and bicycle tubes in good condition don't generally leak so quickly.
  • vanmunchvanmunch Posts: 568
    edited 2011-11-06 15:16
    Hey thanks everyone for your suggestions!

    I think I'm going to try whit's insert idea and if they're too soft, Robert's caster wheel idea. I would normally try the caster wheel idea first, but the wheel rims are such a tight fit that I'm concerned I'll damage them if I try any harder to pull them off. I think the foam or replacing the valve stem would work if I was just trying to stop the air from leaking, but I think that the hard wheel will also make the robot run more efficiently.

    Thanks again everyone for your help and you should check out Robert's soda fetching robot. He based it on Steve Norris's soda fetching robot, but then really expanded it. I saw it at the UPENE and it was very cool and the hand soldering was very impressive for the display face. Robert, do you have a link to the project?

    Dave
  • WhitWhit Posts: 4,191
    edited 2011-11-06 19:10
    Let us know how it works!
  • Ken GraceyKen Gracey Posts: 7,401
    edited 2011-11-06 19:52
    vanmunch, those tires shouldn't be losing air in the way you described. They're made for electric scooters and they hold 90 psi for many months. I've never had to refill any I've seen at Parallax, including many Eddie and Madeusa robots we've shipped.

    I think what may have happened is that when you assembled the tires you pinched the tube between the wheel and ring, causing a little tear and small leak. Or, perhaps the Schrader valve is bad on the tubes. Either way, this doesn't sound right.

    Drop me your shipping address and I'll send you some new tubes and tread to try.

    Ken Gracey
  • Paul K.Paul K. Posts: 150
    edited 2011-11-06 20:20
    Its probably a leak as suggested above.

    At the shop we actually had our boom lift tires foam filled. http://images.search.yahoo.com/search/images;_ylt=A2KJke3TW7dO0UEA8QWJzbkF?p=boom+lift&fr=&ei=utf-8&n=30&x=wrt&y=Search
    So having them foam filled will work, they just need to sit for a few days and a industrial tire supplier will do it for you.
  • vanmunchvanmunch Posts: 568
    edited 2011-11-07 10:31
    Ken, Paul,

    Thanks for the insight and the offer Ken. Ive sent you a pm. There's a good chance that it's leaking around the valve. The one tire holds it's pressure much better. I also didn't know that you could put that much pressure in them. I thought I saw 35psi someplace on the tire? Anyhow I'll let everyone know how it turns out. I don't want to leave anyone hanging. ;)

    Dave
  • RobotWorkshopRobotWorkshop Posts: 2,307
    edited 2011-11-07 10:39
    If it is a slow leak you may be able to try some of the tire sealants like Slime, etc:

    http://www.slime.com/

    http://www.amazon.com/Slime-Tire-Sealant/dp/B003UWC92M

    I've never tried it but it may take care of the problem.
  • Ken GraceyKen Gracey Posts: 7,401
    edited 2011-11-07 15:31
    Dave, new tires and tubes are on the way. Be sure to assemble these very carefully and avoid pinching of the tube. I don't remember the actual PSI.

    Let us know if it works out. You should be leak-free, all the time.

    Ken Gracey
  • vanmunchvanmunch Posts: 568
    edited 2011-11-14 17:53
    Hey All,

    Just a quick update. The intertubes that Ken sent arrived last Friday. They also came with a second set of tires and intertubes. I should be good for 40,000 more miles. Thanks Ken and Parallax for the extra-extra mile of service. ;)

    I was still curious about the hard inserts so I ordered those too last Wednesday, but after waiting a couple of days I looked at their "fine print". It says that all items will ship in !90! DAYS!! I think it will be a while be for my next update....
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