Replacement is definitely a good idea, the rim is #2903 and the tire is #2092. 

You can find replacements:
http://brickowl.com/catalog/lego-tyre-81-6-x-15-motorcycle-2902-87911
http://brickowl.com/catalog/lego-wheel-81-6-x-15-motorcycle-assembly-2903
http://www.bricklink.com/search.asp?q=2902
http://www.bricklink.com/search.asp?q=2903

Some sort of framing as suggested by Michael would also help, but you'll need to be careful because adding support inside the wheel could likely increase the turn radius of the robot which will have rippling effects throughout all your programs (unless you're turning with the gyro, I guess).


If you haven't seen http://www.masteringlegorobot.com (http://www.masteringlegorobot.com/) then you might want to check it out, especially the PDF for Building the Robot (http://www.masteringlegorobot.com/Building%20Robot/Building%20a%20Competitive%20Robot.pdf).  Check out page 15 and they join 2 of those motorcycle wheels together which might be another option to improve stability of the wheels.

One last thing you could try is a quick test to see if you can get the wheels to straighten out by using a quick wheel test: http://pmthium.com/2012/02/wheels/

Thank good old Murphy for bringing this to you the week before competition.  My team just realized they cannibalized their "safe zone" attachment to build one to retrieve the boy by the house, a mission that we're probably going to scrap.

Good luck! 

-- 
Jeff Schoolcraft


On Monday, December 2, 2013 at 8:34 AM, Michael Brown wrote:

> My guess would be to replace the tires on the rim if they are chewed up.  If the tires are not the problem, support the wheels on both sides of the axle to avoid splay. 
> Michael Brown
> ESVA FLL Mentor
> "What we discover is more important than what we win." 
> On Dec 2, 2013 8:23 AM, "Jayakumar Dwarakadas" <[log in to unmask] (mailto:[log in to unmask])> wrote:
> > We are using NXT kit for the state tournament and we have been using big wheel from the beginning. Since we have been using them for quite sometime, now the wheel are bent either inward or outward and we are losing accuracy. Any advice from past experience would be useful.
> > 
> > Thanks,
> > Kumar.
> > 
> > To UNSUBSCRIBE or CHANGE your settings, please visit https://listserv.jmu.edu/archives/vadcfll-l.html and select "Join or leave the list". 
> > VADCFLL administrative announcements are sent via VADCFLL-ANNOUNCEMENTS-L. Visit https://listserv.jmu.edu/archives/vadcfll-announcements-l.html to subscribe. To UNSUBSCRIBE or CHANGE your settings, please visit https://listserv.jmu.edu/archives/vadcfll-l.html and select "Join or leave the list". 
> VADCFLL administrative announcements are sent via VADCFLL-ANNOUNCEMENTS-L. Visit https://listserv.jmu.edu/archives/vadcfll-announcements-l.html to subscribe. 


-- To UNSUBSCRIBE or CHANGE your settings, please visit https://listserv.jmu.edu/archives/vadcfll-l.html and select "Join or leave the list".

-- VADCFLL administrative announcements are sent via VADCFLL-ANNOUNCEMENTS-L. Visit https://listserv.jmu.edu/archives/vadcfll-ANNOUNCEMENTS-l.html to subscribe.