Tread Wear

[RyanN]

I searched Tread Wear and never found any threads directly talking about tread wear, so this will be a thread for just that so I and future users of Chief Delphi can find this. A little over a week ago I started a thread about what wheels to use. Well, we bought a 6" x 2" Colson wheel, and a 6" x 2" IFI wheel. We didn't really like the Colson wheel because it's coefficient of friction didn't seem very good on carpet, but the IFI wheel with the rought-top seemed to do the trick very well.

Now the question: For teams that use the IFI wheels, how much wear and tear can you get from the treads? Did your team use the same tread for more than one competition? Did they rip? Were they worn out before even one regional was over? Any problems with the IFI wheels?

[Billfred]

Not the IFI wheels, but 1618 ran similar tread on skinned AndyMark FIRST Wheels (thus making our width 1"--wider treads have been linked to longer tread life). We tried a few different treads, and only the wedgetop on the front wheels is starting to show wear through practice, demos, Palmetto, and now Brunswick Eruption. The roughtop still looks and runs fine.

[Lil' Lavery]

We (116) used the v.1 IFI traction wheels in 2006. We had two 1" width, 8" diameter int he front and two 2" width, 8" diameter in the rear, both with wedge-top tread. We periodically rotated the wheels due to a number of issues, so no one wheel (and consequently tread) ended up playing in every single match. Even despite this, during our second regional one of the treads actually sheared the rivets holding it to the wheel in half, causing the tread to come loose from the wheel and us to disable our robot to avoid being DQed (metal on carpet contact).
This is more a problem in general with using rivets to attach tread then specifically the IFI wheels, although this has happened to more than one team using these before. Some teams use epoxy in addition to the rivets. Also, the AndyMark performance wheels feature larger rivet holes than the IFI wheels.

[ChuckDickerson]

We used IFI 6”x2” wheels for the last two years with absolutely no problems. In 2006 (old style wheels) we had a typical center lowered 6 wheel bot built on a kitbot chassis but only went to one regional. Just before the robot shipped we put new tread on all 6 wheels just to be safe. All 6 treads still look practically new after the one regional and we were in lots of hard pushing matches that year. In 2007 (new style wheels) we went with an 8WD setup with 4 IFI 6”x2” center wheels and 4 AM 6” omnis in the corners. We competed in one regional and the championships in Atlanta all on the same original set of wedgetop treads that we started with when we put the treads on at the beginning of the build season. They still have plenty of use left in them today but don’t quite look as new as the 2006 bot. Our biggest concern was not the tread wear but rather if the treads would stay attached to the wheel. In 2006 we lost a couple of treads during practice in the build season and discovered the secret to keeping the treads on the wheels is to use rivets with large heads. The rivets that come with the treads have standard heads. Order a big box of big head rivets from MSC or McMaster-Carr and pitch the ones that come with the treads. Both years we went with wedgetop tread so we have no experience with the roughtop. I think it is pretty much a coin toss between wedgetop and roughtop. Maybe we will try roughtop this year just for kicks.

[lukevanoort]

Like 1618 we haven't actually used IFI wheels, but we used a similar tread (SBR Roughtop incline conveyor belt) retrofitted to the 8" kit wheels in 2006. Although the wheels supposedly had a 1" width they were really closer to .7" so we probably had significantly more wear than you would on that 6"x2". Anyway, they held up amazingly well (1 regional); what finally started wearing them down noticeably was driving on asphalt... bad idea. It was actually quite surprising to me that they held up so well, as we left some rubber behind on the carpet whenever we accelerated quickly or pushed another 'bot hard.

As for the roughtop vs wedgetop debate; from what I read on CD and observe, it appears that roughtop has a slightly higher CoF and wears in a less noticeable manner (whether or not the wear level is actually lower for roughtop or if wear is just more visible on wedgetop, I do not know).

[clydefrog88]

more specifically, we would like to know the wear on a 1" wide wheel as compared to a 2'' width. Is the tread wear on the 2" width significantly less to justify the jump up from 1"? Also, if you use either width with roughtop, how often do you replace the tread?

[wilmo]

We used a caster/ifi combo with the ifi's being 2 wide per motor. We replaced the tread after 2 regionals, driving on concrete for 5 hours, and other presentations. The tread was about 1/2 to 1/4 worn, still enough to grip very well. Hope this could help.

[Stephen Kowski]

in 2006 we used the 4" X 2" wheels and we have been using that conveyor belt material for years. The gum rubber wears pretty quickly from what I've seen; the blue nitrile roughtop wears a lot better, but it is a higher durometer material. I would say you can probably get away with two regionals with gum rubber without a huge problem.

[ewankoff]

we used the 6" x 2" IFI wheels with rough top treads through 2 regional, champs, and 2 off seasons so far. We use a six wheel drive set up with a lowered center wheel. After two regionals we noticed that the centered wheel was pretty worn down. We purchased new treads but determined it would take too much time to change them at a competition. still with pretty worn treads we can still push around other bots just as well as day 1.

[Peter Matteson]

2006
We used 4 IFI 1x4 wheels and 2 IFI 1.5x4 wheels. We blew one tread off a wheel at the Philly regional during elims. We changed tread after our second regional at the Championships even through we didn't really need to.

2007
We used our own custom 1.75"x4" wheels with the same tread and there was very little wear on them after two regionals, the Championship (20 matches!), BattleCry, and IRI.

My take away from this was that we had a tendency to wear our tread far more on the lexan and diamond plate surfaces from last year than this year's carpet only surface. I believe the worst field element culprit for tread wear was the 2003 grated ramp. I would say fequency of tread change depends more on the field surface than anything else based on my observations going back to 2003 when we used pnuematic tires.

Pete

[AdamC]

We, 395, used the 1"x6" IFI wheels with the wedge tread. It held up throughout both regionals, nationals, and extensive off-season expos and tests. However, by the end of it all, we had ground off all the tread and were left with a thin layer of gum-rubber over the fabric base. Needless to say, I HIGHLY recommend that you replace your wheels AT LEAST after your regionals and before ATL. We're looking into alternative tread functions, but as of yet have not found anything.

[Cory]

We used 4" wheels this year with appx. 0.8125" tread width. We changed the treads once or twice per event. Roughtop seems to wear quicker than wedgetop. However, this comparison is from 6" to 4" wheels, and 4" wheels will wear quicker right off the bat.

We can retread all 6 of our wheels in about 10 minutes if we're working quickly, so it's never really a big deal.

[EricH]

Originally Posted by AdamC

Needless to say, I HIGHLY recommend that you replace your wheels AT LEAST after your regionals and before ATL. We're looking into alternative tread functions, but as of yet have not found anything.

I agree. 330 used four stock AM 6" wheels, no tread, and two pneumatic 6" wheel/tire combos this year. After about one competition, the center tires would be replaced. The AMs were almost never replaced due to tread wear.

The advantage of the pneumatic wheels? If you see red, replace immediately. Otherwise, once an event. And, you only have to switch tires.

When we did use tread, we replaced it about once per competition. I can't remember exactly what type we used last.

Originally Posted by Cory

We used 4" wheels this year with appx. 0.8125" tread width. We changed the treads once or twice per event. Roughtop seems to wear quicker than wedgetop. However, this comparison is from 6" to 4" wheels, and 4" wheels will wear quicker right off the bat.

We can retread all 6 of our wheels in about 10 minutes if we're working quickly, so it's never really a big deal.

Interesting. Our wheels were exactly the same size as yours, and we never needed to retread. In fact, we still have the same tread on, and it's just fine. We used the McMaster Blue Nitrile roughtop...

I'm wondering what the difference was between our setups, as they were surprisingly similar.

[Cory]

Originally Posted by 114ManualLabor

Interesting. Our wheels were exactly the same size as yours, and we never needed to retread. In fact, we still have the same tread on, and it's just fine. We used the McMaster Blue Nitrile roughtop...

I'm wondering what the difference was between our setups, as they were surprisingly similar.

We were wondering the same thing a few weeks ago. We're planning on doing some wear/traction tests with the different roughtop types.

The blue is supposed to wear significantly better than the brown that we used. Other than that the only explanation I have is that our outer wheels generally dont wear very much, but the center wheels wear down way quick since the robot is constantly changing it's wheelbase between front and center and rear and center.