Re: Tank Treads
 

In the 2003 season we used similar treads, the craftsman snowblower treads they were good, cheaper than brecoflex but didnt quite have the traction the brecoflex did. Def. good for a newer team to use to make a good sturdy/powerful drivetrain and def. a gateway to designing track systems.



Side note: We didnt lower the idler(middle wheel). What we did was just use a larger wheel so it offset each of the two drive cogs sorta like this

O O O

Okay its upside down but you get the point.

Re: Tank Treads
 

234 used treads on our 2004 robot that were specifically made for climbing stairs and for great traction. The most unique feature is the 24mm pitch...they are some of the most aggressive treads around! We were very pleased and they were easy to work with. For pictures and ordering info: http://www.thistle.uk.com/stairclimbing.html

Re: Tank Treads
 

1141 used a pair of old snowblower treads for our first year. They didn't give us a huge amount of traction, mainly because our drill motors were unscrewing themselves from our drivetrain, and if we tried to push, we'd put ourselves out for the match. If you're looking for the cheap direction to go, they cost us a trip to the dump.

Re: Tank Treads
 

Nobody has mentioned cost yet, surprisingly. Just a belt can set you back around $200, if I remember correctly, and the pulleys for the belts will cost you a pretty penny as well. Most teams who use treads end up needed more than one belt obviously, since they tear, wear down, etc.

All this adds up to quite a bit, and can be very prohibitive for some teams.

Cory

Re: Tank Treads
 

Yes the brecoflex will cost you. But these belts are built specifically for this application. They are built to last. We are still on our first set of belts. We've gone through practice and testing, demos a competition and within the next month and a half two more. We are comfortably within the belts working limits. They are very durable belts (least the set we are using).
You really gotta look at your application and and cost benefit relation.

-Pat

Re: Tank Treads
 

They may have worked fine for you, but they really aren't built for this application. They're built for material handling, in factories, etc. We often put tons of torque through them, and much more wear than they will ever see in a factory.

I know for a fact that teams like 226 and 61 have torn multiple treads in half until they got some super reinforced version of the belts for like $300 if my memory serves me correctly.

I have heard from multiple teams that they have had to replace their treads at least every competition, especially last year with the cheese grater ramp, which adds up to a lot of money.

Personally, I think the decision to use tracks or not comes down to money, more than anything else.

Re: Tank Treads
 

I agree whole heartly in what your saying. One of the biggest things with tracks is that you need to make sure that you have attiquit(spl?) belts. I think the belts we used this year would have probably shredded last year. You have gotta match the right belt to the application. I know I've seen alot of teams use too thin of a belt (specifically brecoflex but im sure there are others) and watched it tear in half. Obviously it wasnt strong enough for the job. We used a 75mm belt. Thats a fairly wide belt that your less likely to tear. There is always the possiblity of tearing. Thats a part of the cost benefit relationship.

SO to my point i agree with you cory.

-Pat

Re: Tank Treads
 

What was the type of belt that you used from Brecoflex. Also what was the cost of these belts. I am looking into using the SuperGrip belts.

Re: Tank Treads
 

Team 61 has used tracks for 10 years. We also use Brecoflex belts. We have modified it little bit every year. First slicks. Then with traction and a center wheel. Then we had to increase our shafts from 1/2inch to 1inch. We have lots and lots of power and traction. Below are some pictures.

Early Tracks. No Center grove = bad.. kept throwing the belts
http://www.valleytech.k12.ma.us/robo.../Robot1996.jpg

Slicks. They have a center grove but they have no traction. Still use them till this day for testing.
http://www.valleytech.k12.ma.us/robo...res/Robot6.jpg

and from this year testing

http://www.valleytech.k12.ma.us/robo...2004track1.JPG

These are the green tracks. man do they have so much traction. They bent a lot of shafts
http://www.valleytech.k12.ma.us/robo...2%20Monday.jpg

and

http://www.valleytech.k12.ma.us/robo...2002Track1.jpg

and

http://www.valleytech.k12.ma.us/robo...02%20Track.jpg

This is the bad part of haveing a lot of power and a lot of traction
http://www.valleytech.k12.ma.us/robo...s/MVC-673S.JPG

and

http://www.valleytech.k12.ma.us/robo...s/MVC-671S.JPG

Even with the Red tracks. Less traction but still a lot
http://www.valleytech.k12.ma.us/robo...rokenTrack.JPG

Advantages to have tracks

http://www.valleytech.k12.ma.us/robo...%20T59%20A.jpg

and

http://www.valleytech.k12.ma.us/robo...ng%20Robot.jpg

and you can give good piggy back rides

http://www.valleytech.k12.ma.us/robo...OHBuzzonUs.JPG

All pictures of our robot can be found at http://www.valleytech.k12.ma.us/robotics/

Check out this years build season and see how it all started!

Re: Tank Treads
 

Yeah 300 is kinda low closer to 400 i belive for a set. We have still torn those belts but the center stays connected so that its alright that the out side tore. The bad part is we would rather break a track then burn out a moter. Throught just testing automode last year and kept hitting the side the moters where really hot. We did not run with them becuase if we had to fight for the top they would not slip at all and our moters would burn out.

We just use different traction. There are four kinds. Slicks, Red Slicks (Not thick red on the track), Thick Red (Thick red on the track) and Green (The most traction you will ever need). Last year was good for the thick read. Did not mess them up. Once we tore one it sliced the red slick to peaces. This year the thick red was awsome! Great on the surface to climb!

My adivise. Dont go with the Green unless you have the solid center. Go with either the Slick Red ones or the Thick Red ones. Having a pair of just slicks is a good a idea for emergencrys.

Check out our web site at. www.valleytech.k12.ma.us/robotics

Re: Tank Treads
 

We have used the Green/Blue (Known as SuperGrip) Brecoflex the past 2 years and I doubt we will go with treads again next year.
Both years we have had a shifter with quite a bit of power, last year we shredded I believe 6-8 belts total mostly on the wire mesh area. In low it will spin them even up against a wall so there is a bunch of stress.
We found that it wasn't worth it for us to go with the solid core center since our tracks always ripped first at the edge inward. At the price of the solid centers you literally get twice as many with the serrated center. I have seen a bunch of new pneumatic tires that can easily provide the same amount of traction as the supergrip belts. I can bet that we will be a wheeled bot next year, probably 6 wheels that are 3-4" wide 6" diameter pneumatic. Also keep in mind the delivery on the Brecoflex is pretty terrible, usually at least 2 weeks and up to 4-5 sometimes.
If I was going to use them again I would look at the Gum Rubber and Red belt self centering.

Also I would advise against the sno-blower treads, one of our sister teams used them and it just doesn't seem like the best application for them. First, they are HEAVY, lots of steel in the assembly. Second the compund is some sort of hard rubber that has somewhat limited grip on all surfaces. The track footprint is only about 20" long. Lastly, the pulleys are HUGE, which makes it difficult to have a nice low robot. BUT, if you want premade tracks, it is an option.

Re: Tank Treads
 

If we where going to be around next year we would probily have a design simmilar to team 25's. 6 wheels like that.

The shipping we have never had a problem with tho. Always recive them within two weeks

Re: Tank Treads
 

Its listed somewhere in this thread. They're green-blue, probably the same ones matt mentioned. They costed us $200 a piece. Another reason why belts have a tendency to rip is the tension on them. You really need to find your happy medium with them. If theyre too tight theyll rip and youll lose traction. If theyre too loose theyre can bind or crease/rip and youll loose traction. You gotta find the happy medium with them.

-Pat