Re: Colson Wheels??
 

It might be doable. There is a way to mathematically calculate the proper distances, but you have to ensure that you account for tension. Also, With two short wraps like that, the deflection needed to cause ratcheting is very low, The tension needed to avoid might cause parts to warp lead to binding. If somebody who has tried this disagrees, I would love to hear about your setup, but generally, this isn't done.

I suggest one longer wrap on one side of the pulley and idlers that guide the other side of the belt around the pulley.

Re: Colson Wheels??
 

We used Colsons last year on our pivot drive and were very satisfied. See photographs:
http://wiki.team1640.com/index.php?t...0412_csm-2.jpg

http://wiki.team1640.com/index.php?t...27_ csm-3.jpg

It was not as easy to install a sprocket as with AndyMark or VexPro, but these wheels are designed to accept sprockets. Still, not so difficult.

We opted for AndyMark HiGrip wheels this year. Light, inexpensive and easy.

Re: Colson Wheels??
 

Was weight/ease(ie. not having to make your own hubs and mountings) the only factor in using the HiGrip wheels this year?(as well as lack of a plexi surface like the bridge)

(As a huge fan of your swerve as well as a huge fan of Colsons, this was one of the questions I forgot to ask while taking a look at your swerve at Lehigh)

Re: Colson Wheels??
 

We run colsons every year, you will not be disappointed. As for belts, calculating the center to center distances for the pulley placement is well worth the effort (and it isnt very difficult). The Gates HDT belts that come in the KOP will not stretch or wear over the course of a competition season if they are tensioned properly and your belt runs are straight. Even if you implement them terribly, Gates makes really high quality belts, it is doubtful you will break one.

Also, that WDC looks great, if you use this drivetrain, chances are it will be one of the best at any regional you attend.

Re: Colson Wheels??
 

Haha thanks! even though I competed against 118 and 148 this year :p I take that compliment quite nicely. I am a rookie this year and that was a chassis I designed after our only regional. We are looking to develop our team for next year and really prove ourselves in our second year.

Re: Colson Wheels??
 

There are a couple other local teams that could probably help you out with this project. You could take a look at 1477's drive from 2012 (and the one they used this year, also WCD but IFI rough-top) and 624's from this year (6 wheel Colson WCD) if you can. They used Colsons (not sure the specific ones) and a frame design nearly identical to the one you've posted, but with chains instead of belts.

Re: Colson Wheels??
 

My team is actually shares sponsors with 624, so I might have to take a trip down to their shop again and see what they think.

Re: Colson Wheels??
 

If you're insistent on one belt run per side, I think the simplest belt path is this. You can see the real thing here. I personally prefer this system, where there is no need for idlers.

Some tips and tricks for this system:

1.Make sure your pulleys are large enough. We had 15t pulleys and 9mm belt in 2011 and the belts ratcheted pretty badly. Since then we have used 24t pulleys and 15mm belt with no problems.

2. I assume those windows are for internal belts. I'd recommend covering them with 1/16 lexan to prevent debris from getting inside. You can see how we did that if you look closely in the pictures above.

3. Think long and hard about how you are going to weld this. We have moved away from welding in recent years because it is faster for us to gusset. If you are going to weld this, I'd suggest using the belly pan and some gussets as a jig for the welder to keep everything square during welding and to make sure everything is assembled properly. The belly pan can be welded directly to the frame and the gussets can be removed at the end.

4. Also think long and hard about how you are going to do your bumper rail. You can weld them, and if you do, I again suggest you mount the pieces in place first using some 8-32s. Alternatively, you could use rivet nuts to mount all the pieces together like we did here.

5. You need a way to retain your axles. We put a snap ring on the inside and we tap the ends of our axles and retain the wheels with a bolt and washer, like we did here.

Re: Colson Wheels??
 

Thanks for all the info, this is really what I was looking for. My team is going to have a CADing session soon so I will bring up all these ideas.

Re: Colson Wheels??
 

Decision factors (from most important to least) were:
1) We measured the friction coefficients of the HiGrip wheels (on carpet) and were favorably impressed.

2) The weight and cost of the HiGrips were in the direction we wanted to go with our swerve units.

3) Ease of mounting was tertiary consideration. That said, I've always been a big fan of easy when it doesn't sacrifice performance.

Mechanically, we never had a problem with driving the Colsons, but the same is true (so far) with the HiGrips. The HiGrips do wear faster.