pic: FR 1771 Drivetrain Revised



This is an updated version of the previous west coast drivetrain I posted. I have changed many things including:
Switch to single speed
Custom aluminum hubs attaching wheels to axles.
Lightened frame members
Still uses timing belt but the entire operation of switching a belt should take less than 5 minutes.
Total weight = 28.5lbs

Nice weight drop and design. Thinking about doing the same to parts of the sides?

Im thinkin about it but i dont know for sure. It would really be something that depends on the manipulator and 28lbs is lighter than probably 90% of drivetrains in FIRST.

Looks nice but also looks like alot of machining. Have you looked at how much you are gonna spend in machining costs/materials or is it all being student done or donated.

Nice job, 28 pounds is fantastic!!!

intresting design
I have to agree with the wiegt statement about it being lighter than most out there so that will be a great advantage.
But why did u go with belts?

Are you sure you are accounting for the weight of all fasteners, bearings, washers, belts, etc. correctly?

I am going with belts because they are the absolute lightest option, they are easy to deal with in this particular drivetrain, and the are simply cool. Also the tensioning method on this drivetrain is very good and will allow us to set the proper tension and keep it this way.

This drivetrain is kind of an extreme study in light weight as it is single speed and belt driven. I am finishing up a new 2 speed transmission using #25 chain and will post that one up when done. Altogether the 2 speed version will probably gain ~4lbs however that seems like a very good tradeoff for the added performance.

This does require a decent amount of machining however a lot of the machining can be done in large batches (wheels and bearing blocks) and the rest is not that much really. We are fortunate to have a couple machine shops that donate time to us so we can have things machined.

The weight calculation are completely correct minus the actual belt and I believe 12 bolts so yes it is very close and there is still more weight that can be removed. One of the huge weight savers is the UHMW wheels which should actually be more dent resistant than aluminum.

Finally this drivetrain is not necessarily what the team will decide on. It does require a substantial amount of machining; however, it is the most cut down and easiest drivetrain to maintain. Tensioning is accomplished by turning a bolt and wheels/tread can be changed in a matter of seconds. Particularly if bumpers are allowed again I will push people in this direction if we can accomplish the machining.

I must say I have admired 254/968 for a long time for their drivetrains being the absolute minimum necessary and functioning imo as good or better than all other forms. Thanks for the Inspiration teams 60/254/968