Make sure to get a Contitech Synchroflex tooth profile, or equivalent, which allows enough room for chunky teeth. For example, HTD (round profile) does not allow enough room for the teeth to function properly in a tight diameter.
RepRap attempts to print its own parts wherever possible, including toothed drive pulleys. 5 mm pitch (or imperial equivalent XL pitch, 0.2") belts have been investigated because at the time of the research a 5 mm pitch was the most achievable to print. See the Mendel assembly data sheet for the belt specifications.
Splitting wide belts
Wide belts need to be split to a width of 5 mm, which can be achieved using the belt splitter jig (two reprapped parts).
If you don't have a belt splitter jig you can split the belt pretty easily as follows:
- Put the blade from a Stanley knife in a vice (just the metal blade). Make sure it is steady.
- Take the belt, and pull it slowly over the knife. Have a second person pull back on the belt so it doesn't go too fast. Don't do this in your own.
Belts people use with appropriate pulleys:
- T5 -- 5mm pitch belts would with easily printable pulleys http://www.thingiverse.com/thing:11256
- XL -- 0.2"/5.080mm pitch
- T2.5 -- 2.5mm pitch belts
- MXL -- 0.080"/2.032mm pitch belts. Use machined pulleys or try http://www.thingiverse.com/thing:14308 or the pulleys in http://www.thingiverse.com/thing:14208 on a well-tuned printer. US: http://www.mcmaster.com/#mxl-series-timing-belts
- GT2 Timing Belt