ISO 120T 5mm Pitch HTD Timing Belts (8.5mm width)

We puchased 120T 5mm HTD timing belts via Vexpro for our drive system. Vexpro, WCP and the Robot Space are all out of stock on these. Vexpro customer support said not to expect any to show up before the end of the FRC season.

The hex shaft pulleys also purchased from Vexpro are 17.5 mm wide. The “9mm” wide belts are actually 8.5 mm to so that two can fit on the 17.5 pulley. I cannot locate another supplier who has actual 8.5mm belts instead of 9mm.

If you have spares to sell or can suggest a supplier for 5mm pitch 120T HTD timing belts with an 8.5 mm width I’d appreciate a link.


I believe that most generic “9mm” belts are actually 8.5mm, rather than exactly 9mm. Someone from vex can correct me if im wrong, but i dont think they did anything special to their belts to make them fit this way.

If that doesn’t work out, you can purchase raw pulley stock and make a custom pulley of slightly greater width.

I ordered some from B&B manufacturing and found that to not be the case. They come out at 8.9mm. Too tight to fit two onto the Vexpulley and a real tight fit for one vexpro belt and one BB belt on the Vexpulley.

Gates have 120 tooth 5mm HTD belts. 600-5M-09 Check their web site for a local distributor. BB Man sells them on line, but they are not showing stock. Depending on how much adjustment you have you might have to go up or down a size.

Never mind these are 9MM belts.

Reprap style belt splitter, maybe?
Parametric 3D Pinted Belt Splitter
Acrylic/Lexan laser cut or hand cut belt splitter
I was considering this as an option when it looked like we might need some 8.5mm belts in lengths not carried by Vex. I would assume you’d start with a 15mm belt and either split it 7.5/7.5 or 8.5/6.5 and get 2 or 1 belts out of it depending on your load requirements. There’s downsides, of course. Namely, if you can’t cut through the fiberglass tension member, your belt width is going to change slightly. And it’s obviously not going to be quite as clean or reliable as a factory cut belt.

A few seconds with Google turns up this custom HTD belt supplier. They will cut any width you want, such as 8.5mm.

Oh right. I saw those guys. And then noticed they were based out of England, which makes things slower and more complicated…

Try we buy all kinds of belts from them.