What is the best timing belt

I am currently running a 3M 15mm belt and it seems to work well, however it seems hard to find the correct pulleys at 3M 16mm at 8mm and 10mm bore (depending on what motor I am running).

What are the pros and cons of 5M over 3M belts? Would a 10mm 5M setup be better than a 15mm 3M?

I’m not sure there are any cons to using a 5m belt… maybe slightly more drag, but the pros are there for sure. You’re less likely to have your belt slip and it provides superior torque transfer, not to mention it’s pretty easy to find parts for.

I’ve heard good things about GT belts, apparently they’re quieter than HTD belts. But I’ve also heard the HTD belts can handle more load without slipping. 5m HTD can handle more than 3m, the main downside is that you can’t go smaller than 11 or 12 teeth because there’s not enough engagement. Idlers help a lot.

I’m running 9mm 5m belts on my dual and the board will throw me off before a belt slips. For a single, I’d go with 12mm wide.

Here are some really cheap closed loop htd belts http://www.ebay.com/itm/HTD300-5M-Timing-Belt-Synchronous-Pulley-60-Tooth-PU-Closed-Loop-15mm-Width-New-/401115203967?epid=1593186030&hash=item5d6454497f:g:2ewAAOSwmtJXYSL8

Great thanks for the info, think I will upgrade my pulleys and belt.

Usually , 5m belt is better than than 3m belt , please check it here : https://vbeltoutlet.com/tming-belt-products-performance-index ,