Probat Coffee Roaster Replacement Belts

For the other 10 people out there in need of custom coffee roaster belts, like us with our Probat L12, here’s a source: Hudson Belting.

This is more of a Public Service Announcement than anything. We were desperately looking for a domestic source for the main belt for our Probat coffee roasterA machine for roasting coffee. Or the person operating it! The basic requirements for a coffee roaster are a heating element that gets suitably hot and a mechanism... ...more L12 model. The local custom belt maker was sadly gone, like a lot of old time industrial businesses.

And frankly, Probat Burns site for accessories, support and supplies is basically defunct. They have a shop though. You can find mugs and tshirts there. Uh, great.

I found Hudson Belting through some creative web searches, and they were able to make backup belts for me that are working well. The cost for me was about $45-$65 each.

I ordered endless loop belts as well as ones that separate with a pin. When we received this Probat L12 from a used local source, it had a rather loose all-leather belt that looked really old, and had the hook / pin latch in it. It lasted about 8 years!

Hudson recommended leather belts with a synthetic layer to decrease stretching and increase strength. I ordered a couple of those as well as all leather belts for old times sake.

Our 1990s Probat L-12 measured out as 2030 mm and 20mm wide. It may be different for yours. These fit our L-12 perfectly but I am aware the all leather ones may stretch in time.

(2025 Update Note: the synthetic belts we ordered fit snug, but the leather belts that separate with a pin were a little long, by probably 1 to 2 cm. That makes them kinda useless though since I don’t have a way to shorten them and redo the metal stitched clamp that binds them)

Here are the questions they asked to be sure they made the right belts for us.

1. How did you measure the belt length? 
2. How wide are your pulleys on the inside where the belt sits?
3. Do you have any adjustment on your machine?  
4. What is the smallest pulley diameter that the belt goes around?
5. Do you want the old school Leather Belt or the newer, much stronger Nylon Core Leather Belt?
6. Laced belt with metal hooks and pin OR a glued endless belt?

You can reach Hudson Belting through their site or email them at [email protected].

I was just happy to find a source for drive belts and wanted to share the info, saving someone like me a lot of time. When it comes to older Probat machines, it seems people are simply on their own, with no obvious way to order parts from Probat and google searches yielding little to no information on specific issues.

Belt Tension Adjustment

The Probat L12 manual outlines how you adjust tension on the belt, noting that it should deflect with light pressure. In other words the belt is not supposed to be super tight.

Adjustment is made by moving the larger upper pulley, in the first photo, upward or downward to add or relieve belt tension. This will impact the chain tension, but those can also be slightly loose (as long as you don’t hear and noises or the chain skips – thats bad.) The nut to loosen the positon of the large pulley and move it up or down is not located in the back of the roaster. It is accessed from the other side toward the front. In the secind photo you see it, back of the cooling tray, on the wall separating front and back of roaster.

Probat L 12 Chain Adjustment

How do you adjust the chains if they are way loose (or tight)? You can take them to a bike shop and have them add a link, half a link, or take away links!

I havent had to do this even though the drive chain is quite loose, with a good 1″ of deflection! But it never skips or makes any moises in protest as it operates… I keep them well lubricated and the looseness hasn’t caused any issues.