Joined Oct 2017
88 Posts | 8+
japan
So I thought I'd do a little review since my google search didn't bring up any results of others posting about Flennor timing belts.
My experience: At 18,000km, I reshimmed some of the valves and changed my OEM belts out for a cheap set of Flennor belts while I was at it. They are easy enough to find on eBay. And half the price.
At 23,xxxkm, I noticed an abnormal amount of belt dust in the covers when I removed them. This was due to the belt/belts running off the pulleys or spindle a bit and then rubbing against the engine case. Now, this could be from not installing the belts perfectly aligned on the crank, bearings in the pulleys slowing failing, or the belts themselves. I didn't notice any defects in the belts like cracking or excessive wear. The yellow ink print on the top of the belts didn't look to wear off much at all. My bearings seem fine and unlikely to fail within the first 20,000km, so it was either my error during installation or the belts.
I'm at 25,xxxkm now, and recently had the bike apart again. I noticed some more belt dust on the inside of the covers. I thought checking my valve clearances would be a good idea at this point. Going by the lower-end valve measurements of 0.02 - 0.05, all my valves were out of spec. Some were still in spec according to Ducati's really high clearance values like 0.15 - 0.25mm. But I like my valves closer to the lower end measurements of 0.02 - 0.05mm. These values are recommended in the Snyders workshop manual. I'm not sure why my valve clearances got so out of spec from 18,xxxkm to 27,xxxkm. Maybe belt-related, maybe not. I reshimmed all my valves very close to 0.02 -0.05 and refitted the flennor belts. I'm at 27,*** and it seems to run fine. My conclusion is I wouldn't use the Flennor belts again. I think they might be fine brand new but I wouldn't refit them a second time if you notice any belt dust.
This time I saw the Ducati Tri fit belts on sale and picked them up from Gotham cycles. I will fit them next week and see how they do. I have heard nothing but good things about the Exact fit belts. I think they are worth a try.
There seem to be a few brands out there now when it comes to Ducati timing belts. The most notable ones are :
Ducati OEM -
Ducati Tru fit - Not sure of the manufacturer, but the description says close to OEM as possible. Got mine from GothamCycles.
Ducati Exactfit - CAcycle works branded belts. Sources them from some manufacturer.
Flennor - German Manufacturer
Dayco -
Gates - This is the manufacturer that makes OEM belts for Ducati based on Ducatis specifications.
This thread was very informative. https://www.ducati.ms/threads/loud-noise-after-timing-belt-change.123051/#post-1206194
The post from Shazzam, who is a well-known veteran on the Ducati ms forums had a particularly interesting opinion. "Aftermarket belts, although dimensionally the same, can exhibit differences in internal construction and materials. Ducati’s product specification for tensile and fatigue strength, durability, heat resistance, etc., isn’t published, so there will be some differences exhibited between OEM and aftermarket belts".
Although I believe this is true, I also think the aftermarket brands can take an OEM belt and reverse engineer it to the point of getting a very close copy. But he made another point of saying that the sellers of the aftermarket belts won't even give you a proper tension setting for used belts. They say 120hz for new belts, but they don't say anything about used belts as the tensile strength of aftermarket belts is different from OEM belts. And offer no warranty for damage due to belt failure. Due to these issues, and thinking about my experience using the Flennor belts, I think I will buy OEM for my next set of belts, even though it's double the price. My guess is that aftermarket belts are close to OEM belts but with no long-term testing done. There is a reason Ducati has certain specs for making timing belts. And it's based on their years of trial and error doing long-term testing.
"For example, one aftermarket manufacturer sells a stronger belt that tests show will fail at higher tension force levels than the Gates(OEM) belt. So is this a better product? No, as it turns out. The stronger aftermarket belt is stiffer in tension, so when you install the belt to Ducati’s cold tension specification when the engine heats up the hot tension is higher than you get with the Gates belt. Loads on the pulley bearings become excessive, noise increases, and heat build-up (from flexing a stiffer belt) increases. So a stronger belt could lead to premature failure."
My experience: At 18,000km, I reshimmed some of the valves and changed my OEM belts out for a cheap set of Flennor belts while I was at it. They are easy enough to find on eBay. And half the price.
At 23,xxxkm, I noticed an abnormal amount of belt dust in the covers when I removed them. This was due to the belt/belts running off the pulleys or spindle a bit and then rubbing against the engine case. Now, this could be from not installing the belts perfectly aligned on the crank, bearings in the pulleys slowing failing, or the belts themselves. I didn't notice any defects in the belts like cracking or excessive wear. The yellow ink print on the top of the belts didn't look to wear off much at all. My bearings seem fine and unlikely to fail within the first 20,000km, so it was either my error during installation or the belts.
I'm at 25,xxxkm now, and recently had the bike apart again. I noticed some more belt dust on the inside of the covers. I thought checking my valve clearances would be a good idea at this point. Going by the lower-end valve measurements of 0.02 - 0.05, all my valves were out of spec. Some were still in spec according to Ducati's really high clearance values like 0.15 - 0.25mm. But I like my valves closer to the lower end measurements of 0.02 - 0.05mm. These values are recommended in the Snyders workshop manual. I'm not sure why my valve clearances got so out of spec from 18,xxxkm to 27,xxxkm. Maybe belt-related, maybe not. I reshimmed all my valves very close to 0.02 -0.05 and refitted the flennor belts. I'm at 27,*** and it seems to run fine. My conclusion is I wouldn't use the Flennor belts again. I think they might be fine brand new but I wouldn't refit them a second time if you notice any belt dust.
This time I saw the Ducati Tri fit belts on sale and picked them up from Gotham cycles. I will fit them next week and see how they do. I have heard nothing but good things about the Exact fit belts. I think they are worth a try.
There seem to be a few brands out there now when it comes to Ducati timing belts. The most notable ones are :
Ducati OEM -
Ducati Tru fit - Not sure of the manufacturer, but the description says close to OEM as possible. Got mine from GothamCycles.
Ducati Exactfit - CAcycle works branded belts. Sources them from some manufacturer.
Flennor - German Manufacturer
Dayco -
Gates - This is the manufacturer that makes OEM belts for Ducati based on Ducatis specifications.
This thread was very informative. https://www.ducati.ms/threads/loud-noise-after-timing-belt-change.123051/#post-1206194
The post from Shazzam, who is a well-known veteran on the Ducati ms forums had a particularly interesting opinion. "Aftermarket belts, although dimensionally the same, can exhibit differences in internal construction and materials. Ducati’s product specification for tensile and fatigue strength, durability, heat resistance, etc., isn’t published, so there will be some differences exhibited between OEM and aftermarket belts".
Although I believe this is true, I also think the aftermarket brands can take an OEM belt and reverse engineer it to the point of getting a very close copy. But he made another point of saying that the sellers of the aftermarket belts won't even give you a proper tension setting for used belts. They say 120hz for new belts, but they don't say anything about used belts as the tensile strength of aftermarket belts is different from OEM belts. And offer no warranty for damage due to belt failure. Due to these issues, and thinking about my experience using the Flennor belts, I think I will buy OEM for my next set of belts, even though it's double the price. My guess is that aftermarket belts are close to OEM belts but with no long-term testing done. There is a reason Ducati has certain specs for making timing belts. And it's based on their years of trial and error doing long-term testing.
"For example, one aftermarket manufacturer sells a stronger belt that tests show will fail at higher tension force levels than the Gates(OEM) belt. So is this a better product? No, as it turns out. The stronger aftermarket belt is stiffer in tension, so when you install the belt to Ducati’s cold tension specification when the engine heats up the hot tension is higher than you get with the Gates belt. Loads on the pulley bearings become excessive, noise increases, and heat build-up (from flexing a stiffer belt) increases. So a stronger belt could lead to premature failure."
