Last summer I had a couple of problems with the drive side chain tube on my Mango velo coming loose, to the extent that I wrapped it around my chain ring twice. Needless to say it was not as round and quiet afterwards. Well last Saturday I finally got frustrated enough and got rid of the tubes and installed a chain keeper on the Terra cyle idler I was using. Plus I found the plastic chain guide on the mid drive derailer was barely screwed on (vibrated loose last year i guess) which also was contributing to chain noise and crappy shifting. My Mango has the plastic two sided cage with the capscrew and the three little plastic tube bushings with screws through them. The cap screw was almost 3/4 out, yikes!! I added a drop of blue loctite when I retightened it. I see from more recent videos on the Sinner site there is a jockey wheel now in that part. Harry if you read this, can we change the guide to the one with a sprocket? Does it really make a difference? Oh, I also shortened the chain by 4 links! I had moved my BB last summer and thought the tensioner would be tight enough, but the chain was skipping when I changed gears since. Ever since I got the Mango I could not free pedal backwards, NOW I CAN with these changes! I got in a quick loop or two in my shop and about 6km is it ever quiet and shifting is a lot smoother!