Electric Fat Cargo Bike project - Will that long chain need a chain guide?

[j0hnj0hns]

Hey folks,

I'm retiring the Rocky Mountain Blizzard and moving the BBSHD over to a titanium cargo bike frame (similar geo to the Salsa Blackborow). I've put the chain on and realised its bloody long and has a bit of movement. Now I think I can squeeze another link out and I've got a new narrow/wide chainring and a XT clutch derailleur but I'm wondering if I should look for a chain guide as well?. This beast will be used for single track maintenance so it's going over rough terrain. Anybody else had long chain woes with cargo bikes?

[steve marino]

I've owned tandem bikes with longer chains, but they weren't powered by anything but people power. On my high end bike there was no guide, just an adjustable bottom end that allowed tensioning by adjusting a couple of screws to move the bottom end forward or back. On my low end tandems they saved money by putting an idler wheel tensioner. The latter was a little noisy. The problem you might run into is even if you take a link out and get the chain nice and tight, as it and the gears wear you will develop chain sag. I wonder if it might not be a good idea to put something like a derailleur on the bike even if you aren't changing gears just to keep the chain taut when powering on w/ the motor?

That's a beauty of a frame.

[j0hnj0hns]

Thanks for the feedback Steve. I have been testing the bike and watching the chain bounce but it only gets noticable when in the hard gears. I won't be in those gears while on rough singletrack so I might be okay with the current setup.

Another question for you though, what did you do for chains on a tandem?