Chain retention issue on RecumbentUSA.com bike.
 

My father has a RecumbentUSA.com bike, we are unsure of the model, but I'll have pictures later if anyone is wondering. He's had the bike worked on by a LBS a few times and can't quite get it working the way he wants it to. One of the main issues he is having is the chain retention tube is sliding around which allows the chain to drag across the chainstay... it's cutting the stay up, which is bad news. I didn't know about this issue until today so I had him take some pictures so I could ask you guys the PROPER way to fix this issue before it damages his frame any further.

I'm not familiar with recumbent cycles so dealing with a chain this long is a foreign idea to me. I really appreciate any help you could provide. Thank you in advance!


The bike overall.
http://farm4.static.flickr.com/3348/...6146d4.jpg?v=0
http://farm4.static.flickr.com/3595/...79b497.jpg?v=0
They way it's currently cobbled together, and the damage.
http://farm4.static.flickr.com/3593/...8ffe805e1c.jpg
http://farm4.static.flickr.com/3622/...d26484.jpg?v=0
One last larger photo.
http://farm4.static.flickr.com/3614/...9bd735ba_b.jpg




Let me know if there's any other information I need to provide. It's nice to see my father out exercising, but this has me concerned. I'd like to fix it for him right, since it would appear the LBS isn't willing to.

My initial, basic thought is to just break the chain and put on a longer piece of tubing.

...but like I said, I'd rather do it a better way if possible.

Are you sure the chain is supposed to go UNDER the idler wheel beneath the seat? I'm not really familiar with this particular brand of recumbent but from the looks of the angle at which the chain runs, running it over the top of the idler would make it clear the frame. My Haluzak Horizon does have the chain going over the top of the idler as it goes back toward the rear wheel. There is an L shaped bar (chain keeper) that keeps the chain in the channel. You might try switching it to see if it helps.

He needs to contact the company and ask them. Send them the pictures, also. From the one on their website, he might not have enough tension on the chain.

I think so too. A flaw in the design of this frame means that you must have that idler and the chain must run above it. The hub is in line with the frame tube so the drive side of the chain must go above the chain stay, it doesn't matter that the chain may have the correct tension as there'll still be chain slap if not rub unless the chain is routed through an idler and correctly. So I don't think chain tension is really the issue.
Re-route that chain, get rid of that black tube and cable ties then give it a try.

P.S from the looks of the idler this is one of those soft or rubber idlers, not the hard plastic variety, so likely to wear out soon. I had one on my TW Bent and replaced it with a Greenspeed idler (although you might not have that clearance). Something to sort out after you've got the bike running.

I've looked at the pictures at recumbentusa.com.
It's clear that a straight chain line is not possible.
A straight chainline would intersect the seat.
That's why the chain has to go on the bottom on the idler.
First, I would determine whether the chainstay rubbing occurs when the chain is taut.
If so, I would see if I could install a second idler just forward of the chainstay with the chain on top.
Otherwise, if the chain only touches when slack, then you could protect your chainstay with some kind of replaceable protective surface.

It will rub when taught, I saw and heard it doing this while riding with him. I appreciate the replies! It is finals week next week and I'm working on a couple papers and preparing for a big presentation.

I'll be looking into this ASAP.

I woudl do one of two thigns.
1) Lose the chain tube there and protect the stay with a Lizard Skin.
OR
2) Get a new length of chain tube from Hostel Shoppe and install it using a set of chain tube spring clamps. That's these:

http://www.hostelshoppe.com/cgi-bin/...ory=1159554927

These would allow you to hold the tube in place such that it floats with the chain, and does not move fore or aft. You could probably attach the spring clamp to the seat stay or the idler axle.

Nobody has suggested contacting RecumbentUSA? They might know of a 'fix' for their sh***y design. I was going to suggest a Terracycle Catrike idler but that would only put the chain into the rear brake. Failing that, I'd recommend making an idler bracket that could attach a chain tube, and run a longer chain tube from the power idler to a point past the chain stay.

I e-mailed them yesterday. Hopefully they will have a thought.

Thank you all for your continued help!

The chain should run over the TOP of the idler below the seat .. the small piece of chain tube now attached to the stay should be freed and either removed (best) or tethered behind the idler.

Next the boom should be set to the length needed (perhaps already correct) and the chain length set using the instructions found here: http://www.hostelshoppe.com/tech_chainlength.php.

In all likelihood right now the chain is too long and slapping the stay .. in any gear if the chain is adjusted to proper length there should not be enough slack on the top run to slap the stay and no tube is needed. The ActionBent/RecumbentUSA units are inexpensive, but ya gotta know how to assemble 'em.

It's not that simple. Judging from the photos, if you run the chain across the top of the power idler, then the chain runs through the handlebars. That can't be good! And as it is, the chain is trying to run through the chainstay. That's not good either. The obvious solution is to move the pulley, but that's where it's designed to go. If it were me, I'd try to fabricate a bracket that placed the top of the pulley 2-3 inches below the main frame tube, then I'd mount a Bacchetta-type double idler. That might mean moving the brakes, and at some point the fix would cost more than the bike. Overall, a terrible design that was apparently not road-tested before it was marketed. (IMHO)

The piece of tubing that you have zip tied on the chainstay should be free floating. Zip tieing it that tightly will interfere with shifting, cause a lot of drag, and eventually the failure of the tube. Getting a new length of tube and proper spring clips sounds like the best solution.

If the chain is only bouncing off of or occasionally rubbing against the chainstay shortening the chain may help. Since the boom is adjusted to compensate for rider height this bike was probably shipped with enough chain to accomidate the tallest possible rider which could be well over 6 ft. I would shift this bike to the big chainring, big cog combo and trim the chain down to the minimum amount necessary.

Guys, the rubbing is happening on the top (power side) of the chain, so regardless of the chain length, it will be tight when pedaling. Take the pic in the OP and draw a line from the bottom of the power idler to the top of the small cassette cog. The line goes right through the chain stay. The best fix (out of several poor choices) would be to add another power idler back by the stay, and run the chain *over* that idler. Hmm... maybe that's the fix -- get a Catrike idler from Terracyle and mount it upside-down, just ahead of the chainstay.

Good Day..I'm a newbe here..I wanted to know if your father still has this recumbentusa..I just bought a used one and can't find any info in this bike Any info would great and updates you did to said bike..Thank You..John