Saturday, November 03, 2007

Adult trikes

My wife is borrowing her mom's adult trike, to make it easier to walk the dogs with her bad ankle. It looks strange, but it works--She takes the dogs through the alley to the bike path while riding the trike, from there to the river where they can go off leash.

The trike is a Walmart special, a Worksman Trifecta. I'm not impressed. It started grinding, and when I investigated, I found that one of the bearings has chewed itself, because the rear axle shifted. There's nothing to center the axle except the chain and side loading of the cheap bearings--If I remember right, this type of bearing isn't designed to handle side loads.

I was able to swap the chewed bearing with the one in the drive wheel, which is used as a bushing instead of a bearing. Don't know what I can do to prevent this from happening again.

Walmart.com also sells a Schwinn adult trike for a few dollars more. I haven't seen it in person. Schwinn is nowhere near the brand it was even 10 years ago, but I'd get it over the Worksman just based on the internet pictures.

Adult trikes are surprisingly hard to get used to for someone who rides a bicycle. When you steer a bike (or motorcycle) you countersteer--First steer away from the direction you want to go. This doesn't work on a trike. To make matters worse, the trikes at work have one drive wheel in the back, and the coaster brake is on the drive wheel. The first time I rode one was at work--I wound up crashing into an electric flatbed truck.

2 comments:

  1. Rob in New Mexico12:26 AM

    Hello,
    By description you seem to indicate you have dissected the rear axle of the Trifecta.
    I have one and the drive wheel bushing/bearing has been destroyed and the resulting interaction points of the wheel and axle housing is surrounded by metal powder.
    I would slide a bearing race or bushing in but I can't seem to remove the chain sprocket. It seems to be braised on to the axle.
    Is this freewheel supposed to be removable? The owner may have had this braising done previously unless it was manufactured that way.
    Any tips on removal of the axle from the housing or in lieu of that, the suggested bushing for this without being able to remove the freewheel?
    Appreciate any tips.

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  2. The freewheel on mine was a standard screw on BMX type, although I don't think it had removal slots. This was attached to a mounting piece that had set screws and a key to hold it to the axle. It was not welded or braised.

    Through a series of errors I wound up having to cut the old mount piece off the axle with a Dremel. My favorite bike shop (Tipp Cyclery) had a new mount in their spare parts that he sold me for a trivial price. I also ordered a new freewheel with 2 extra teeth to lower the gearing a bit.

    The damage on mine included a deep groove in the axle, and the end of the frame where the bearing mounts was chewed by the drive flange, in addition to the damaged bearings. I ordered a new axle (around $40) and bought new bearings from a local farm/tractor supply place. I also got washers and 2 collars to fit the axle from the tractor supply.

    Before I reassembled, I cut off the damaged section of frame and squared it up, about 1/4 inch total.

    When I reassembled, I replaced the damaged bearings. I also added a washer between the drive flange and the axle both to take up the space squaring up the frame left, and in hopes that if the axle did shift again the washer would keep it from chewing into the frame. I added the collars on either side of the freewheel, and another washer between the non-drive wheel and the frame. Once I had the axle and freewheel aligned, I slid the collars so they were in contact with the inside bearings, in hopes that they would add a little more resistance to the axle shifting.

    If yours is braised in place, I can't think of any repair that would not require a new axle and freewheel mount.

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