30 May 2008

Trike repair - Episode 2

The seat of the Greenspeed Anura attach to the main frame with 2 allen screws underneath (picture below) and a couple more all the way in the back. This arrangement makes it easy to remove and reattach the seat. But at the same time, the seat is not entirely stable.

Soon after I started riding mine, the screws underneath the seat started getting loose, making the seat wobbly. I would tighten them before each ride, but within about a half an hour, they would be loose again. I do most of my riding on bumpy trails with many twists and turns. As you can imagine, that creates a whole lotta shakin' and shiftin' that undoubtedly contribute to the loosening of screws. But still, the seat itself shouldn't get loose so easily. Do I dare claim there is a design failure here?


So, a week ago I e-mailed Paul Sims, the "Production, Tech, R&D and Web Guy" at Greenspeed Trikes all the way down under in Australia. He responded as quickly as the time difference between Maryland and Melbourne allowed and has since been very helpful. Paul suggested that I replace the allen screws with ones with bigger heads and put some thread locking glue on them.


I followed Paul's advice and replaced the 2 screws underneath the seat. Before screwing them in, I also put a liberal amount of Loctite Thread Locker on each. Loctite comes in removable and permanent varieties, the latter requiring application of heat to break the cured glue should it ever become necessary to remove the screw. For starters, I decided to use the removable kind.

Since then, following two 45-min rides on the same bumpy trails, the screws have remained tight. If they start to loosen again, I may switch to permanent Loctite. I was also going to replace the screws in the rear that connect the tubes coming down from the back of the seat to the frame, which are narrower and longer, but couldn't find anything comparable in Home Depot. The original ones are so far holding on with a little help from Loctite.

Trike repair - Episode 1


xoggoth said...

Have screws of exactly same appearance on my exercise machine and they constantly keep coming loose too. I suspect the problem is with chromed hard steel, plain steel grips much better because it deformable.

Anonymous said...

When you replace these screws make sure they are of appropriate hardness, otherwise their head may be sheared. A broken screw held tight with permanent Locktite ... good luck with that repair.


That's a good point. However, "permanent" Loctite can still be loosened by applying heat.