Recumbent repair

24 06 2008

Yes, I have had three goes on my recumbent when I discovered the shell (seat) was quite badly damaged! The seat is attached with two bolts bolted to a small metal bar welded to the frame. The shell is made from fiberglass and it had some bad cracks already, and horizontal cracks coming from the vertical one, and the bar was starting to push through. I could feel that allready pricking in my back when riding up-hill or when riding over a little bump.

The white bits are serious damage, there is a big vertical crack to the right. There are two sets of holes: the upper two are superfluous and have weakened the shell.
Bummer! But hey, after some research I discovered that the Sinner-company , who have been making this bike design for the last few years, are actually based at a village very close to where I live! And looking up their website I discovered they even have an auxiliary branch in Groningen!

So I went there last week, and had a look (nice place!) and enquired about a replacement seat, and a headrest. I find it hard work keeping my head up (because of my heavy, heavy-duty-brain)
Aaaaarggghhhh!!!!! a new shell would set me back at least €85,- !!!!!!!! And a headrest €55,- !!!

Ok, for that small fortune, and my current shell being a total loss if I were to do any more biking, I thought I could just as well do a bit of experimenting. If it works out I don’t have to buy a new shell; if it doesn’t I would have had to buy a new one anyway.

I have been thinking it over, and decided to repair the shell with fiberglass, and reinforce it with some extra layers front and back, and add a small aluminium plate at the back to give a much wider distribution of the pressure.

To remove the seat I had to remove the luggage rack. On the top of the photo you can see the small bar welded on the frame where the back of the seat is bolted on. Actually the bit which has to cope with the heaviest pressure. When you need to put pressure on the pedals you press with your back against exactely that point. (sorry for the bad quality; it was dark and I had no patience to wait for the morning)

Here you see all the layers of fiberglass added. Where it is white at the right I had to add smal bits of fiberglass, because that bit was so dented I had to build it up to make it even again. After this I added one more layer of epoxy and then added the aluminium plate, any unevenness will be filled out by the epoxy and it will glue the plate to the shell.

The seat now rests on the aluminium plate, I replaced the crumbling rubber rings, and used slightly larger bolts (M8 instead of M6) so I re-drilled the holes in the frame to fit. The added plate also gave me a nice surface to engrave my name and postalcode. In case of theft.

The headrest

As I was shopping for the materials to repair the shell, I also brought an aluminium strip, a piece of foam, bolts and a piece of imitation leather, to make up a headrest.
I bend two pieces of aluminium strip to match the shape of the shell, and as I had an aluminium plate I could also saw out a nice circle. I used it as a template to cut out a circle from the foam, and the imitation leather, which I used to sew a cover.

All the different pieces.

everything attached to the shell

From the front

I just had a short spin in the park with it: it is sΓ³ much more comfortable. I really notice a great difference!
Just keep hoping the seat won’t fall apart!




13 responses

25 06 2008

Very nice job! Although, I must admit, I can really see a fine leather recumbent “saddle”… I’m just saying… πŸ˜€

25 06 2008

The luxury bike … the ES model….

for me I just bought the cheapest bike at Canadian Tire…. still here..

25 06 2008

If the seat falls apart, I’m sure you think up a way to fix it better than before.

25 06 2008

You could be a very good engineer. πŸ™‚

25 06 2008

Very proffesional job,
I woulda just wrapped some duct tape around it….

25 06 2008

Wow, great work! I should’ve sent you our coffee maker when it quit working last week! For a while I was riding around on my (regular) bike with a cracked seat post; fortunately it didn’t snap while I was on it, that would’ve been bad …

25 06 2008

Aafke, WHEN WILL YOU STOP AMAZING ME???? I’m yeling because I am, well, jealous that you are so talented with your hands and also because I love your bike. BTW, I am scared of bikes too πŸ˜›

25 06 2008

Lofter, no not a good idea: your back can get really sweaty when riding the recumbent. There are much better more modern cushions now, which really have air flowing through them, but they also cost too much for me right now.

Haleem, my other bikes are very cheap secondhand bikes! And this one was cheap for a secondhand recumbent πŸ™‚

Marahm, thank you for the confidence plced, bur if the seat falls apart now, I may have to buy a new one after all!

Shahrzad, thank you! Great praise from the queen of university grades!!!!

Tony: duct tape is great stuff, but wouldn’t have been sufficient here! πŸ˜€

James: scary!!! Didn’t you notice? How could it be cracked?

Achelois: But you are so talented yourself! And the lovely things you let your students make! I never had such nice art-lessons myself when I was at school.
Just wait until you’ve tried a recumbent: lovely!!!!!! And cycling is great! And it gives you freedom!

25 06 2008

“The seat is attached with two bolts bolted to a small metal bar welded to the frame. ”

This seems to be design flaw, an accident waiting to happen, as welds can’t take applied moments for very long without failure. They should have used bolts instead and/or changed the design of the bar to distribute the applied moments against the tube, not the connection.

I really like your headrest.

25 06 2008

Well done!

25 06 2008

Bah! I still like the saddle idea… besides, I’d get sweaty just watching someone else ride that thing! Leather is good for you!

25 06 2008

Solomon2, I don’t think that little crossbar can ever get damaged, but it damaged the fiberglass seat.
The headrest works great; I’ve just returned from a visit to the Tarq πŸ˜€

~W~ πŸ˜€

Lofter; It’s soooo relaxing riding the recumbent! sure you’ll tire, but you just don’t really notice it!

22 07 2008
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