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View Full Version : Make a lightweight seat for your High Roller



taloch
01-28-2009, 11:46 AM
Hi,

This is just one way to make a strong, lightweight seat for your High Roller. I have been using this design for a couple of years now and I am very pleased with the results. This seat design directly supports your spine and not your butt, as you are lying back on your spine.

You need 1/8th thickness checker plate. It's alluminium and at this thickness can be bent to shape by jumping on it. I tried 1/16th thickness but it wasn't rigid enough and needed a supporting frame which added more weight, and a piece 3/16th thick was far too hard to shape and also too heavy. So I went with 1/8th and it has stood the test of time, being light, rigid enough to hold it's shape and not needing any maintenance. Can also be drilled for lightness and ventilation if you wish. Checker plate was easy for me to acquire so I used that, but I suspect any hard grade (Dural) 1/8th alumimium would do the job just as well.

I jumped on mine for about 15 minutes before I was happy with the resulting shape.

You will need a piece about 36 inches long by 7 inches wide. The width you choose will have a direct relationship to the width of your shoulder blades! For me, 7 inches it just right to fit between mine and is comfortable to ride over long distances at this width. You don't want the seat chafing the insides of your shoulder blades... believe me it is painful. The seat is the same width all the way down because as I said it is supporting your spine not your butt.

Have a look at the picture of it on my 24"x24" Black Diamond in the Short Wheelbase Gallery as it will explain most of what you need to know; how to fix it and what it looks like etc. Use a flooring grade foam for the cushion and double it up if you want more comfort! Make sure you get closed cell foam for waterproofness. I know some people get their girl friends/wives/partners/mothers/grandma's to knit a nice cover for it! You can remove the foam+cover if it's rainy, and take it with you.

Have fun. Then have some more!

trikeman
01-28-2009, 12:07 PM
Nice writeup taloch. There are few things more I would like to know.

I assume you made some sort of mold to shape it to? If so, what shape did you use?

Is the diamond plate pattern you used raised, or just some sort of surface pattern?

Got any pictures of the build process?

That is a great looking seat and bike by the way. I have always admired it and the aluminum seat 25Hz put on one of his bikes here:

http://www.fleettrikes.com/flying%20v451.jpg

Thanks for posting your method.

Side Note : For those of you in the US looking for 1/8" Aluminum to make one of these and want to know the cost, I just bought a piece yesterday from my local welding and fabrication shop. It is 1/8" x17" x 24". I cost me $25, so that worked out to be about 6 cents per square inch. I didn't buy mine for a seat, so I wanted a wider sized sheet I can cut some brackets and a few large chain rings out of. I am not sure if I got a good deal or not. The piece I bought was a drop, so it has a few scuff marks on it. On the other hand, I didn't have to pay shipping or wait for it. Since Taloc's seat is about half the number of square inches (252 sq in vs 408 sq in), I am guessing the aluminum for it would cost about $12-$15 unless you can find a good source of scrap that long. Not a bad price for a nice seat base.

taloch
01-28-2009, 01:18 PM
The shape is derived from a basic shape then elaborated on later if you wish.

Make any shaping cuts to the ends of the flat sheet before starting the bends as it is easier to do this while the sheet is indeed flat.

BASIC SHAPE:
The basic shape is just a long, flat, straight seat back with a curve at the base for the butt. This curve starts 10 inches from the front of the seat, and was made by bending the alluminium around a 10 inch diameter off cut of mains utility PVC pipe. The sort they bury in the ground and run gas and water through to your home, but anything like that would do just as well. This curve is mainly there to stop you sliding off the front, so make it fairly pronounced.

The next curve is at a straight line measured 20 inches from the front of the bend you just made. Again jump it around the 10 inch diameter pipe for a nice round curve. Have a look at the picture to get an idea of what we are after here. Honestly, any angle will do here, so long as the back of the seat fits you and doesn't bang you in the neck or back of the head as you ride. It's easy to adjust later if you get it wrong, prop it up against the garage wall, sit in it and adjust it until it fits you. Some people leave this curve out and still have a nice ride. It really is for you to decide. Maybe jump this second curve in after you have tried it without?

LUMBAR SUPPORT:
That's it for the basic shape, but feel free to put in lumbar support. This is an "S" shape which starts just after the butt curve. I gave up with this on a previous seat as all I ended up doing was putting a twist in the seat. If you have good workshop benders/rollers available it's not a problem and easy to do, but for the average garage hacker is not so easy to get right. Maybe a friendly chat with a local workshop would get good results.

For me the basic seat is very comfortable, and some people ride fine with just the butt bend and a slight bend all the way up to the top.

Looks nice too...

trikeman
01-28-2009, 01:26 PM
Thanks for that further explanation taloch. I have an AutoCad file that John Lewis kindly provided with the curve for his euromesh seat, including lumbar support, but it may be just as good to get the curves the way you have - and if it doesn't feel right bend it some more.

When I made my mesh seat for the DW, I roughly followed the pattern on the recycledrecumbent site. I liked the way they told you where the bends started and ended on the straight tube (page 8 of the plans), as you do. I marked off all the bends on the straight tube before I bent any and it worked out well. That pattern would probably work well in aluminum too, if someone doesn't just want to bend it till it feels right. That method pretty much eliminates the need for a wooden buck.

http://www.recycledrecumbent.com/ez1draw.htm

I think I have to try one of these aluminum seats on a future build.

taloch
01-28-2009, 03:15 PM
[QUOTE=trikeman;17807]
Is the diamond plate pattern you used raised, or just some sort of surface pattern?


The checker plate comes with the pattern raised on the surface and is used for decking on a mezzanine floor in a warehouse for instance. The raised pattern is slip resistance, and it is also used as steps with the front edge bent over. I have also seen it used to patch up old volkswagon campers where the bottom edge of the doors and sills have gone through with rust.

Of course I used mine with the smooth side against my back.

I got mine from the local scrap yard and cost just 5.00 for 3 different thickness pieces! (About $2.50 then)

Edit: That should be $10. I got the exchange rate round the wrong way!

That AutoCAD section drawing looks great and should make a great seat in alluminium sheet, but as I said, I tried and failed to get that shape in mine mainly due to skill and the right tools, but not for the lack of trying. I hope you have better success with yours.

Bending it until it fits you is the better idea I think, as you will be the one using the seat.

lock
02-02-2009, 09:45 AM
Hi Taloch,
When I read your description of jumping on it to bend it etc I was looking for something resembling a crumpled rubbish lid in the gallery; not the sleek seat pictured!

Thats a very stylish seat solution you have there! Its a great idea and looks fairly light to boot. A couple of questions for you:
How did you attach the base of the seat to the boom?
Is there any noticable boom flex when you dont use the seat stays to reinforce the frame?

trikeman
02-02-2009, 10:13 AM
Lock - I will let Taloch answer as to how much flex he gets, but I did notice that in his picture he has the supports coming straight down from his excellent seat to the main tube. Struts don't resist the twisting moment set up by the pressure of your back pushing on them very well if you are applying the pressure essentially perpendicular to the strut. You should get less seat flux if you move the bottom of the struts back to the rear triangle as I have in yellow in the picture below. That change will put the strut in compression, instead of trying to resist a bending moment.

http://www.atlantamusclecars.com/DeltaWolf/SeatSupports.png

If my right knee were not bothering me from trying to push it too hard and too far with the seat too close when I first got it, I suspect I would be getting more flex (I can feel some now) on my RANS seat, since the designers of that bike essentially ran out of bike to put the stays any further back.

One thing you are not supposed to do with these recumbent bikes is mash too hard on the pedals using that back support. I can attest its really hard on the knees. Imagine doing 10,000 squats (or how ever many times you pedal in 20 miles) with a heavy weight on your shoulders. Instead, you are supposed to spin up to 80+ rpms on cadence if you can, so perhaps its better if I can't really put a flexless seat on mine :eek:.

http://www.atlantamusclecars.com/DeltaWolf/DSC00105.JPG

Big Moe
02-02-2009, 10:42 AM
Veeery interrrrresting -
Got me thinking of all kinds of variations for different machines.

Trikeman - they say that form follows function. That swb with the yellow braces is the cleanest, slickest design going. Not one unessential element. If I rode swb's I'd be stealing that design.
MOE - Three wheels and an old crank

trikeman
02-02-2009, 11:06 AM
Moe - just to clarify, its not my design, its Taloch's from the AZ gallery. He did a really great job, and it pre-dated Brads very similar design for the HighRoller. As Brad says, there are only so many ways (one?) that you can build one of those lol. They sure do look clean though. All I did was to reposition the seat supports with GNUPaint.

http://www.atomiczombie.com/gallery/chris%20axford/swb.htm

taloch
02-02-2009, 11:25 AM
Hi Lock and Trikeman,

I used a counter sunk M10 to attach the seat front to the boom. No one else is likely to use my bike so there is no adjustment built in. I made it to fit me from the outset.

The seat back is braced by the two verticals and no attempt was made to reinforce the "rear triangle". I can push really hard against it using pedal pressure and it is solid. They are just seat braces and are appropriate for their purpose, combined with the front seat bolt the seat doesn't move. But I do agree that a more logical approach is to extend the braces to the rear forks, but doesn't look as cool somehow. It does the job and that's all I worry about! To be honest I got the idea from the Burrows Ratcatcher 2 when it was in Bath for a while, only he used a short carbon piece for the back stays in the same place.

Picture of Mikes Ratcatcher (scroll down to the side view with the knitted seat cover:
http://www.bikefix.co.uk/index.php?unique=7bfdd2282c6bb934c2e65ab107a612e0&get_ol_id=1&get_gl_id=9&news_full_id=12#nItem12


I used a whole mountain bike front fork stuffed up the end of the boom and welded it in place, and it seems plenty stiff enough, even after 18 months riding there are no cracks or joint movement at all. OK, so I took infinitely more care than "stuffed up" but you get the idea!

That's how I made my high racer, but you can attach the seat to the original High Roller made from Brad's plans, in the normal way. I just went for simplicity and lightness as I knew I was the one who was going to ride it every day. It weighs in at 27lb with a Nexus 7 speed hub gear in the rear wheel, which seems reasonable for a sturdy steel home built steed. Try saying that after a few!

trikeman
02-02-2009, 12:04 PM
Taloch - As I said before, that is sure one great looking machine. Its good to know you are not getting any major flexing of the seat, since I want to make a seat like that myself using the details you provided. I will probably go with the more rearward seat stays, but I also agree it looks really good the way you did it. 27 pounds is a good weight too with a Nexus rear end, considering that the Bacchetta Giro 26 weighs 28 pounds with the recurve seat.

Good idea on using the whole fork "stuffed" into the boom too. I had thought about doing that myself, but haven't tried it yet. Its good to know it works well. It would sure take away the hassle of lining the two fork halves up when you weld them.

There are so many inspiring and great ideas on this forum. Thanks again for posting the details.

lock
02-02-2009, 05:36 PM
27 pounds!!!
Thats a great effort with a steel frame! I also echo Trikeman's sentiments about using the whole fork. Thanks for answering my questions and providing so much detailed info!

taloch
02-03-2009, 04:12 AM
I should add a little note here:

A good-practice tip when "stuffing" the whole fork up the end of the boom is to secure the steerer tube top to the boom.

Before welding the fork in place, weld an M8 bolt through and to the top of the steerer tube so that it will pass through a hole you previously drilled under the boom to accept it. Pass the fork up through the boom until the M8 bolt sticks through the hole. Once everything is welded at the end of the boom, weld and clean off the M8 bolt for an nice invisible engineering job.

This gives us an extra degree of leverage and strength just where it is needed. This makes sure that we are not just relying on the welds at the end of the boom but there is now leverage inside the boom too.

Hope my explanation is clear. If not, then I will try to clarify.

ditz
02-04-2009, 08:30 PM
Hey Mr. Taloch

I would like to have a little more explanation on the stuffing and bolt thing. I have the plans but have yet to start the build. I have most of the "stuff" collected for the build except for the boom. I am still considering using the rear triangle rather than the intended fork legs of another bike though I do have the extra fork legs. Nice build by the way. :cheesy:

taloch
02-05-2009, 12:04 PM
As promised a more in depth explanation...

1. Use the whole fork with the steerer tube still attached. Remove any bearing cups. Spread the fork to fit the back wheel using a car jack before welding starts, ensure the fork ends 2" to 3" are parallel with each other. Remove the back wheel and we are ready to fit the fork to the square boom tube.

2. File the end of the square tube boom so that the fork shoulders fit snugly.

3. Weld an M6 or M8 (1/4" or 3/8" US) bolt onto the steerer tube threads. Weld the bolt HEAD to the steerer tube with the threads sticking up. Position it so that it is 1 inch from the open end of the steerer tube, and so that when the fork is inserted into the square boom (read "stuffed!") the M8 bolt will be pointing down towards the ground, and out of sight.

4. Measure the position of the welded M8 bolt on the fork from where the fork fits the end of the boom. Transfer this measurement to the underside of the boom.

5. Drill a hole to accept the welded M8 bolt at this position.

6. Pass the whole fork up the square boom-end untill the welded M8 bolt sticks through the hole you just drilled. You may have to cut a bit off the welded M8 bolt length to achieve this.

7. Weld the fork shoulders to the end of the square boom.

8. Weld the part of the M8 bolt that is sticking out of the underside of the boom, to the boom.

9. Grind the excess M8 bolt length off flush with the underside of the boom.

10. Finished.

Work safely at all times, and have fun.

trikeman
02-05-2009, 12:14 PM
Great idea with the bolt Chris. Obviously if you use a 1" steerer tube in the inside of a 1 1/4" steel tube there will be just enough space to get the steerer tube with the welded bolt in and to the hole where it will be welded, or did you use 1 1/2" square tube? Sorry for the imperial measurements. Quite an ingenious way to take up the slop and ensure alignment.

If one could find a 1 1/8 steerer tube (they make em, but I never seem them), it would fit exactly and then you could cut a few slits in the square tube and weld it that way.

taloch
02-05-2009, 12:44 PM
Hi Trikeman,

I buy 40mm square tube here. That's about 1 and 5/16" I think (says he, squinting at 2 steel rules side by side). The steerer tube I use is 1" so it is a good clearance.

That would be great if you could find one that nearly fits as it would simplify things enormously.

I am sure there are many other ways of doing the same thing. There usually are!

I just started working on my next project which is an unstable (on purpose) narrow track trike. You interested in sharing ideas? PM me if you are.

trikeman
02-05-2009, 01:07 PM
Thanks. I have a bunch of those $1.99 (US) plastic calipers, since I can never find one when I need it. When I open it so the metric scale reads 40mm, I get 1 9/16" on the Imperial scale. So, I would say that is probably close to our 1 1/2" square tube. That would leave you about 3/8" (9.5mm) of space once you get the steerer tube stuffed in.

I am not always diligent about checking my PMs here, but I sent you one.

taloch
02-05-2009, 02:16 PM
Yes you are right, it is 1 9/16". So yes, near enough 1 1/2" your size.

The UK was all imperial at one time and now that we are metric I can't seem to get my head round fractions of this and that any more. I will try my best, I promise!

Got your PM. Thanks.

Greenhorn
02-05-2009, 02:32 PM
Great idea with the bolt Chris. Obviously if you use a 1" steerer tube in the inside of a 1 1/4" steel tube there will be just enough space to get the steerer tube with the welded bolt in and to the hole where it will be welded, or did you use 1 1/2" square tube? Sorry for the imperial measurements. Quite an ingenious way to take up the slop and ensure alignment.

If one could find a 1 1/8 steerer tube (they make em, but I never seem them), it would fit exactly and then you could cut a few slits in the square tube and weld it that way.

I'm considering using a "really" beefy oversized 1 1/8 road fork. I don't know if I can spread it enough to fit a rear 26" wheel though.

trikeman
02-05-2009, 03:42 PM
I'm considering using a "really" beefy oversized 1 1/8 road fork. I don't know if I can spread it enough to fit a rear 26" wheel though.

They bend pretty well (at least the steel ones). I have heard (or maybe I read that in one of Brad and Kats books) that it works better if you do it in stages, but a little heat from a torch works well too.

ditz
02-07-2009, 11:04 AM
Thank you Talock for the explanation of the stuffing proceedure. Sounds very good to me.

taloch
02-10-2009, 08:08 AM
Hi,

I found this.... a letter size paper print out that you can cut up to make a full size profile for the seat:


http://www.archive.org/download/RibSeat/Rib.PDF

Greenhorn
02-10-2009, 09:59 AM
Sweet.


I think I may opt for a plywood version of this. I can't seem to find the type of aluminum you used for a reasonable price.

trikeman
02-10-2009, 03:34 PM
I got my piece of 1/8" aluminum from my local welding shop. They use lots of aluminum to make things like truck boxes.

Greenhorn
02-12-2009, 02:59 AM
I got my piece of 1/8" aluminum from my local welding shop. They use lots of aluminum to make things like truck boxes.

This is the cheapest I could find: Is it reasonable?

Aluminum 5052-H32 Bare
Sheet
0.125"
Cut to: 12" x 48"
$36.77
per piece $36.77
MTR's are available for this item
Check here to have MTR's sent:
Sub Total $36.77
Shipping via UPS Ground $14.36
Cut Fee $0.00
Total $51.13

taloch
02-12-2009, 06:42 AM
I had a look on eBay and found a supplier for 12"x36"x.125" Aluminum Diamond Plate, which is the same thing as Checker Plate I guess in the US.

The price is US $27.00 plus shipping.

http://cgi.ebay.com/12-x36-x-125-Aluminum-Diamond-Plate_W0QQitemZ200234212222QQcmdZViewItemQQptZBI_R aw_Materials?hash=item200234212222&_trksid=p4634.c0.m14


Interestingly, I bought a new piece of 3m x 180mm x 1000mm Checker Plate for 10 at a local metal shop yesterday in Bath, UK. He even cut it to the size I wanted. So I have an instant recumbent seat for a new project I am starting soon. When this cold and snow clears away that is!

He stocks 2mm and 3mm and also has an off-cut bin of half price sheet steel and aluminium. I rummaged through it all but none of those were the size I wanted, and was surprised when he said he would cut me a piece. At 10 for a seat I couldn't refuse his offer.

trikeman
02-12-2009, 08:11 AM
This is the cheapest I could find: Is it reasonable?

Aluminum 5052-H32 Bare
Sheet
0.125"
Cut to: 12" x 48"
$36.77
per piece $36.77
MTR's are available for this item
Check here to have MTR's sent:
Sub Total $36.77
Shipping via UPS Ground $14.36
Cut Fee $0.00
Total $51.13

Seems a bit high, but you are ordering new and paying shipping. As I mentioned earlier in this thread I got a 1/8" aluminum drop 17x24x1/8 for $25 from one of my local fabricator and welding shops. Obviously that is not the size you want for a seat, but mine sells it by the pound (about 6 cents sq foot in the 1/8" size). If you can find a few in your phone book try giving them a call. Not all shops are interested in selling drops so you may have to call more than one before you find a hobbyist friendly one.

Greenhorn
02-12-2009, 09:40 AM
OnlineMetals has 12x36 .125 for $29.42 + $14 shipping. I may go with that

BTW, SWMBO is talking about going to Bath for our honeymoon




I had a look on eBay and found a supplier for 12"x36"x.125" Aluminum Diamond Plate, which is the same thing as Checker Plate I guess in the US.

The price is US $27.00 plus shipping.

http://cgi.ebay.com/12-x36-x-125-Aluminum-Diamond-Plate_W0QQitemZ200234212222QQcmdZViewItemQQptZBI_R aw_Materials?hash=item200234212222&_trksid=p4634.c0.m14


Interestingly, I bought a new piece of 3m x 180mm x 1000mm Checker Plate for 10 at a local metal shop yesterday in Bath, UK. He even cut it to the size I wanted. So I have an instant recumbent seat for a new project I am starting soon. When this cold and snow clears away that is!

He stocks 2mm and 3mm and also has an off-cut bin of half price sheet steel and aluminium. I rummaged through it all but none of those were the size I wanted, and was surprised when he said he would cut me a piece. At 10 for a seat I couldn't refuse his offer.

KoolKat
03-27-2009, 12:23 AM
Hey Taloch - Threads you're subscribed to are being rejected by the email address you originally registered with.

It's causing alot of unwanted messages to be sent to our forum admin email system. I tried to send you a private message, but that also came back undeliverable.

Please change your Email address in the User Control Panel under Settings & Options.

Thanks.