Adapting for (really) big and tall?

Joined
Apr 25, 2021
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3
Hi folks.

Background: I am unusually big & tall (6'3", 390 lbs.) I do strongman, Crossfit, and powerlifting as hobbies, so I'm not quite the physical basket case that might sound like. But I'd really like to do some biking. I also have strange proportions (very short legs, very long torso) and I think a recumbent would be a much better fit for me than traditional bikes. I've talked to folks at bike shots and they really struggled to figure out how to fit me. Mostly, I'd probably be riding on roads or paved paths, but there are some really nice developed mountain bike and combination use trails nearby (Fredericksburg, VA) that I'd love to be able to hit.

Questions:
  1. What style/plan would be best suited for someone of my size? I'm leaning towards a tadpole style because the shorter wheel base will mean less moment arm, but it would also seem to place most of my weight on the smaller (and presumably less stout) wheels.
  2. I notice that most of the plans are based on 1" mild steel tubing. Should I consider upgrading the frame materials (either by using a larger size, thicker wall, higher grade of steel)?
  3. What other upgrades should I consider? I should probably mention that I don't mind spending a few hundred on components if that will result in a better bike, but the boss says I can't buy a $2500 recumbent even if I could find one rated for my size. :D
  4. Any other thoughts/tips before I embark on this?
Last, I should probably mention that I learned how to weld in high school and have done a bit of welding around the farm since, but I'm definitely not either qualified as a welder or a machinist.

Thanks for any comments or suggestions!
 
Joined
Apr 16, 2017
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347
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Winnipeg, Manitoba
Most of the tadpole or delta plans recommend 1 1/2" sq tube. Usually in a 16 gage which is I think 1/16" wall thickness. For extra strength look into 1/8" wall thickness. That's what my deltas use, there is a weight penalty but it is strong. If those mountain bike trails are singletrack you can prob forget about taking a trike down them. Look up Hase trikes, they make a delta style trike that looks to be good for off roading, I'm not suggesting you buy one, they are really expensive, but just to get another idea of whats out there. Considering your size a 20" wheel would offer the best strength. Trike wheels deal with side loads 2 wheeler's don't have to contend with so 20" wheels are good, larger wheels are possible but you would not to be taking really fast corners. I have built a fat tire trike, it was passable off road although that wasn't the purpose it was built for. I got lucky and found a local store selling cheap fat bikes so for a bit over $400 I got 2. That gave me the wheels, headset, shifters, etc for the project.

Personally I now prefer the delta style of trike, using 3/4" axle and 4 pillow block bearings it would be very stout. Find a 48 spoke 20" wheel from a BMX bike. I would merge the Voyageur keeping the front mono beam and incorporate the loderunner back end. Use a jackshaft so the rear derailleur could be right beside the wheel which keeps it out of the weeds and grass etc.
 
Joined
Apr 25, 2021
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3
@Hugh Thanks for the response! What do you prefer about a delta trike? I'm completely new to the recumbent world, so I'm open to anything.
 
Joined
Oct 19, 2012
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Wakefield, UK
  1. Smaller wheels are stronger. At your size go for 48 spoke 20" wheels with preferably double or triple walled rims and use 20" all round, front and back. Alternatively go for 20" fat wheels, though finding suitable hubs if going tadpole (20mm axles with a wide flange spacing and disc mounts) will be hard. Finding 20mm narrow hubs for regular width wheels is easy enough but the extra wide bit for the fat rims is the hard bit and at your size you'll need that full spoke triangulation. If using fat wheels be aware they are relatively heavy though I'm suspecting generating power to move them won't be an issue. Fat wheels do offer a softer ride, particularly for heavier riders.
  2. Most of the strength in a frame comes from the tubes diameter rather than it's gauge. I'd up the 1.5 tubing to 2" square and go for 14 swg. I'd avoid the longer frame designs and opt for the shorter tadpole designs as recumbents use the frame in a beam format so opt to keep the beam shorter and therefore stronger. Also using a design with suspension will relieve some of the stress on the frame.
  3. When looking for donors you'll want a steel framed cheapie or two for such things as the bottom bracket and head tubes. It's often a good investment IMO to buy one nice bike to use for such things as chainrings, levers shifters and brakes etc. In your case buying one mountain bike with hydraulic brakes as a donor may work out cheaper than buying the bits separately and I would recommend you opt for decent disc brakes.
  4. In your position I would opt for a Streetfox with discs or a Warrior front and Streetfox rear. The shorter frame of the tadpole will help with frame strength whilst not being excessive on it's weight. You have two front brakes instead of one and considering what you are slowing down that could be an important factor. The rear suspension will take some stress from the frame and put it into the spring.
You may want to consider seat options. A fibreglass seat probably won't fit or take the weight. The std type of AZ design to your size requirementsmay be suitable, possibly with some stronger wood. A mesh seat may be the better option with steel frame made to your size and your choice of strong mesh fabric.

Deltas generally turn tighter than tadpoles but tadpoles corner better at speed where the weight shifts to the outside front which doesn't exist on the delta. There will be examples that turn that on it's head so take it as a generality only.
 
Joined
Apr 16, 2017
Messages
347
Location
Winnipeg, Manitoba
I have built the warrior trike and rode it for a couple thousand km's. It was a great ride and very comfortable and for sure great in corners although I did manage to tip it over in one fast 90 degree corner. Then I tried a couple of Brads delta designs. The warrior was definitely faster and cornered better though the aurora delta I am currently riding will go around corners fairly quick. The main thing I prefer about my delta styled trikes is the ability to make tight turns. I also like fooling around with coroplast and trying different bodies, roofs, etc and find the delta style lends itself to experimentation better than a tadpole. One of my delta is 2 wd and that has worked out very well. Now I have bought the plans for the tandem loderunner which is also a dual drive. Popshot does make a good point about the main beam on a tadpole being a bit shorter and thus stronger. Basically you will have to decide on your own but be warned building can be addictive, I,ve built 5 and now am gathering part's for number 6.
..
 
Joined
Apr 25, 2021
Messages
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In your position I would opt for a Streetfox with discs or a Warrior front and Streetfox rear. The shorter frame of the tadpole will help with frame strength whilst not being excessive on it's weight. You have two front brakes instead of one and considering what you are slowing down that could be an important factor. The rear suspension will take some stress from the frame and put it into the spring.

That was my thought too - necessarily, a shorter beam means less strength required at the center of it and the tadpoles are a LOT shorter. On the rear suspension, when I've ridden mountain bikes that had suspension they've tended to bottom out. On my motorcycle, I was able to add stiffer springs. Anybody know if there's something equivalent made for bikes?
 
Joined
Oct 19, 2012
Messages
1,571
Location
Wakefield, UK
You could take the easy option of an air shock and simply pump it to the required resistance. You could alter the rocker ratio of the rear triangle but that would limit travel a little or you could weld on two sets of mounts for two std suspension units.
 
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