Looking for help on ideas on wheel and hub sizes for a trike project

Joined
Apr 10, 2021
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Greetings and salutaions to all, I would like to get some opinions and ideas for wheel sizes and hub widths as well as spoke count for a tadpole trike. I would like to build a modified Streetfox, without rear suspension, but with the back half of an old mountain bike. I need to overcome a few obsticales (literaly), 1-need to handle up to 500lbs (prefer it overbuilt), 2-be able to slowly go over curbs, 3-seat height between 14 to 18 inches. I was thinking about 26 inch wheels all the way around, I don't want fat tires, but between a 26x2-2.4, maybe 24 inch front wheels. I would go with 20 inch in the front but I'm worried about getting hung up on a curb. I'm guessing running 36 or 48 spoke hubs, didn't there use to be some 26 or 700C rims for tandems that were 48 spoke? Would a better idea be to make some custom passthru hubs for thicker axles in the front? would making the hubs wider or narrower for more or less spoke lean help with the lateral forces? Maybe use motorcycle front hubs for a thicker axle and still have a disk brake, could a bicycle wheel even be redrilled for stronger motorcycle spokes? I'm not as concered about weight of the trike as it being able to fit my needs as gearing can always be changed to help with weight. I also know the seat height will be less stable, the only limit to width would be to fit through a 36 inch door, I also don't mind less of a turning radius for running taller wheels for ground clearance. I hope this will spark some great ideas and that I posted this in the right place.
 
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Sep 14, 2013
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eire
Consider wheelchair wheels for the fronts. Side axles with cage bearings on thick axles. Take off the hand holds. However not so easy to attach disk brakes.
 
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Sep 16, 2018
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Spokes, the more the better.
I have on one 32 and my new one 36.

Front 20inch but 2 different builds and 2 different sizes of axle.
First build I used hubs from China with 20mm size for axle. I used m16 and used a tube over it with 20mm diameter.
Second build, I got the wheels from icletta with 12mm axles. Those hubs are a lot narrower than normal hubs.

Rear I have 26inch.

My new build has rear suspension, cso I went for 20x1,5 and 26x1,5
My old build has no suspension, so I used frond bmx tires. In the back I have 26x2.

As you have no suspension, I would use thicker tires and 26x2 is the minimum in my opinion.

20 inch is stronger than 24 inch but it will work fine.
Riding on and off a curb is also something that you don't want to do. As you do that a lot, tgsb go 26 inch.
700c is mainly used for race trikes. 26 is a better option as you don't race.
Smaller like 24 or even 20 inch, will give more traction.
As you ride off road, I would do 26 all around.

I prefer to put high pressure in my tires, but that makes that you feel more from the road. But I ride mainly on good roads.
As you go for a lower pressure, you get more comfort that is clearly noticeable. The disadvantage is, is that you will roll faster in a corner. But as you don't ho fast and know that, it is no problem.
 
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If weight and comfort ain't priority, I would think about motorcycle wheels.
Most modern motorscooters have small diameter wheels with BIG diskbrakes. My scooter has a 12" front wheel and a 14" back wheel. But the big tires make them as large (or lager) as a 20" bike wheel.

Otherwise, Aliexpress sells things like that as sweetcakes. I looked at those for Grey Ghost, but width is the issue for this machine.
 
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Apr 10, 2021
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I won't be using it for off roading, I live in Phoenix AZ and want to be able to get away from cars if they come at me, so being able to ride over a curb is a good thing. The idea for this trike is for getting groceries, general cruising, some comfort, ease of getting on and off the trike, and for a couple friends to try it to see if they might want one, I have one friend with a very bad back and another that is heavier than I and I'm over 300lbs and a big bear of a guy, lol. I am having a problem with my eyesight and am legally blind right now, I got an adult trike to get around while driving by braille, it is fun to ride, but hard on my back as I got use to a full suspension mountain bike, so I can't take it for a long ride as it makes my rear go numb and makes my leg go numb. If this project goes well, I will build a full suspension tadpole trike if I can find shock that can handle my weight. My current mountain bike is a Mobgoose Detention as it was the only bike I tried that would handle my weight. Am I over thinking this, would a grade 8 20mm golt be strong enough to maybe handle 500lbs, the trike I ride has a 15-17mm rear axle and I don't think the axle is bending , but it is an upright trike so I don't know if that is a good judge of the forces a tadpole would be under..
 
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As I read it, than I think 26 front and rear will be good for you. 26x2 front and rear.
You get comfort and you can easily go on and off the curb.
You don't race, so it will be fine.
 
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Apr 10, 2021
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While I am a speed junkie, I'm not going to build this for speed, but safety, strength, ease of getting on and off, and reliability are going to be key factors, I am also thinking about a heavy duty rear rack with saddle bags and a trunk or a trailer to haul food home. I was also curious if wider front hubs would let the wheels take the lateral forces better, say like use fat tire front hubs with normal heavy duty rims or would that make the wheels more likely to give or taco?
 
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The bigger wheels will be better for mounting and dismounting curbs but will be weaker for cornering. No bike wheel is expected to take any cornering stress and the bigger the wheel the larger the lever on the rims. If you corner hard there's a good chance that 24 " or bigger will simply fold under the weight applied. I'd stick to 48 spoke 20" with double walled rims. 20mm axles will hold a rhino. Something-else will bend before they do. I realise you don't want fat wheels but they would be ideally suited to mounting and dropping off curbs. The huge amount of air they hold will protect the rim much better than thinner tyres. The stronger rims would also have a higher likelyhood of surviving if you went to 26" on the front. Failing that opt for the fattest normal tyres you can find.
 
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26 inch wil not bend that fast as you don't race.
Yes 20 inch is stronger, but by normal riding, you can use 26 inch.
20 inch going on to curbs is hard if it is possible. It depends on the size of the curbs, but I had to go off on some curbs, to lift my trike.
 
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Apr 10, 2021
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I use to have a diamond back serento, ridged frame mountain bike and it would just barely clear the curbs without hitting, so rough gues would be between 6-8 inches high, I just want an escape route as Phoenix drivers are notorious for not seeing motorcycles and bicycles, so better safe than sorry. I was even considering painting the trike hi vis orange, just so it screams LOOK AT ME, lol
 
Joined
Apr 11, 2021
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I wouldn’t go with 26” for the front because your going to have to make the front wider to avoid peddle and foot scruff from the tires when you turn. If you want to get through a 36” door you’ll have to make the fronts 20”. I’m not sure about the 24”, I’ve only used them for the rear so far. Your design constraints will guide you in your size decisions but you can modify parts of the frame to help with those constraints. Good luck with your build, hope to see pics in the future.
 
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Yes 26 you need to ho wider.
You need to check the hight of the curbs. 20 inch wil not always got on them that easy as it is high.
 
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