A New Type of Vehicle

Joined
Mar 7, 2020
Messages
11
Hello All!

I am going to get straight to the point and talk about a new kind of vehicle that I have been thinking about.

I suspect that if a vehicle constructed from hobby and bicycle parts which gives it features paralleling an automobile, it would solve a few problems in the dual-standard advocacy between separate cycle routes and vehicular cycling.

On one hand, vehicular cycling uses rules which enables a cyclist to employ a defensive method of sharing the lane with motor vehicles. While that would embolden an advocate’s entitlement to the road it is not hard to see how that can anger some motorists and can cause increased accidents considering a conservatively weighted bicycle of 25kg would be a mere speed bump to vehicles over 1000kg moving over 50kph.

In terms of segregated routes (trailways & greenways) that prevents a majority of the former issues from occurring and where I live, there’s little of anything like that except one several miles to the south. I’d see something like these as places where velomobiles can go as fast as they want, but still have to treat pedestrians and other cyclists (who may/may not use them for leisure) with respect by passing them. Nothing I don’t normally see driving on the freeways, as a matter of fact, but considered debatable.

Regardless, it is clear that when you look at the spectrum of vehicles with wheels, you go from roller skates to large trucks. But one thing becomes evident: there is an apparent class change for an order of magnitude of mass. Shoes, Roller Blades, skateboards and scooters represent the smallest of these (1-10kg). Bicycles slowly give way to vehicles with more, larger and wider tires and above 100kg you get into motorized vehicles territory.

This is extremely important to understand because 2 vehicles in the same order of magnitude will have some damaging or deforming effect (whether that is on the persons themselves or the vehicles) which damages both vehicles. A car —> bicycle will likely result in the cyclist being injured if not being outright killed with no resulting damage to the car’s A-frame. Don’t forget the presence of larger vehicles on a road like semis (>10,000kg) which may also take advantage of a designated cycle lane for services like electrical or garbage collection. Ouch.

Getting past that, my proposal is an ideal vehicle which could be designed with a weight between 50-75kg. I have been looking at many videos lately involving motorized bicycles, very old vehicles from the first days of the automobile and velomobiles, as well as possible power sources for something like this.

The vehicle is much like a velomobile in appearance, but with a few major differences which would allow it to function as well on a interstate highway/freeway as it could on a greenway. I don’t want to set specifics but for that to work it would have to be able to accommodate a license plate since that’s the law around where I live. Another factor is emissions, in case of using a motor or fuel cell. Alsoase you think motorizing a velomobile is insane, A historic vehicle called a cyclecar did in fact place itself between a motorbike and a car like that:

in that case the cyclecar was replaced by increasingly cheap and bigger automobiles due to refinements to the manufacturing lines in car factories.

But hold your horses calling me a gas guzzler! I wouldn’t even think about using gas in it due to it being nonuniform (it’s a slew of different hydrocarbons which make its emissions hard to predict), so I figured a ethanol/butanol blend would be more efficient due to predictability.

As for the method of propulsion if it is mechanical like for an Internal Combustion Engine, the human part of its power would be difficult to implement if both sources go through a common driveshaft. A good example of an engine for an application like this is a predator 212cc with modification for E85.


If electrically powered, it could be hooked to a direct ethanol fuel cell with similar heat coming off of it as an ICE.



What this could allow could potentially be on the realm beyond imagination. Having it set up for fuel efficiency, someone could expect to start with motorbike mileages at 100mpg multiplying through 500mpg! The fairing of a velomobile would improve aerodynamics enough to remain stable at speeds exceeding highway speed limits.

I don’t guarantee it could be made better than a well made bicycle or a refurbished used car, but after realizing that multiple open source technologies like RepRap 3D printing and Raspberry Pis, Arduinos, and the stuff done on here can be used to make a vehicle like this, it might work. Hope to get feedback from it. Cheers!
 
Joined
Oct 19, 2012
Messages
789
Location
Wakefield, UK
Ethanol and butanol have less energy than petrol. Alcohol dragsters use methanol which has even less but it can be burned in much higher quantities for a given amount of oxygen than petrol hence the biger horsepower. If you want to use alcohol because of emissions you need to factor in the extra fuel that will be used because of it's inherent lower power. With alcohol dragsters they tend to run very cold, often freezing inlet parts shut or open. That could be due to the vast amounts burned rather than just the fact they run on alcohol. The E85 mods may or may not work on 100% alcohol.

The obvious question is why do you want to build what is essentially a very light one man car?

If you stick a 212cc engine on 100kg of cycle parts you are going to exceed the likely design specs of such things as bearings and tyres.
 

Radical Brad

Garage Hacker!
Staff member
Joined
Mar 13, 1999
Messages
5,903
Location
Kakabeka Falls, Ontario, Canada
A great topic for discussion, thanks for starting it!

As Popshot has mentioned, I have always found that the when considering speeds greater than say 25 Mph, the choice of wheels, brakes, and suspension instantly go from lightweight bicycle components to full size motorcycle. Most of these velomobiles I see around would probably handle 99% of the road conditions, but it is that one huge pothole that turns them into twisted metal. For that reason, I have not bothered because it is not in my rule-book to make something almost good enough.

If I was taking on a project as you described, I would be starting with a street bike chassis, and probably end up with something like this (but fully electric)...

4550

I actually really like this one. of course, not practical for us in the Great White North.


Brad
 
Joined
Oct 19, 2012
Messages
789
Location
Wakefield, UK
That looks like the type of chassis and components that would be needed to cope with a 212cc engine's power. It is a particularly nice looking example too. As a toy I could see myself in such a vehicle. Such a "car" offers few positives over a motorbike and a number of negatives such as size, weight and cost.
 
Joined
Mar 7, 2020
Messages
11
Ethanol and butanol have less energy than petrol. Alcohol dragsters use methanol which has even less but it can be burned in much higher quantities for a given amount of oxygen than petrol hence the biger horsepower. If you want to use alcohol because of emissions you need to factor in the extra fuel that will be used because of it's inherent lower power. With alcohol dragsters they tend to run very cold, often freezing inlet parts shut or open. That could be due to the vast amounts burned rather than just the fact they run on alcohol. The E85 mods may or may not work on 100% alcohol.

The obvious question is why do you want to build what is essentially a very light one man car?

If you stick a 212cc engine on 100kg of cycle parts you are going to exceed the likely design specs of such things as bearings and tyres.
You and Radical Brad have a lot of good points! I did not say explicitly 100kg for a vehicle this heavy. In fact, I mentioned as soon as you exceeded this kind of weight you’d be getting into typical motorized vehicles that absolutely do need super wide tires.
However, I was thinking about a vehicle half of this from 50kg-75kg. It would account for the weight of a design that looks like the Deltas on this website (which were already 30-40kg) and adding 5-10kg of fairing, 10-30kg of engine and minimizing other weight factors by 3D printing parts with PETG, Nylon and other materials. A RepRap is a Replicable Rapid Prototyper, which means a 3D printer capable of printing most of its own parts. That would help someone with developing industrial parts, especially if using waste plastic as the source material.

This is definitely not a one man car, because that would be impossible to be made producible without industrial processes. I specifically mentioned examples of open source electronics because if you can get ahold of schematics of this, eg. the frame design, cable work and electronics, mechanical systems and fabricate them using either what you have or with self built machines, you won’t have to fork money on the scale of a car or a motorbike. And that doesn’t mean I’m assuming people are going to know everything about it.

Aside from that I have more inspiration about what this could be from a man named Buckminster Fuller. He proposed the Dymaxion Car from the 30s featuring the first spaceframe chassis and 3 wheeled design with a similar layout to a tadpole tricycle. He took advantage of that to make the rear wheel turn 180 degrees so it can rotate in place. It is the space frame though that gets me intrigued. Normally a velomobile employs a monocoque shell made from lightweight material for aerodynamics, but for vehicular riding it could use a rigid frame to survive impacts. I wouldn’t want what happened to a guy in a 1974 Porsche 917 spider where the legs were in front of the front axle with no protection, and an accident during a race had bent his legs in the wrong way. To say the least, front impact or side impact would be seriously injuring, hence using a semi-monocoque/space frame for rigidity and stabilizing the vehicle at high speed.

What I didn’t mention in the first post was that instead of using car or motorbike tires I considered using 29er plus tires. By reducing rolling resistance and maximizing grip off road it can do most of what mountain bikes can do without sacrificing grip on the road, with the correct tires that is. Plus, having tubes in them means not having to replace them as often. Having 2 rear wheels improves traction with the motor as well as possibly producing a fulcrum in case someone wants to add a long tail or short tail for racing (Apparently Koenigsegg and McLaren are reintroducing long tail models to their cars) or even wings, a 10kW electric impeller and elevons to convert the craft into a Long-EZ mini-me.

speaking of Kilowatts, another point is that most electric-motored tricycles are 500W-5kW, and remember that 746W= 1hp. So having an ICE like a lawn motor engine could produce a lot of power to the wheels with the right gearing, electric motors have a lot of torque and ICEs are worse in that category, but then again so are humans. And considering this is primarily a pedal powered vehicle with motor power as an option when traversing car-classified roads, even a series hybrid with a ICE generator for electric motors would be useful.

Another question to posit: why alcohol? It’s true that gasoline has higher energy density than ethanol, but butanol is a close match to petrol. For that matter a reactor with a specific type of bacteria culture, a fuel like Starch, Sugar or even CO2, and a containment vessel with solar-distilled rainwater can produce ethanol without electricity with a solar powered distillation process. Bacteria because yeast would simply produce Food grade ethanol which would require registration; bacteria-based fermentation produces other byproducts which, entirely separate, can make it fuel grade by being poisonous. in addition to that Ethanol can be employed in the fuel cell.

Having a vehicle with at least half of its weight in the person driving it (150kg with considering an overweight person being its primary power source) gives it the low center of gravity needed to handle. The secret is putting all the power between and towards the rear of the vehicle, but enough forward to not be unstable in flight (if that floats your boat!). I don’t want it to be a one man car because then it would be only fit for the roads, not for bicycle appropriated infrastructure like greenways. At first I thought it would be designed to the brink of insanity to get you from A->B. But bicycles and velomobiles are social vehicles: they allow people to talk to each over and move in groups. Hence I considered the project of making it to be named Minnow. The vehicle name I’m going with is the Vanguard Mk. I, in light of the Ford GT40 Mk I which also had a low stature and was built to be brutally fast. On paved rail-trails to be completed in the future as well as greenways, a car built from cycle parts small enough to be acceptable on surfaces outside car roads while being able to handle the latter equally as well might enable people to make cheaper cars. I don’t want a more expensive bicycle or trike; we already have those. I want something at or below those in price but far cheaper than a car, and an ideal replacement if it can have over 1,000km in range with pedaling being a significant component.
 

Radical Brad

Garage Hacker!
Staff member
Joined
Mar 13, 1999
Messages
5,903
Location
Kakabeka Falls, Ontario, Canada
Keep the ideas flowing!

So far I have found that anything over 1000 watts is motorcycle territory, where no bicycle rim will survive, not even the most expensive downhill mountain bike rims. Proper suspension on every wheel is also going to be a must. Avoid aluminum unless you are a Jedi of weld with 2 decades of hands on experience as well.

Brad
 
Joined
Oct 19, 2012
Messages
789
Location
Wakefield, UK
However, I was thinking about a vehicle half of this from 50kg-75kg
That just means less chassis and lighter components trying to control a 212cc engine! Even a poor 212cc engine is going to hit 70mph with that little weight. What components at that weight will survive the first pot hole that's hit? It's going to fold horribly. Even if you could make a chassis that can act as a safety cell, which seems somewhat unlikely at that weight, the first time a wheel folds as it hits that pothole, and it will, it'll have the lot spinning end over end. I'd also not want to use cycle brakes from 70mph nor trust cycle tyres not to fail catastrophically. Even fast ebike specific tyres are only rated to 50KMH. I'd agree entirely with Brad that 1000W or so and the 30mph that that produces are the limit of what cycle parts will reliably take. I'm aware the solar challenge racers use cycle components and can exceed 90mph. They also crash and break a lot despite using the very best components money can buy. Some race cars can exceed 200mph but many won't survive 70mph on a potholed road either.

If you want to make it simply for the joy of doing so that's always a good enough reason. I've done such myself many times. I simply can't see any niche for it though. Perhaps where you live the requirements are completely different. Here anything with an engine requires registering, an SVA test, MOT, road tax and has to be built to comply with more regulations than you can shake a stick at. Electric cycles are limited to 250W / 15mph for road use and I believe many European countries are similar if not identical.

Why would you want 1000km range? Who would make such a journey in such a vehicle?
 
Joined
Oct 19, 2012
Messages
789
Location
Wakefield, UK
Another point.
I would suggest you use 20" wheels not the 29er you mention. Tadpoles and deltas generally use 20" because the wheels have to take lateral forces in cornering they were never designed to take. 26" wheels are known to buckle under hard cornering and 29er whells will only be worse. I would suggest 20" with 48 spokes and probably laced into 20mm axle hubs are the only cycle wheels with even a modest chance of coping. I appreciate that then limits the design.
 
Joined
Mar 7, 2020
Messages
11
Keep the ideas flowing!

So far I have found that anything over 1000 watts is motorcycle territory, where no bicycle rim will survive, not even the most expensive downhill mountain bike rims. Proper suspension on every wheel is also going to be a must. Avoid aluminum unless you are a Jedi of weld with 2 decades of hands on experience as well.

Brad
In the case of exceeding 1000 watts, I’ve seen enough ebikes to figure out that a bigger wheel seems to handle the torque and power better. So having a 29 plus wheel was part of the method of getting a bicycle rim to survive. I originally considered a 29x3.0 mountain bike tire but other widths have more options of tires for roadable use.
 
Joined
Mar 7, 2020
Messages
11
That just means less chassis and lighter components trying to control a 212cc engine! Even a poor 212cc engine is going to hit 70mph with that little weight. What components at that weight will survive the first pot hole that's hit? It's going to fold horribly. Even if you could make a chassis that can act as a safety cell, which seems somewhat unlikely at that weight, the first time a wheel folds as it hits that pothole, and it will, it'll have the lot spinning end over end. I'd also not want to use cycle brakes from 70mph nor trust cycle tyres not to fail catastrophically. Even fast ebike specific tyres are only rated to 50KMH. I'd agree entirely with Brad that 1000W or so and the 30mph that that produces are the limit of what cycle parts will reliably take. I'm aware the solar challenge racers use cycle components and can exceed 90mph. They also crash and break a lot despite using the very best components money can buy. Some race cars can exceed 200mph but many won't survive 70mph on a potholed road either.

If you want to make it simply for the joy of doing so that's always a good enough reason. I've done such myself many times. I simply can't see any niche for it though. Perhaps where you live the requirements are completely different. Here anything with an engine requires registering, an SVA test, MOT, road tax and has to be built to comply with more regulations than you can shake a stick at. Electric cycles are limited to 250W / 15mph for road use and I believe many European countries are similar if not identical.

Why would you want 1000km range? Who would make such a journey in such a vehicle?
Someone absolutely bollocks. But also someone who would be willing to make 20 trips of 50km (30 miles where I live) without refueling. Essentially I could go to a local Community College for 2 weeks (5 days per week) before having to refuel for 10 round trips. As for its niche, there is no niche. If it were niche there would be only one reason to buy it and it wouldn’t be of much use unless it were given different body designs. Coupé utility? Possible. Berlinetta? That’s the design I had most in mind. As for potholes, that’s exactly why you wouldn’t want this to be anywhere near the side of a car road. For cycling on greenways or traveling on an interstate highway, the speed limit is 55-65 mph, and even faster in western US.
You do have a point about a spectacular failure of either the bicycle rims or the brakes, but disk brakes are not a design limited to bicycles. They were invented to replace drum brakes in automobiles, and they so did!

I’m surprised nobody mentioned Bicycle rims that aren’t fit for something like this either need good suspension inside the vehicle’s hull, which would cause space problems if the engine is to be placed in the same compartment (I’m sure that can be done not that differently from most mid-rear engined cars these days) or a suspension placed within the wheel hubs themselves (which I’ve considered, like the cursed idea of SoftWheel).

Initially this may seem complicated but there is a stark departure between that word and complex. Complicated means this is uncontrollably complex and will likely end in failure. To have a complex issue like this means it has to be well managed. Luckily since this isn’t even drafted up yet but sketched and in words, there can be good management of this from the beginning.
 
Joined
Mar 7, 2020
Messages
11
The important part here is that it is a smaller vehicle, meaning that since it is light it doesn’t take as much braking as a car but more than a bicycle to stop it. Other people have built motorized trikes like this successfully already, with none or some errors:




Definitely not impossible to put a motor on a recumbent trike, nor 29 inch wheels for that matter.

For all that I don’t want to get ridiculous to start. It’s simply a matter of taking a preexisting design like the Delta Wolf or Aurora, adding a relatively small motor (doesn’t have to be 212cc, but for the weight being equivalent to a go kart I would go there) and adding a fairing. 3 changes. Electric motors can follow.
 
Joined
Mar 7, 2020
Messages
11
Some additional thoughts on the pothole problem:

  1. I currently drive a mid size Jeep SUV. Potholes are annoying as heck but often enough I come to have no choice but to go over them because that either means going over the yellow or the white. Of course I go over the white. But in a velomobile like this one with 29 plus wheels it doesn’t matter because the wheels have a lower angle of attack to the ground, meaning going over the bump will be less severe.
  2. Since I’m in a smaller vehicle, as long as the pothole isn’t the width of the lane (which by then it would be repaired because of the hundreds of calls to the DoT) it would be possible to avoid the pothole as long as you could see it, leading to...
  3. If you were put in a vehicle with bigger wheels, your field of vision would be greater than a vehicle with smaller wheels due to the higher ride height. That allows me to get away with putting a rider in a somewhat highly reclined position but still able to look ahead. If you’re going 180kph (50m/s) and you see a pothole at 200m away, you have 4 seconds to avoid it. That’s not hard to understand, as well as being close to the speeds of our hopes and dreams but we’re going to be going well slower than that, hence even at 100m such an obstacle would be entirely avoidable. But remember this is a vehicle that can go on the road less traveled. As long as there isn’t any serious traffic on paved trails it wouldn’t be a bad idea to use them primarily. Just treat cyclists and pedestrians like cars.
 
Joined
Oct 19, 2012
Messages
789
Location
Wakefield, UK
I'd suggest most bike wheels are expected to miss potholes as the bike is only 2" wide at the road surface and the rider has excellent vision. Having said that they are expected to cope with off-road conditions. It's the potholes sharp far edge that's the difference between the two and, in your case, the potential for meeting that edge at a much higher speed. Bigger fatter tyres and effective suspension will make a large difference. Just like any type of suspended vehicle though there's a suspension compromise between off-road ability and on road cornering. Suspending any type of 2 wheeled axle, including independent, introduces roll in a fast corner. Cars use anti-roll bars to mitigate it but that adds weight. On a type of vehicle you are designing it may be better to simply compromise between the two and limit suspension travel off road to limit roll on road.

The idea of being higher with a bigger wheel depends entirely on the chassis design. Axles can be dropped or raised, stub axles can be mounted higher or lower to a chassis. Don't forget the higher the rider the easier it'll be to roll it. With a traditional style 26/20 tadpole and low seat height I've felt the inside wheel start to rise on occasion and if my memory is right that was on a 30" track. Unfortunately the rider is by far the heaviest component So there's not much room to mitigate the centre of gravity of a higher rider. The more upright the rider the more their weight is placed lower down than their eyeline. Bad for aerodynamics - good for centre of gravity. As ever, it's a compromise.

Just because you see a video or picture of a set of components together doesn't mean they worked well. I've made that mistake myself. Getting bike components to take a high power engine is easy. It's not primarily the power itself that's the issue it's the speed that that power can generate that many bike components will not take. The trikes in the videos looked like an accident waiting to happen. Very high centre of gravity on a machine that would rarely be expected to exceed 10mph in intended use. The first swerve that's required at those speeds will be the last.
 

Radical Brad

Garage Hacker!
Staff member
Joined
Mar 13, 1999
Messages
5,903
Location
Kakabeka Falls, Ontario, Canada
In my 40 years of building bents of all kinds and taking them out in the war zone (street), I have mangled my share of rims! In my experience (considering trikes and faster moving HPVs), a double wall 20" BMX wheel with a fat tire will take a medium size pothole as long a s vehicles is suspended well. A 24 or 26 inch rim of any quality (and price) will absolutely not take a medium sized pothole at over 25 mph. You will replace the rim every time. Could be just the city I used to live in, but I would never use anything less than a moped rim on a vehicle that intended to drive at the city speed limit, especially one that may be forced to ride to the side where the road is in rough shape.

A 400cc motorcycle chassis would be a great start to a small vehicle like this for sure. You can often find a gutted bike on a budget.

Brad
 
Joined
Mar 7, 2020
Messages
11
I'd suggest most bike wheels are expected to miss potholes as the bike is only 2" wide at the road surface and the rider has excellent vision. Having said that they are expected to cope with off-road conditions. It's the potholes sharp far edge that's the difference between the two and, in your case, the potential for meeting that edge at a much higher speed. Bigger fatter tyres and effective suspension will make a large difference. Just like any type of suspended vehicle though there's a suspension compromise between off-road ability and on road cornering. Suspending any type of 2 wheeled axle, including independent, introduces roll in a fast corner. Cars use anti-roll bars to mitigate it but that adds weight. On a type of vehicle you are designing it may be better to simply compromise between the two and limit suspension travel off road to limit roll on road.

The idea of being higher with a bigger wheel depends entirely on the chassis design. Axles can be dropped or raised, stub axles can be mounted higher or lower to a chassis. Don't forget the higher the rider the easier it'll be to roll it. With a traditional style 26/20 tadpole and low seat height I've felt the inside wheel start to rise on occasion and if my memory is right that was on a 30" track. Unfortunately the rider is by far the heaviest component So there's not much room to mitigate the centre of gravity of a higher rider. The more upright the rider the more their weight is placed lower down than their eyeline. Bad for aerodynamics - good for centre of gravity. As ever, it's a compromise.

Just because you see a video or picture of a set of components together doesn't mean they worked well. I've made that mistake myself. Getting bike components to take a high power engine is easy. It's not primarily the power itself that's the issue it's the speed that that power can generate that many bike components will not take. The trikes in the videos looked like an accident waiting to happen. Very high centre of gravity on a machine that would rarely be expected to exceed 10mph in intended use. The first swerve that's required at those speeds will be the last.
See though the fun part of this concept is the part of using bigger wheels. When you use 20” wheels most applications have the wheels below the cyclist. In fact you can visibly see in bicycles with the progression from small to big wheels that the cyclist is placed deeper between the wheels. Having the wheel base longer than the delta designs but shorter than the LWB designs on this site is key: I can guarantee my 6’2” 100kg body at a 20° angle parallel to the ground can be placed between a delta configuration of 3 wheels with a somewhat long wheel base and still have enough height to see potholes far ahead. By their nature, velomobiles are small enough that even when taking a relatively big guy like myself, they could accomadate substantial amounts of equipment and still be several times lighter than the lightest automobile on the market today.

In fact, the world’s smallest automobile ever produced, the Peel P50, is 59kg in curb weight. 3 wheeled and hilariously tiny yet in the range of what can be if a velomobile was motorized. You can’t tell me that the cycling industry spent the past 100 years making derailleur systems so fragile that even the trained super-cyclist could shred gears because that’s rubbish. If people have successfully geared and motorized bicycles, there’s no reason to look at recumbent tricycles and experiment.
Regardless, there are no parts that would take that kind of speed because they are not geared for those kinds of speeds. No, that is why you would want to have what would be considered absurd gear ranges (exceeding 1000%). Something like a 64/96t chainring to a 128-8t cogset which would either have to be machined or 3D printed. I had experimented with such ratios in a calculator and the insanity of the speeds that resulted, especially when using bigger and fatter wheels, are truly nonsensical. Not that bigger is always better but then again tell that to Ford who used a 7L NASCAR engine into a sports prototype in 1966.

But I’m not here to rehearse some lines in history which proves my points. I’m here to tell you guys that foregoing the concept of a pothole (which seems bizarrely cherry picked for this exact comment section) having a vehicle which can make better use of cycling on roads not intended for human powered vehicles, as well as dedicated roads for pedestrian/cycling travel would be even better if it could use an interstate highway.

Both have an inherent lack of potholes in common for opposite reasons: for interstate highways it’s for the heavy use by all forms of traffic and in the case of greenways, the inherent lack. Since highways bypassed a lot of towns which now don’t produce a lot of income, something could be built up to go as fast but quite obviously not for roads in between the two extremes.
Hence limiting suspension travel to avoid rolling would be, for the first time here, a constructive idea I can see work. There’s no point in making it work completely off road to go over trees, so no problem at all to limit its travel. All it needs to do is ride on roads as undeveloped as a gravel or hard pack trail and as well developed as an interstate highway. If you wanted a completely off road vehicle get a 4x4 quad.
 
Joined
Mar 7, 2020
Messages
11
In my 40 years of building bents of all kinds and taking them out in the war zone (street), I have mangled my share of rims! In my experience (considering trikes and faster moving HPVs), a double wall 20" BMX wheel with a fat tire will take a medium size pothole as long a s vehicles is suspended well. A 24 or 26 inch rim of any quality (and price) will absolutely not take a medium sized pothole at over 25 mph. You will replace the rim every time. Could be just the city I used to live in, but I would never use anything less than a moped rim on a vehicle that intended to drive at the city speed limit, especially one that may be forced to ride to the side where the road is in rough shape.

A 400cc motorcycle chassis would be a great start to a small vehicle like this for sure. You can often find a gutted bike on a budget.

Brad
At this point I can see you’ve completely gotten lost on the perspective you should have. Referring to the last paragraph of the guy I had just replied to, this entire website let alone the videos on YouTube of the great set of projects would be just as implausible if someone wasn’t crazy enough to come up with them. Clearly the delta trikes are the magnum opus here, since nobody else had come up with trikes with low ride positioning and longer wheel bases.

To refer as well to my mentioning of insane derailleur system configurations, it doesn’t have to be like that. Perhaps a hub gear could augment something of such insanity in a way that allows a single chainring on the front while said hub gear can change the actual ratio to something much higher, or super low. Also just because something doesn’t exists on the market doesn’t mean it’s utterly impossible. Someone just needs to fabricate it, which can be easier done than it can appear in words.

I assure you though that anything related to a motorcycle has nothing to do with this. There’s no point towards it being anything like a human powered vehicle if we’re just going to lug around in a vehicle that fully deserves an ICE to be faster than 20mph on a daily basis. But in this case it doesn’t even have to have a motor, but if it did it would make getting to fast speeds a whole lot easier. All I can say is that where I live all the speed limits make sense because the highways are faster without any potholes to speak of and state roads are faster when they don’t get potholes. But when they do they’re not going to make you go fast enough to die going over one.

But forgetting potholes existed, having a human powered vehicle run at highway speeds makes sense especially if you get to the point where the human is producing more CO2 than fuel cells in general. But having the latter for such a case would help efficiency if it gets that way.
 

Radical Brad

Garage Hacker!
Staff member
Joined
Mar 13, 1999
Messages
5,903
Location
Kakabeka Falls, Ontario, Canada
I certainly want you to build everything you just mentioned!
Hey, I rode a 16 foot tall bike in the city for a year, so I am all about "doing the implausible".
Having said that, I fully believe that in no way will anything less than a 48 spoke triple wall 20 inch rim handle what you are asking of it. Not even close.

I will now sit back and watch in hopes that you prove me wrong so I can think that this old dog can learn new tricks.
You're up!

Brad
 
Joined
Oct 19, 2012
Messages
789
Location
Wakefield, UK
You can’t tell me that the cycling industry spent the past 100 years making derailleur systems so fragile that even the trained super-cyclist could shred gears because that’s rubbish.
I haven't told you that. Specifically I said "Getting bike components to take a high power engine is easy. It's not primarily the power itself that's the issue it's the speed that that power can generate that many bike components will not take." Most bike components will take 50mph for a few seconds as you fly down a very large hill. They aren't designed to take such speeds when maintained for some time. Bearings will fail and tyres will shred.

the world’s smallest automobile ever produced, the Peel P50, is 59kg in curb weight
And uses tiny steel wheels that are vastly sturdier than anything ever placed on a cycle. The tyres are similarly vastly more robust than a cycles. It also uses a 49cc engine not a 212cc! There's a pattern there - less speed, more strength. You propose more speed, less strength yet expect no repercussions. Do you not wonder why the maker didn't use lighter cycle wheels? BTW the modern P50 is now 105KG to meet emissions and other regulations.

I’m here to tell you guys that foregoing the concept of a pothole (which seems bizarrely cherry picked for this exact comment section)
Potholes exist. If your plan doesn't include them, your plan fails at the first one you hit. If you hit it at 20mph you may be inconvenienced / embarrassed and/or somewhat hurt. If you hit it whilst a 212cc engine is driving it flat out you'll be the recipient of a Darwin award. The P50 hits a maximum of 28mph yet the designer used massively stronger wheels and tyres than you propose. They may be small and give a poor ride compared to a 29er but after that pothole they'll still be round.


If I haven't convinced you by now then I'm not going to, nor am I going to keep trying. Darwin awards exist - don't collect one. Proove me wrong by building it and using it for a few hundred miles without major issue.

Brad - old dogs only get old by not collecting a Darwin award. Most winners are usually young.
 
Top