Due to a disease that spread throught most of known world, all horses died. Without a replacement that was easy to grow, roman engineers found a solution. They invented the bicycle ! Now the roman army is prepared to commission the first bike riders legion. Part of the legion will fight as infantry and use bikes as mobility tools. But, a special modified group will ride the bikes at war, as if they where horses. Bikes will have a sharp point at the front, to be used as lance, in the event of a direct charge at enemy infantry.

Will it work ?

  • It's a bicycle, not a motorbike.
  • Not all charges are from the front, you can charge from the flanks or from behind. Actually romans were quite fond of attacking from behind infantry using cavalry.

New edit:

People said thats impossible to ride and fire, and to move a great mass etc. What about those bikes that have two sets of pedals to allow to persons to ride and power it ? Imagine a bike with two persons, the front one pedals and drives it, the back one has a bow and can fire at enemy while pedalling (he does not need to keep bike direction). Would this be effective as cavalry ?

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    $\begingroup$ The enimy army doesn't have horses either, right? So roads and traversable ground will be well defended with the advantage. $\endgroup$
    – JDługosz
    Jul 1, 2015 at 3:24
  • $\begingroup$ Jorge, could you clarify if you meant motorbikes or bicycles? IMHO your question seems to be related to the latter, but both answers focus on the former. $\endgroup$ Jul 1, 2015 at 6:02
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    $\begingroup$ There is a troop category called "Dragoons" - troops equipped with horses for mobility, but horses and riders are not trained for mounted combat, so they dismount when engaging the enemy. Bike-mounted troops could easily replace these. $\endgroup$
    – Philipp
    Jul 1, 2015 at 9:03
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    $\begingroup$ Don't dragoons typically have guns? If so, bikes can be a good replacement by using drive-by (or rather, ride-by) tactics. Also, IIRC the actual Roman army have poor cavalry unit (they usually rent them as mercenary), the actual Roman cavalry was so poor that near the end of the Western Roman Empire they have abolished Roman Cavalry altogether $\endgroup$
    – Raestloz
    Jul 1, 2015 at 9:42
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    $\begingroup$ Centurions were the 'officers', the foot soldier was the legionary. $\endgroup$
    – Oldcat
    Jul 1, 2015 at 20:29

9 Answers 9


Bikes were used by infantry scouts and couriers for a period of time into WWII (the Finnish ski troops who devastated the Russians during the winter war were bicycle scouts during the rest of the year, riding through logging trails.), as most nations simply did not have the industrial resources to mechanize their armies (even the German Army had more the 50% of its strength in dismounted Infantry divisions and supported by horse drawn wagons). For scouts hiding in the woods and sniping with rifles, this is effective to a certain extent, but only in situations where terrain, troop concentrations and so on favour the cyclists. Using bicycles as "shock cavalry" isn't going to be an option for the Romans, or anyone else, for that matter, since the physics simply are against you.

In fact, since the Romans were primarily a heavy infantry formation which used cavalry mostly for securing the flanks, scouting and pursuit of the fleeing enemy, their bicycle units would simply ride around the legions doing the same things. Someone noted "Dragoons", and this might make a good model; the Roman bicycle troops ride up, drop their bikes and run forward throwing javelins at an exposed flank before running back and riding away. Auxiliary troops might do the same, but use bows and arrows, or perhaps more useful for a cyclist, slings. A sling can be worn like a belt or bandolier while riding, and saddlebags full of lead pellets or stone shot could be carried without much difficulty so the slinger can reload his pouch after each encounter.

Cyclists trying to attack a Legionary formation will discover they are a hard nut to crack, being deployed in mutually supporting formations, fully protected by shields and armour and capable of throwing heavy "pilla" a considerable distance. Standing off and shooting at them with javelins, arrows and sling stones will certainly slow them down, and if you are good and lucky, might disrupt their formation, allowing your heavy infantry the opportunity to move in on them and engage in close combat.


One major drawback would be power. Horses were the engines of the ancient era. The earliest engines used horsepower as a unit because they were meant to replace horses.

Momentum = mass x velocity

Not only does horsepower create higher velocity, but they also bring in a lot of mass. An adult horse is roughly 500kg. Combined with the rider, that makes them 9x heavier than an average person.

Which means that if an infantry charged into a mounted rider, the infantry would be knocked back 9 times as far.

Bikes do not bring in this much mass. A chariot might, but without horsepower, it won't be very effective.

Some military applications of bikes:

  • Scouting
  • Skirmishers. Cycle in, throw some javelins, cycle away.
  • Blitzes. The Japanese used bikes go take over Malaya in a few days during WW2. With manufacturing, you can afford a bike for every infantry, which gives armies a lot of mobility.
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    $\begingroup$ Not only power but mass. Horses weigh a lot, and that adds a lot of kinetic energy to a cavalry charge. Some of which makes it into a spear point or sword blade. Also, it hurts when they gallop over you. Bikes, not so much. $\endgroup$ Jul 1, 2015 at 17:06
  • $\begingroup$ Thanks. I suppose I actually meant mass, but didn't want to make it sound so geeky. Edited it. $\endgroup$
    – Muz
    Jul 1, 2015 at 17:18
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    $\begingroup$ There's no such thing as too geeky. Especially here—there is a question about the tactical advantages of putting riders on dragons in the sidebar. $\endgroup$ Jul 1, 2015 at 18:37
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    $\begingroup$ Heavy might be up to 30kg, which is still nowhere near the weight of the lightest horses. It could still work off road. Design the tyres right. WW2 japs used them effectively against an underdeveloped jungle/rainforest British colony. And the ancient era involve lugging some artillery around and chariots; the people were likely familiar with how wheels performed off road. $\endgroup$
    – Muz
    Jul 1, 2015 at 21:55
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    $\begingroup$ Tires use rubber from across the world. It would have to haveWood or iron wheels like a cart, with consequent lack of traction. $\endgroup$
    – Oldcat
    Jul 8, 2015 at 17:23

It seems unlikely they'd be useful for a charge.

Light riding horses weigh over 800lbs (over 380kg), usually quite a bit more. That mass helps break through whatever they're charging. A bicycle could be weighed down to match, but pedaling that over even level rough ground at all, much less at charging speed, will probably require your cyclists to have been sent to Earth as infants from an exploding planet.

Bicycles might be useful for mounted archers. If your Romans can make a rugged bicycle effectively nearly as good as modern mountain bike, then they might be able to outrace infantry while pausing once in a while to attack with arrows. This does leave them vulnerable if the infantry has archers as well, but they'd actually be smaller targets than horse-mounted archers, so there'd be at least a little benefit.

It would be pretty impressive for the Romans to be able to make anything like a modern bicycle, by the way.

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    $\begingroup$ +1 for the last sentence... There is a tendency among fantasy / speculative fiction to believe that as long as it doesn't use electricity or plastic, it could have been invented in the iron age... :) $\endgroup$
    – komodosp
    Jul 2, 2015 at 10:11
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    $\begingroup$ The chain might be a problem. Perhaps they would use a belt and capstan instead. $\endgroup$
    – JDługosz
    Jul 2, 2015 at 15:18
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    $\begingroup$ There would be lots of problems. There was a question about the Roman bicycle and I dismissed it as slow, uncomfortable and ridiculously expensive. The Romans simply lacked lots of things that make bikes cheap and convenient for us. The time bikes actually became common is pretty much the earliest everything was available for it. $\endgroup$ Jul 6, 2015 at 23:00
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    $\begingroup$ Yeah. The chain is one. Just having a material that is lightweight and able to survive off-road -- cast or rought iron, bronze, and wood would all have problems, I think, as a man body, and be worse for tension as in wheel spokes. The wire wheel, the chain as JDlugosz mentioned, rubber tires, or even ball bearings, would seem beyond Roman technology. Admittedly, the image of armored Roman warriors girmly riding penny farthings into battle is worth something just by rule of cool. $\endgroup$ Jul 7, 2015 at 0:02

EDIT: Finally a clarification has been made: it's a bicycle!

The original post above assumes motorbike because why would anyone charge at anyone with a bicycle?

But let's re-answer with the clarification

Probably not.

In order to understand why, you need to see why horses were chosen in the first place: because they're fast and menacing. The point of a charge is to deter the enemy with a thundering shock and break the enemy ranks, this is impossible with bicycles because:

1) Cycling a bicycle requires physical effort on the rider, by the time they've reached the enemy while maintaining a charging speed, they'd be exhausted, which is not a goal of riding something in the first place.

2) If you crash against anything while cycling, you'll most definitely fall and not be able to continue your charge, the pointy end might hurt any poor sod that got stuck on it, but it also will render the bicycle useless until the guy is taken off the bike.

3) The momentum a bicycle provides is much less than that of even a young horse, thanks to the fact that bicycles have much less mass and weight, most people can carry a mountain bicycle, virtually nobody can piggyback a foal.

4) It is possible to have a bicycle with one cyclist and one archer to cycle-by, this is true, similar to a chariot archer, but a chariot archer has the luxury of standing on a relatively stable platform, which the passenger of a bicycle doesn't have. The closest you can get is if you utilize a bicycle with support wheels, which technically would make it a quadcycle. A Tricycle would also work well.


An archer would actually prefer staying behind the enemy lines and not join the frontlines. The "arc" in archer refers to the shape an arrow makes as it flies to the heavens and fall down to kiss gravity, this allows archers to shoot from great distance, the most popular long-distance archers being English Longbowmen. When archers join the frontlines they're usually as Chariot Archers that have fast mobility and don't need to fear enemy infantry (and relatively safe against cavalry too), or they're horse archers, which are archers themselves riding a horse, both of which are there to do ride-bys.

There is not much point in having archers charge at the enemy.

At most, bicycles will help you traverse the landscape, and not much beyond that

Original post for motorbike: Probably not.

Unlike bikes, Horses are capable of standing upright with no support, largely thanks to the fact that they have 4 feet instead of 2 wheels. This allows you to take your hands off the reins for a moment and do something else like fighting while being stationary.

Even if we assume that your bikes are American bikes the likes of Harley Davidson instead of Japanese bikes the likes of Kawasaki (the ones used in MotoGP) or even worse an Italian scooter, charging at something with a pointy tip at the front might cause the rider to fall down along with the bike, and as anyone with a huge bike can tell you, getting it back up is a pain, even more so during a skirmish. To test this theory, try to charge at a fridge cardboard box filled to the brim with enough weight to simulate human weight, see if you can withstand it and not fall down.

Then there are other issues: Horses are tall, we're not talking ponies here but real horses, this means if someone slashes at you, they'll get to your feet first before your head, the same cannot be said to bikes. This trait is obsolete with the advent of guns, but if you need to charge at the enemies for melee fight in the first place while the enemies have guns, you probably should replace your commander instead of your ride.

You also need stability to ride a bike, something that will interfere with your ability to swing weaponry. If you charge with a lance, the drag from piercing someone's chest might cause you to lose a bit of balance. Not a problem for the best of the best, I'm sure but that's something to think about.

Finally, bikes are the worst against offroad like the woods or rivers. They're cumbersome to turn around and if you get stuck on a mud, Kratos help you. Not to mention the complex nature of such machinery, so many things can go wrong.

It's not all doom and gloom, bikes are very good on plains and they don't need horse riding training like horses, you also can build bikes faster than you can raise horses, and they don't poop, so there's the morale boost.

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    $\begingroup$ Are we talking about bicycles or motorbikes? $\endgroup$
    – o.m.
    Jul 1, 2015 at 5:12
  • $\begingroup$ I can only assume a motorbike. Yes, both bicycle and motorbike can be shortened to "bike". Whether it's true or not has to be brought to English stackexchange. But considering that a pro cyclist has a problem maintaining speed and stability on perfectly smooth road, trying to use bicycles to melee fight is probably a bad idea $\endgroup$
    – Raestloz
    Jul 1, 2015 at 5:17
  • $\begingroup$ If they can build motorbikes, they can build jeeps and armored cars. The original question was doubtful if it could be made to work -- the answer seems to be bicycle dragoons, but not bicycle shock cavalry. $\endgroup$
    – o.m.
    Jul 1, 2015 at 5:29
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    $\begingroup$ If they can build jeep and armored cars, they wouldn't need to charge at anything, those things were invented after the gunpowder, they'll simply have a wall of armored cars roflstomping over the enemies $\endgroup$
    – Raestloz
    Jul 1, 2015 at 5:37
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    $\begingroup$ Note that you don't ride a horse with a leash! You may walk it on a lead rope, but when you're riding, you use reins. Horses are also a problem in some sorts of terrain, such as mud, or anything with animal holes. They also need quite a bit of training before you'd want to take them into a combat situation. I once spent about 15 minutes getting my horse to cross a creek that was about a foot wide. And then there was the horse-eating road grader... $\endgroup$
    – jamesqf
    Jul 1, 2015 at 18:13

Is a bicycle lance charge feasible?

As a cyclist I'd just like to re-state the point a lot have put here.

force = mass x acceleration

Bikes do not have the mass required to make a lance charge realistic. The whole point of modern bicycles are that they have a high power to mass ratio - they create a lot of movement for little mass. At the end of the day, someone's got to pedal it! That's why bikes are made with more and more space-age lightweight materials - think carbon fibre, aluminium, light alloys etc. Assuming your Roman engineers created something usable and similar to a bike, they obviously wouldn't make them quite so light due to access to different materials. for them to be viable they'd still have to be light, however, so would likely be made of wood or something similarly light. Unfortunately this would also make them relatively brittle.

Lance charges worked because the mass behind the single point was huge - a charging horse and the person riding it PLUS all their gear would weigh a huge amount.

Can't I just make my bikes weigh the same as a horse?

Any bike weighing roughly 500 kilograms (average weight of a horse as per googling "average horse weight") would simply not be usable. Horses are so good as cavalry mounts because they carry their own weight! and remember, bikes are far easier to cycle across roads than they are rough terrain - at least without serious modification that the Romans would be unlikely to copy - suspension - fancy tyres etc...

What about other sorts of charge?

A different approach would be to use bikes to increase the speed and manouverability of your soldiers. Unfortunately this is not without its own pitfalls.

Firstly, bikes only work if the wheels can turn. All it takes is for your enemies to have some short lengths of wood or metal on them to shove through the spokes and your bike charge turns into a massacre as your soldiers are forcibly removed from their bikes and killed.

Secondly, collisions. Anyone who's hit something on their bike knows that this can be pretty dangerous in itself. I myself have broken bones as a result of a bicycle crash. as for riding into a skirmish where people are actively trying to kill me? no thanks!

Finally, maintenance. Bikes are pretty pernickety things at the best of times to keep maintained. Wheels are easily bent, brakes and gearsets easily damaged, headsets misaligned, derailleurs bent... How are you going to repair anybikes that survive combat? (if there are any!)

What about other sorts of combat?

OK, so that's charging out! what about archery?

Archery would be a serious possibility from a bike. It's conceivable that you could have some sort of tandem where the archer fires from the back, but again, over rough ground this would be hard. Horses would provide a far more stable platform to fire from and don't require two people to operate!

The best use for your bikeS? Logistics. fast movement of troops, and maybe mounting artillery pieces on some Frankenstein's Monster of a bicycle with four or five people pedalling at once could enable it to keep up.

Charging? Unlikely!

  • $\begingroup$ Point taken regarding maintenance, but remember that horses are also pernickety things to keep maintained. They too are easily damaged in combat, and also in normal use. Actually, so are tanks and helicopters! If the Romans were forced by the horse-killing plague to develop ways to use bicycles in their army (probably as mounts for scouts and messengers rather than in combat directly, for the reasons you and others have said), then they would also develop a system of army bicycle repair shops. In our timeline military mechanics can do wonders of improvisation under pressure. $\endgroup$ Jul 2, 2015 at 15:43
  • $\begingroup$ This is true, but horses are relatively easy for the Romans to keep maintained - the Romans would've had a harder time keeping mechanical things working! My point was more the experience Romans would've had maintaining things. Modern machinery is only kept working on the battlefield thanks to historical advances in wartime maintenance. I'm aware the Romans had some technology at their disposal, but as far as I remember its things its users would've had little trouble fixing with nothing more than bits of string, some glue and some wood. $\endgroup$
    – Miller86
    Jul 2, 2015 at 15:52
  • $\begingroup$ Horses, with lances or no, will not finish a charge into formed infantry. Charges rely on fear to make the infantry run before the lancers get there, and then they stab them in the back. The main issue is that a painfully slow ride of bikes across a grass field would scare nobody, and it is trivial to stop a bike short by grabbing the handlebars. $\endgroup$
    – Oldcat
    Jul 8, 2015 at 17:27

The idea of bicycle-borne lancers does not seem feasible. At the very least, it would take the defending infantry only a few minutes to dig an obstacle that will stop such an attack. Maintaining any sort of speed on a bicycle requires very smooth, firm ground, especially if the rider is carrying any sort of load, which makes the idea problematic for troops wearing armor.


What about other animals? For other uses there will be burro and mountain goats as pack animals.

Other animals that are not rideable or trainable to go where you want them to may still be usfull for power. There were treadals and walking in circles.

So... if mechanical vehicle technology is available, perhaps they will put animal power inside. Maybe a weapon platform or truck will use a rack of pigs or lions under the hood. Even if not for a weapons platform, the breeding of animals for power but not going where you want them etc. will put them in a power take-off rather than along a hitch.


WhatRoughBeast suggested it would be easy for infantry to dig some kind of obstacles. I do not think they would even need to. What proportion of terrain is actually suitable for bicycles? Not much, I suppose. There are accounts of the Persians clearing rocks away to make ground suitable for chariots, which presumably they did not do for the fun of it.

Things with legs generally handle bad terrain better than wheels. A mountain pony can get where a jeep cannot. A human can scramble up a cliff where no car or bike could.

  • $\begingroup$ And thus we get the movie, In Pursuit of Honor. good point! $\endgroup$
    – JBH
    Dec 30, 2018 at 17:58

I've seen this very thing (medieval combat on bicycles) in Portland, Oregon... ;)

Terrain - The location of your battles becomes very important; traversing through forests or across streams becomes more taxing. Not to say that you can't dismount and carry the bikes. Design considerations - large, flexible (leatherbound?) tires for going over rocks; light, sturdy frames (steel?).

Protection - It becomes critical to offer protection on the bike, rather than having your soldier hold a shield. Design considerations - thin, sturdy protective shield on the front and sides. It is also important to protect the wheels and the gears. Much like bringing down a horse, it could be very easy to immobilize a bike.

Advantages - You don't have to feed a bike. You can take a bike apart for transport over long or difficult terrain. A bike can be hauled up a short cliff a lot easier than a horse. Riders can change out on a bike indefinitely (barring the need for maintenance).

Limitations - Before switching to bikes, I think the Romans of the day would switch to the Camel Calvary: larger, stronger, faster, and suitable in many conditions.


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