Do 100mph bikes exist??

it would be interesting to see how little power would be required to hit 100mph.

my 1000w 26" hub on a 1500w conntroller does 55mph+. if i doubled the voltage, and found a good enough amperage controller...maybe did a oil cooling mod. would it do 100mph?

tyres are a concern.

i remember someone explaining that world land speed record car tyres were super thin rubber. as a thick wall would generate too much friction/heat.

tat being said....my road tyres on my big bike have lastest tread wise for over 3 years. where as ive seen mine and my friends dirt tyres last all of a few weeks to a month.

jimmyhackers said:

it would be interesting to see how little power would be required to hit 100mph.

my... if ..., and.r...maybe ....do 100mph?

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... a... " poof" of magic smoke.

I am pretty sure this would certainly result in. End result.

liveforphysics said:

My next ebike will have the HP to run 150-175mph, but I will gear it shorter to be optimized around 1/4mile trap speeds at redline (~140mph).

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when your doing those kind of speeds what tyres and rims do you use? and do you balance your wheel rims with weights?

jimmyhackers said:

liveforphysics said:

My next ebike will have the HP to run 150-175mph, but I will gear it shorter to be optimized around 1/4mile trap speeds at redline (~140mph).

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when your doing those kind of speeds what tyres and rims do you use? and do you balance your wheel rims with weights?

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When the race class requires bicycle tires, I run the double-ply count maxis hookworms on bicycle rims with balancing weights. These are iffy to survive more than a dozen lap event or so on a kart track before the tires are damaged so badly they pop.

When the race is unrestricted, I run a superbike front tire and 17inch moto rim for a rear, and later I also started running roughly the same tire and wheel for a front as well. These handle huge power, and I've not had a failure of one yet.

liveforphysics said:

When the race is unrestricted, I run a superbike front tire and 17inch moto rim for a rear, and later I also started running roughly the same tire and wheel for a front as well. These handle huge power, and I've not had a failure of one yet.

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I forgot about that 17inch rim failure. Lol

Broken so many wheels and brakes and tires and motors and controllers it's tough to keep track.

Makes me wonder what the minimum limit is for hub motors before stuff starts breaking at the different points.
Average brand name bicycle stuff vs downhill/ebike bicycle stuff vs motorcycle stuff

looks like the spokes failed rather than the rim.

spokes do look like flimsy wire when they're that shape :lol:

my friends managed to crack his 3000w hub motor rim after a few month of owning it.

hit a nasty pot hole.

front wheel rim with double skin and eyelets is perfect (halo brand). (no brand china) rear rim that is double skinned and without eyelets had cracked right from the spoke hole outwards on both sides of the outer skin.

a lot can be said for fit, finish and proper materials being used.
i guess buy cheap and youll be doing the first two a few times, while cursing the thirds absense.

jimmyhackers said:

it would be interesting to see how little power would be required to hit 100mph.

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Math suggests that an electrified Milan SL velomobile could do it on a bit under 3 horsepower. I intend to build a more robust vehicle with approximately twice the Milan SL's drag, but in exchange, more ground clearance, more suspension travel, stronger wheels/tires/hubs/brakes, among other changes. I think it is possible for a single-seater enclosed vehicle made to be practical for on-road use to RELIABLY maintain 100 mph on about 4 horsepower if designed for it. I plan to build such a thing.

Now reaching 100 mph in the 1/4 mile, you're going to need at least an order of magnitude more power than what it would take for the vehicle simply to maintain 100 mph steady state on flat ground...

I have been up to 56 mph on a heavily loaded touring bicycle some where on the Alabama Georgia border. Tour de France riders go faster. One rider had his brake melt so he layed the bike down and skidded to a stop. Tandems are 20 percent faster than singles. The Romp family said they routinely hit 38 mph on a the level and ran out of gears. This was on a four seater. I think a strong team on a six seater could hit 70 on the level and would need a small hill to hit 100. Forget using what Santana makes. You would need standard motorcycle tires and an engineer to build the thing.

zerodish said:

I think a strong team on a six seater could hit 70 on the level and would need a small hill to hit 100. Forget using what Santana makes. You would need standard motorcycle tires and an engineer to build the thing.

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Only if it had a faring of sufficiently low drag. Theoretically it may be possible, but due to all of the weight of the riders it will be very slow to get there. In practice, the fastest unmotorized human powered vehicles have been single-occupant. The Eta has been to 89 mph at Battle Mountain, NV, on flat ground. No tandem has come close to that.

Generally speaking, motorcycles suck for a human powered application. Motorcycle tires have such a high rolling resistance compared to bicycle tires that it will be a tall order to find ones with low enough rolling resistance for it to be feasible to pedal to decent speed without a motor. Motorcycle tires tend to have a Coefficient of rolling Resistance of 0.020 or thereabouts, whereas car tires are around 0.007-0.015, and bicycle tires around 0.004-0.01 depending on what type of tire they are and their application. Motorcycle tires have such a high amount of rolling resistance that in a dedicated streamliner or one of the more slippery velomobiles, one would have to be doing 45+ mph to see any sort of significant aerodynamic benefit from the body shell, and even with the most efficient bicycle tires, that is not a sustainable cruising speed even by top athletes. Going to low rolling resistance bicycle tires reduces rolling resistance so significantly that slippery aerodynamics become beneficial at 15-20 mph, and thus 30-35 mph can be maintained at wattages that humans of decent fitness are capable of sustaining for appreciable lengths of time. The problem is that bicycle tires are ill-suited to the speeds that cars are capable of sustaining. Finding a good middle ground is difficult.

One motorcycle tire that shows a lot of promise for handling freeway speeds and is DOT rated for such speeds, while possibly remaining pedalable at decent speeds due to relatively low rolling resistance(as far as motorcycle tires go), is the Mitas MC2. I do not have a tested Crr value for this tire, but I suspect it is somewhere between 0.008 and 0.010. Which if that is the case, would be comparable to a mountain bike tire, except greatly stronger, and heavier. Solar race car tires are also worth investigating. Do note that while the Crr value of such a solar car tire may be low and possibly comparable to a bicycle tire, it will be significantly heavier than a bicycle tire which will adversely affect acceleration when the vehicle is being propelled strictly by human power.

BTW, I'm an engineer, in the event you're wondering how I know these things.

The Toecutter said:

in the event you're wondering how I know these things.

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So what strictly defines the difference between a mc tire and a bicycle tire in your assertion? I would presume the contrary without thinking too much as to a car tire vs a mc tire.


I feel my tire has very little RR. I glide for hundreds of feet, after the hill, in my pinon. I have ridden alot.I can conserve enrgy well, with my slower rolling. From my experiences.

I have a tire I try to clone, pass off a s a bicycle, but is certainly a 4 ply 8lb DOT 75mph tire by Duro in standard sizing. Not a bicycle tire. Has a 2.5" width. Not to fat, or large, like a large motorcycle tire.... but yes it is. However, I can glide as long, or longer, than a knobby, 26" bicycle tire with no weight in its assemble... ( the only other bicycle tire I have exp. to compare with)... I do see how thin and how nimble, the roadracing bicycle tire is, with its 1" cross section and large diameter..... But is this not impractical and negligible when we discuss higher powered vehicles ( with stored energy systems contributing to the traction an propulsion)?

DogDipstick said:

So what strictly defines the difference between a mc tire and a bicycle tire in your assertion?

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DOT certification.

Albeit, that definition is not all-encompassing, as there are off-road motorcycles that do not use DOT rated tires, but when I speak of motorcycle tires, I'm speaking exclusively of DOT-rated rubber.

I feel my tire has very little RR. I glide for hundreds of feet, after the hill, in my pinon. I have ridden alot.I can conserve enrgy well, with my slower rolling. From my experiences.

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It isn't so much about how the tire feels, as it is what is its rolling resistance coefficient. It is the latter that determines the amount of power required to overcome rolling resistance versus speed for a vehicle of a given mass.

Force Rolling resistance = Crr * Mass * Gravitational Constant

The power to overcome rolling resistance varies linearly with speed.

The above model is not 100% correct from a purely technical basis, but for speeds concerning any ground vehicle moving at road legal speeds, it is very accurate.

I have a tire I try to clone, pass off a s a bicycle, but is certainly a 4 ply 8lb DOT 75mph tire by Duro in standard sizing. Not a bicycle tire. Has a 2.5" width. Not to fat, or large, like a large motorcycle tire.... but yes it is. However, I can glide as long, or longer, than a knobby, 26" bicycle tire with no weight in its assemble... ( the only other bicycle tire I have exp. to compare with)... I do see how thin and how nimble, the roadracing bicycle tire is, with its 1" cross section and large diameter..... But is this not impractical and negligible when we discuss higher powered vehicles ( with stored energy systems contributing to the traction an propulsion)?

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It is possible for a motorcycle tire to have a rolling resistance coefficient comparable to a bicycle tire, if it were designed for such. A tire's width has less to do with its rolling resistance than other factors such as the compound it is made out of, tread design, belts, construction type, how it handles mechanical hysteresis, number of plys, temperature, air pressure, ect. The problem is that rolling resistance is generally an afterthought when it comes to tires designed for moped and motorcycle applications, unlike cars which go through fuel economy testing, or bicycles which have to do as much as possible with greatly less power. You'd need to set up an experiment and test the Crr value of your tires to see how it compares to any bicycle tire you have on hand. It is possible you might have a motorcycle tire that does have a low Crr value. It is also possible that your bicycle tire has a high Crr value and the motorcycle tire you are using is still worse than most bicycle tires. There ARE bicycle tires with high Crr values, but they are an oddity, specifically because humans have very poor continuous power capabilities compared to any motor, thus requiring almost universally a low Crr value to be able to propel a bicycle to an appreciable speed.

Website with Crr values for bicycle tires:

https://www.bicyclerollingresistance.com/

Study with pdf for Crr for car tires(see page 5 for chart, I had to enter the defunct link into archive.org, the link being "https://greenseal.org/recommendations/CGR_tire_rollingresistance.pdf"):

https://web.archive.org/web/2005112...ecommendations/CGR_tire_rollingresistance.pdf

A number of car tires that you can buy today have Crr values approaching that of bicycle tires, albeit they are far too heavy to pedal a vehicle using them and accelerate as one is accustomed(not to mention disruptive to the airflow of a bicycle given a car tire's cross sectional area), but once a rider got a low rolling resistance car tire up to a bicycle-appropriate cruising speed they'd find it similarly easy to maintain that speed on flat ground. It would take a lot more effort and time to get up to that speed, due to inertia.

My application is something unique. I'm trying to build a vehicle capable of sustaining freeway speeds using an electric motor, but is low drag/low mass enough that it can still be pedaled like a velomobile to faster than bicycle speeds with the motor shut off. This means I need a narrow and relatively lightweight DOT tire rated for highway speeds that is also low in rolling resistance. Most of the candidates with low rolling resistance are for cars and are far too big/heavy, while the bicycle tires I've considered don't have enough rubber or durability for the application I require.

If you have a low rolling resistance motorcycle tire that can fit in a 16" DOT wheel, I'm all ears, because that is exactly what I'm looking for. I have some Mitas MC2 tires in my possession and will eventually try them when I upgrade my velomobile, but they are an experiment and I'm not certain if they have a sufficiently low Crr value for my application, but they are the most promising candidate I could find given that solar race car teams use them after testing many candidates. Dedicated solar race car tires could also work for my application, such as the Schwalbe Energizer series with DOT rubber(not to be confused with the Schwalbe Energizer ebike tires), but they are unobtanium in the U.S.