2.5 It can’t all be that good! Where’s the hidden bug?
O.K., this new 3-Wheeler may be great, but where’s the bug?
Any system, even if better than a lot of others, still always has limitations. What are they?
We believe that showing these limits increases both our credibility and our new 3-Wheeler’s credibility.
We do not hide anything and we rather think that the fact of seeing the real limitations of this product helps getting a better global picture of it, with its real capabilities.
We also think that a manufacturer of such a 3-Wheeler should not hide this product’s weaknesses, in order for his clients to accept it in full knowledge, avoid bad surprises and finally be more satisfied.
A) Not the best accelerations:
In forward acceleration, weight is transferred to the rear. This adds weight to the rear wheels of a rear drive vehicle, to let the rear wheels push more in order to accelerate faster. But this removes weight from the front wheels of a front drive vehicle, which limits its forward accelerations. Its the reason why almost all vehicle racing at a 1/4 mile drag strip are rear drive vehicles. Its the reason why Formula 1 cars, Ferraris and Corvettes are rear drive vehicles.
Our new 3-Wheeler is a front drive vehicle, so it will never beat a regular 2-Wheel sports motorcycle on a 1/4 mile drag strip. But is it a problem?
No, its not that important since the accelerations can still be quite good. Also, sport road holding certainly calls for a good acceleration, but it definitively calls for more.
Furthermore, the Trihawk tested by Road & Track in may 1982 ( http://designmassif.com/trihawk/articles/r&t/article_text.htm ) clearly shows the potential of this type of vehicles, of which our 3-Wheeler is an upgrade: In a slalom course, it was faster than the Audi Coupe and the Porsche 924. On the skidpad (a constant radius circle), the Trihawk was only beaten by four cars: The BMW M1, the Ferrari Boxer, the Lamborghini Countach and the Porsche 930 Turbo. “Lofty company indeed”, they added.
B) No rear brake:
Our new 3-Wheeler is a front drive vehicle. So like for a front drive car, a sudden application of the rear brake can block it and cause a spin. This 3-Wheeler should thus be equipped with excellent front brakes and rear brakes should be avoided.
In the case of such a 3-Wheeler that’s loaded correctly and that’s braking hard, weight is transferred to the front so that the front wheels brake hard and well, while the rear wheel keeps the direction like a car or plane rudder.
On the other hand, if this 3-Wheeler is heavily loaded on a slippery road, braking cannot be hard. In this case, there is little weight from the rear to the front and this weight is kept on the rear wheel that does not brake. So the vehicle cannot use the maximum available braking power.
O.K., but is it a problem?
Not at all. On such a slippery road, a regular motorcycle would risk falling without even applying the brakes. It would be even worse if the brakes were applied.
Moreover, it’s certainly possible to add an anti-lock brake at the rear, in order to use all the braking power of the 3-Wheeler that does not risk falling.
C) Traveling on the snow:
Our new 3-Wheeler has 75% of its weight on the front driving wheels, compared to 40% for rear-drive cars like the Mercedes and Corvettes, and 60% for front-drive cars. So this 3-Wheeler has an excellent potential for good traction in the snow. Moreover, the rider can stand up and lean forward to increase the weight on these front driving wheels, and gain even more traction. Also, if he gets stuck in the snow, he can get up and jump on the seat to press down the snow under his vehicle. If it’s not enough, he can get off and easily removed the snow under his vehicle which is narrower than a car. He can then push on the handlebar while actuating the accelerator that’s on the handlebar, like it’s done with snowmobiles. He can finally simply lift the rear and turn 180 degrees backwards to return where he came from, just like it’s done with a snowmobile except that the rear end is lighter since there is no track underneath.
On the other hand, this excellent snow-traveling capability is not mentioned in the advantages of our new 3-Wheeler.
The reason is simple: During winter in northern regions, roads are often covered with slush: A mixture of dirty snow, sand, road salt and unfrozen water, often about 100 millimeter thick. As soon as our 3-Wheeler will pass another incoming car, its passengers will be covered with this slush mixture. So there’s no possible comparison with the pleasure of going through a white snow immensity on a snowmobile. Furthermore, there is the added risk of a spin when hitting a road side snow bank, as described below.
Here again, is it a problem?
Not at all. Regular motorcycles travel even much less easily on ice and snow covered roads. Our new 3-Wheeler at least offers the advantage of being able to travel at the beginning and end of the summer season, without risk of falling on the ice.
D) Possible spin in extreme riding conditions:
In certain extreme conditions, our new 3-Wheeler could spin.
On one hand, it’s reported in the may, 1982 issue of Road % Track, that: “… our tester noted some wiggle as one or the other driving wheel went hydroplaning during an atypically wet day at the track. We should also observe that he was approaching the Trihawk’s 90+ mph top speed at the time and aiming for the deeper puddles.”
On the other hand in northern regions, it’s known that small and short front-drive cars do more easily spin, like the Austin Mini, Renault 5, Volkswagon Golf, Honda Civic, Pontiac Firefly, Suzuki Forsa…
So what’s the problem?
At ‘high speed’, a deep water puddle or a snow bank that are hit by only one front wheel, generate a longitudinal force against this single front wheel while braking the vehicle.
The longitudinal force applied on only one side tends to spin the vehicle.
Also, there’s a weight transfer towards the front because of the braking. And this causes a weight reduction on the rear wheels, which limits their ability to act as a plane or ship rudder. This is even worse for a small front-drive vehicle that has little weight at the rear.
Thus, there’s simultaneously a longitudinal force tending to spin the vehicle and a reduced capability to avoid a spin.
This explains why these small front-drive vehicles present more risk of spinning. And spinning can be even faster since our new 3-Wheeler has a low polar moment of inertia (around the vertical axis), because it’s a light and short sports car.
And what are the solutions?
1) The front suspension must be designed with a well ‘calibrated’ negative shrub radius so that a longitudinal force on one front wheel pushes ‘adequately’ the handlebar in the opposite direction to avoid a spin.
A positive shrub radius as illustrated on the picture by the (+++) signs, must be avoided. It’s a Renault Le Car (Renault 5) front suspension similar to the Tri-Hawk’s that showed ‘some wiggle’ at 90+ MPH. If a snow bank or a deep water puddle hits a front wheel, this wheel is further pulled towards the snow bank or water puddle. On the contrary, if the shrub radius is negative, this wheel is rather pushed away from the snow bank or water puddle, as it is with a Volkswagen Golf that has such a negative shrub radius.
2) Discourage use of the 3-Wheeler during winter, when it’s not interesting anyway.
3) Recommend being very careful on slippery roads, when there are deep water puddles. And note that slippery roads and water puddles represent a lesser danger than for regular 2-Wheel motorcycles that can slide or where the front wheel may be locked by application of the front brake.
E) Nose diving when braking:
Our 3-Wheeler’s engine is at the front and the vehicle-occupants center of gravity is close to the front wheels that are alone to avoid rollover in curves. So there’s about 75% of the weight on the front wheels, as explained above. Thus, only about 25% of the weight is left on the rear wheel.
When braking, weight is transferred from the rear to the front, which further reduces the weight on the rear wheel.
When the brakes are applied hard and suddenly, the rear wheel of a poorly designed 3-Wheeler could lift off and the nose of the vehicle could dive forward. This could theoretically result in an accident.
Here again, is it a problem?
Yes it may be if it’s not considered carefully, but there are solutions:
The solutions are simple:
1) The center of gravity must be close to the front wheels, but not too close to avoid tipping forward. Better, there should be a safety margin against forward tipping. This margin should be positive in all loading situations that may cause tipping forward. The worst situation could be the case with a light single rider without luggage and with a nearly empty gas tank.
2) Riders must be warned to load correctly their 3-Wheeler and to avoid overloading: Heavy luggage must be placed close to and preferably lower than the center of gravity of the vehicle-occupants assembly without luggage. In other words, the 3-Wheeler must be loaded with concern and be considered carefully like a road motorcycle.
F) Why 3 wheels instead of 2 ?
Many motorcyclists will reject 3-Wheelers because there’s an added useless wheel and they don’t lean in curves. So why keep on trying to use a useless added wheel, further considering that it will cost more?
This question was asked and must be answered correctly.
There’s no doubt that an added wheel will cost more. But the extreme complexity of modern motorcycles, needed to keep the 2-Wheeler light enough to be maneuvered by it’s rider, also implies added costs not to be neglected.
There isn’t any more doubt that an added wheel increases the 3-Wheeler’s width. So 2-Wheelers may always be the narrowest vehicle to go through narrow and crowded downtown streets. But as a counterpart, we can also see that in the case of an accident on the highway, for example, police cars, ambulances and tow trucks will often use cross-roads and even reach the accident site going in the wrong direction on the highway. A 2-Wheeler then offers no real advantage.
As for leaning in curves, it’s probable that potential clients will react the same as snowmobile riders that do not complain about not leaning or leaning little in curves.
Ultimately, it’s the product value in the eyes of future clients that will sell 2, 3 or 4 wheels. Obviously and as explained in previous sections, our 3-Wheel concept benefits from an impressive set of advantages compared to 2 and 4 wheelers.
Thus, as an example and although it may seem peculiar, a regular touring motorcycle nearly doesn’t have anymore room in front of a well developed touring 3-Wheeler with two front driving-steering wheels and passengers sitting astride each other: In terms of safety, in terms of ease and fun to drive, and in terms of practicality with its large luggage space, with its large gas tank, with its parking ease and with its tow ability.
G) Why 3 wheels instead of 4 ?
A 4-Wheeler is more stable in curves than a 3-Wheeler. So why keep on trying to use one less wheel ?
This question was also asked and must also be answered correctly.
As far as stability is concerned, a well designed 3-Wheeler can be as stable as any 4-Wheeler. And compared to 4-Wheelers, our new 3-Wheelers will always be alone to offer the free-air feeling of regular motorcycles with added safety, added comfort and added practicality over these motorcycles.
Some skeptics could still think of other vehicle systems like a 4-Wheeler with passengers sitting astride each other.
Obviously, there must exist other such systems that we still do not know about and that could present other advantages. And it will be great if such systems can someday appear and be useful.
As for now, we can at least consider that in the case of such a 4-Wheeler with passengers sitting astride each other, the vehicle could be loaded more heavily than a 3-Wheeler while offering the same safety margin against rollover. On the other hand, the fourth wheel adds weight, volume and complexity with the necessity to add rear brakes plus a fourth suspension and its fender, which adds more costs.
Moreover as for now, such a 4-Wheeler has to meet the legislation applicable to cars which is more stringent than the legislation applicable to regular 2 and 3 wheels motorcycles.
Finally, such a 4-Wheeler is not as narrow and light at the back as our 3-Wheeler. This 4-Wheeler then doesn’t offer to its passengers, the same narrowness and lightness feeling that motorcycle, snowmobile and our 3-Wheeler passengers get.
Worst, this 4-Wheeler doesn’t offer the driving ease of our 3-Wheeler that has its widest parts easily visible in front of the driver.
Also, this 4-Wheeler does not offer the ability to laterally and manually move the light rear end as it’s done with snowmobiles and our new 3-Wheeler, in order to park in a tight place.
It can also be added that in case of a rollover, that is still possible as with regular cars, the increased width and weight of the rear end have more chances to cause injuries when rolling over the passengers.
H) Why should the passengers sit astride each other ?
Cars have their passengers sitting side by side, including the costliest and most comfortable ones. So why should the passengers sit astride each other ?
This is another question that was asked and should be answered correctly.
Right from the start, it’s obvious that certain automobilists will always prefer sitting side by side. But it’s also obvious that millions of motorcycle, snowmobile and watersled fans have no problem sitting astride.
Moreover, there are technical reasons for this layout:
– As explained in previous sections, it lets the vehicle be the smallest and narrowest, thus offering a more favorable power-to-weight ratio.
– It also offers a smaller frontal area for less drag, higher speeds and better fuel economy, along with more ease to go through dense city traffic.
– Moreover, the passengers sit in the middle of the vehicle so they are better protected in case of side collisions.
And there are also psychological reasons:
– It may certainly look peculiar for many, but sitting astride and closer to each other is no problem at all for others, whatever the gender, or the age, or… On the contrary, it’s an advantage for many, even more so when it’s cold…
– Also, the two riders’ heads are closer to each other when sitting astride. It’s thus slightly easier to speak together on the road, certainly easier than on a 3-Wheeler that has it’s loudly roaring engine right behind it’s two side-by-side passengers.
– For many motorcycle, snowmobile and watersled fans, it’s the handlebar and sitting astride position in the wind, that makes the difference with cars. Whether the vehicle leans or not and whatever road, snow or water surface it goes on, these fans get the same freedom-free-air feeling. With it’s handlebar and sitting astride position, our new 3-Wheeler clearly offers a better potential to generate these sensations, than do the Scorpion, T-Rex, the Cyclone or the G-Max.
Conclusion:
This 3-Wheeler component layout with two front driving-steering wheels and passengers sitting astride each other also has certain disadvantages that should not be ignored, but that doesn’t block its usage as an excellent road motorcycle.