Four Wheels Velomobile Working Suspensions.

Quadri-mobile project.
http://www.amidesign.ch/en_hpv-velo-mobile.htm
In July 2008, I decided to build a quadricycle.
It is very hard to design the front axle suspension and steering. The front suspension is a parallel double wishbone. It achieves a constant track.
It is a big challenge to make a fairing on front wheels and assume the steering.

Category:

Autos & Vehicles

Tags:

• Recumbent bicycle
• recumbent trike
• recumbent
• velomobile
• velomobil
• trike
• quadricycle
• pedal car
• HPV
• vehicle
• streamliner
• homemade
• fairing
• disc brake
• blender design
• sprocket
• double wishbone
• 20 mm thru axle
• Blender.org

[TheGr8scott]

Please tell me how you made that animation. I am working on (in my opinion) a far superior suspension system and it is messing with my head. I have got a working prototype but i need to see it in action. My idea uses one single suspension arm on each of the front tyres, in front of the suspension arm which will be a Cannondale Lefty MTB shock will be a drive shaft, this will run parallel with the shock. With the 26 inch by 3 inch tyres this will give me 26 inches of clearance.

[amidesign]

@TheGr8scott Hi, I realized this video with "Blender" software. It is a free open source 3D content creation suite.

Best regards.

Aleksander.

[Jesus45U]

Biggest problem is that suspension is generally heavy, and bicycles/tricycles work best is they are as light as possible.

So far, the most efficient version of front suspension on a trike I have seen, is basically make a very wide U and fit both front wheels to the vertical part of the "U", using them as kingpins with springs over them.

It's very much like a MacPherson Strut suspension.

The advantage is both frame, steering & suspension is one unit, which saves weight.

[amidesign]

@Jesus45U

Tank you for your comment

My work on the four wheel velomobile is each day a race to save weight

Now for the first prototype I took the decision to do not have any kind of suspension

The velomobile is lighter but can not be driven on bad roads ...

Aleksander

[amidesign]

Hi, you have right, I do not design the steering mechanism

I have to study this problem to conserve correct toe angle

With this architecture I do not need anti-roll bar

In fact the rear suspension is not independent

It has only one axle and one shock absorber

In other hand, now the project uses four independent suspensions

But with only plus and minus 11 mm vertical displacement

An inch vertical total wheel travel

Tank you for your comment

Best regards

[Samqdf]

@Jesus45U @Jesus45U couldn't agree more, I use a 24T front + 34T mountain drive rear and a 19" wheel on my trike, so I have some good range. That's one of the neat things about our kind of bikes, we can go as slow as we want without having to balance

[Samqdf]

@Jesus45U couldn't agree more, I use a 24T front + 34T mountain drive rear and a 19" wheel on my trike, so I have some good range. That's one of the neat things about our kind of bikes, we can go as slow as we want without having to balance. I look forward to your next video

[Jesus45U]

@Samqdf

Yeah, when I go serious mountain bike crawling, I will also lower the tire pressure.

But then, my speed also drops to a pace, where the added drag is insignificant.

Some of us use the lower 5 gears, y'know ? :)

[Samqdf]

@Jesus45U yes very well said. A nice seat is under-rated and the same concept is used in almost all trucks to stop driver fatigue, they use an air suspension seat. The other option is to run large diameter tyres such as 20 x 2.5's and then lowering the tyre pressure when needed. I for traction reasons run about 15psi in my 19 x 2.5" creepy crawler when doing slippery off-road. The catch is of course extra drag but I guess you can adjust it for the type of riding your doing on the day.

[Jesus45U]

@Samqdf

Yeah, the increase in center of gravity is an issue, which is another part of why you often end up having an easier time making a strong frame with a low center of gravity, than a fully suspended frame.

Hence why I usually go for a good seat instead of a real suspension, since most roads aren't that uneven, ad to really need a suspension in the first place. A nice foam seat with come gel pads, can go far towards a comfortable ride.

[Samqdf]

The other problem I have found with most trikes nd now a quad that has front suspension is that the rider ends up sitting fairly high and hence a high CG. As always it's a compromise as if the double A arms are brought closer together the leverage forces on the frame drasticly increase, then back to the weight thing again. Anyway that aside amidesign please keep posting videos.

[Samqdf]

@Jesus45U if you have a low conrol arm linked to the bottom of the strut then you can just make the steering arm parallel to that, problem solved. However if it's just a sliding arrangment then it's a matter of picking your compromise. I would love to give the front suspension concept a go to see how light I could make it however I also have something very complex in the works, it's 3X3.

[Jesus45U]

@Samqdf

I partially agree, getting the forces centered is advantage, but I find it's often easier to build a simpler and stronger structure and make it lightweight, than one that is complex like a suspension would.

As for the bumpsteer, that's entirely a question about getting your angles and linkages right.

A simple McPherson suspension can have as little bumpsteer as a parallel a-arm suspension.

11 years of driving and building semi-professional RC cars taught me that much.