Bicycle
A list of advantages directly connected suspension, and this design of three structural members linkage front suspension, where the lower ball joint is positioned above the front wheel, have over telescopic forks and independent suspension units; to include: -
1. Efficiency a lack of bouncing when peddling corresponds with no loss of energy. The input the rider applies at the pedals is received at the rear wheel, just like a hard-tail, but now with the benefit of superior grip from the rear tire.
2. Strength and stiffness - in comparison to a conventional steering head, the extra distance between the two ball-joints, with the lower one situated above the front wheel, gives increased strength and stiffness for any given weight of frame.
3. Lightness - the frame construction can be made lighter than conventional telescopic fork designed bikes without a bulky steering head due to reduced leverage from the front suspension members.
4. Lack of complication as seen, with only 14 bearing surfaces whereas the average mountain bike motorcycle and motocrosser has 15 bearing surfaces (they have 2 telescopic sliders, 2 steering head bearings, 2 swinging arm bearings, 6 suspension linkage bearings, 2 bearings on either end of the shock absorber, and, 1 shaft of the shock absorber). Therefore there is a reduction of one bearing surface.
5. Reduced maintenance - fewer bearings, fewer moving parts, and no longer having telescopic forks with potentially vulnerable surfaces to damage/protect. (KTM Motorcycles use the WP PDS suspension system for similar reasons.)
6. Reduced frame pitch - as tested, there is a vast reduction in frame pitch. Stability is superior in all dynamic conditions.
7. Superior front suspension - linkage front suspension systems have been found to give superior suspension action compared to telescopic forks where the rider is now further greatly isolated from the impact of sudden jolts with these designs in comparison to other linkage suspension arrangements.
8. Superior rear suspension - without the use of a mechanical linkage for the shock absorber, the rear suspension action is greatly improved with the impact from the bumps no longer registering directly with the frame/rider. Further, connected suspension reacts to place greater emphasis on the workings of the respective shock absorber, both front and rear, which gives more efficient performance, again improving suspension action.
9. Superior braking nearly all linkage front suspension systems have been found to give superior braking on motorcycle application, i.e. shorter stopping distances. This new design has also been found to put weight onto both the front and rear wheels when front braking force is applied greatly increasing overall braking potential.
10. Increased braking feedback - with the brake caliper mounted onto the member of the suspension that rotates in an arc with the front wheel spindle this increases feedback to the brake lever.
11. Safer Braking with telescopic forks, when applying maximum braking force first load has to be applied to the front suspension before full braking force can be safely applied; now initial braking force acts to load up the front suspension therefore maximum braking force can be instantly applied. This has the secondary advantage of again reducing braking distances. Plus, trail-braking into corners is now safer.
12. Increased feel through the handlebars - it is now possible to design in the amount of feel required by the amount of rotation there is with the handlebars and how close they are positioned to the upper ball joint, plus retain superior front suspension action. Telescopic forks had the advantage of superior feel compared to other linkage front suspension systems, but now with this design the feel is amplified. There had been a paradox with telescopic forks where stiffer suspension action gave greater feel but now feel and suspension action are separated where superior feel and superior suspension action are both possible.
13. Lighter steering - there is the possibility of steeper steering head angles which will offset the effects of the greater polar moments of inertia associated with the forward front pivot point being so far from the line of the steering axis. Reduced structural strength is possible with these members where this pivot and members can be made of lighter construction.
14. Reduced diving during braking - the suspension can now fully function with only a minimum of dive during braking of the front wheel; enough to ensure increased front tire grip and perform like telescopic forks but not an excessive reduction of suspension travel. The amount of braking suspension dive can be determined at the design stage.
15. Shorter wheelbase - with the stabilizing effect from fully connected suspension it is now possible to have a shorter wheelbase to benefit overall handling, cornering, weight saving, stiffness and strength. Directly connected suspension gives a natural anti-wheelie aspect to it, which dictates a shorter wheelbase be used.
16. An automatic altering of the suspension ratios for cornering and straight-line traveling - when cornering forces act to compress the suspension, with the outward end of both shock absorbers allowed to move by means of the respective opposite arms this alters the suspension geometry where it is now possible to gain more ideal settings for different dynamic conditions.
17. An automatic altering of the suspension settings under braking when braking forces act to compress the front suspension this can alter the rear suspension leverage ratio to a lighter setting where the possibility of the rear wheel kicking under braking is greatly reduced. On motorcycles internal damping settings have been designed to do this with conventional systems but the spring rate remains unchanged therefore it is relatively ineffective whereas now the entire geometry can be beneficially altered. As a side advantage rear wheel braking is improved by this. Likewise, the front can be configured to give a stiffer setting under braking therefore perform better and dive less.
18. Superior suspension action on square-edged bumps the system was designed specifically to combat this menace (for motocross and mountain bike racing), in particular the dynamic conditions leading to the rider being thrown over the handlebars, where this could be considered the design's forte.
19. Reduced impact from heavy landings with both ends of both shocks being compressed together on two-wheeled landings this gives a higher rate of compression with the shock absorbers, i.e. stiffening up automatically on heavy landings. The actual amount of travel will be reduced slightly but it is at a much stiffer ratio. Further, there is no direct connection to the frame where the forces do not directly impact on such.
20. Lateral flex can be easily designed in at the design stage, control over lateral flex is now easier to regulate where the ideal amount is now achievable for the given circumstances. The actual design of telescopic forks made it difficult to calculated and achieve the desired amount of side flex. (With road and race motorcycles the yokes are designed to give lateral flex.)
21. Aesthetic pleasing one of the visual appealing benefits of telescopic forks is riders can see the connection between the handlebars and front wheel. This remains the case with this new design of linkage front suspension where the visible connection can be emphasized, if required, solely for design and style purposes.
22. Mass centralization with the main weight from the suspensions (the two shock absorbers) positioned close to the centre of the bike, opposed to the bulk of a substantial steering head and telescopic forks being so far removed from the centre of gravity, benefiting maneuverability. (Honda currently pursue this theme for a handling advantage with their MotoGP bikes and new sports bikes such as their motocrossers and Fireblade etc, giving their bikes reduced polar moments of inertia to benefit handling and cornering.)
23. Lower centre of gravity again benefiting handling plus giving the impression of the bike feeling lighter than it is for any given weight.
24. Geometry which beneficially changes with the dynamic conditions with telescopic forks the rake trail and wheelbase decrease dramatically under braking making the bike less stable therefore these have to be increased from their optimum setting making overall steering heavier than it should be, whereas with the new design of linkage front suspension is it now possible to get optimum settings for different dynamic conditions.
25. Aerodynamic advantages with the design of bicycles and motorcycles about to change with these new designs this will open up new possibilities where it may be possible to get an aerodynamic advantage.
26. Rising rate front suspension just like the rear suspension there is now a superior rising rate suspension at the front instead of linear telescopic fork action. (Some telescopic forks use progressive springs to achieve this but such offer limited potential.)
27. Increased rider confidence with so many advantages plus weight savings and an all round reduction in any sudden movements when travelling the rider will benefit psychologically from these new suspension systems.
28. Less rider fatigue superior suspension has less impact transferred to the rider plus less pitching motion of the frame thus giving a less tiring ride. A massive advantage for winning any race whatever the discipline, and, ensures any travelling is more comfortable/enjoyable. And, of course, now there is now no energy loss when peddling leading to the largest possible advantage when cycling for fun or racing.
29. Reduced compression of the bike during cornering both outward ends of the shock absorbers displace to extend the opposing suspension, an advantage for increased ground clearance that can be transformed into an aerodynamic advantage and possible handling/maneuverability advantage.
30. Familiar feeling riders are now accustomed to the feeling of telescopic fork designed bikes and now it is imperative a similar feeling prevails, which is the case here. The present prototype mountain bike is designed to dive a little at the front under braking just like a conventional design. (Alternative suspension systems such as BMWs Duolever suspension had test riders mention a fore and aft motion which they found unsettling.)
31. Reduced spring resonance with two spring units operating against each other at different frequencies this reduces the possibility of spring resonance having a prolonged effect on suspension action - i.e. dampening out any bouncing motion.
32. Greater stability/more predictable over jumps the risk of nose diving over jumps is reduced as the front suspension extends on take-off and the rear suspension compresses giving a level or upwards flight-path for the frame/rider on take-off.
33. Suspension that alters its settings for up-hills and down-hills the suspension can be so configured to automatically give stiffer front and softer rear on down-hills, and, softer front and stiffer rear for up-hills, benefiting both riding conditions.
34. Lighter suspension settings reduced compression and rebound dampening can be used to the benefit of suspension action. Such has less energy absorbed by the suspension and is felt by the rider as superior propulsion. It also assists reduced tire wear.
35. Settled suspension the effect of the chain pulling on the suspension/drive members no longer causes a rocking motion as the center of gravity wants to marginally lift which reduces any potential for back and forth rocking motion from the interaction of driving and suspension forces, thus wanting to find an equilibrium of forces.
36. Reduced unsettling motion from loading and unloading of the suspension in quick succession in circumstances such as a chicane where the suspension is loaded unloaded and then loaded, as the suspension has initially compressed less it has then less travel/weight to unload then recompress for the next dynamic condition.
37. More fluid suspension action telescopic forks, and in particular Telelever (used by BMW and others) have a degree of binding action between sliding members, whereas now with pivot points and a small shock absorber shaft with reduced bearing surface such is greatly reduced.
38. Greater design freedom without a bulky steering head and substantial connecting members bicycle design can radically alter for the better.
39. Greater longitudinal stiffness with the three main suspension/frame components in a more direct line such gives greater stiffness for any given weight and aids handling and braking.
40. Greater scope for differing rider weights with directly connected suspension spreading rider weight over both wheels such allows the suspension to accommodate differing rider weights over a larger range.