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Benest progressive suspension system

All Benest frames profit from our patented Benest progressive suspension DELTA system. Why it is so complicated, what for so many pivots and how does it work? In a nutshell it is our goal to utilize the positive aspects of, and neutralize the disadvantages of rear suspension. When designing a suspension system there are several antagonistic specifications: Well working non-progressive (linear) suspension systems usually offer long rear wheel travel due to better contact between the tyre and ground (to be in contact with), improved comfort and safety.

DELTA 1: A softer spring is usually used by normal linear suspension systems to "eat" small stones or bumps. (the A angle is relatively small, or we use to say the curve is flat) It is a fairly painful and dangerous experience to ride a soft and short suspension. It can be friendly and smooth, so long as the road is. But you will discover very soon that there is a sudden limit, the end of the shock absorber - the bike is going to kick you. (the susp. unit is not able to absorb all the energy).

DELTA 2: Sure, bigger shocks press the spring with more power, which demands a longer spring and pulls the centre of gravity higher and higher, (generally it is important to keep it as low as possible, while the crossover height is at an acceptable level. It is a sad fact that when crossing slow technical parts you don't need maximum wheel travel and your bike is often too high, and when landing on the bumpy ground you pray not to scrape the crank). And what's more - long suspension travel changes the wheelbase - again a bad influence on the controllability of the bike. Of course you can use a harder and shorter spring, but for linear suspension this means lower sensitivity to small bumps. And there are many occasions when you will miss it.

DELTA 3: The angle is fairly big - the curve is "abrupt". There is a straigthforward difference when sweeping in a smooth curve with a soft or hard suspension. With a well adjusted suspension, wheels can be gently pasted down, copying the surface and giving you essential control. If the suspension is too firmly adjusted (too abrupt angle from the beginning so the susp. unit is not sensitive enough) - your bike will fly from the intended path after any small bump or stone. This is a vicious circle. Sensitivity on small bumps on a soft spring, bigger bumps and kickless ride on a long, soft spring which causes a high centre of gravity and improper bike geometry. Or a harder spring, low centre of gravity and stable geometry - but less control and no comfort on smaller road surface bumps. There are other solutions to this problem but we are sure that our DELTA system is the most credible and exactly adjustable. As you can understand from the pictures we are looking for a system which can offer us a comparatively flat curve at the beginning (soft and sensitive suspension) but pretty abrupt at the end (to absorb the biggest shock on short wheel travel).

DELTA 4: What's more it is very important not to join those two directions too sharply (the suspension must stay smooth and gentle otherwise we cannot call it suspension anymore) So the theoretic curve of suspesion progressivity shall be gently flexed.

DELTA 5: And here we are, as seen on the picture, our DELTA system makes this possible and more. By modification of the proportions of the arms our designers can control the shape of the curve, to tune-up the suspension to fit the demands of each discipline (the dotted line simulates any linear suspension system trying to fit the DELTA curve, just notice where the endings of them are - in other words where the suspension starts to react and at which point it finishes its effectivity).

DELTA 6: The level of progressivity for different levels of stress (the way and the gradation with which the curve bent) was virtually simulated and finally balanced by live tests to use maximum shock absorber travel to offer maximum control, comfort and to eliminate any possible hard end-kick.

DELTA 7: The series of pictures illustrates the point of the DELTA system. One fact which is useful to understand is that the normal spring itself is ofcourse linear. To compress it a certain distance means to use a certain power at any point in the working area. What is the secret? As with most good ideas, the DELTA system works clearly and simply. To simplify the situation we have phased the smooth motion of the swing arm into 9 steps, all of them the same angle. This motion is transformed and progressively scaled by the DELTA system. So the first step pushes the spring a shorter distance than the final one. Putting those facts together explains - the first steps of the swingarm pushes the spring less and in shorter lengths (absorbs fine bumps) and the very last step of identical length pushes the spring a much longer distance so it appears to be harder (absorbs progressively more energy and compensates the end-kick) To put it in another words - from the beginning the curve is faily flat and it fluently reaches the wide angle at the end. There is enough sensitivity, the back wheel travel is shorter and there is no risk of the "end kick." Then the No. of progressivity (P.No.) is representing virtual comparation with linear suspension having simillar sensitivity from first 1/10 of its travel. Biger it is - the curve is more bendet and accordingly more progressive. The level of progressivity for different levels of stress (the way and the gradation with which the curve bent) was virtually simulated and finally balanced by live tests to use maximum shock absorber travel to offer maximum control, comfort and to eliminate any possible hard end-kick.

DELTA 8: The last picture is representing basic comparation of our frames and according curves of progressivity. Levels of progressivity and size of back wheel travel are modified to fit each discipline and to extend maximal performance. You think that now you understand it perfectly? We were trying our best in this article, but I have to say - no way! You have to taste it, to ride it to be clear...


Legend:
X) Back wheel travel (in milimeters)
Y) Shock absorber travel (in milimeters)
1) Freelander 90 (X=90, Y=35), 140%
2) Freelander 115 (X=115, Y=35), 128%
3) Downhill DS120 (X=120, Y=35), 126%
4) Downhill DH200 (X=180, Y=50), 120%

About Benest

Our profile: Benest CZ was founded in the spring of 1996 in the Czech Republic. We specialize in the production of fully suspended bicycle frames, shock absorbers and bike components of the highest quality. Our designers are well experienced in moto-cross reconstruction and tuning. This experience is an essential and principal part of our philosophy.
Materials end technology: High quality materials, the latest well-tested technologies, clear and simple assembly design guarantee unique, excellent, and long-lasting products. At present, we use only chrom-molybdenum steel (SANKO 25CrMo4) for our frames because of its outstanding durability. All our frames are welded and painted by Fort Frames so that the highest quality is achieved. Their expert staff provide welding - the most important aspect of any work with metal profiles. The TIG method is used - the welding is done with an unmelting tungsten electrode by adding material into the stream of inert gas. As reliability plays an important part in our suspension systems too, we carefully select our suppliers of bearings.
Our success: The most precious success for us so far have been results

of Milan Kozár - the Downhill Champion of Slovakia in 2001 and 2002 and in 2003 winner of the Slovak Downhill Cup.

Milan Kozár and many more top riders use our frames every weekend to compete in downhill and dual races in the Czech Republic or elsewhere. We hope that you will join this circle of happy and satisfied users and fans of the Benest frames.

Benest CZ, s. r. o.
U Lipek 616
561 64  Jablonne nad Orlici
the Czech Republic
e-mail: info@benest.cz
Telephone:
+420 603 581 924

dh frames | absorbers | fr frames | photos | more about | info@benest.cz | homepage | česky / czech

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