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Let's assume the following saddle heights:

  • ultra low (bmx, DJ)
  • low (slopestyle)
  • medium
  • high
  • ultra high (XC)

In videos on the internet we sometimes see pro DH riders riding with a medium to high saddle height. I understand that this needs experience and works for them because on some ocasions they may control the bike by pressing on the saddle or something like that.

But how can they absorb impacts from 5 (or more) feet drops? Either drops to flat or drops with a bit of a transition.

My problem is that even when my saddle is at low to medium position I'll sometimes crash my b@ll@cks when trying to absorb landings. So I either:

  1. decide not to absorb anything and let the bike (suspensions) handle it, or
  2. absorb a bit by leaning my back (humping) which is obviously super wrong and dangerous and has already caused me some lower back pains

Any ideas on how they do it and whether [1] is the key on those situations?

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Professionals drop the seat to avoid the crushing: youtube.com/watch?v=Cj6ho1-G6tw :-) –  Rory Alsop Feb 22 '13 at 10:36
    
@RoryAlsop: I'm talking about downhill (youtube.com/watch?v=jFxzprY7iM4) and not trials. –  cherouvim Feb 22 '13 at 11:16
    
Trials, BMX-park, racing, DH, going to the store, I keep my seat at my knees while standing in my pedals. I like the extra control you get in cornering and such when you push your leg against the seat. I have been riding BMX Freestyle since 1987, park, street, dirt, ramps, dropping off roofs, and have had lower back pain, but never from dropping, almost all from sleeping weird. The only time b@ll@cks were EVER an issue was when I jumped and hit the backside of a landing, and that really has little to do with seat height (I hit it from the back). Maybe its to do with HOW you are absorbing? –  BillyNair Feb 23 '13 at 23:40
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3 Answers 3

I always thought that a low saddle height was used in BMX because there is no suspension so the legs have to absorb all the impact whereas on a downhill bike the massive suspension should mean the legs need to absorb very little. I am not a regular downhill rider but have done it occasionally and I think that letting the suspension do the work is key. Although if you are crushing your under-carriage into the saddle it does suggest that something isn't working right. Maybe by releasing the pressure on the bike (pedals) by trying to absorb too much of the impact you are stopping the suspension's natural dampening.

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Low seats on a BMX came about because you don't sit down to ride, unless you are going to 7-Eleven, but seats are required in competitions. I used to take the seat off my bikes and just duct tape padding around the seat tube so you don't stab yourself. In BMX, the seat is more or less protection from the seat tube and something to sit on between runs. And no seatpost, or shorter seat posts saves weight. –  BillyNair Feb 23 '13 at 23:54
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If you're banging the boys against the seat even when it's low, it's the result of poor technique. The pros are using a of proper technique in conjunction with their suspension.

Unfortunately, it's very difficult to learn proper technique riding a full suspension bicycle. The suspension does the work that proper technique should be doing and you just never need to learn it.

It's not a technique that I can explain either. The best I can explain it is that you land in sort of a pseudo-manual and then simply set the front end down. The best way to learn better technique is to ride a fully rigid bike for your DH, street, etc. for a while. It's learned through muscle memory more than any cognitive process. When you land rough, you feel it in a way that you don't on a full suspension. After a few dozen rough landings, your muscles start to react and the landings start to smooth out. All of the sudden one day, you take a big drop on your rigid bike and the landing is fluid and you don't feel a thing.

I know that getting an extra bike just to learn better technique is not a cheap solution, but it is the best one that I know of.

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I suggest you go back to the beginner DH trails if you do go ahead with great suggestion. –  mattnz Feb 23 '13 at 8:16
    
This is terrible advice. Hardtail riders have to do this in order to make use of their full leg extension (i.e. their legs become the suspension), their weight goes backwards to make the extension more vertical, and conversely the front of bike is pushed forward to maintain balance. Doing this on a full susser will quickly SNAP THE FRAME! You must land with both wheels at the same time so the suspension can do the work for you, and the forces are distributed through the frame as the designers intended. There is no 'proper' technique for both frame types - because they too different. –  cmannett85 Feb 23 '13 at 9:47
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The pros you see on the videos set their saddle depending on the DH course. If the course has a lot of possibilities for pedalling and not many drops - set it high, so on flat sections they can rest their bum on the seat and give it a full pedalling power.

If the course is rough and steep - no racer will have the seat high. So you should do. You know what you are riding, you know that you are going to do drops - set the seat low.

And leaning back is not always wrong. As long as you don't overdo it and don't send yourself flipping backwards. It all takes practice and time.

If on the drop you let your suspension handle it all and keep your legs straight - at some point suspension will bottom out and shock through your straight legs will go into your spine. And that is a direct ticket to spinal injury.

So the best is to learn to to do a bit of both - work your legs and let the suspension do work as well. If you feel that the landing is going to be rough - move yourself to the side a bit, protect your groin, take the hit with your thigh. You might crash in that case, but your kids will be happier -)

And one more thing, in DH drops to flat higher than 5 feet are very rare and are considered dangerous. It's not trails for you, where guys carefully absorb 10ft flat-drop with their whole body. On the other hand, drops to transition do require different technique (comparing to drop to flat) and give less stress on a bike and a rider.

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+1 This is the correct answer. There are sometimes >5 ft drops on world cup courses, but they are always at the bottom of the course (where the crowds and cameras are) and are usually man-made. –  cmannett85 Feb 23 '13 at 9:49
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"If you feel that the landing is going to be rough - move yourself to the side a bit, protect your groin, take the hit with your thigh." - That is EXACTLY what I have done to keep myself safe and to have kids! A slight twitch of the hips is all you need! –  BillyNair Feb 23 '13 at 23:42
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