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Old 09-09-10, 05:29 PM   #1
Zephyr11
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First time at a BMX track

I'm coming from a mountain bike background, and I've messed around on a BMX bike before, but this was my first time at an actual BMX track. It was just practice, not racing, but I had a lot of fun with it. Anyway, I had a question. One of the stretches had a tabletop that was high enough that I was losing all of my speed over it. I'd come out of the turn, pedal for all I was worth, suck up the face of the jump...yet still lose all my speed. The next time I tried jumping, but again, by the time I got to the lip, I lost pretty much all my speed, so I got all of two inches of air and landed on the top with no momentum. I watched some of the better riders do it, and they sucked up the face, pedaled across the top, and then pumped the backside, but even trying that, I still slowed down to a crawl for most of that straightaway since I would lose speed and not have enough time between jumps to regain it (and I do realize ideally I'd be pumping and gaining speed over the jumps, but hopefully that will come with practice). I'm not sure if they just carried more speed into it or if they did something completely different or what. I'm sure most of it is needing practice, but I'd really like to figure out what kind of technique I should be using, and then practice that technique, rather than practicing something inefficient. A couple people mentioned that it would be easier if I were using a race bike rather than a freestyle bike, but I'm not so stupid as to think that the bike is the problem. Any ideas on what my problem is here? Thanks!
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Old 09-09-10, 06:30 PM   #2
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When I first started I had problems like that. After a few times watching and going around you start to get it. Personally I try to go as fast as I can before I go up it, pump, and keep my bike on the ground unless I can jump and clear it. I found that clipless pedals help a lot.
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Old 09-10-10, 02:50 PM   #3
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Go faster. I've only been to a track three times, but by the third time I was over that problem. For me it wasn't one jump necessarily, it was just certain spots that I couldn't hold my speed through and I wasn't really going as fast through the berms as I could. Try to focus on a better line through the berm to hit the jump faster. For me it was just a combination of nerves and inexperience. The jumps kinda freaked me out so I was subconsciously not willing to ride as fast as I can. I can go faster now and I'm finding myself hitting the brakes before the big doubles and stuff cause I'm going too fast to roll over but I don't think I'm ready to actually clear the jump. Really wanna get back out to a track...
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Old 09-10-10, 05:33 PM   #4
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Thanks for the tips. I'll try going into it with more speed, which probably means I need to experiment with different lines through the berm, and then pumping it. I'm not hitting the brakes or anything, but I am losing some speed in the berm.

I did see a lot of people using clipless pedals. I figure I should start with platforms so I don't cheat like I do on my mountain bike, but probably something to consider sometime down the line.
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Old 09-28-10, 12:11 PM   #5
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I'm pretty much in the same situation. I started BMX racing with my son just a few weeks ago. never done it before. I've been paying close attention to the other races and picking the brains of the other guys in my moto.

For a tabletop, It's been suggested to "pre" it. (I believe that "pre" is short for "pre-jumping") That is, loft the front wheel up far enough that it just clears the top of the jumps face. The front wheel should then set down on the top of the roller. What this does (in theory) is reduce the magnitude of the backwards force on the front of the bike.

This seems to jive with what I can remember from high-school physics. When you're rolling along on a flat surface, you're got rolling resistance (friction at the tire/track and bearing surfaces) and wind resistance. When your wheels encounter a bump in the track, a force containing backwards and upwards components is imparted to your bike. It's those backwards forces that slow you down. By "pre-jumping" you minimize the backwards force by lofting your wheel up and over the face of the jump. Your rear wheel will still experience that force as it encounters the face of the jump, but you've reduced the bump force to the front wheel).

Then you suck up the face and keep pedaling. Lather, rinse, repeat.

I'll also see racers manualing through a series of rollers/jumps (called a rhythm section). This uses the same principle of the "pre-jump".

BMX racing is all about technique. So practice makes perfect, I suppose.

I'm a loooong way from perfect!

good luck!
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Old 09-28-10, 12:17 PM   #6
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Tabletops are meant to be jumped. You are not going fast enough. Look at the gearing you have and crank length.
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Old 09-28-10, 07:04 PM   #7
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It seems to be working a lot better when I have more speed going into it. I still can't clear it, but I don't slow down so much on it.

i_r_beej, thanks for the detailed explanation!

Dr. Banzai, I'm using a freestyle bike, so I'm sure the gearing isn't ideal. I think it's 28x10, but I'd have to check to make sure (although that should be the same ratio as a 44x16, shouldn't it?). Crank length is 170, which is a little short and I think I'd be happier with 175's, but that's what the bike came with and I haven't bothered replacing it. If I need more speed, I'm sure it's much more technique than the bike.

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Old 09-29-10, 12:29 AM   #8
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Quote:
Originally Posted by Dr. Banzai View Post
Tabletops are meant to be jumped. You are not going fast enough. Look at the gearing you have and crank length.
Not really. Manuels work just as good. The only time I see people jump tabletops in races are the pros and some experts at my track.
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