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View Full Version : Rider ergonomics explained... LONG



Derrick Adams
01-20-2008, 12:44 PM
I thought it would be a good idea to write down some information on basic set-up for your machines to fit your body. Jason and I spent a lot of time working on this last winter while building my bike, and weíve had real good results with it. This is general information that anyone can use to make themselves faster, safer, and more comfortable on their machine.


First I would recommend removing the foot pegs and handlebars. Set those aside for later. Place a block of wood or floor jack under your lower frame with a 2x4 long enough to simulate foot pegs. The theory here is that when you sit down, the frame will rest on your jig, but if you stand up on the 2x4 the frame will rise off the jig allowing you to move the bike under you. Once you have that set-up, you want to sit on the seat where your body feels most natural. Keep in mind that you want your weight to be as centered on the bike as possible. Now move your foot peg jig forward and back until your body position is most comfortable where youíre sitting. This is where you want your pegs to be mounted. Also check that when your in the front pocket of your seat that your legs arenít cramping or difficult to move in and out. (this will ultimately be where youíll spend the most time on the seat so free movement is very important). Mark your frame rails where your pegs should be for future reference.


If you donít have access to a welder, then you may be limited to your stock foot peg location. If you can weld or have access to a welder, now is the time to build some foot peg mounts to locate them where youíve marked. I would also recommend at this time that you upgrade your stock pegs. Most of the original pegs are bent, worn, or just too weak to hold up to hard riding any more. Weíve found that the TRX450R pegs are very nice upgrades with wide platforms and deep teeth. If you watch E-bay you can pick these up for around $15 shipped. For Motocross set your pegs as low as possible on the frame. This will help keep your center of gravity low and make the bike corner much better. For a trail rider, raising them up an inch may help with ground clearance.

Now that you have your peg location and your body comfortable on your bike you can set your handle bar location. What youíre looking for is that your body is comfortable while sitting and standing. Weíll come back to sitting later. For standing, what you want is to be able to stand up on your bike with out being hunched over (this may not always be possible but get it as close as you can) and your arms straight. The theory is, that your body and machine will be much easier to control in the air and on the ground, while standing up if youíre in a natural position. This will always lead to safer jumping and less rider fatigue. So holding a set of bars in your hands, where is the height comfortable while standing? It may be right on while they sit in the cups on your triples. If they feel to high (your arms are bent while standing) then you need a lower rise handlebar. If your arms are straight but the bars arenít touching the clamps then you will need taller bars or bar risers.


Along with handlebar height there are a couple other choices you have available. First is the degree of sweep that your bars have. Iíve seen bars from 10 to 14 degrees. This allows you to set how your wrists are angled while riding. This is an important adjustment for rider comfort. Everyoneís opinions will be different on this, as it is mainly feel and riding style. Too much bend can put your wrists in a bind while turning tight, and wear on your wrists. Not enough bend makes it more fatiguing while riding in a straight line. The other is distance from your seat location to the bar clamp (forward to back). This is a critical measurement that unfortunately most of us canít adjust, unless your lucky enough to be building new triples. If you are taller than average, this will most likely effect you most, as you need this location further forward. If your clamp location is off, it can cause your bars sweep to curve up or down as you rotate them which can cause wicked angles on your wrists. There are some bar risers available now for taller riders which locate the bars forward and up. For those of you that are short, you may not be as lucky.


Ok, lets get back to bar location while sitting now. This is an area that is debatable. Hereís my theory, based on my own experiences. I think that excess height of your bars while sitting can cause serious rider fatigue. I think this is adjustable only by seat height. I came to this conclusion after spending some time on the newer 450 quads. Basically what happens is, your arms tend to pump up more from hanging low off tall bars. This (in my opinion) explains why the seat height is so drastically tall on the newer machines. I have no real way to measure the correct height of bars to seat, but I can argue that seat height to handle bar height is very important.


I used to be of the mindset that a lower seat height would make the machine much more stable while riding because your center of gravity is lower. Iíve since changed my mind on that. My argument is that while riding aggressive you never tend to be on the seat anyhow (turning and jumping), and that a proper seat height to handle bar relation assists in transition from setting to standing, hence reducing arm pump and fatigue.


This is all my opinion based on my experiences. This is merely a guide to those looking for answers. If you donít agree with it, donít try it. If you have contradicting information, please post it so we can discuss it. I really hope this helps some of you improve your riding experience.

SWIGIN
01-20-2008, 01:01 PM
yup, i agree 100%

a quad is easyer to set up since the stem can be made longer or shorter too.

on my trx 350rx i like pro pegs with a plus 2'' back 1'' stem with my low profile tap fatty bars