Topic: Motorcycle ergonomics

[trueblue]

Does anyone know what to aim for when setting up a bike?  Like what knee angle, forward lean angle, arm angle etc are best.  I've been searching the net for the past few nights but I can't find anything that gives you ratios, angles or anything like that to aim for.  I did find this site :- http://cycle-ergo.com/  .  It is a good simulator, but it seems more suited to someone who is comparing new bikes than modifying an old one.  I don't particularly need a computer program to give me simulations or what have you, I can  work with numbers on a piece of paper, I just need to know where to aim for.

[Retro Rocket]

Gday Blue, the way i found best was to go to as many shops as possible and test ride mate, riding them is definitely the best way to find out what suits you best. I was lucky enough to work in a fairly big motorcycle shop a while back, some bikes are plain uncomfortable, some fit like a glove, you need to ride them though, just sitting on them isn't the same...

[trueblue]

I'm in the process of building a 350 twin.  I'm in working on all the little things I can while I'm off work with my back.  I have been thinking of how I want it set up, I was thinking clip-ons with rear sets.  But sitting on the bike in the position that I was originally thinking, just about cripples me atm.  That's what got me thinking about the ergonomics, also my 650 causes a little lower back pain when I sit on it, I have been thinking about putting slightly higher handlebars on it so I can take the pressure off my lower back a little.  It is stock but the pegs are higher and further back than the 750's, so I was wondering just how high to raise the bars, I'm currently thinking about 2-3" higher than what they are at the moment.  This will straighten my back a bit, but shouldn't raise it too high. 

[Retro Rocket]

Ever considered wearing a back brace..?

[trueblue]

Ever considered wearing a back brace..?

Yeah I have, and I may have to start wearing one yet.  When I was racing pushbikes, I had a list of formulas for setting up seat height, crank length, seat angle, frame top tube length, gooseneck length and handlebar height.  There was different formulas for road, velendrome, criterion, downhill mountain bike, cross-country mountain bike and BMX.  I no longer have these charts/formulas because I haven't raced for a few years.  I am suprised however that there isn't such charts for motorcycles, with the amount of people who ride motorcycles, but it seems most people don't realise how much of a difference moving a component as little as 1" can make.

[flybox1]

How do you know what angle actually works, and feels good for you on an all day ride?  For my 6'5" frame, and 36" inseam, Norman Hyde M-bars and stock foot pegs keep me comfortable for hours. Only by trying different bars, and sitting on others bikes could I come to this setup.

[trueblue]

The way to set pushbikes up is quite well documented in cycling circles, it is all relative to angles.  The angles don't really change that much from person to person, what does change is the distance between your joints.  I was really suprised at the lack of information available on setting up a motorbike and also the lack of understanding on what is required to make the human body work at its peak.  It all seems to be about looking cool.  I know from experience that you can ride over 100km on a well set-up pushbike in one sitting and get off with no pain or stiffness at the end.  Where-as on a poorly set-up bike you can be lucky to make it 10km down the road before you start to feel it.  The same applies to motorbikes, the only thing is people seem to be happy to go with a trial and error method with motorbikes, rather than do some measurements and get it close to the mark with only a little fine tuning required to get it exactly right. 

[flybox1]

"Pushbikes" are set up so that your gluteals, hamstrings and quadriceps can work at their peak.  Aerodynamics and comfort are secondary. 
 I don't think the same setup angles translate, and only on occasion do I scare myself so bad that I have to use my gluteals   

[bwaller]

If you have an idea what seat you like you can always adjust it's height somewhat. I figure the most comfortable peg position is directly under your mass (or ass) this is something the sohc4's didn't do. This peg position is rear set somewhat but not overly so, (probably aligned with axles/swing arm pivot when your on the bike) and 4-5" behind the arm pivot. When you find this comfort zone, pick h-bar height and width. As a suggestion for someone with back issues consider superbike type bars with the pull back that suits. It'll leave your hands at about triple clamp height .

As RR stated try different bikes, then take bar/peg/seat measurements if you find something you find comfortable. This measurement triangle will prove invaluable.

Good luck.

[trueblue]

Thanks bwaller, my 650 has it's pegs nicely under my m/ass, it came with rear sets from factory, but because of my height when I'm holding the bars it causes my lower back to arch a little.  This never caused an issue in the past, but in light of recent events I'm thinking I need to raise the bars a little just to straighten my back a bit.  I used to spend regular long days on the bike, but haven't done it now for about 6 months because of my back.  In regard to the 350, I'm starting with a blank canvas.  If I use clip-ons I have about 2" of fork protruding above the top triple that I can make use of.  I'm not sure how this would relate to superbike bar height.  Here is a picture of me taken with my bike whilst I had Godzilla with me, take into account that I was leaning forward when this photo was taken.