To second
adelorenzo's comments, you should start with the saddle as most everything else falls from there. From what you have said, I think you need to get fit properly to the bike before deciding if this is the bike for you. The Troll is a great ride and I see no reason, unless you are very strangely proportioned, why it wouldn't work for you if adjusted correctly. I ride both a 29er and a 26er and both are immensely comfy, so wheel size is not going to be at the source of your problems.
There are many online sources that give a good breakdown of the process for a simple home fitting. You will need a friend for some of it. I always find Sheldon Brown’s site to be extremely helpful as he also provides links to other sources. Plus he just explains things so well!:
http://www.sheldonbrown.com/frame-sizing.htmlBelow is some basic info. But if you have the cash, I would recommend a professional bike fitting. I have not had one done myself, but many friends have and they all have said it is worth it. Do they tweak things afterwards? Yes. But it got them in the zone where small adjustments are making small improvements on the details. They also learned a lot in the process.
Here is what I do (and I am not a bike expert or mechanic. Some may disagree with certain points)
Saddle height: For mountain biking, your knee should be slightly more bent at the knee at the bottom of the stroke than in road cycling. A good rule of thumb that works for me is to get on the bike in your cycling shorts and shoes (whatever you regularly use – does not need to be biking specific) and have a friend hold it up. Put your heel on a pedal. At the bottom of the downstroke, your leg should be fully extended. Not so much so that your hips rock to that side, though. That should be a more or less ideal height, giving you a bend at the knee when the ball of your foot is on the pedal.
Fore/Aft: This one is a bit more tricky and requires at least one helper, maybe two. It’s the most “scientific” of my process. First, you will need a plumb line (a cord with a weight at the end). I have used nylon cordage and a large lead fishing weight. Get on the bike and have a friend hold it so you are fully seated with hands on the bars. Rotate the pedals so they are at 3 and 9 o’clock (crank arms are parallel to the ground). For the foot that is at 3 o’clock (in the forward position), you should be able to have a friend hold the plumb line on the side of your knee. The line that is drawn from the knee (where the cord falls), straight down, should pass through the center of the pedal’s spindle. Again, one strong friend may be able to hold the bike and do this, but two friends might be easier. Or if you have a stand for the bike, that’s great. But most people don’t. Slide the saddle forward or back to get it right. There is some wiggle room here as I am never quite sure where on the side of the knee I should be measuring from (I usually go with the little nub at the outside top of the tibia).
Saddle Angle: the last adjustment you can make to your saddle is tilt. To some degree this is personal preference, but you want to be more or less parallel to the ground for most saddles. At least to start with. Nose too far down and you slide forward while riding. Too far back and you will experience discomfort in the “taint” region. Some saddles like Brooks are sometimes tilted back, but they are built differently from most modern saddles (some would say better…).
Bars: Ok, now that your saddle height is proper, you need to deal with the bars. When you ride your bike, you have three points of contact – the saddle, the pedals and the bars. These should be more or less balanced with each other for most all around riding. Too much pressure on any point and you will get sore or experience numbness. Plus, when they are balanced, you have some ability to shift weight around during a ride to avoid discomfort over the long term. A good rule of thumb for this is that sitting on the bike, you should be able to lift your hands off the bars and, for a moment or two, support your body weight while still leaning forward. Below gets at how to achieve this balance.
Bar Height: for the bars, you can essentially adjust how high they are and how far you reach to get to them. I would suggest starting with the bars at the same height as the saddle and go from there. I don’t recommend raising the bars above the saddle for mountain biking. Many like them a bit below the saddle. Puts you in a more aggressive position, but may be less comfortable for long rides. I put a level with one end on the bar ends and the other on the highest part of my saddle to get it even and then make adjustments from there. Raising the bars on a removable stem (your basic modern stem, not an old style “quill” stem) usually means getting a bar with more rise (as opposed to flat bar), a stem with more rise, or, if you have extra stem length above the stem, you can move the spacers from above the stem to below it to raise the bars. This requires removing the stem cap first and then loosening the stem bolts to remove. Consult the web for proper tightening of the stem cap when reinstalling if you go this route. Its very basic. If you need to lower the bars, you can move spacers from below the stem to above it, or turn the stem over so that instead of rising, it descends.
Bar reach: How far you reach to get to the bars can have a big impact on back pain (but is not the only culprit – you would be surprised how problems elsewhere result in pain in weird parts of the body). For a mountain bike, if your stem is longer than 120mm, the bike is probably too small IMO. I like mine at 90mm, but I also have a bike with a 70mm stem and extra wide bars. Bear in mind that stem length is also impacted by the bar’s width. The wider the bar, the shorter the stem should be and vice versa. A wider bar is more stable, especially on descents. A narrower bar is better in the climbs and more responsive (“twitchier”) when cornering. But with somewhat less control. Stem length also effects control, though I won’t get into the mechanics of it (mainly because I don’t really understand it well) These are just things you will need to feel out for yourself. But I would suggest just sticking with the bars on your bike and adjusting the stem first.
If you tackle all of that to get in the zone, go for a ride with your tools and start making adjustments. But, and I can’t emphasize this enough, ONLY ADJUST ONE THING AT A TIME! These parts all interact as a system and, just as with science, you have to control for each adjustment independently. It takes some time, but you will also get to know your bike very intimately which, I believe, will make for better riding.
So, get the seat set, then move on to the bars. Good luck!
