A trail mountain bike is a robust bike that can be rode in various different types of terrain.they are designed for all day rides where there is a lot of pedaling up and down hills and through trails.so a trail mountain bike is designed to be rode in technical rough terrain fun to play on flickable a nimble bike that really gets you around the woods comfortably.most trail bikes are centered well so they go up as well as down.there riding position is comfortable because these bikes are designed for those epic all day long rides so they have to be comfortable they are just a well rounded bike that is good for about anywhere you want to ride them.
FULL SUSPENSION OR HARDTAIL
Hardtails are a good choice for beginners or for those that just like hardtails. they have really good pedaling efficency and are a good bargain bike.for a smoother ride I would go the extra for full suspension if you like small jumps and drops or just like to go fast downhill the full suspension is a lot smoother ride and smooths out the bumps a lot better.to me full suspension is the only way to go in my opinion the ride characteristics are so much more stable and to me it gives you more confidence because of the stability.and you know you have some cushion there.
HOW MUCH SUSPENSION TRAVEL DOES MOST TRAIL BIKES HAVE
Most trail mountain bikes usually have between 120mm and 130mm rear and 120 to 130mm front some have 140mm that much travel provides a good pedaling platform because these bikes are designed for long trail rides with a lot of pedaling up steep trails and down. you really want a good pedaling platform because when you are logging in the miles you want the most efficient pedaling platform you can get.
Geometry on a trail mountain bike tells a lot about how the bike will handle.bikes that are designed for trail will usually have a head degree angle of 66 to 67.5 degrees.the more head degree angle the sharper the steering which means it will turn a lot quicker.but when you go downhill it tends to be more jittery or nervous 66 to 67.5 seems to be the right angle to minimise this so it is great for trail.especially when the trail is steep or technical it gets you around better.Seat tube angle is something to consider 74.5 to 77 degrees is really good because it puts you more centered over the cranks that gives you better pedaling effiency.Standover and reach is something to consider.standover is something you need to know before you buy.first you need to measure your inseam from the middle of your inseam to the ground this will tell you what to look for in standover.standover on a bike is measured usually from the middle of the top tube to the ground most manufactures have this in the geometry section.Reach is measured from the seatpost to the front of the headset or gooseneck and that changes slightly with height of the seat 450mm for a medium and around 470 mm for large usually makes for a comfortable ride for most.
TRANSMISSION OR GEARS
Most trail moutain bikes the higher end ones around 2000 and up come with a 1×12 gearing personaly that is all I would go with to me that seems to be the best for the trails.they usually come come with a 30 to 32 front and 10 or 11 through 50 or 51 rear.in my opinion this is the best you can do right now for gearing especially for trails.they usually come with shimano or sram trannies sram comes with different type depends on what you want personally I like the eagle setup but shimano is a very good setup that I have used for years.so for which ever setup you choose if you choose sram or shimano you will have a good setup that should last a long time.
Well we have covered the basics of what to look for in a trail mountain bike and what it is designed for.I reccomend that if you can go to a bike shop and demo some different bikes and see for yourself what fits you the best but for a lot of us that is not possible so we have to look over all things very closely before ordering.I myself wished I had known the basics of what to look for when I first got back into this sport.I have outlined the basics here to show you what to look for in geometry and suspension in a trail mountain bike.there is a lot of good brands to choose from to name a few Devinci,Ibis,Pivot,Nukeproof,Yt there is a lot of other good brands out there.I hope this helps you on your path.one more important thing is to take account of where you are really going to be riding and this will help you choose your suspension and geometry platform better. Thanks Dave.