Hello everyone. I rode my bike a ton when I was a kid, but when I turned 16 it was thrown to the curb. I now would like to get back into biking. I just turned 40 and I am in good shape (5'10", 155#), I work out on a regular basis. I still have a Giant Sedona mountain bike from 1991 that I occasionally ride around. I plan on riding on bike trails: paved, gravel and dirt. In fact, I am going to ride the 400 and Elroy-Sparta trails next weekend.

I have several questions. First, do I need a new bike or is my 1991 Giant Sedona adequate? Second, I have been struggling with the fit of the bike. I realized, after reading a blog, that after all of these years of riding the Giant, that the seat had been set too low and that perhaps the seat was also too forward? I read several blogs and am having a difficult time getting the fit correct. With the pedals at 6/12, My knee is slightly bent, but when I do the elbow to stem test, my finger only reaches the bottom of the stem. Additionally, I believe that my knees are over the center of the pedal (recently had knee surgery). Somehow though, I find my self constantly changing my grip so that I am holding the bar with my fingertips, which leads me to believe that my seat is too far back or that my bar is too low? I just can't figure it out.

Thank you in advance for the advice.

Welcome to the forums.

Honestly, anyone answering your fit question is 100% guessing.
Can you do a side profile picture of yourself sitting in riding position - preferably pedaling through the frame?

That said - the recommendation is still going to be to stop at your LBS and just ask them to help you out - throw it up on a trainer.

As for your other question - if the bike works, then your bike will be fine on any of the indicated surfaces. It will not be optimal for all three, and with a front suspension will certainly not be fast. Whether it works for you is another question - my suggestion, get out there and ride. If you have the cash, see what they have at your LBS. If you don't, look to make sure your bike is operating efficiently, mechanically, and possibly get some tires (at the least) to suit your intended terrain.

Since you already own a bicycle, I'd suggest starting with what you have. Every time that you ride, make a mental list of what you like about your Sedona and of the things that you hate. Don't be afraid to tinker with your saddle and handlebar position - you can always move it back the way that it was.

If you do that for a little while, the decision to buy (or to not buy) a new bike will be easy. You will also be much better prepared to make an informed decision about whatever new bike you choose to buy.

Retro Grouch gave you good advice. I strongly suspect that a new bike will give you more riding pleasure and you won't regret it.

Take your bike to a bike shop and get them to give it a good service, then help with a bike fit, even if only basic. If your old bike is broken in some way, and honourable shop will tell you.

Knee over the pedal spindle is a theory that was discredited back when your bike was new. It's still used by some fitters, even professional ones, but it means nothing.

To get your saddle height right, sit on the bike and put your HEEL on the pedal - if your knee just straightens, you're pretty close to right. It doesn't hurt if your saddle is a little low, just not too much.

The stem test doesn't really mean anything either. Base it on how comfortable you feel, the trouble being that you need some miles under your wheels to get your body used to cycling. You adjust reach by changing the neck (that holds the bars), not by shifting the saddle backwards and forwards.

You move the saddle to give you balanced position on the bike. For the moment, just put it in the centre of the seat rails.

You change the height of the bars either by moving the neck up and down the bars or buying a new neck. You can buy adjustable necks which can be useful. If you're lucky enough to have a bike with a quill stem, you can loosen the bolt at the top and slide the whole thing up and down - the bike shop will help here.

Constantly changing your grip is not a bad thing, it just means that you're varying the pressure on your hands and changing the angle of your back. It's all good and is why so many of us prefer drop bars because even on the top of the bars, you have a lot of hand positions to choose from.

Basically though, get your bike sorted out by a mechanic, get him to give you a basic bike fit, then ride the wheels off it. Eventually you'll know whether you want/need a new bike, but I'd give it six to twelve months. Equally, some never replace the old bike.

Flippin' dog biscuits, there were no replies when I started mine, now I'm fourth in the rank

Go to a shop and test ride a modern bike. The thinking around geometry has changed radically in the past few years. Bikes from the 1990s typically have short top tubes, long stems, and big saddle-to-bar drops, all making for a fantastic over-the-bar experience . Try a couple of newer bikes at a shop. See what you think. Also, a shop can help you sort out your bars and other fit issues. There's nothing wrong with an older bike per se, but it's no fun riding a bike that doesn't fit comfortably.

If the Giant has knobby mt bike tires, for trail riding you might look for some "gravel" tires for it.

Just make sure your bike is in good mechanical condition, it should be fine.

Then is you find cycling is something you really want to do on a steady basis, and only then a new bike may be in order.

Thank you for the advice everyone. Good stuff. The bike does not have shocks though and I did replace the tires 10 years ago with tires that are smooth on top and have knobs on the sides. They do pretty well I think. I will definitely move the seat forward if it has no bearing on knee safety. After moving it back to make sure that my knees were over the middle of the pedals, I do feel like in am leaning back too much. Thank you again.

Your seat is too far back, and your bar is too low. Get the saddle centered fore-and-aft on the post, and pull the stem up.

If the mechanicals are in good order, a '90's rigid MTB is a good re-entry bike. They're modern enough to have indexed (rapidfire) shifting, but old enough so that they're pretty simple, and that makes them durable. 21 speeds (3x7) make a wide spread of gears for any terrain.

Lots of them end up with drop/trekking bars and narrow(er) 1.5" tires as touring bikes and long-distance commuters.

You can lose some of that 31 lbs of bike weight by installing Kinesis aluminum fork, 1.25" slick tires, racing saddle and a double crankset. The double-butted frame of the Sedona is good, but you'll like it more if you can gradually replace heavier components with lighter.
I also am just barely touching my handlebar with my fingertips when I am sitting upright on my mtb, but when I lean forward, everything is perfect, so I don't worry about it. As long as your knees are slightly bent at the bottom of your pedal stroke and your shoe-tips are not hitting your tire while turning, you should be good.

First make sure the bike is big enough now after you probably grew 2 inches since you were 16. One inch standover is plenty. Then it needs a bar with curl back grips and chuck the HORRIBLE broom handle bar. So then you can lean or not and the seat position will matter less. But raise the bar anyway. Look for old parts at the local bike co-op.

First, thank you for all of the advice everyone. My son and I just came back from a touring trip in WI, we did 96 miles in a little less than 2 days (I had all of our gear in panniers). I think that we did well for our first time out. I was comfortable and can't wait to get back out again!