Why is my fixie so very hard to pedal?

If you have brakes, make sure they're not dragging on the wheels. Also, make sure (if you have quick release) that you haven't tightened the wheels in too much.

Fixed gear bikes are not easy -- they're primarily fashion statements at this point, and fashion statements often are not comfortable. You're stuck with one gear combination, and you can't freewheel (i.e. coast) when you want to. Also, for many people, resisting the turning of the wheels (rather than applying something like a v-brake) is the primary method of braking, which does take energy. A lot of fixed gear bikes ship with too high gear combination for many riders, so you may want to try getting a lower gear combination by replacing the rear fixed cog, or if you have a flip-flop hub, use the other side (and take advantage of freewheeling).

It is something you have to get used to, but its impossible to say over SE if it is normal or not [for example, if you're very not fit, you may have trouble on any bike]. It is also harder in an urban area since you have to start and stop a lot.

The most likely explanation is too high of a gear ratio. Your local bike shop can swap out your rear cog for a larger /easier one. They can also check to make sure everything is running smoothly ( bottom bracket, hubs, brakes).

There's not really enough information in your question to tell for sure what the problem is, so let me just list a few possible explanations that come to mind:

• As others have noted, your gear ratio might just be too high for you (since you say it takes a lot of effort to get going).

  You can take your fixie to a bike shop and have them swap the rear cog for a bigger one and see if that helps. While at it, you can also have them check for other problems, too.

• Something (like, say, the brakes, if your fixie has them) might be dragging against the wheel(s), slowing you down and making you work hard to keep going. Or, just possibly, there might be something wrong with your wheel bearings, causing the same effect.

  There's an easy way to check for this: just flip your bike upside down, give the pedals a quick spin with your hand, and see how long it takes for the rear wheel to stop spinning. Then do the same for the front wheel, too. (You'll have to spin the front wheel by pushing on the spokes directly. Be careful not to let your fingers get caught between the spokes and the frame while doing so!)

  On a well-oiled bike with decent bearings and nothing dragging against anything, the time to stop should be measured in minutes rather than in seconds, and there should be little if any noise. (That goes especially for a fixie, where you don't even have the ratchet mechanism ticking.) Certainly, there shouldn't be any grinding or scraping noise, and the wheel should certainly not stop in less than ten seconds.

• If you're used to freewheeling bikes, you might be unconsciously trying to slow down your pedaling after you get up to speed. On a freewheeling bike, that lets you relax and let the bike roll along — on a fixie, it brakes the bike.

  There's no simple fix to that, other than switching back to a freewheeling bike. If you want to keep riding a fixie, you'll just have to unlearn that habit. Fortunately, simply with enough practice, that will probably happen naturally.

• More generally, you might just be unused to riding a fixie. It does require a somewhat different set of muscles and riding behaviors than a freewheeling bike, and so you might initially find yourself putting a lot of stress on muscles you're not used to using so hard. Your description sounds a bit extreme for just plain unfamiliarity, but it certainly might contribute, perhaps together with an excessive gear ratio and/or poor riding position.

  Again, this is something that will only be fixed by practice. After ruling out (or fixing, if necessary) all the other issues, just keep riding regularly and see if it starts feeling any easier. If yes, you're making progress, and should keep practicing until you can ride your bike comfortably.

• Also, make sure to check your riding posture. A poor posture can make riding a lot harder than it needs to be. This is true also for freewheeling bikes, but it's particularly true for a fixie, since there you can't just stop pedaling to rest your legs.

  In particular, check that your saddle is not too low, as that seems to be a common error. Ideally, when sitting on the bike with the pedal is at its lowest position (i.e. pointing at 6 o'clock), your knee should be just slightly bent. (An angle of about 25° short of straight seems to be commonly recommended.) If your seat is too low, you get less power on the downstroke, and have to expend extra energy to lift your leg on the upstroke, making your legs tire faster.

You may want to check your chain tension too. This answer has a lot of information you could use: How tight should a fixie's chain be?

I have been riding a Fixie for years. My bike has a gear on each side of the hub. (One poster called it "a flip-flop hub"} One gear is fixed (no coasting or pedalling backwards) and the other gear is not fixed (allows coasting and pedalling backwards). It is easy to turn the wheel around. Just loosen two nuts, move forward to create slack and take the chain off the gear. Be aware that some tires have a rotation indicator and in that case you would have to deflate the tire and take it off the rim to turn it in the proper direction.