I am a beginner to commuting by bike and I find it very tiring. Is it my fitness level or my single-speed bicycle?

This is an updated form of my answer, partially in response to the other answers.

It is you, not the bike. The bike may be a bit of a tough, perhaps over-ambitious choice, but it is in principle ok for the task.

Many of the other answers argued that a singlespeed drop-bar bike is fundamentally not suited for a city commute. I disagree. Such a bike can be used perfectly well in a reasonably flat city. In fact, precisely because the tempo changes so often & spontaneously, it can be more effective to just handle efforts by getting out of the saddle briefly, rather then shifting down and up again. This does demand either some fitness (which you would probably build up with this bike quicker than with more comfy ones) or a rather lower gear ratio (note that the Holland-style bikes popular with non-sportive European commuters are also often singlespeed).

I would still say that some gears would be good to have, but they're not necessary. If right now this bike as it is is your only option, here's how to use it for minimum frustration:

1. DON'T PANIC. If you exhaust yourself going to the limit right at the start of your ride, it's obviously getting harder later on.
2. Stand up to accelerate. In principle, getting out of the saddle makes pedalling less efficient, however it does allow you to put down more torque using muscle groups that are also trained in non-cyclists. So on each traffic light or ascend, make use of that.
3. Sit down and relax as best as possible. A race-ish bike encourages going fast right away, and it can go fast, but even though it has better aerodynamics than more upright bikes you will require a lot of power if you accelerate to the tempo that feels appropriate for the bike. Instead, accelerate only to a tempo where you can almost-coast in sitting position.
   In order to get the sitting position comfortable, you may need to experiment with saddle positions a bit.

If you do it that way, then the commute should never be a disaster like your first attempt. It will still be slow of course. But the nice thing about that bike of yours is that it will naturally encourage you to go a bit faster each time. Ramp it up slowly.

Original answer

Wow, you've really took it to your heart to analyse the problem, hm?

Unfortunately I have to say that it is most likely you, not the bike, that's the problem.

Fortunately I'm optimistic that the problem will mostly solve itself if only you keep going! If you haven't really done any cycling for years then it's inevitable that you're not in great physical condition for it. And that makes a huge difference. A well-trained cyclist on a poor-quality, horribly misfitting bike will easily beat a non-cyclist on a top-notch high-tech road bike.

And training comes with... well, training! It's not going to come in a matter of days, but it will you come over time if you regularly ride that bike.

(Case in point, at one time in my life I was so out of shape that I would basically collapse after 25 km of flat riding. Nowadays I have no trouble with 100 km/day through the Norwegian mountains, and that is still laughably little to any pro cyclist.)

The bike does matter too. Yours is certainly a capable machine, but the one thing that I would consider a really bad idea is that it's singlespeed. 48/19 is not a crazy ratio – a trained cyclist will be able to ride this on almost any road, though not at best efficiency and the uphills will require getting out of the saddle. For a beginner, climbing in such a gear can however quickly become painful. Switching to a smaller chainring would definitely help with the burning thighs, albeit of course at the cost of lower top speed. Well, if only there was a device that could modify gear ratio during the ride as needed...

The other thing that can have a significant influence is saddle position, but I won't go into that. You'll find plenty of advice on how to set up your saddle on the internet.

Then there are plenty of smaller details like clips vs flat pedals, handlebar measures, crank length, tyre pressure etc. etc.. Listening in to cyclists' conversations can make you think that these make all the difference world. Well, it's not that they don't matter at all – all together they can very well win or lose a race, but compared to rider physique they're absolute peanuts.

Gross mis-setup, like strongly rubbing brakes, obviously would be more harmful, but this really doesn't seem to be the case for your bike – if both wheels stay spinning for > 1 min it means that this has a negligible contribution to total drag.

This size frame seems pretty small for your height. I would think a small or medium (50/54 cm, according to Cinelli) would be the right size for you. But that wouldn't account for the problems you experienced. It does mean that getting into an efficient, comfortable position will be harder.

When you find it hard to turn the pedals over, is that because you're encountering mechanical resistance, or because your legs are shot? After a few minutes/hours/whatever to recover, is the bike zippy again, or is it still fighting you? I could imagine the rear wheel getting pulled out of alignment in its dropouts and rubbing against the chainstay if the axle nuts are loose, but that would not self-correct.

I'm not an expert on single speeds, but chain tension seems fine. You want it loose enough not to bind the gears when you pedal, but not looser.

Are you riding the bike on the fixed gear or the freewheel?

Jay a couple things to think about:

• It is good you are getting back into riding. I was in a similar position where I got back in to riding after taking a break and thought how hard can 13 miles be. Well the short of it was harder than I expected.

• So with that said you probably are using muscles you have not in a while and it will take some time to build up endurance.

• A simple thing to focus on when starting is first be able to ride for a certain period of time on flat terrain that lets you pedal for 45 minutes straight. If you have a cadence meter you can focus on keeping your rpm between 75-90.

The difficult part is with a fixie or single speed bike, you as the rider have to compensate in effort for the terrain. While 48X19 is not too tough to push for a road bike cyclist, starting out on certain hilly terrain that can be less than ideal (e.g most road bikes come with 50X(34-11) ).

You have two options. One is you could train a bit on a stationary cycle/turbo trainer to build up endurance and strength. The other is you could get another bike that has gears in the back that will allow you to ride outside and not feel like you have to work as hard on hills.

If I was to go the route of a road bike with gears, I would go with something that has a 105 groupset at least and this way once you build up endurance and strength you have two options of great bikes to ride vs. one of them feeling like it is just the other bike.

I know that may not be the answer you want to hear, but usually people on fixie that are riding them far have some time on other bikes that they have built up their endurance on or they are not worried about how fast they get to their destination because they know they may have to go slower to compensate for the lack of gears.

Great effort on both the write-up and the commitment to start riding again.

Try and separate the issues:

• Your route was suboptimal due to trusting google
• Getting off and walking a bike is surprisingly tiring
• your speed is quite fast for someone who is just coming back to riding after a multi-decade long break
• You were under time pressure to avoid being late, and therefore pushing hard.
• I bet your park pathways were nice smooth asphalt, and the roads are less-smooth which adds to the resistance
• You're on a fixed gear which is hard work at the best of times. Fortunately there were no hills on your path!

Some of these you can resolve and minimise, your choice of bike is locked in for now.

ROUTE

It looks like you have few good options. Based on the Strava Heatmap, https://www.strava.com/heatmap#13.23/-73.92722/40.66005/hot/ride suggests that the most popular road for cycling is Pitkin Ave, which has "sharrows" allowing you to "take the lane" This can be scarey especially if you're on a fixed gear.

I notice Blake Ave has bike lanes too but doesn't show up well on heatmap. This is likely a distinction between sporty riders and those riding for transport.

Oddly, the Belt Parkway comes in as popular but streetview shows its not at all bike-friendly. Google may have made similar bad suggestions.

I notice Flatlands Ave is very car-centric and to be avoided, but one road north is Cozine Ave which looks much quieter and has shoulder space. Van Siclen Ave also has cycle lanes.

Without knowing your general start and finish, its hard to suggest exact routes, but find the one that you feel safest on, even if its a little bit longer. You can use Street View to check out the road before you ride too.

Not sure of the rules in New York - you should check if you're legally allowed to ride on the pavement/sidewalk/footpath which adds more options. edit no, not legal in New York, but may be elsewhere.

Preparation and planning prevent poor performance :)

---

ALSO give yourself more time. Being late and stressed did not help.

Set a backup Wakeup alarm on your cellphone which is battery powered, to help prevent this happening again.

For at least the first few days, allow more time, and ride a bit more relaxed rather than pounding along as fast as you can.

Talk to someone locally who can see you on your bike, and might be able to suggest better fitting. Could be your saddle is too low or something, we can't tell from the bike alone.

4.1 miles, mostly flat, are on paper doable by any human with two legs in about 90 minutes. Walking. A bicycle? it should be at least 1/3 quicker (although I would expect it to be 3 or 4 times faster than walking). Even a super-heavy dutch bike will allow you to cruise at 8-10 miles per hour, so the distance should take you about half an hour.

So it is the bike.

As other pointed out, your bike is a fixed bike, maybe a single speed, but it is an aggressive bike, it means you have to push hard on it. Given the gear ratio (how many teeth you have in the crank divided how many you have on the rear wheel, the higher they are the higher the optimum speed ... and the harder you have to pedal to reach it).

Likely it has an optimal speed of about 25 km/h. In the park, you could easily push until reaching that speed, then coasting freely and happily, but out in the urban jungle you have to accelerate and brake depending on external conditions, so you probably never reach the optimal cruising speed, but you are constantly trying to reach that speed, getting extremely tired.

Add to this the continuous checking of the map (no offense in this, but the first ride always takes longer and it is tiring because your brain has to accomodate all the visual and sensorial informations ... a car detaches you from the exterior, so it is much more relaxing to travel in unknown lands/streets/cities by car).

So I suggest to get rid of that bike (and get another one, really any other one that is not a fixed bike or a single speed road bike with drop bars). Do that before someone else does that for you: your bike is a magnet for thieves.

Despite their already being multiple good answers I am going to post this because I think each answer has good points but it is useful to have them in one place.

I agree with everyone who said a single speed bike is a significant source of your problems. Even a three speed internal hub would have been much better for you. As your fitness improves you will become better with it so if you can't trade it for a bike with gears you will probably find it works for you eventually. Fixie and single speed evangelists make these bikes seem amazing and that can be very misleading.

It is normal to have to optimise your route. Criggie's answer showing heat maps is a great example of how to research and change the route you take. When I start a new job it often takes me a couple of weeks before I find the exact route that is best for me. The shortest one might have too many difficult junctions. The flattest one might be longer than it needs to be. The fastest one might miss a short detour down a beautiful tree lined lake shore drive. It should be rare to have to make huge changes but you should try small changes until you find the best route for you.

It is totally normal that you will have muscle pain and other discomfort when starting to cycle. You may be fit in general but cycling will be a bit different than your normal exercise. Going from out of shape and 10 years of not cycling to a 15km uphill commute meant I got to work with sore legs and a sore ass. A month later I was a lot faster and had no discomfort at all during the commute. Don't be concerned if you are experiencing discomfort (not pain) now and be confident that is a temporary circumstance.

Your detailed explanation of your bike set up makes it seem fine to me. If the wheels spin freely when off the ground there are no brake problems. Rear wheel stopping after over a minute seems fine to me too. Your saddle does not sound like it is too low, in my opinion your feet should be able to touch the ground! Toes only though, not flat on the ground while you are still in the saddle. Another (better probably) way is to verify that your knee almost, but not quite, locks straight at the maximum extension of your pedalling stroke.

It's worth pointing out that this is probably the worst time of year to take up cycling. If you keep it up in a months time I predict you will love cycling to work and will be kicking yourself for spending an hour on public transport to get to work for so long.

Both.

• You really, really, really don't want a bike without gears. In the city you'll rarely ride at the optimal speed for that transmission; instead you need to stop and start frequently and adapt to flow with the traffic which is much easier if you can switch gears. Try to sell yours as long as you can advertise it as "practically unused" and buy some standard commuter bicycle in the same price range. That will serve your purpose nicely. I cannot make a specific recommendation here because I'm not acquainted with the American marked. But I would prefer a neutral position (no lowered handle bar) because in an urban environment you are unlikely to spend long stretches at high speeds where it really pays to minimize wind resistance at the cost of comfort — there are just too many intersections and other obstacles.

• You may be in reasonably good shape physically but biking is a fairly lopsided affair physiologically: It's mostly thigh muscles. It's good cardiovascular exercise, too, no doubt, but it uses few of the other muscles in your body. Don't be surprised that your thigh muscles tire, you are stressing them more with that commute than you ever have in your life (which is, in the grand picture, a good thing).

A bit of advice at adjusting your new bike:

The one thing to pay great attention to because it directly affects the legs is the saddle height. Make sure it is not too low: While it may feel safe and even comfortable in the beginning a low saddle would hurt your knees over time. A high saddle, on the other hand, tends to hurt your lower vertebrae because there is a lot of see-saw action in your hip, bending the spine back and forth sideways, when your legs try to reach the bottom. Of course both maladjustments also make your riding less efficient.

For the handlebar height: Riding too upright will hurt your back over time because all bumps are going vertically into the spine. Make sure to sit roughly at a 45 degree angle or lower. Riding too low is not bad but may be generally uncomfortable. You'll have to keep your head up (even more with eye glasses) which can stress your neck. Your hands may start to hurt on hard grips if pedaling with tired legs does not provide enough lift for your upper body.

I will just add that when I was your age I resumed commuting by bike after a hiatus of a couple of years. I was riding from Astoria, Queens, New York, to downtown Manhattan, a distance of just over 9 miles each way by my most frequent route over the Williamsburg bridge. I had moved to New York a couple of years before from Amsterdam, so I was no longer accustomed to riding a road bike, and that took a bit of adjustment.

The commute took about as long, 40 to 60 minutes, as the subway ride, but the variation in the subway time was due to the degree of rush-hour congestion, while the duration of the bike trip depended on the wind and the temperature.

I had a 12-speed Raleigh road bike that I picked up second hand in Astoria, which I think was made in the early 1980s. I'm adding this answer to recount my experience on the bridge. At the bottom, all the young whippersnappers hipsters would breeze by me on their fixies, and I would just churn away in one of my lowest three gears. A couple of minutes later, halfway up the bridge (or sometimes rather sooner than that), I would pass them, huffing and puffing, standing on their pedals, straining to keep the bike and themselves moving. Of course they were all in much better shape than I was, but I had the better tool.

They also reminded me of myself in my late teens. Then I had a ten-speed road bike, and I had this idea that I should set myself a goal of being able to make it all the way around Central Park in top gear. Don't do this. I still have problems with my right knee that first appeared when I was trying to achieve that goal.

I never understood the fad for fixies. Some people are obsessed with weight, and gears add weight, which is why track bikes don't have them. Who are these people kidding? They're not competing at the top levels of international sport, they're getting around town. How much faster are they going to get to the office or the gym?

Another reason track bikes lack gears is that tracks are flat. The real world isn't flat, and it has unpredictable winds. Look at the great road races like the Tour de France and others. Are they riding fixies? Of course not. It would be insanity. The benefit provided by the gears far outweighs the cost of a couple of pounds of extra weight.

Get a bike with gears. Your commute is mostly flat, but you'll have the flexibility to adjust to a stiff headwind or tailwind, either on your commute or while biking to the Rockaways or elsewhere around Jamaica Bay. Take your bike to Cypress Hills or Prospect Park. The circuit on the Prospect Park drive is a nice bit of exercise. It's downhill on the west side and uphill on the east side. With gears, you can adjust the intensity of the workout to suit your mood.

Another advantage of gears is that you can use them to help keep warm in very cold weather. Use a lower gear and spin faster than you otherwise would: you generate more heat, and there's less wind. Now I live near downtown Brooklyn, and when the temperature goes much below freezing I tend to take a heavy Citibike over the Brooklyn bridge instead of my road bike, because it's warmer.

Think about gears as letting you work at a constant level of intensity, which you get to decide, and the gears let you adjust the speed of the bike to the conditions so you can maintain that intensity. With a fixed-gear bicycle, you are at the mercy of your environment. Gears give you control.

As a serious multi decade rider with two bike clubs I will say that it is both.

It is partly you because you are out of shape but that will fix itself if you ride regularly.

It is more the bike.
You got the WRONG bike for what you want to do.

Even a clunky bike with 3 speeds would have been better than that single gear racing bike you bought.

Far better would have been a cheap ten or 12 or whatever speed is common these days.

You need much lower gears for your use, although you should have some in the higher range too, but not super high.

I took a Sears lugged frame and changed out the gearing and wheels to make a 15 speed (12 usable) WIDE speed (24-105) touring bike that I rode for 30 years. I climbed mountains with it leaving others in the club behind because I had a genuine very low LOW gear. On the other end I was limited by my fitness for speed on the flats (but still above average just not A level). Going downhill my weight gave me the edge in speed.

I strongly suggest you get a new bike and also exercise during the winter to keep your fitness up. I wore out two indoor bikes and one treadmill doing that.

I am a 39 year old who also commutes via a fixed gear bicycle. It will take time to get used to riding like that. I was in to cycling for years before I bought my first fixed gear. I hated it for the first 3 weeks, because the feeling is much different and it can be a lot of extra work.

If you want to stick with this, I’d suggest waiting until spring when you aren’t fighting weather as well. Riding fixed can be a real pleasure, but it’s an acquired taste.

Also, and this is just my opinion, using the freewheel with a bike designed as a fixed gear sucks. When I tried it, I always felt like I was wasting energy as my pedal strokes were quickly eclipsed by the speed of the bicycle on flats and descents.