Hi,
I use my trekking to go at work every day, about 20km per day, no hills, no mountains.
I usually use "heavy" gears because I like going fast and the street is flat, so everything is fine.

I really like how singlespeed bikes look but I'm wondering if the gear is to soft to go really fast...and unfortunately I have no way to test a singlespeed here

what do you think?

thanks

depends

Geared bikes can make it easier to be fast, but it's all down to your legs.

When I used to ride singlespeed/fixed the average speeds of my ride weren't that much different than when I switched to road bikes.

+1. Speed is in your legs -- I routinely take my 71" fixed-gear over 20 MPH (32 km/h), and have hit 34-35 MPH (~55 km/h) on several occasions. Other posters in this forum actually have impressive speeds to brag about.

Actually, you do- just pick a gear combo on your current bike and then don't touch the shifters .

Indeed. And to make it even more accurate: choose the "heaviest" gear combo you can comfortably accelerate from a standing start in. Then see if you can go fast enough in that gear. The fact that there are no hills on your commute means you can probably use a quite heavy gear, though if you have to stop a lot for intersections and such, you don't want to ruin your knees every time

What's your speed and cadence?

I live in a rather flat area with a few shortish hills. Run just short of 70GI on my FG road bike. On the flats I usually run around the 25kmh marker with occasionally 30kmh when I spin faster. It's fun.

Learn to spin.

Speed isn't my top priority. Just cruising the bike path were I ride for exercise I will average 1-2 m.p.h faster on my single speed that my touring bike that is not riding loaded I got a touring bike because I am a large guy
Roy

On a flat road and on my fixed gear, I can pass traffic in a 25mph zone on my commute. In fact it is so much fun that it pushes me to go even faster. You can be fast with one gear, easily.

My commute is basically the same. I climb faster on the SS/FG, but my touring rig has taller gears for the flats.

A few years ago I was in a road omnium that had an out-and-back TT along a canal path. I don't have a TT bike and didn't want to mess with my road bike so I did the TT on my fixed gear. I put on aerobars and a 52x15 gear. Personal PR for that course.

nope. everyone's lying about going fast to look cool. single speeds can't be fast it's like always being stuck in first gear in a car.

Nahh not really.. more like 3. gear I haven't geared my bikes so low what I out-spin at 10 km/h

i have my TT bike set up w/ 53x15 for the street (Fixed).. with a brake. it's not as demanding as many like to believe ....provided you flow smoothly, and time the lights.

You have to spin to win, yo.

That being said, I'm not fast lol

Well if you're running single speed you could still run a very heavy ratio given your ability to coast, but as was said, it's all in your legs pal

Go to the velodrome, then decide.

Can't ride singlespeed on the velodrome. Not allowed.

Um... what? Single speed fixed is the only thing allowed...

Single speed =/= fixed gear

Sure. Single speed can be fixed or free. Fixed for track. Still single speed. Pretty sure I don't have a derailleur on my track bike!

Whenever I heard single speed I think if a single speed freewheel, not fixed, but I'm odd.

Terminology. The term single speed is understood to mean a single cog freewheel, which is illegal on the track, as are brakes which would be required to stop a single speed, unless you intend to drag your feet on the ground. Fixed gear is understood to mean a cog mounted directly to the hub w/o a freewheel, which permits stopping w/o brakes. This is important because the OP is clearly intending to ride a single freewheel with brakes, so the velodrome reference is irrelevant to the discussion.