In reality, my computer tells me I average just over 13MPH over 20 miles or so, when riding in the streets filled with traffic, cross streets, peds, potholes, traffic signals, other traffic, and of course hills. My computer tells me I average just over 16MPH when riding 20 miles or so on a path with nothing to slow me down but hills and headwinds. (cross streets, traffic signals and other traffic really cut into your average speed)

Fully loaded for commuting (panniers with clothes, shoes, and shower kit) I can hold 18MPH easily for a couple miles on a flat road (never had a road flat for more than a couple miles). With no gear, on my drop bar skinny tire bike... 22MPH is the typical flat road speed. And this isn't "balls to the wall" push it as hard as I can sprint... this is comfortable, get a good cadence and go speed.

On long tours, fully loaded with everything but the kitchen sink, my average speed is just about 13MPH.

Sustaining 20 MPH for a short distance-medium disctance can pretty much be accomplished on any bike, but there is a reason most people utilize their AVERAGE speed and not Sustainable.

In Road biking, Averaging 15-17mph is considered "B" pace. This is nothing to shake a stick at especially when doing 30+ miles as most group rides are. 17-19 MPH is considered an "A" pace, at least where I live. Commuting is different, as the distance is usually MUCH shorter and you can choose better routes. But I always was too worried about how sweaty I will be when I get places unless there is a shower I can use.

I haven;t ridden much for a couple of years until the last couple of months, I average 15 mph on my 13 mile commute but with treaded 700x32 tires on a cyclo in the hoods, 60% limestone trail, 40% road. I can do this for around 30 miles but longer I slow. I imagine I could only get a few mph above that with road tires on a road. If I could get myself up to average 16mph, I'd be happy.

Gene

Didn't read the whole thread, but in response to the OP, why limit yourself to flat bars?

If speed is the goal, why not use every available advantage?

Used to set up my fixed gear so that my cruising speed at 90 rpm was 35kmh and used to ride with a fairly fast group of youngsters and would average 30kmh over a 100km route and we'd often chase that with some trail riding later in the day.

In my best shape I could knock down a sub hour 40 but that only comes after 1000's of miles in the saddle and a lot of hard work.

Anyone who can ride over 30kmh for any distance has to be in pretty good shape and this is where things start to get harder and harder ... the difference in output you need between 30 and 35 and 40 is huge as wind resistance is a square of one's speed.

This is what can limit a flat bar bike with a more upright position... you might have optimal gearing and a lightweight frame but wind resistance will eventually kill you. A heavier more aero bicycle will be able to go faster on the flats and descend better and the only edge the lighter bike might have will be on climbs.

Now I am happy if I can maintain 30kmh as the body does not work as well as it used to and this limits time to train and limits saddle time.

Plus there is the issue of commuting with clothing/computer/other gear and the fact that in Road Biking routes are chosen to be optimal for maintaining a fast pace... commuting in rush hour city traffic brings it's own unique issues, of which speed is not on the top of the list.

My 18.5 mile on-way commute has a 7 mile section on a dead flat MUP that runs alongside a river. In calm conditions, it's no problem to maintain 20MPH on this section riding my loaded commuter (CX bike, rack/panniers, drop bars, 25c wheels).

When I first started commuting two years ago, I could maintain 16-17 MPH on this stretch and I was working hard. But two years of ~150 miles/week bike commuting has increased my speed and endurance somewhat :-)

Yes I agree to a point.
Completely dependent on where reside and work. Also, many road routes are designed for practice as well. This means a lot of climbs.

Also, Most road routes end up being lollipop loops or big circles anyways, most likely on a commute you would take the same route there and back unless there are easy work around for certain hills or traffic patterns on a return.

a week and a half ago i took my flat bars off and put on drop bars and man o man is my bike faster i guess i nevere really noticed how much a difference riding postion changes your speed ive had a road bike ontop of my commuter for a while i just figured the difference was in the bike, but bike is quite a bit faster, two days last week i averaged a little over 19mph on my way to work an almost 6 mile ride but on one of the hills i go down i hit 40mph and for almost a mile after the hill i can keep about 30ish with momentum, so that probably ups my average a ton. I was never that fast before on my flats my top speeds down that same hill where in the low 30's. Im gonna have to watch my speed now if i start passing cars ill probably wind up with another speeding ticket
(mind you my commute in the morning is 5:30am so hardly any cars)

If you are reasonably fast on your commute and get out on the road you will be amazed at what kind of speed you can maintain when you aren't having to stop/start/stop/start as long as the conditions are nice.

I ride to see my mom who lives 75km away and once I get out of the city I can maintain 30kmh on my touring bike with a light load... the route is about as flat as one could imagine... unless you live in Florida. Getting out of the city takes about an hour as it is 20km from my home to the highway but once the road opens up you can maintain a really nice pace.

my commute is all city its just all down hill and no cars on way too work, way home is a totally different animal people and cars everywhere and up hill

Here are a bunch of periods and upper-case letters for you to use on your next post. I nearly asphyxiated while reading your post.

............................................................................
ABCDEFGHIJKLMNOPQRSTUVWXYZ

On my Thursday ride there's a couple of big hills that we do for training. There's no other reason to go up them since they could easily be avoided. I'm happy if I can stay in double digits on those so of course they bring the average speed down. The ride also starts and ends in the city. About 1/3 of it is in areas with some starts and stops like what you'd have in a commute. It's a fast no-drop ride so the average speed varies depending on who shows up. It could be anywhere from 16-18 mph.

This is why I have trouble when group rides state what their average speed is and deciding if it's a good fit for me. It's so dependent on the route. There's a triathlon group that says you should be able to average 19+ in order to ride with them. That seems really fast for a group ride where presumably there's no drafting. On the other hand, if they're talking about your average triathlon speed, then it seems more reasonable since there are no starts and stops in a triathlon.

Yep. Avg. speed is a really misleading metric for group rides. I probably average 20-21 mph on the Saturday River Ride, but that includes a neutral roll-out and roll-in. Where it counts, you need to be able to hang on at 27+. It's flat, so it's not usually a problem for an experienced racer or century rider unless it's really windy. But when I was a making the switch from triathlete to roadie I was shocked at the surge and recovery issue.

That's part of the reason I'm considering doing more triathlon specific rides. I get a good workout on the roadie ride overall but it's like you said, surge and recover. Riding in the middle of the pack can feel like no work at all if the leader is trying to keep everyone together. Doing a long pull or trying to catch up to the leaders when there's been some separation is a killer, - completely different from trying to maintain a fast but steady pace (without drafting) like in a triathlon.

you do realize these guys aren't usually on a flat road, are on the saddle for hours and hours and never have to stop for anything right (not taking away from them)?

to compare that average to a commuting average is ridiculous.

well to begin with my period button does not work so i have to edit my posts to add them and i didnt know you had to type that thar good n proper stuff on a bicycling forum my bad ill start having my girlfriend edit all my posts.............................That took like three mins to add those

this past weekend i went for a ride on the west side highway greenway.

i had my kaitai, a 7lb kryptonite chain wrapped on my frame, the biggest mtx trunk bag with a mini ulock in it, the lock for the chain and a couple small things that weigh very little. my kaitai has schwalbe marathon cross 38 (700cc) tires. this older guy on a road bike passed me and he was very chill so i figured i'd use him as motivation to keep a brisk pace for a bit, i never got too close nor tried to pass him, it was done politely. in fact he never even looked back so he had no idea since i never got too close, about 30 feet back. so for about 8 minutes i was going 19-20mph, top speed was 22mph as per my PB computer. it wasnt a sloppy frantic effort but it took concentrated effort on my part to maintain that clip. i got tired and he kept on truckin, after that i went about 15-17 for another 5-8 minutes. then did the 19-20 for another 5 minutes and i was done. retraced my way back downtown on the greenway, cut into the city, and went to get some good eats. finished off with another few miles in the city and went home.

during the first 19-20mph time when i was trailing the old feller, i passed this young guy, full spandex, road bike, etc.. and i think he got a lil upset because he made sure he passed me on parts where i had to slow down later on. then when i did my second fast clip, i passed him again. he said something on one pass, but i couldnt catch it. both times i passed him were very clean and not close calls, so it wasnt about that.

i'd really like to get to a point where i can do 20mph for 30 minutes with all my gear. gonna take a couple months though. if i run into some money i may build a spare set of wheels with skinnier slicks on them see how that helps.

What would be considered a pretty good average speed on a 25 mile ride with a headwind going and a tailwind coming back on flat land?

I occasionally ride along the river trail with strong 12-15 mph head wind one way. Average speed is 17 mph against the wind, and 24 mph with the wind. In general, top speed is dictated by the road condition in my neighborhood. Too fast and you can't spot road hazards or avoid wandering pedestrians