There's one biggish hill on my commuter featuring a ghastly 56 foot drop over about a 1/4 mile. Yeah...Florida has some big hills.... Anyway, it's fun cause it's easy to get up (just attack it and you practically coast up the thing), but going down you can easily coast to 30 or push it to around 40. This is on a Giant OCR3 with allweather 25's. I'm sure slicks would be faster (or knobbies slower). Of course, if I cut into a neighborhood on the right of that hill there is a fun nature trail short-cut that involves lots of mud and other assorted slimes...so I don't think the hill is an everyday thing for me.

New tires don't have to be expensive either. I just picked up a set of Panaracer Urban Max's for like $15 each. They have extremely mixed reviews on here, but what the heck. I got some Kendas for my son's bike (he has a MTB I put slicker tires on) for like $8 each.

I maxed out at 33 mph on the road biike (Giant OCR3). 30 on the 29er mountain bike (Gary Fisher Cobia), and 30 on the single speed commuter (Surly Cross-Check). I have one realy fun hill on my 16 mile route. As long as there isn't a train at the bottom (RR crossing at the bottom of the hill) I just let it fly and see what happens. I average about 15-16 mph overall on the Cross-Check commuter.

I spin out on the two downhills I have on my commute. With the skinny-tire bike, I definitely hit 50 km/h in a tuck [I'm on a single speed]. On the flats, I can do about 40 before I spin out.

My commute starts out with a 15% descent. If I make the light at the bottom of the hill I'm easily rolling out on the Interstate overpass at 52-53. Best ever indicated speed was just over 57. If I have to stop for the light I'll still have a max speed of 48-49. Granted, this is measured with my bike computer, but when I've ridden along with both the bike computer and the Garmin 301side-by-side the bike computer was indicating a pretty accurate speed. Even with a margin of error for the bike computer I'd say I'm still getting into the 50's. Cars seldom pass me on this descent. Sadly, I have to go up that same hill in the afternoons...

--Marcus

My max is down a hill (don't know the grade, but I estimate it's about 5-7%) on my way home from school. If it's dry (no ice/snow), and I have my summer slicks on, I have no difficulty reaching close to 60 km/h. The highest max I know for sure was 57 km/h (just over 35 mph), but I'm pretty certain I've been down that hill faster than that, I just don't look at the max every day. I should add that the speed limit is 50 km/h on that street... Ehrm...

Now, on wintery streets (salted, so ice free) with my 2" studded knobbies, I've only been able to get up to 50 km/h even (31 mph). And if I have cars going down with me, I'm down to about 40 km/h max (25 mph).

My average speed for the entire commute is about 22-23 km/h (14 mph) in the summer, and 18-19 km/h (12 mph) now in the winter. The main problems are other traffic and several red lights. I think my average would probably increase by 20% without them.

1. Your bike computer, even if relatively poorly calibrated, is more accurate than the best GPS unit.
2. Please provide units for your listed speeds.

^^^mpless will have to give a definative answer, but hitting 52 MPH on a 15% descent shouldn't be too hard. 52 km/h on a 15% descent is outright glacial.

Sorry, I meant to specify MPH. I attached a couple of pics, one of the bike computer and one of the bike after a typical round trip commute (2 hours 23 minutes, 35 miles). The average speed really suffers due to the 35-40 minutes of climbing where I'm really crawling. Sadly, the Merckx got wiped out in early January (first commute of the year) when I was taken down by a Crown Victoria. My other commuter is a Poprad, with 32C tires (slicks) and fenders in the winter time. Either bike is capable of flying down that hill if I get a good acceleration and I really tuck in. I'm talking elbows in, hands on either side of the stem, and chin practically resting on the stem tucked in. It's a fun way to start the day, usually around 5:30-5:45am.

--Marcus

I have a really big hill on my full commute (I reserve the option of driving half way). Thus, my top speed going TO work is around 45-50 mph. But then I have to go back up at the end of the day...

[QUOTE=jschen but hitting 52 MPH on a 15% descent shouldn't be too hard. [/QUOTE]

Eh? That's 83 Km/h Fairly hauling arse!
The best I've done is 72 Km/h on my road bike in the mountains, but commuting (flat but: lots of traffic and loads of traffic lights) my best is 46Km/h.
Steve.

15% grade is really steep! The only sustained 15% grade I ever ride is the top quarter mile on Mt. Baldy. I'm a lightweight, and I easily hit mid-40s (without wind) on that section before chickening out and slowing to the mid-30s since just below it is a hiking area where there are likely to be pedestrians crossing. With some planning (rest up on the top, sprint out of parking lot before hitting the descent, have sisters serve as spotters watching for pedestrians), hitting mid-50s within that quarter mile should be doable.

Holy crap -- We have some people that max out their COMMUTE at 40+! While I've gone as high as 50 on very rare occasions, breaking one of the cardinal rules every day (never ride faster than you're willing to crash) seems like a recipe for trouble and great pain...

Yeah, I could totally do a 40mph average on the commute, too! If all roads were 15% downhill in both directions.

There's a short, steep downhill section on the outward journey, where I can get to 42 on a good day. It's an unlit country road, so I don't often travel home that way except in summer. When I do tackle this hill going the other way, a more humble speed of around 7 mph is usual....

Ed

I know this thread is a bit of fun but I'll be the "kill joy" here. Just be careful out there guys.
We don't want any of you to end up like Fabio Casartelli:
"On July 18th, 1995, during stage 15 of the Tour de France in the Pyrenees from Saint Girons to Crête du Lys, Fabio Casartelli crashed and was tragically killed. On the descent of Col de Portet d'Aspet (with parts of 15%) Fabio Casartelli hit a low concrete wall with his head wearing no helmet. On his way to the hospital in the helicopter he died after 3 heart attacks."
- https://home.tiscali.nl/edwinsel/misc_monuments.htm

Just to clarify, I'm not some sort of "Xtreme Commuter". I absolutely agree that people need to ride within their confort zone, and they also need to think about what they're doing before they do it. I know people that get freaked out at the prospect of doing 25 MPH on a bike. If that's where they're comfortable, then so be it.

I'm 45 years old and last year I put in roughly 5500 miles of bike commuting. I try to ride as a vehicular cyclist, ie I ride my bike like I would drive my car or ride a motorcycle. I use the bike lane when it's appropriate, and I'll take the lane when it's appropriate. I stop for lights and I wait in traffic. I just happen to have a couple of nice descents that lend themselves to letting the bike run, if you will. Nice downhills with no cross streets in the middle of the hill.

I would never consider doing 50+ MPH on a road I didn't know really well, on a bike that I knew really well. I build up my own bikes and I ease into things before going for new personal speed records. I've flown in planes that I worked on, and I've gone scary, stupid fast on motorcycles that I built up. I've also taken a few high speed tumbles over the years, so I know what that feels like, as well.

The times and places when I choose to go quickly have been thought about in advance. These descents don't require any great degree of technical skill on my part. If you're on a decent, well maintained bike that doesn't exhibit any wierd behaviours (like a high speed wobble) then it's a lot of fun. But again, I know the equipment and the roads quite well, and I'm well within my comfort zone. Otherwise I sit up and ride down at what I feel is a safe speed.

Like they say, Arrive Alive!

--Marcus

Very interesting about these higherend road bikes & rider speeds.
hmm... i ride a stumpjumper(commuting) & hover between 23 to 27mph on flat with heavy armadillo tires.
Edit: max spd is around(very close) in the 50 mph range down hill.

I have gotten up to 40 once on a long downhill I have in the morning. I generally average about 14 over the 7 miles one way (includes time waiting at lights). I can get another mph on the way home which does not make sense I should be tired and I have that nice long downhill (which is now an uphill). One factor is that I go to work in rush hour traffic and I work usually work late so traffic is much lighter on the way home. When there are fewer cars, I am not having to brake to squeeze between cars and stuff.

This time of year it is pretty windy to hit the really high speeds. But on a pot hole laden, 1800 foot long 14 % grade I can get 41. Got a 45 behind a bus on a 6% grade.

See, now I would never draft off of a vehicle. They can slam on their brakes and you go smashing headfirst into their rear bumper and through the rear windshield. When I do go down a steep grade on a busy street, I always take the lane and give myself enough room to hit the brakes should the cars in front of me suddenly stop. If I can't see in front of them, I slow down. No need to turn my thrill ride into a 1-time event.

Time to give Johan Bruyneel a call then.