Cycle_of_life

Hello, everyone,

I just got back into cycling last year, but didn't buy a bike computer until a few days ago.

I was surprised to discover that my speed estimates were off at both ends of the scale.

On the low end, what I thought was 5 miles per hour turned out to actually be about 8 miles per hour, and at top end, what I was sure was about 25mph turned out to be 17.2mph.

When I was going 17mph, I wasn't peddling as hard as I could; I had some reserve left, but it surprised me that I wasn't even doing 20mph.

I'm in my 50s, in good shape, and I'm riding a Trek 820, which I'm learning from reading various threads here, is a bit on the heavy side, and not really made for speed.

I'm not really interested in going fast, it's just that after finally having a speedometer, and being on a flat highway that doesn't have many cars, and traffic lights every mile or so, I wanted to see what I, and the bike could do.

Is this low top speed common for my situation?

I wasn't sure where to place this thread, since it involved a mountain bike, and someone over 50.

Thanks,
Mike

Nermal

My estimates are also kind of optimistic. Sometimes, ignorance is bliss.

Machka 

Yes ... 17.2 mph (27.6 km/h) is common and quite brisk.

BobbyG

How did you calibrate your speedometer?... What's your gearing?...Three years ago I tried a GPS unit and found it read differently than my bikes odometers that are simple Schwinn bike computers. I finally tried the calibration where you make a mark on the ground and walk the wheel through a full revolution and measure the length. Now both bikes (26" and 700c) concur with each other and the GPS. For 20 years my odometer had been adding a half-mile to my 9 mile commute giving me a lower speed readout.

Also, for the first few years of my current commute I had a Schwinn Cruiser Supreme beach bike that I added a triple crank to. The biggest ring up front had 51 teet and I regularly cruised at 20-21mph on the flats. Then I bought a Nishiki Blazer MTB and my cruising speed dropped to 17mph. I had my LBS fit the largest chainring that would fit; 53 teeth, and my cruising speed on the flats returned to 21mphs. Over the years I have added smooth road tires and an aero bar add on to the Blazer so now, if I want to stretch out and push it a little I can cruise the flats at 24-25 with ease and I'm 52 now.

wphamilton

Yep the bike speedometer was an eye-opener for me too.

Strava is another another one, when I get to feeling like I'm getting fast. Just install the app on your smartphone, and see what your actual speed is on various sections.

Cycle_of_life

I did not calibrate the bike computer, I bought it at my local bike shop, so I trust that they calibrated it correctly. I have the stock 26" wheels on my Trek 820.

I'm also using the stock Bontrager tires, which are supposed to be good for trail and street. On the tire it says to inflate to 30-60 psi.

I'm running them at about 55psi, and I notice that the bike rolls more smoothly than when I had them at 40psi.

When I was going 17mph, I was in the highest gear that the bike has: biggest crank in front, and smallest in the back.

I love this bike, and am very happy with it. I did not buy it for speed, but just for exercise and recreation.

I was originally going to buy a cruiser, but wanted a geared bike, and something that could be used on light trails, but mostly the local streets where I live.

I am a cautious rider, and don't take chances. As the speedometer has shown me, 12mph is fast enough when the road permits. Above this speed, I begin to hear the wind, and that says slow down.

I am not going to try and repeat this.

I was just curious what I, and the bike could do.

I'm new to cycling, and am happy to learn something new everyday.

Thanks to everyone for your replies.

Anyone else?

Mike

Machka 

Nothing wrong with 12 mph.

And it is quite common for people to think they're going faster than they really are.

Your assumption of 25 mph (40 km/h) is really fast. That's a downhill or very strong tailwind speed for most people.

no1mad 

Want a real eye opener, plug your details into Sheldon Brown's Bicycle Gear Calculator. I thought I was slow because of the bike- I have never been able to achieve the speed that the chart suggests

AbsurdChalk

I prefer riding without a speedometer. I like to focus on my rpms while I ride to give a good idea.

fietsbob

I like Tailwinds ..

I only put a battery in my bike computer when on a long tour..

the resettable trip odometer. answers my own 'how much further' question .. when I zero it out at the miles to goto next town road-sign.

and Half way there between signs , I can see i'm getting there.. judge whether I should look for a camping spot, instead..

NJgreyhead

Like BobbyG wrote, you may want to calibrate your computer based on rolling your wheel one full revolution (or 3 then divide by 3 to get an average) with your weight on the bike and typical ride inflation. Don't just go by the package which implies all 26" wheels (e.g.) need such-and-such a setting.
Without proper calibration, the computer can't give accurate readings.

Also, cruising at 17+ mph with mtb tires (presumably) ain't exactly loafing along.

wphamilton

Well sure. If you want an immediate improvement for riding on the road I'd suggest locking out the front shock and changing out some road slicks for the stock tires.

12 mph is about average for an overall speed, riding around on the roads. By overall speed I mean total distance divided by total time - it's usually at least a couple of miles per hour lower than what we see looking down at the speedometer on a steady pace, because of traffic lights, slowing down and accelerating and so on. People will scoff at that and say it must be higher, but if you don't believe me then go to Google Maps, show directions for some trip, set the mode to "bicycle" and divide the distance by the time it estimates. Google is pretty good at this sort of thing.

BobbyG

BTW, I didn't mean to imply I could sustain my cruising speed for my whole commute. My average speed is only 13-14 mph downhill into work, 12-13, uphill on the way home my best was 16 into work and 14.5 home, and that was quite a few years ago.

Cycle_of_life

You know, I never thought about changing my tires, although I'm happy with the tires that came with the bike, which are these: Bontrager: LT3 26" (Model #08058)

I read some reviews on them, and some people referred to them as very tough, and very puncture resistant.

I ride mostly paved city streets, which are in decent shape (hard to believe in NYC) but they have their share of bumps, dips and cracks, for which I think these tires are good. Then again, I'm still learning.

What advantage would locking out the front shock have?

If I may ask another question: What's the difference between having a front shock, and hard seat, as on a mountain bike, and a hard front fork and shock-absorbed seat as on a hybrid bike?

Thanks for the suggestions, wphamilton.

Mike

Cycle_of_life

This is one of the reasons I had to get a bike computer.

The other reason was for the odometer; I never knew how far I was riding.

Mike

Cycle_of_life

Thanks for the link, no1mad.

Mike

wphamilton

The stock tires will have higher rolling resistance, slowing you down.

The front shock costs you energy, which is why you don't see them on road bikes. I'd lock it out for around town, unlock it if going on trails or mountain biking.

Visualize the kinds of jars that the front shock will absorb, and the seat or rear shock. Bumps on the front tire basically pitch the front of the bike up and down, and some bit in the direction you're going. Springs on the saddle would reduce jars straight up through your back.

On the streets I prefer to let the tires do the job of absorbing the bumps which are generally smaller. For rougher streets, larger tires which can run at lower pressure.

For a mountain bike or hybrid at those speeds, reducing rolling resistance and increasing efficiency is the most effective way to get a bit more speed, if that's the goal.

Cycle_of_life

I'm quickly finding out about perceived speed versus actual speed, NJgreyhead. When the conditions allow, I'm content with 15mph and under.

If any of you are wondering where I tried to break the sound barrier, it was here: https://www.google.com/maps/place/Br...5495122c023c4e

Between Howard Beach, and Rockaway sits the lovely little island town of Broad Channel.

There's about 3 miles of fairly straight road, with only some gentle turns. In the middle is The Jamaica Bay Wildlife Refuge, which is a great place to visit, if you like bird watching, turtles, and nice, winding paths to clear your mind.

No bicycles permitted in the Refuge itself.

Thanks for all the ideas and comments; keep them coming.

Mike

Cycle_of_life

Very good info, wphamilton, I will let all this sink in before I decide to change anything.

Thank you very much.

Mike

Altair 4

I have a Trek 820. Unless they've changed the spec since my model came out (entirely possible), you won't be able to lock out the front fork. I ride mine on limestone dust trails and it handles these well. In the city, it handles rough pavement and even cobblestones pretty well. It's not built for speed, but it is a fairly comfortable riding bike. I keep the front tire pressure at around 50 and the rear at 60 PSI. The calibrated Sigma wired computer on-board matches readings off my smartphone and distance markers on local trails. Top speed of 17 is nothing to sneeze at, given the weight of the bike and the riding position. I usually maintain an average speed between 12 and 14 mph (trail and pavement, respectively).

The one thing I did change out on my 820 was the saddle. The OEM saddle was like sitting on two baseballs - I never really adjusted to it. A different saddle made a big difference in comfort. Enjoy your new bike!

Cycle_of_life

Thank you very much, Altair 4.

I really like this bike. I, too, changed the original seat, as it was uncomfortable.

I am really starting to think of changing the stock, mountain tires for smoother, more pavement-friendly tires, as I really don't ride on trails much.

Not so much for speed, but for a smoother ride.

Mike

Altair 4

It will make the bike quieter, too.

Cycle_of_life

I just got back from a 20 mile ride, all of it on paved roads. I pumped both tires up to 60psi, which is maximum for the tires on my bike.

The ride was the smoothest I've had so far on my Trek 820.

If street tires will make the bike roll more easily, and quieter, I may just have to find the money for the new tires. My local bike shop said they would cost $20 to $40 per tire, $20 to mount them, then tax.

I'm also noticing two things:

1.) I'm not looking at the speedometer as much, as I can estimate my speed by now, and only look at the trip odometer when stopped.

2.) I'm not shifting at all on my rides, which are mostly flat and level. I'm getting to like 4th gear in the back with the middle sprocket in the front. It gives me quick acceleration to 10mph, and I can attain 13mph for a few moments without getting winded.

This is great!

Mike