[Uphill70]

I started cycling about 3 wks ago and am pleased with the way things are going so far.
I bought a giant Defy advanced 3 and have been going on short 25km rides and according to strava doing about 20-21kms per hour.
This week I picked up a Garmin 810 and just got my shoes and pedals (was riding on flat pedals for the beginning) and today went for my longest ride - 50kms.
I know the distance is nothing to you guys - but it is my longest and I wanted to see how I would do. I gave myself about 2 1/2 hours based on my past speed - but actually finished in 1:53.07 -so I am pleased.
When I got back - I felt my 810 calculations for distance and speed were off - I had entered 700 for my wheel size - but now see that I needed to enter 2096 (for a wheel of 700x23) - could this have been it?
I double checked on Garmin's connect site as well as google maps and the distance I did is indeed 50 km - and found an online calculator that averaged my speed to be 26.?? mms - I am stoked.
I also managed to pedal a bit out of the saddle on flats and even on a climb - which on past rides - standing on a climb resulted in me burning out .
The climb was pretty short - maybe 1/2 km - but it was steep (form) at 17- 19% - my other climbs have never past 10% - so overall I am very pleased.

Needless to say I am hooked and cant wait to get out and ride again except for the fact that my balls are killing. Does that Chamois cream help?

 

[Kerry Irons]

When I got back - I felt my 810 calculations for distance and speed were off - I had entered 700 for my wheel size - but now see that I needed to enter 2096 (for a wheel of 700x23) - could this have been it?

Typically computer calibration numbers are the circumference of the wheel in either cm or mm. 2096 is pretty close for a 700c 23mm tire.

 

[Uphill70]

Typically computer calibration numbers are the circumference of the wheel in either cm or mm. 2096 is pretty close for a 700c 23mm tire.

Thx Kerry - so would having entered 700 as opposed to 2096 account for the miscalculated distance and speed then?

 

[Donn12]

I dont think 700 vs 2096 will affect it. I have a few bikes and have played around with different settings but 20 miles in 1 hour is always 20mph avg speed accounting for stops. Make sure you have your set to autopause when you stop.

 

[Uphill70]

Update:
I held my bike up and spun the pedals by hand with the computer set to 700 for wheel size and got anywhere between 12-14 km per hour. Set it to 2096 and got aprox 35-38 - so I guess this is what created the issue. Ill know for sure on my next ride and ill do the same course.

 

[gte]

The computer needs to know the circumference of the wheel. You can easily measure it using a tape measure. Stretch it to 2.5 meters, put the wheel with the valve down at the beginning of the tape measure, roll it until the valve is at the bottom again. This is the value (in mm) that you need to put in your computer.