I wonder if I could seek advice regarding selecting the correct wheel size for inputting into a cycle computer.
Tyre size = 26 x 2.00 Wheel size 559 x 22mm (roughly 26 x 2)
Instructions advise as follows:
Either:
1. Multiply the wheel diameter (in millimetres) by 3.1416 2. Use the table supplied with the instructions (approx. values it says) 3. Push the bike along until a wheel has completed a full turn and then measure the distance covered, in millimetres.
After doing all three I get the following three completely different answers:
1. 559 (or 26 inches) x 3.1416 = 1756mm 2. Table suggests (for a 26 x 2.00) = 2074mm 3. Measured distance after turning the wheel one complete turn = 218 cm / 2180mm
My maths isn't good at the best of times so I would appreciate your input...please ;o)
-- Regards, Paul (R) My Lake District walking site: www.lakelandwalker.co.uk
1. 559 (or 26 inches) x 3.1416 = 1756mm 2. Table suggests (for a 26 x 2.00) = 2074mm 3. Measured distance after turning the wheel one complete turn = 218 cm / 2180mm
I wonder if I could seek advice regarding selecting the correct wheel size for inputting into a cycle computer.
Tyre size = 26 x 2.00 Wheel size 559 x 22mm (roughly 26 x 2)
Instructions advise as follows:
Either:
1. Multiply the wheel diameter (in millimetres) by 3.1416
That is pi*d which is the circumference of a circle. They mean the actual diameter not the wheel size.
Quoted message said:
2. Use the table supplied with the instructions (approx. values it says) 3. Push the bike along until a wheel has completed a full turn and then measure the distance covered, in millimetres.
The empirical method of finding pi*d the circumference of a circle.
Quoted message said:
After doing all three I get the following three completely different answers:
1. 559 (or 26 inches) x 3.1416 = 1756mm 2. Table suggests (for a 26 x 2.00) = 2074mm 3. Measured distance after turning the wheel one complete turn = 218 cm / 2180mm
Go with number three you have got that right and it what they should tell you to use in the first place, the distance travelled per revolution of the wheel. -- Phil Cook looking north over the park to the "Westminster Gasworks"
"Phil Cook" <[email hidden]> wrote in message news:[email hidden]...
Quoted message said:
Paul Rose said:
I wonder if I could seek advice regarding selecting the correct wheel
size
Quoted message said:
Quoted message said:
for inputting into a cycle computer.
Tyre size = 26 x 2.00 Wheel size 559 x 22mm (roughly 26 x 2)
Instructions advise as follows:
Either:
1. Multiply the wheel diameter (in millimetres) by 3.1416
That is pi*d which is the circumference of a circle. They mean the actual diameter not the wheel size.
Quoted message said:
2. Use the table supplied with the instructions (approx. values it says) 3. Push the bike along until a wheel has completed a full turn and then measure the distance covered, in millimetres.
The empirical method of finding pi*d the circumference of a circle.
Quoted message said:
After doing all three I get the following three completely different answers:
1. 559 (or 26 inches) x 3.1416 = 1756mm 2. Table suggests (for a 26 x 2.00) = 2074mm 3. Measured distance after turning the wheel one complete turn = 218 cm / 2180mm
Go with number three you have got that right and it what they should tell you to use in the first place, the distance travelled per revolution of the wheel.
Hi Pete and Phil
Thanks for your feedback and advice. Much appreciated.
Now that I know number 3 is the way to go, I have just carried out the measurement again, a little more accurately hopefully, and the measurement was 209 cm / 2090 mm. (as opposed to 218 cm - don't know how I got 218 the first time!).
That's what I'll be inputting in to the cycle computer. Thanks again,
-- Regards, Paul (R) My Lake District walking site: www.lakelandwalker.co.uk
I wonder if I could seek advice regarding selecting the correct wheel size for inputting into a cycle computer.
Tyre size = 26 x 2.00 Wheel size 559 x 22mm (roughly 26 x 2)
Instructions advise as follows:
Either:
1. Multiply the wheel diameter (in millimetres) by 3.1416 2. Use the table supplied with the instructions (approx. values it says) 3. Push the bike along until a wheel has completed a full turn and then measure the distance covered, in millimetres.
After doing all three I get the following three completely different answers:
1. 559 (or 26 inches) x 3.1416 = 1756mm 2. Table suggests (for a 26 x 2.00) = 2074mm 3. Measured distance after turning the wheel one complete turn = 218 cm / 2180mm
My maths isn't good at the best of times so I would appreciate your input...please ;o)
Use no.2. No.1 is the bead seat diameter, which is actually in the rim! No.3 is only accurate if the bike is loaded while doing the rollout test.
For best results, start with the valve at bottom dead centre and make a chalkmark on the ground against the valve position; roll the wheels several complete rotations (more is better, but limited by the availability of suitable measuring tape etc) until the valve is once at bottom dead centre; again make a chalkmark on the ground against the valve position, measure the distance between the two chalkmarks, and divide by the number of rotations.
You've also got to load the bike (e.g. by leaning your chest and most of your weight on the saddle). There is a significant reduction in rolling diameter. From the figure given, I reckon the manufacturer's recommendation has allowed for this.
"Zog The Undeniable" <[email hidden]> wrote in message news:422b47a2.0@entanet...
Quoted message said:
Paul Rose said:
Hi All
I wonder if I could seek advice regarding selecting the correct wheel
size
Quoted message said:
Quoted message said:
for inputting into a cycle computer.
Tyre size = 26 x 2.00 Wheel size 559 x 22mm (roughly 26 x 2)
Instructions advise as follows:
Either:
1. Multiply the wheel diameter (in millimetres) by 3.1416 2. Use the table supplied with the instructions (approx. values it says) 3. Push the bike along until a wheel has completed a full turn and then measure the distance covered, in millimetres.
After doing all three I get the following three completely different answers:
1. 559 (or 26 inches) x 3.1416 = 1756mm 2. Table suggests (for a 26 x 2.00) = 2074mm 3. Measured distance after turning the wheel one complete turn = 218 cm
/
Quoted message said:
Quoted message said:
2180mm
My maths isn't good at the best of times so I would appreciate your input...please ;o)
Use no.2. No.1 is the bead seat diameter, which is actually in the rim! No.3 is only accurate if the bike is loaded while doing the rollout
test.
Hi, thanks for your input and advice. I might try No: 3 whilst sitting on the bike and see how close it matches No: 2.
-- Regards, Paul (R) My Lake District walking site: www.lakelandwalker.co.uk
"Simon Brooke" <[email hidden]> wrote in message news:[email hidden]...
Quoted message said:
in message <[email hidden]>, Paul Rose
(') said:
Hi All
I wonder if I could seek advice regarding selecting the correct wheel size for inputting into a cycle computer.
Tyre size = 26 x 2.00 Wheel size 559 x 22mm (roughly 26 x 2)
Instructions advise as follows:
Either:
1. Multiply the wheel diameter (in millimetres) by 3.1416 2. Use the table supplied with the instructions (approx. values it says) 3. Push the bike along until a wheel has completed a full turn and then measure the distance covered, in millimetres.
After doing all three I get the following three completely different answers:
1. 559 (or 26 inches) x 3.1416 = 1756mm
Yes, but you're not allowing for the tyre.
Quoted message said:
2. Table suggests (for a 26 x 2.00) = 2074mm 3. Measured distance after turning the wheel one complete turn = 218 cm / 2180mm
My maths isn't good at the best of times so I would appreciate your input...please ;o)
Use (3). For best results, start with the valve at bottom dead centre and make a chalkmark on the ground against the valve position; roll the wheels several complete rotations (more is better, but limited by the availability of suitable measuring tape etc) until the valve is once at bottom dead centre; again make a chalkmark on the ground against the valve position, measure the distance between the two chalkmarks, and divide by the number of rotations.
Thanks for the info. Will try measuring a number of rotations etc. and see what sort of figures I get. -- Regards, Paul (R) My Lake District walking site: www.lakelandwalker.co.uk
