What the best way to find the correct seat height ?
What does cause calves cramps ? What can I do about it ?

There are many methods, but I mainly go by feel. Whatever height that allows me to spin comfortably. If you are getting cramps, I guess it is because your seat is too high and it causes you to tip-toe too much. Otherwise, maybe you just need to drink Gatorade while riding.

In my opinion the correct seat hieght is so that your nees are 'slightly' bent at the full extend point of the pedal stroke. this way you get full leverage out of your legs which is most efficient. note your legs should not be fully extended as i think this is bad just slightly bent. if you have your seat hight too low you do not get full leverage and its poor eficientcy.
maybe this causes you cramp? having your seat too low?

The best way would be to have yourself measured by a pro bike shop. If you don't have access to one, then follow these steps, but remember that these are only basic guidelines and are not dead accurate:

• Don your cycling shoes and sit on your bike as you would when cycling.
• Rotate the pedals so that they are in a 12 o' clock - 6 o' clock position.
• Put your heel on the 6 o' clock pedal. Adjust the seat so that your leg is only just bent.
• Once the seat is adjusted, you'll find that when you clip your shoes in, your leg is slightly bent.

Thats about the closest you'll come without proper measuring. Still I would suggest you have yourself measured by a pro bike shop. Incorrect seat height can have you end up with knee-ache.

Cramps are your body's way of telling you that you're pushing the envelope too far. People might tell you to up your magnesium supplementation or use more salt, but the fact is that if your muscles are not used to the exercise intensity, they will cramp, no matter how much anti-cramping supplements you use. The solution: GET ON YOUR BIKE AND RIDE IT.

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Pain is inevitable...suffering is optional

I'm with VO2 on this one as this is the technique that I've used. Its good to ask others for comments on your saddle height as they will be able to identify any problems with it.*If your hips roll as you pedal your saddle to too high and if your legs are too bent then its too low.

Remember that some cyclists pedal toe down/up and others with their feet level.*There are examples from the pros of all types of pedaling technique, all you need to do is to remember to adjust your saddle height to compensate for your pedalling technique.*

Generally, pedalling with level feet is best and extremes of toe up/down can cause problems with your knees, legs or back.*To correct a poor technique you'll need to do training specificaly geared to improving pedalling technique.

Thanks for all the help. much appreciate it. I'll share the prize money when I win