How to choose a belt for DIY TT?

[CrownHill]

Building my first DIY turntable. Belt drive. How do I choose the right belt? I am not talking about brand name, but rather the length in relation to how far the motor spindle is from the platter. What do I measure? Is there some ratio based formula for then choosing the belt length?
Thank you.

 

[russc]

Use a piece of string to measure the total distance round the hub and motor. Then deduct ~5% to give some tension.

 

[Bare]

IF your motor pulley is straight as in Not barrel shaped.. then Unwaxed Dental floss (just knotted makes for a 'fine' belt.
You won't be needing to look further.

 

[lexx21]

Absolutely Bare. Dental floss works very well.

 

[CrownHill]

I tried dental floss once, but all that happened was my platter got cavities.

 

[lcsaszar]

I tried dental floss once, but all that happened was my platter got cavities.

Use a good quality factory flat belt, and a barrel shaped motor pulley. Make the motor to platter distance adjustable, and tension as necessary.

 

[MagicBus]

I' m completely irrelevant to the subject but FWIW I was reading that old cassette tape is fine for the purpose!