# 406 or 451 rim diameter on 20 inch tyre?



## fredstaple (Jun 2, 2003)

I bought a Japanese Micro bike, OSSO, made in China. It has 20 inch wheels. Does anyone know how I tell if the rim diameter is 451 or 406? The tyres that came on it are 20 x 1.5 inch. 

My guess is 406 since the tyre size is in decimals, but this is not a hard and fast rule. Anybody know how I can tell?

Thanks.


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## Dave Hickey (Jan 27, 2002)

It's 406.... Most of the micro bikes sold have 406 sized tires and the decimal labeled size is a sure indication of the 406 sized tire

You can also measure the rims... my 451 rims on my Swift measure approx 46cm diameter..


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## kbiker3111 (Nov 7, 2006)

Look on the old tires?

451's tend to be skinnier and 406's tend to be wide, BMX style rims.


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## fredstaple (Jun 2, 2003)

*Thanks*

Part of my confusion was caused by the Gios Micro velos, they have 451 diameter tyre beads. I really wish the cycling industry as a whole could settle on a standard measurement system.


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