circumference of wheel

[FLOGGED]

Hey guys, very very random question, i thought i would ask here.

i have a mini bike racing tire, im trying to find the circumference so i can set up my speedo.

it is a - 110/50-6.5 Racing Slick



circumference needs to be in MM.

Hope someone can help.

Cheers

[XB GS 351 Coupe]

Tape-measure would be your friend here.

[FLOGGED]

Originally Posted by XB GS 351 Coupe

Tape-measure would be your friend here.

Thanks! do you know how to messaure it using a tape? cheers

[LG17]

Wrap a cloth tape measure around the middle of the tyre, make sure it's fairly firm.
If you don't have a cloth one, use a piece of string and mark it clearly, then measure it.

[Falcon Coupe]

If you have trouble getting a tape around it try marking the edge of the tyre with chalk. Move said mark to the bottom and mark the ground where it touches.
Then move the tyre a single full revolution and mark the ground again. Then measure the distance between the two marks you have on the ground.

This is how I used to setup my Husaberg speedo when using the Trail Tech Vapor. Would be best fitted to a rim and inflated before measuring.

[SumoDog68]

It is 110 mm wide and 50% profile which is 110 (55 mm top and bottom ) plus 6.5 inch wheel which is 165.1mm . Diameter is 110 plus 165.1 which is 275.1. Circumference is 2rp which is 863.8mm.

[FLOGGED]

Originally Posted by SumoDog68

It is 110 mm wide and 50% profile which is 110 (55 mm top and bottom ) plus 6.5 inch wheel which is 165.1mm . Diameter is 110 plus 165.1 which is 275.1. Circumference is 2rp which is 863.8mm.

Woah Thanks , i really should of paid attention in maths class.

[Giant Cranium]

Originally Posted by SumoDog68

It is 110 mm wide and 50% profile which is 110 (55 mm top and bottom ) plus 6.5 inch wheel which is 165.1mm . Diameter is 110 plus 165.1 which is 275.1. Circumference is 2rp which is 863.8mm.

the 50% side wall includes the part that goes inside the wheel right? so that maths may be out

[Giant Cranium]

just checked you are correct
http://tire-size-conversion.com/tyre-size-calculator/

[esppwr]

Measure outside diameter then multiply by PI (3.142)

[Mechan1k]

Although tyres do have set dimensions ... not all are equal ... but come close to be classed for that size.

For ultimate accuracy though ... it is best to have the tyre in front of you on the rim at the inflated pressure and measure that way preferrably.

[NTF6]

As esppwr said PIxD (3.1416 x ?)

[SumoDog68]

Originally Posted by Mechan1k

Although tyres do have set dimensions ... not all are equal ... but come close to be classed for that size.

For ultimate accuracy though ... it is best to have the tyre in front of you on the rim at the inflated pressure and measure that way preferrably.

Tyre manufacturers publish dimensional data of a tyres they produce mounted on approved rim. Same nominal tyre sizes differ in actual size depending on manufacturer and type of the tyre , pressure , rim width , speed , load etc
Radius of a tyre changes depending on pressure and speed when mounted on a vehicle . Manufacturers will publish both static and rolling diameter of a tyre at 60 km/h ( bit hard for us to measure a rolling tyre ).
Here is the example of a tyre calculator that uses dynamic and static diameter , contact patch size , air volume , tyre comfort suspension value etc.

http://bndtechsource.ucoz.com/index/...alculator/0-20

[Crazy Dazz]

But Pies AREN'T squared? They're round.

[aussie muscle]

Originally Posted by esppwr

Measure outside diameter then multiply by PI (3.142)

wow, 10 responses before someone used their high school maths.

Good on ya esppwr.

[SumoDog68]

Originally Posted by aussie muscle

wow, 10 responses before someone used their high school maths.

Good on ya esppwr.

And tape measure .