622 tyre size help. Building a wheel.

[Dave_C]

My friend has a ~4 year old Focus Crater 3.something. I'd like to build a dynamo wheel for the bike and give a set if lights for Christmas. But the website suggests it has 622 rims. Sheldon says these could be 700cc but with a different sized rim, width?

Can anyone help me with a suitable rim. I can figure out the spoke length from the hub and exact rim, but identifying the right rim is my problem. I've to-date built 700cc wheels on Mavic and Ambrosio rims, and they are simple as I ride 25mm tyres.

Any help, much appreciated. Thanks.

Oh and before you ask, I can't ask, as that would spoil the surprise.

Cheers, Dave C

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[FifeingEejit]

622 is the ETRTO rim diameter for 700c wheels.

Should be in the format width-diameter e. g. 19-633 is 19mm wide rims
Can't remember if it's internal or external width though.

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[Brucey]

622mm is the bead seat diameter of 700C rims .

If you can find out the specification of the rims on the bike it may be possible to provide suggestions for a close match

cheers

[FifeingEejit]

https://www.focus-bikes.com/gb_en/95621-crater-lake-3-9#!

Says 21mm wide rims.

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[sojournermike]

21mm internal

This in the 700c version would work I think

https://spacycles.co.uk/m20b0s116p4025/KINLIN-TL-21

Or this

https://spacycles.co.uk/m20b0s116p1569/EXAL-ML21

Both 21mm internal, so would match the current rim for size of not style.

[Dave_C]

Thanks chaps, I've ordered a rim and spokes to fit the Shutter Precision hub.

Dave C

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[rogerzilla]

The width quoted for rims is the internal width.  21mm is very wide and the optimal tyre size is going to be over 30mm.

[zigzag]

The width quoted for rims is the internal width.  21mm is very wide and the optimal tyre size is going to be over 30mm.

21mm internal is pretty standard and popular these days, it can accommodate wide range of tyres, from 25mm (that's what i use) to 55mm mtb tyres. optimal tyre (according to current "expert" opinion) should be a bit narrower than a rim, if going fast is important.

[FifeingEejit]

The width quoted for rims is the internal width.  21mm is very wide and the optimal tyre size is going to be over 30mm.

The Crater Lake I linked to comes with 40mm tyres.

[Cudzoziemiec]

The quoted width should be the internal width but some manufacturers quote external width only. H+Son do this, unfortunately.