• So I am basically committed on putting down a deposit on a low trail 650B adventure bike, all happened rather quickly after looking through a random Flickr feed belonging to a German builder... proper thread to follow in current projects but... I just got an email from builder in question saying:

    Are you sure about the rake-trail?  I put it into bike cad last night and I think I needed more rake to get the 34mm of trail.

    The figures/angles I had given him were 73 deg head angle, 65mm of rake giving 34mm if trail... Have I got my angles wrong or is he missing something? I know more rake offset will decrease the trail but my figures suggest 65mm offset equals 34mm rake with a 73 deg head angle... I am no mathematician... thoughts?

    edit - could it be that we are using different length forks? my figs for 650B his for 700c?

    edit* - @edscoble

  • different wheels and tyres make a noticeable difference in trail, ask him again to ensure he got the correct wheel sizes on it (650b x 42mm is equal to 700c x 23mm).

    With 700c and 38mm tyres, the trail go up to around 40-45.


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