i thank you very much for the advice. well, i guess its time to buy a metric ruler.i am new to the forum, and have deviously gotten my two boys into dirtbikes.its been 23years since i had one. we now have a ktm65, honda 70, polaris 90, xr400. all brand new! i,m trying to get the ktm tuned for my 8yr old to get used to by spring. he will be racing at the moriartymx.com track. my wife and i figured that the first thing should be suspension. the first thing in suspension is sag. we can't get the sag set right using inches so we will try mm's. we want the bike to do its best for himand i was wondering if anyone knows of a book that deals with setup ? maybe it would be best to send the shock and fork to race tech or someone else?