sean brady scooters wrote:it looks great ,did you have to modify the swing arm on the engine to accomodate the larger wheel at all ?
i don't exactly what he has done to the swing arm, he might have had to grind a very slight bit off the curved section, but
its all about offsets - like on a car when fitting alloys, depending on the rims off set will depend on how he has spaced it out from the engine, im guessing he will have had to make the hubs or machine and alter px ones, as with some of the earlier sip wide wheel kits the tyre rubbed on the clutch covers and therefore it needed grinding down slightly or a new cnc clutch cover with a flat face replaced the original.
as for the rims and tyres fitting in that space all you have to do is the maths.
i know from running wide wheel kits that the maximum size tyre you can fit on a px at the rear is a 130/90 -10, even with this size you are pushing it to mere millimetres from the casing and the exhaust bracket.
so the radius - centre of the hub to the outer edge of the tyre for a 130/90 - 10 set up is 242mm
you work this out by 130 (width of the tyre in mm) 90 (the height in percentage of the width) and half of the 10 inch rim (125mm - (1 inch = 25mm approx)) -
so thats 90% of 130 = 117mm + 125mm = 242mm - that i know is a few mm off the engine casing.
hence when fitting an 'wide tyre' on a sip kit you put on 130/70-10 or 120/70-10, as this gives it roughly the same profile (height of the tyre) as the original 3.50 - 10 tyre.
when putting an 'over size' tyre on - i.e. wider and higher, the maximum you can put on is 130/90-10, pushing right to within a millimetre or two of the engine mount, which is unsafe as tyres can and will expand up to 4mm,
therefore i run 120/90 -10 as an over size on my sip kit, (233mm)
so for the gts rims - on the books they run two tyre sizes - 130/70 - 12 on the front and 120/70 -12 on the rear
so it depends what tyres he is running but either should also clear the engine by a few millimetres
the 130/70 - 12 altogether radius is - 150mm(6inch) + 91mm = 241mm
the 120/70 - 12 altogether radius is - 150mm + 84mm = 234mm - the safer option
hope that helps