Pug Wheels ! So, you’ve trashed your standard rims on curbs and you’re
looking for a shiny new set. Your not sure whether or not to try and put your
mates Ford Escort 18's on your Mini Metro!!! Which ones do you go for? Well the
choice is endless but first we need to get a few things right. A small hint
is that if the tyres are chaffing (because the sidewalls on some tyres are
straighter than others), then try fitting Bridgestone, Dunlop, Continental or
Pirelli rubber as they are more rounded and run into the arch better. There
are a few things that we should all know.
Another tip, if you want cheap tyres (e.g. 205/45/16’s for £45
inc VAT), then click below and believe your eyes!:
Enter The Wheel Gallery
Glossary:
Number of
bolts or studs! It
goes without saying you can't fit a 4-bolt wheel onto a 5-bolt wheel hub.
Sounds obvious, but people have been known to fork out for an expensive set of wheels only to
find they've got the wrong number of mounting holes.
Pitch Circle
Diameter! So you know how many holes there are. Now you need to know
the PCD, or Pinch Circle Diameter. This is the diameter of the invisible
circle formed by scribing a circle through the centre point of each mounting
hole. If you've got the right number of holes, but they're the wrong
spacing, again the wheel just won't fit.
|
Offset, Inset
and Outset! Ignore
this and you'll end up with handling problems. Offset is the distance in mm
between the centreline of the rim and a line through the fining face.
Offset can be inset (negative offset), Outset (positive offset) or neither.
Offset plays a large pant in how the suspension and self-centring steering
behaves. The most obvious problem if you get it wrong is the steering will
be so heavy you can't turn the car, or so light you spend all your time
keeping it in a straight line. You may also suffer problems ranging from
wheels fouling bodywork or suspension, and high-speed steering judder.
|
Rolling Radius! Very important. It's the distance in mm
from the centre of the wheel to the edge of the tread when its unladen. If
it changes because you've mismatched your new wheels and tyres, then your
Speedo will lose accuracy and the fuel consumption might go up. The reason
is because the manufacturer built the engine/gearbox combo for a specific
rolling radius. Mess with this and the whole thing could start to fall down
around you.
|
The plus one
concept! The plus
one concept describes the proper set-up up of a wheel and tyre combo.
Basically, each time you add 1 inch to the wheel diameter, add 2Omm to the
tyre width and subtract 10% from the aspect ratio. This compensates nicely
for the increase in rim width that generally accompanies increases in
diameter. By using a larger diameter wheel with a lower profile tyre, it's
possible to properly maintain the overall rolling ratios, keeping odometer
and speedometer changes negligible. By using a tyre with a shorter
sidewall, you gain quickness in steering response and better lateral
stability.
|
|