Hopefully the spacers are as safe as people say they are (ie., don't add too much stress on the hub)!
Well I just spent a few hours researching this, and it definitely becomes as complicated of a matter as one wants it to be. I DON'T think there are any horrendous safety issues, but just performance related ones. My takeaway is actually NON-EXISTENT at this point because my brain has melted from information overload. :wave: It seems there's no straight answer because it depends on your suspension geometry and wheel offset/backspacing.
The three things I for sure learned are:
- Decreasing offset increases Track Width
- Decreasing offset increases Scrub Radius
- Decreasing offset decreases Wheel Rate (suspension rate)
Each of these has an affect on your car's handling, steering, and traction, as well as the lifespan of suspension components.
An
article on eHow.com simply says:
"The effects of wheel offset have mainly to do with the forces that are exerted on wheel-bearings. Most manufactured vehicles come with a wheel offset that is designed to minimize the load on the wheel-bearings."
A more detailed article in Honda Tuning Mag titled,
Wheel Offset: Why It Matters (Look Cool Without Being A Dummy), says this about track width:
"Reduced offsets result in larger track widths. This can improve cornering speeds by reducing lateral load transfer from the inside tires to the outside tires. By keeping the tire loads uniform, tires can generate increased lateral grip. This is why most race car tires are as far outboard as possible. On the other hand, changing the wheel width does not change the track.
Another way to increase track without having to purchase new wheels is to install wheel spacers. Spacers are available in different thicknesses, from about 5mm to 30mm or more, depending on the application. Eibach manufactures one of the nicest sets of spacers on the market. Their spacers are precision machined with tight tolerances, which helps ensure that wheels stay securely attached to their hubs."
The article also says this about scrub radius:
"Altering wheel offsets also affects the scrub radius. Recall that the scrub radius is the ground-level measurement between the kingpin inclination axis (KIA) and the tire contact patch's center.
A negative scrub radius is preferred for front-wheel-drive cars since it gives a stabilizing effect when traction between the left and right wheels varies.
Spacing wheels out by means of smaller offsets or spacers increases the scrub radius. This makes a negative scrub radius less negative, maybe even positive. This could lead to unequal front-wheel traction depending upon the difference between the old and new offsets."
And it goes on to mention spring/wheel rates:
"Offset also affects suspension stiffness through the suspension's motion ratio. With less offset, the wheel's leverage about the inboard lower control arm pivot increases while the suspension spring leverage remains constant. The net effect is a reduction in the effective wheel spring rate. For example, a stock DC2 Integra fitted with wheels with 10mm less offset will have a 5 percent lower wheel rate. Therefore, to recover the lost suspension stiffness, a 5 percent stiffer spring is needed."
I was able to confirm all of this (and more) by reading other forums. For example, this
maxima.org thread has similar information:
"Wider stance actually does make a slight difference. In the front it will decrease wheel rates and roll rates (softer feeling suspension), but not by a significant amount. In the rear it won't decrease roll rates but it will decrease individual wheel rates, so if you hit a bump on one side it will soak it up a bit better.
None of this is anything you will notice though.
Spacers will increase scrub radius, which means that your steering wheel will recenter itself more and will be harder to turn (especially if you're stopped and on the brakes). This is something I definitely noticed going from stock wheels to +35s. Depends on the offset of the wheels and size of the spacer.
They will also increase wear on wheel bearings, something like a 5mm will be unnoticeable but try a 25mm and you may notice a difference. With the A33 wheel bearing issues I've heard about this may be a setback, but wheel bearings go out so infrequently as it is I wouldn't worry about it with an A32.
Finally there are safety issues, which are the main concern. Some shops will flat out turn you away if you have spacers. Extended lugs, lug pattern converting spacers etc are all rather risky, some people argue that it's negligible and some argue otherwise. I personally have never heard of a story of something happening because of a spacer but that's not to say that it won't."
I'll probably just throw some 10mm in the rear and call it good.
-duck
