[YvesD]

When adding wheel spacers, is it necessary to get the geometry set up again ?

It is altering the wheel base at the end of the day and hence the presentation of tyre to road ?

Yves

[Malek@MRF]

Spacers don't alter the wheelbase at all, it alters track width.

If you widen out the rear considerably, you have a better chance of understeering, but at the same time, you have a more stable rear end.

[Ferg]

Are you talking about alignment?

[YvesD]

Originally Posted by Ferg

Are you talking about alignment?

Yes,

I have just added a set of front and rear spacers and the car doesnt quite feel the same as before, cant really put my finger on it..

Yves

[Malek@MRF]

Originally Posted by YvesD

Yes,

I have just added a set of front and rear spacers and the car doesnt quite feel the same as before, cant really put my finger on it..

Yves

you do not need an alignment from installing spacers. It has no affect on it at all.

Spacers widen out wheel track (essentially making the car wider). It does not alter wheel base either as you mentioned in your first post.

A wider stance (if front and back is done in correct propertions) will actually improve your handling and traction because you are spreading out the force applied to each corner.

Think of it like this... you are standing on a sheet of glass which has no support except around its edges. The closer you bring your mass to the center of that sheet of glass, the greater the flex and the greater the chance of breaking that glass. Now, lets say you start to spread yourself out over the glass, you are distributing your mass away from the center. Does that make sense?

When you widen track width, you are essentially allowing the car to spread its mass out. Many automotive instruments can back this up (ie. tire pyrometer).

[Josephkao]

How big is your front spacer did you go? Is you car with the spacer now do not track as straight as without spacer?

[Orb]

Originally Posted by Malekreza11

you do not need an alignment from installing spacers. It has no affect on it at all.

Spacers widen out wheel track (essentially making the car wider). It does not alter wheel base either as you mentioned in your first post.

A wider stance (if front and back is done in correct propertions) will actually improve your handling and traction because you are spreading out the force applied to each corner.

Think of it like this... you are standing on a sheet of glass which has no support except around its edges. The closer you bring your mass to the center of that sheet of glass, the greater the flex and the greater the chance of breaking that glass. Now, lets say you start to spread yourself out over the glass, you are distributing your mass away from the center. Does that make sense?

When you widen track width, you are essentially allowing the car to spread its mass out. Many automotive instruments can back this up (ie. tire pyrometer).

The wider track reduces load transfer but at the cost of increasing KPI offset which effect your scrub radius offset (tire will run hotter due to shear). The result is that you generally get less traction and possibly bump steer. The 5 link rear system is less sensitive to this change but the strut is another story. Putting in a 1 to2 degrees of negative camber will correct it within reason.

FWIW, suspension designer will sacrifice camber curves and other variable for proper KPI offset. In just happens no one really cares.

Orb

[Rugs]

Originally Posted by Josephkao

How big is your front spacer did you go? Is you car with the spacer now do not track as straight as without spacer?

I had to take my H&R 5mm spacers off the front. Since they don't have the larger defined Hubcentric lip of the rear 10mm spacers that are on the rear of my e93, they wouldn't stay perfectly centered and the front wheels would vibrate & the car seemed to track strangely...

[YvesD]

Originally Posted by Rugs

I had to take my H&R 5mm spacers off the front. Since they don't have the larger defined Hubcentric lip of the rear 10mm spacers that are on the rear of my e93, they wouldn't stay perfectly centered and the front wheels would vibrate & the car seemed to track strangely...

Exactly what I have been experiencing.

5mm spacers are now off the front and the wobbles have gone away.

Leaving the 12mm hubcentric rears on as they seem OK handling wise and no vibrations.

Just goes to show that BMW really do know what they are doing with the set up and if you change just one small thing, something else usually suffers.

Doesnt stop us fiddling though does it !

Yves

[AlanAZ]

at the cost of increasing KPI offset which effect your scrub radius offset (tire will run hotter due to shear). The result is that you generally get less traction and possibly bump steer. The 5 link rear system is less sensitive to this change but the strut is another story. Putting in a 1 to2 degrees of negative camber will correct it within reason.

I'm consider putting 12-15 mm spacers on the back of my 325i sport with stock wheels. Will this increase the camber and/or cause increased tire wear? What will the net effect on handling be?