Wheel Spacers

I bought a 30mm kit from H&R before taking delivery of my 550. When I received it, I found that it already had the Hill 25mm kit installed. PM me if you have interest in them.

 

Good info, Taz, and it addresses my largest concern regarding that type of spacer. I would still not use them though, as there are other problems with that style of spacer. To name a couple, the number of potential failure points is still doubled (we've had at least two FChatters have problems with those very spacers), and since the retaining bolts are most likely not going to be removed and replaced very often I can foresee them seizing in the hubs and/or the spacer itself seizing to the hub face/lip.

The above does bring up an important aspect of fitting any spacer to any car though. When installing spacers you should ensure that the brake disc face and hub lip are smooth and free of rust deposits. I like to use a single edge razor blade to lightly scrape the mounting surface since there is often surface rust in the areas where the mounting surface of the wheel has not been in contact with the face of the brake disc. Follow up with a wire brush, paying particular attention to the lip on the hub itself. Since spacers usually have more contact surface than wheels there's a good chance that they will ride on the areas of surface rust instead of the clean hub face unless all of the surface rust is removed. It may seem like a minor issue, but as you're scraping that rust away it becomes obvious that it creates an uneven mounting surface for the spacer. The bottom line is that you want as much clean, smooth contact surface as possible between the spacer and the hub..

Secondly, I'd suggest applying a very thin coating of anti-seize paste to the inner face of the spacers, especially in the recess for the hub lip. The Hill spacers are machined to very tight tolerances so it's easy to imagine them becoming seized to the hubs over time. They'll be much easier to remove in the future if anti-seize is applied on installation.

Thirdly, it is absolutely imperative to recheck the bolt torque after the spacers have been run. My suggestion is to recheck them after a short drive, and then again after a longer drive. It is all too easy for the spacers to not be perfectly seated upon initial installation, which causes the bolt torque to be incorrect once the car has been driven a bit. This brings up another objection to the bolt-on style spacers-- they have double the number of fasteners to recheck, and you must remove the wheels to check the ones that mount the spacers to the hubs. It is far easier to check for loose spacers when all you have to do is check the wheel bolt torque.

HTH.

 

Good info & advice from Caeruleus11, but I'd suggest that increasing track by the same amount on both the front and the rear is not always the best course of action. There are situations where there's not as much room for added track in the front than there is in the rear, in which case you might want to run more spacer on the rear than the front. Also, there can be a handling advantage to running more spacer on one end or the other. As an example, I think there's enough room to add 25 mm of spacer to the rear and 20 mm of spacer to the front of a standard 348. On the 348 Spiders and Speciales, the factory increased the rear track by 50 mm by changing the rear wheel offset by 25 mm, but they left the front track alone. Subsequent testing by an FChatter fdetermined that the best handling improvement comes from following the factory's path, but some people still prefer the look of the wider track on both front and rear even if it compromises ultimate handling somewhat. As an aside, I run either 42 or 45 mm spacers on the front and 3 mm spacers on the rear of my M3 track car, so keeping spacers the same front and rear is not always possible or desirable. That's why it's a good idea to consult with knowledgable people before deciding on a particular course of action, since the need for and desirability of spacers varies greatly from car to car.

 

Thanks Mike- great posts and given me something more to think about! I agree with you about seeking out knowledgable people. I'd also hazard a guess that its probably a good idea to have the alignment redone.

Mike, why such a big discrepancy on your track car? Is it because the rear track is so much wider and now you are equalizing them? Does a wider rear track typically result in more understeer?