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Old October 17th 2009, 08:22
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evilC evilC is offline
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Join Date: Jun 2008
Location: UK Where Leics is more
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Quote:
Originally Posted by oasis View Post
It has been a year and a half since I lost my 1302 in a fire. It dawned on me the other day as I was looking through some old notes and books currently stored in an off-site storage facility I asked a lot questions that were all over the place until I bought my 1302. Oddly, most questions then focused on a 1303 until I made my purchase. Nevertheless, many questions have popped into my head as I try to do some conceptualizing and I need to once again rely on everyone here who has the experience I lack.

The first questions for my second project have to do with staggered wheels. I know some stock Porsche's have wider wheels on the rear than on the front.

(1) Is there an advantage to staggered wheels if applied to a 1303? Would there be disadvantages?

(2) Is there a formula for staggered wheels? It doesn't have to be a genuine mathematical equation ot anything but is it better to be one-inch wider on the rear? One and a half? Two inches?

(3) Is there a point of no return on the advantages of wider wheels? Is an 8/9½ better than a 6½/7½, for example?

(4) Since wider wheels may mean wider fenders (wings), are there advantages and/or disadvantages to going wider there as well? I have seen some wider fenders that require a second look to even notice they are wider, and I have seen some that almost border as an extreme measure. I'd prefer not going the extreme route but if that route would be better, then so be it?

I'll ask other questions in other threads in their appropriate forums. Thanks in advance.
The correct sized wheels for the front or the rear for ANY vehicle is that which is suitable to support the weight of that corner for the application. However, a moderating factor is the slip angles that are provided by each tyre. There are other factors relating to physical fit and gearing that will be ignored here.
IF you could get equal slip angles front and rear then for a bug with say, a 400hp engine you could be looking at a front wheel width of 160-180mm and a rear width of 250+mm. That would be impractical so it ends up as a compromise on slip angles, traction under power and front end slide.

There is no magic formula and you will find that the differences in wheel width are the result of all sorts of suspension perameters and personal preference. For example, some super cars run rear wheels that are ridiculously wide if you consider the front wheel width and slip angles but the compromise with traction under power and suspension set up moderate the effect.

A good starting point with any car is to run equal tyres front and rear at say the minimum width and then increase the width of one end or the other to suit driving preference and power since you are unlikely to vary the suspension geometry too fundamentally.

Remember, too wide is too slow.

Clive
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