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Wheel Rim Width
smart51 - 5/4/06 at 11:42 AM

I am looking at some new wheels and tyres. The tyres are reccomended for use with rims from 6" to 7.5" wide.

What will be the effect of the wider and the narrower sized rims (other than the extra weight of the metal)?

[Edited on 5-4-2006 by smart51]


smart51 - 5/4/06 at 06:31 PM

I guess the narrower rims will pinch the tyre more but how would it affect handling?


Mark Allanson - 5/4/06 at 06:40 PM

The optimum width of the rim should be 85% of the tyre width


smart51 - 5/4/06 at 06:45 PM

OK so 85% is best, which is 6.5". What would be the effect of fitting a 7" rim or a 6" rim?


Liam - 5/4/06 at 06:54 PM

Probably nothing you'd ever notice...

Liam


britishtrident - 5/4/06 at 07:00 PM

Wide tyres for the rim width = bad tyre squirms, more so with higher profile tyres.
Narrow tyres for the rim = no that bad partiularly on higher profiles.


zilspeed - 5/4/06 at 07:03 PM

I certainly remember at least one article I have read where the driver chose a wider wheel than was the norm for a given tyre width, purely to keep the tyre under control - i.e. to reduce squirm.

May be worth lookin into.


ned - 5/4/06 at 10:08 PM

on our racecar (slicks) we went to wider wheels (well, split rim halves) and it stabilised the tyre wall flexand made the tyre more consistent.

personally i'd want the rim at least the same width as the tyre, something like 6" for 185 and 7" for 205.

imho

Ned.


Fred W B - 6/4/06 at 06:04 AM

This is what my wheel/tyre supplier told me -

Quote

Ok, the tyre sizes. For road tyres (tyres you buy from your local tyre supplier), the widths are generally wider for a certain size rim. But for race tyres (slicks or Dunlop R's), the sizes I gave you are what were recommended by my supplier and by a fellow race freak!! What will happen if you go wider, is that the tyre will roll too much on the sidewall, and you'll end up stuffing up the sides of the tyre before you've made good use of the centre, plus you will have to use a very high tyre pressure to try keep the sidewalls hard, which will be at the expense of handling. I had this exact conversation with another racer today!! He now wants wider wheels from me, so that he doesn't have to lose out on tyre width.


Unquote

On his reccomendation I am going with 195's on 7" and 205's on 8" rims

Cheers

Fred WB

[Edited on 6/4/06 by Fred W B]