geoff@denelvx.UUCP (Geoff Baum) (07/31/85)
It seems that as a result of my recent detailed response to queries about equivalent tire sizes (plus 1, plus 2 conversions, etc) I have become the network expert on the subject (all I did was write a program to calculate all the numbers for me). Well, there is at least one thing, reguarding this, that I don't know and would appreciate an answer to (I have also had people ask me about this by mail). What affect (if any) does changing wheel width have upon overall tire diameter? I know that increasing wheel width increases the effective tire width (at ground level), but what does it do to sidewall height (or tire diameter)? It seems to me that making the sidewall more vertical by increasing the wheel width would increase the tire diameter. It also seems that causing the tread to lie flatter on the road (by increasing wheel diameter) would tend to DECREASE the tire diameter. Does anyone really know which effect dominates? Do they cancel each other? Does the dominating factor depend on the tire pressure, or what? I don't want to fill up the NET with responses to this, so please respond with factual information. Theories should be limited to those not already mentioned in this article. Thanks in advance. Geoffrey Baum