h8tr post of the day 'cause I'm an old fogey...incorrect use of wheel spacers
06-02-2003, 09:02 AM
#15
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**EDIT**beat me to it!
by my quick caluculations, since ET is 43 stock with 7.5 inch wide wheel....i **think**optimum offset of 8 inc wide wheels would be 30.3. wonder fi that is right, since most have ET35 for 8 inch wide wheels...hmmmm.
**EDIT***actually 36.65 would be the correct ET for 8 inch whide wheel so 35 is pretty close
30.3 would be for 8.5 inch...
**EDIT***actually 36.65 would be the correct ET for 8 inch whide wheel so 35 is pretty close
30.3 would be for 8.5 inch...
06-02-2003, 09:19 AM
#19
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manufacturers allow SOME tolerance and...
one of the factors is (of course) accounting for the wheel lug bolts and how it is all attached to the hub (a different but equally vital safety concern).
If a manufacturer doesn't actually SELL factory spacers (you can buy them from Porsche for instance), they probably never thought about it so didn't test it and have no idea what's safe so you are doing the R&D in that area. Pretty sure Audi sells spacers to attach the RS4 wheels for instance.
If in doubt, try to contact the manufacturer before changing things like that. If you are DETERMINED to do it, you HAVE to get the kingpin inclination intersection the same as stock so the load through the center of the tire won't have moved.
HOWEVER, you STILL get the unpredictable effect by as much as DOUBLING the lever arm from the wheel bearing to where the wheel attaches to the hub...it may not seem like much in distance but it's a lot in proportion...yet another reason there's a SAFE LIMIT to wheel spacers and the manufacturer is the most knowledgeable source on what they consider safe:
<img src="http://images3.fotki.com/v27/free/4ae6/4/41918/109066/kingpinleverarm-or.jpg">
If a manufacturer doesn't actually SELL factory spacers (you can buy them from Porsche for instance), they probably never thought about it so didn't test it and have no idea what's safe so you are doing the R&D in that area. Pretty sure Audi sells spacers to attach the RS4 wheels for instance.
If in doubt, try to contact the manufacturer before changing things like that. If you are DETERMINED to do it, you HAVE to get the kingpin inclination intersection the same as stock so the load through the center of the tire won't have moved.
HOWEVER, you STILL get the unpredictable effect by as much as DOUBLING the lever arm from the wheel bearing to where the wheel attaches to the hub...it may not seem like much in distance but it's a lot in proportion...yet another reason there's a SAFE LIMIT to wheel spacers and the manufacturer is the most knowledgeable source on what they consider safe:
<img src="http://images3.fotki.com/v27/free/4ae6/4/41918/109066/kingpinleverarm-or.jpg">
06-02-2003, 10:01 AM
#20
heh reminds me what I used to preach to kids in highschool with "reversed" rims...
All those roller-skate cars had serious problems with their bearings. Just imagine those bearings going bad while on the highway. Freaky thought..