Bazza Posted January 5, 2009 Report Share Posted January 5, 2009 been trying to work this out (head's now hurting) wheel is 6" wide with an offset of 38mm if this was replaced with a wheel 6.5" wide with an offset of 40mm where does this put it in relation to the existing wheel position on the car ? ps..why does the tyre and wheel industry use two different measuring units !!! Quote Link to comment Share on other sites More sharing options...
Tony Posted January 5, 2009 Report Share Posted January 5, 2009 Inner clearance is 8mm less (the inside of the wheel to the strut housing) Outer position extended an extra 4mm (position of the outside edge of the wheel) Quote Link to comment Share on other sites More sharing options...
Bazza Posted January 5, 2009 Author Report Share Posted January 5, 2009 that was quick as they say "its going to be tight" Quote Link to comment Share on other sites More sharing options...
Tony Posted January 5, 2009 Report Share Posted January 5, 2009 Spacers? Quote Link to comment Share on other sites More sharing options...
Mat Posted January 5, 2009 Report Share Posted January 5, 2009 ps..why does the tyre and wheel industry use two different measuring units !!! First, the US has been the major market for tires for most of the past century. Second, although scientists and technologists in the US have embraced the metric system, the common man in the street (including members of Congress) know little or nothing about the metric system and actively resist any changes from the English (as we call them here) system of weights and measurements. Third, government bureaucracies have cast English units into law making it very difficult to change to metrics given the feeling of the voters. This includes the powerful US Department of Transportation (D.O.T.). Before the introduction of European made radial tires for passenger cars into the US in the 1960s, American-made tires used English units to denote the size of a tire. Some size examples are: 6.00X13, 8.25X14, 5.60X15, 7.00X14, 7.50X15, 6.00X15 The first 3 numbers of the size measured the width of the tire casing at its widest point. For example, the 6.00 of the size 6.00X13 is 6 inches wide. This called the section width. The 13 of a 6.00X13 is the diameter of the wheel, in inches, that the tire is to be mounted on. For each diameter of tire there was only one standard width! While domestic tire manufacturers and the D.O.T. were changing the tire sizing systems from Numeric to Alpha-Numeric during the 1960's, the European tire manufacturers went to a Metric system of sizing predominantly because of radialization. Some metric size examples would be: 165SR13, 175/70SR13, 185SR14, 195/70SR14, 155SR15, 215/60HR15, 165SR15. You will notice there is little similarity here in some of the numbers to numeric or alpha-numeric sizing except for the last 2 digits; 13,14 or 15 which is still the diameter of the wheel, in inches, that the tire is to be mounted on. However, where the numeric system used a 6.00 or 7.00 to denote the cross- section of a tire in inches, the Metric system uses the numbers 165 from the 165SR13 to denote the measurement of the cross-section in millimeters. Thus because historically Americans did not need to know about tire dimensions, except for the wheel diameters, European tire manufacturers were able to use metric dimensions for tires except for the diameter which was written into previous US law to be measured in inches. Thus, all European manufacturers needed to do to get into the vast US market, which did not produce radial tires at that time, was to change one number on the tire into inches to meet US law. Also, the 1960 radialization and technology increased the tire manufacturer's ability to improve the performance of the tire dramatically by increasing the section width and reducing the sidewall height of the tire. This change of the aspect ratio needed to be reflected when stating the size. An example of section width increase in size on the same wheel diameter would be 155"82"SR13 or 155SR13 to 175/70SR13 or 205/60R13. All 3 sizes essentially have the same sidewall height but notice the section widths increased from 155 mm to 175 mm and 205 mm as the aspect ratio respectively changed from "82" to 70 to 60. The overall tire diameters of these 3 sizes should be within 3% of each other. However, this 3% difference in diameter did cause some problems for the general public in the US because standard automobile odometers indicated less mileage using the reduced diameter of radial tires. The general public thought that the radial tires were reducing their car’s fuel economy. Today, the global market, and concerns about tire safety have resulted in an ongoing series of international meetings trying to standardize tire parameters, including loading. Reference: http://www.dunloptire.com/lib rary.html Quote Link to comment Share on other sites More sharing options...
Bazza Posted January 5, 2009 Author Report Share Posted January 5, 2009 Spacers? would prefer to stay away from them if possible, strangely its only going to be tight at the front !.........oh the joys of negative camber Quote Link to comment Share on other sites More sharing options...
Bazza Posted January 5, 2009 Author Report Share Posted January 5, 2009 ps..why does the tyre and wheel industry use two different measuring units !!! First, the US has been the major market for tires for most of the past century. Second, although scientists and technologists in the US have embraced the metric system, the common man in the street (including members of Congress) know little or nothing about the metric system and actively resist any changes from the English (as we call them here) system of weights and measurements. Third, government bureaucracies have cast English units into law making it very difficult to change to metrics given the feeling of the voters. This includes the powerful US Department of Transportation (D.O.T.). Before the introduction of European made radial tires for passenger cars into the US in the 1960s, American-made tires used English units to denote the size of a tire. Some size examples are: 6.00X13, 8.25X14, 5.60X15, 7.00X14, 7.50X15, 6.00X15 The first 3 numbers of the size measured the width of the tire casing at its widest point. For example, the 6.00 of the size 6.00X13 is 6 inches wide. This called the section width. The 13 of a 6.00X13 is the diameter of the wheel, in inches, that the tire is to be mounted on. For each diameter of tire there was only one standard width! While domestic tire manufacturers and the D.O.T. were changing the tire sizing systems from Numeric to Alpha-Numeric during the 1960's, the European tire manufacturers went to a Metric system of sizing predominantly because of radialization. Some metric size examples would be: 165SR13, 175/70SR13, 185SR14, 195/70SR14, 155SR15, 215/60HR15, 165SR15. You will notice there is little similarity here in some of the numbers to numeric or alpha-numeric sizing except for the last 2 digits; 13,14 or 15 which is still the diameter of the wheel, in inches, that the tire is to be mounted on. However, where the numeric system used a 6.00 or 7.00 to denote the cross- section of a tire in inches, the Metric system uses the numbers 165 from the 165SR13 to denote the measurement of the cross-section in millimeters. Thus because historically Americans did not need to know about tire dimensions, except for the wheel diameters, European tire manufacturers were able to use metric dimensions for tires except for the diameter which was written into previous US law to be measured in inches. Thus, all European manufacturers needed to do to get into the vast US market, which did not produce radial tires at that time, was to change one number on the tire into inches to meet US law. Also, the 1960 radialization and technology increased the tire manufacturer's ability to improve the performance of the tire dramatically by increasing the section width and reducing the sidewall height of the tire. This change of the aspect ratio needed to be reflected when stating the size. An example of section width increase in size on the same wheel diameter would be 155"82"SR13 or 155SR13 to 175/70SR13 or 205/60R13. All 3 sizes essentially have the same sidewall height but notice the section widths increased from 155 mm to 175 mm and 205 mm as the aspect ratio respectively changed from "82" to 70 to 60. The overall tire diameters of these 3 sizes should be within 3% of each other. However, this 3% difference in diameter did cause some problems for the general public in the US because standard automobile odometers indicated less mileage using the reduced diameter of radial tires. The general public thought that the radial tires were reducing their car’s fuel economy. Today, the global market, and concerns about tire safety have resulted in an ongoing series of international meetings trying to standardize tire parameters, including loading. Reference: http://www.dunloptire.com/lib rary.html blooming Americans fault then Quote Link to comment Share on other sites More sharing options...
TarkMalbot Posted January 5, 2009 Report Share Posted January 5, 2009 Check out here: http://www.1010tires.com/WheelOffsetCalculator.asp Quote Link to comment Share on other sites More sharing options...
Tony Posted January 5, 2009 Report Share Posted January 5, 2009 Check out here: http://www.1010tires.com/WheelOffsetCalculator.asp I think we all use the same one Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.