Say you have a 295/35/18 and a 295/40/17 what tire is going to be wider? From my research the 18's tend to run a bit wider. If they indeed do why such a variation in width?
17 vs 18 Tire width question
- Thread starter Silverboost
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I would like to know as well
There are a lot of reasons for this, some minor some a little more noticeable. Here are three.
1. Different manufactures determine a tires size by measuring tires from different points. One manufacture might measure from the flattest point of the tread to the flattest point of the tread, another tire manufacture might measure the width from the middle of the shoulder to the middle of the shoulder.
2. Mold variations can be slightly different. Two tire molds might have been made by two different mold companies. Also Older molds that have been re-tooled might be slightly larger.
3. Wheels widths effect mounted tire widths. The width of your wheel will effect the width of your tire. For example: A 295.40.17 mounted on a 17x9 might measure less than the 11.6" measured wide and the same tire mounted on a 17x10 should measure closer to the measured width. The narrower wheel, to an effect, pinches the tire as the side walls are held in. The wider wheel pinches the tire less allowing the tire to sit flatter and the footprint to be larger. I should also note that 18” wheels usually come in wider sizes than 17” wheels., 18x7.5 and 18x8 are most common 18” wheels for passenger cars. 17x7 and 17x7.5 are most common for passenger cars.
4. Air pressure can also effect the tires width. Too much air bulges the side-wall out, causing the tire treat to spread, too little and the tread pinches together.
1. Different manufactures determine a tires size by measuring tires from different points. One manufacture might measure from the flattest point of the tread to the flattest point of the tread, another tire manufacture might measure the width from the middle of the shoulder to the middle of the shoulder.
2. Mold variations can be slightly different. Two tire molds might have been made by two different mold companies. Also Older molds that have been re-tooled might be slightly larger.
3. Wheels widths effect mounted tire widths. The width of your wheel will effect the width of your tire. For example: A 295.40.17 mounted on a 17x9 might measure less than the 11.6" measured wide and the same tire mounted on a 17x10 should measure closer to the measured width. The narrower wheel, to an effect, pinches the tire as the side walls are held in. The wider wheel pinches the tire less allowing the tire to sit flatter and the footprint to be larger. I should also note that 18” wheels usually come in wider sizes than 17” wheels., 18x7.5 and 18x8 are most common 18” wheels for passenger cars. 17x7 and 17x7.5 are most common for passenger cars.
4. Air pressure can also effect the tires width. Too much air bulges the side-wall out, causing the tire treat to spread, too little and the tread pinches together.
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