19" Tire question
11-04-2010, 05:11 PM
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19" Tire question
I was goofing around on tirerack.com and I noticed that in order to keep the same rolling diameter and revs per mile as the stock 18, you have to use a 235/50 19. I'm basing this on having the Bridestone Dueler Alenza HL.
Is there any reason why Acura decided to recommend the 245/45 19 other than the recommended base wheel diameter for the 19?
Has anyone tried this tire size on a 19 and if so how was the ride compared to the stock 18.
Is there any reason why Acura decided to recommend the 245/45 19 other than the recommended base wheel diameter for the 19?
Has anyone tried this tire size on a 19 and if so how was the ride compared to the stock 18.
11-04-2010, 05:38 PM
#2
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I think the answer is sales potential
Use this link to calculate tire diameter differences.
http://www.1010tires.com/TireSizeCalculator.asp?
235/50-19 is correct plus 1 size up, but there are very few choices (11) on the Tire Rack in that size.
245/45-19 on the other hand is 1.74% too small when compared to stock. There are more choices of tires (42) in this size, however, which is likely why Tire Rack offers the alternate size instead of what Acura recommends
Use this link to calculate tire diameter differences.
http://www.1010tires.com/TireSizeCalculator.asp?
235/50-19 is correct plus 1 size up, but there are very few choices (11) on the Tire Rack in that size.
245/45-19 on the other hand is 1.74% too small when compared to stock. There are more choices of tires (42) in this size, however, which is likely why Tire Rack offers the alternate size instead of what Acura recommends
11-18-2010, 09:41 PM
#3
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I can see the marketing side of this, but M-B is using this size on the GLK so it's not like there isn't another compact SUV using this ratio.
11-19-2010, 10:37 AM
#4
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If you want to compare apples to oranges, you can compare the RDX to the GLK, but the fact that MB designs its vehicle around a particular sized tire has nothing to do with what Acura designs its products around.
In general, with any car, but especially with AWD, you want to maintain the same rolling diameter as stock. Changing the rolling diameter changes speedo and odo readings, and affects your gear ratios, and braking. I believe, though have not confirmed, it may also affect systems such as VSA, which in part, may use wheel rotations as calculation input, in addition to accelerometer data.
With any car, places like the Tire Rack are willing sell you tires that are within 2-3% of the stock rolling diameter...beyond that, speedo/odo, gearing and braking are affected too much.
With AWD, it is critical, unless the manual allows otherwise, to make sure all four tires have the same rolling diameter.
Real world example of a similar situation....Current gen TL and RL drivers suffer the same problem...The 17 inch stocker on the 4G TL FWD, and on 2005-2008 RL's is 245/50-17, a relatively difficult size to find, with few choices, especially in high performance rubber. The Plus 1 to that tire, is 245/45-18, and there could not be more choices in this size...The SH-AWD TL and 2009+ RL use this as their stock size.
Stepping up to 19" finds a similar situation to the 17's. 245/40-19 has relatively few choices, and many wheel and tire vendors recommend instead the 255/40-19, which is a more common (though not by much) size, and is about 1.3% larger diameter than stock...This also allows the vendor to recommend a more expensive 19 inch wheel because in a 40 series, you need a minimum 8.5 inch wide wheel for the 255 section.
Stepping up to a 20 finds a similar situation to the 18's...lots of choices in 245/35-20 tires, and better pricing in many cases, than the more scarce 19's.
In general, with any car, but especially with AWD, you want to maintain the same rolling diameter as stock. Changing the rolling diameter changes speedo and odo readings, and affects your gear ratios, and braking. I believe, though have not confirmed, it may also affect systems such as VSA, which in part, may use wheel rotations as calculation input, in addition to accelerometer data.
With any car, places like the Tire Rack are willing sell you tires that are within 2-3% of the stock rolling diameter...beyond that, speedo/odo, gearing and braking are affected too much.
With AWD, it is critical, unless the manual allows otherwise, to make sure all four tires have the same rolling diameter.
Real world example of a similar situation....Current gen TL and RL drivers suffer the same problem...The 17 inch stocker on the 4G TL FWD, and on 2005-2008 RL's is 245/50-17, a relatively difficult size to find, with few choices, especially in high performance rubber. The Plus 1 to that tire, is 245/45-18, and there could not be more choices in this size...The SH-AWD TL and 2009+ RL use this as their stock size.
Stepping up to 19" finds a similar situation to the 17's. 245/40-19 has relatively few choices, and many wheel and tire vendors recommend instead the 255/40-19, which is a more common (though not by much) size, and is about 1.3% larger diameter than stock...This also allows the vendor to recommend a more expensive 19 inch wheel because in a 40 series, you need a minimum 8.5 inch wide wheel for the 255 section.
Stepping up to a 20 finds a similar situation to the 18's...lots of choices in 245/35-20 tires, and better pricing in many cases, than the more scarce 19's.
11-19-2010, 12:06 PM
#5
I think the answer is sales potential
Use this link to calculate tire diameter differences.
http://www.1010tires.com/TireSizeCalculator.asp?
235/50-19 is correct plus 1 size up, but there are very few choices (11) on the Tire Rack in that size.
245/45-19 on the other hand is 1.74% too small when compared to stock. There are more choices of tires (42) in this size, however, which is likely why Tire Rack offers the alternate size instead of what Acura recommends
Use this link to calculate tire diameter differences.
http://www.1010tires.com/TireSizeCalculator.asp?
235/50-19 is correct plus 1 size up, but there are very few choices (11) on the Tire Rack in that size.
245/45-19 on the other hand is 1.74% too small when compared to stock. There are more choices of tires (42) in this size, however, which is likely why Tire Rack offers the alternate size instead of what Acura recommends
If you want to compare apples to oranges, you can compare the RDX to the GLK, but the fact that MB designs its vehicle around a particular sized tire has nothing to do with what Acura designs its products around.
In general, with any car, but especially with AWD, you want to maintain the same rolling diameter as stock. Changing the rolling diameter changes speedo and odo readings, and affects your gear ratios, and braking. I believe, though have not confirmed, it may also affect systems such as VSA, which in part, may use wheel rotations as calculation input, in addition to accelerometer data.
With any car, places like the Tire Rack are willing sell you tires that are within 2-3% of the stock rolling diameter...beyond that, speedo/odo, gearing and braking are affected too much.
With AWD, it is critical, unless the manual allows otherwise, to make sure all four tires have the same rolling diameter.
Real world example of a similar situation....Current gen TL and RL drivers suffer the same problem...The 17 inch stocker on the 4G TL FWD, and on 2005-2008 RL's is 245/50-17, a relatively difficult size to find, with few choices, especially in high performance rubber. The Plus 1 to that tire, is 245/45-18, and there could not be more choices in this size...The SH-AWD TL and 2009+ RL use this as their stock size.
Stepping up to 19" finds a similar situation to the 17's. 245/40-19 has relatively few choices, and many wheel and tire vendors recommend instead the 255/40-19, which is a more common (though not by much) size, and is about 1.3% larger diameter than stock...This also allows the vendor to recommend a more expensive 19 inch wheel because in a 40 series, you need a minimum 8.5 inch wide wheel for the 255 section.
Stepping up to a 20 finds a similar situation to the 18's...lots of choices in 245/35-20 tires, and better pricing in many cases, than the more scarce 19's.
In general, with any car, but especially with AWD, you want to maintain the same rolling diameter as stock. Changing the rolling diameter changes speedo and odo readings, and affects your gear ratios, and braking. I believe, though have not confirmed, it may also affect systems such as VSA, which in part, may use wheel rotations as calculation input, in addition to accelerometer data.
With any car, places like the Tire Rack are willing sell you tires that are within 2-3% of the stock rolling diameter...beyond that, speedo/odo, gearing and braking are affected too much.
With AWD, it is critical, unless the manual allows otherwise, to make sure all four tires have the same rolling diameter.
Real world example of a similar situation....Current gen TL and RL drivers suffer the same problem...The 17 inch stocker on the 4G TL FWD, and on 2005-2008 RL's is 245/50-17, a relatively difficult size to find, with few choices, especially in high performance rubber. The Plus 1 to that tire, is 245/45-18, and there could not be more choices in this size...The SH-AWD TL and 2009+ RL use this as their stock size.
Stepping up to 19" finds a similar situation to the 17's. 245/40-19 has relatively few choices, and many wheel and tire vendors recommend instead the 255/40-19, which is a more common (though not by much) size, and is about 1.3% larger diameter than stock...This also allows the vendor to recommend a more expensive 19 inch wheel because in a 40 series, you need a minimum 8.5 inch wide wheel for the 255 section.
Stepping up to a 20 finds a similar situation to the 18's...lots of choices in 245/35-20 tires, and better pricing in many cases, than the more scarce 19's.
11-19-2010, 02:01 PM
#6
TwinTurboG
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Quick question. Can the Odometer and Speedometer be recalibrated to acurately represent the smaller diameter tires? I knew the speedometer would be off but never considered that the Odo is representing slightly more mileage on the vehicle as well.
11-20-2010, 10:43 PM
#7
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I would imagine that when your spedo is recalibrated, it would automatically calibrate the odo.
I see how places like tirerack are motivated by sales. My original point is why does Acura recommend a 19" tire that is not actually the correct size when a much closer option is available?
I see how places like tirerack are motivated by sales. My original point is why does Acura recommend a 19" tire that is not actually the correct size when a much closer option is available?
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11-20-2010, 11:11 PM
#8
^Chas2 already answered that question. Availability.
When I searched the 235/50 19 size on the Rack I got ten responces. When I used the 245/45 19 I got 35 tires. I think this is the primary reason.
When I searched the 235/50 19 size on the Rack I got ten responces. When I used the 245/45 19 I got 35 tires. I think this is the primary reason.
Last edited by Mr Marco; 11-20-2010 at 11:15 PM.
11-23-2010, 02:34 PM
#11
^Without using any expletives or derogatory language I will attempt to refute your claim. I have been riding on the Yoko AViD ENVigor 245/45/WR-19 for a little less than 1,000 miles and I can honestly say that there is minimal difference between the stock Michelin 18" tires and the 19" Yokohama. Another tire with a different side wall structure, tread pattern, and compound may provide a "abysmal" ride. The only negative aspect in ride quality that I have noticed are when the RDX is rolling over small speed bumps. The handling has improved. However, gas mileage is down.
11-23-2010, 03:42 PM
#12
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. The ride quality has actually improved for me with the Yokohama Avid ENVigor 245/45/19's. It's been confirmed by my wife, her mother, and her grand mother who is used to riding in a Lincoln. It's amazing that a lower profile tire could give a better ride quality, while still improving handling characteristics and inspire driving confidence. I can't speak for any other tire in this configuration but I can confidently say that the only negative aspect of upgrading to this setup is about 2 mpg so far.
02-03-2013, 03:40 PM
#13
I'm guessing all the people noticing a reduction in gas mileage have chosen heavier wheel-sets than their stock setup. You can easily step up to a 19" wheel on the RDX and improve your MPG. A good affordable example would be any of the rotary forged TSW models paired with a 245/45-19 Continental DW or DWS tire. The 19" tires weigh 26 lbs compared to 30+ lbs their 18" competetors. The stock RDX wheel weight is 27 lbs. if you can get a 20 lb or close wheel, you are cutting off ~10 lbs per corner. That will result in improved handling and gas mileage.
Why would Acura offer that as an option size wheel if they knew it would result in an "abismal" ride.
Why would Acura offer that as an option size wheel if they knew it would result in an "abismal" ride.
02-03-2013, 04:05 PM
#14
OEM wheels are made to take abuse.
For that reason, they are heavy and not designed for sport. This is true with most mass market motorcar companies. I have replaced the factory wheels on every ride I've owned. Have a set of 18" Enkie Raijin with the Potenza RE-11's for the TL. Lightweight and superfast summer only tires.
Sadly the Yoko's on the RDX are gone. Got a nail in the sidewall of one of them and decided to step up to the Michelins.
The Yoko's were lighter, but these are tighter.
For that reason, they are heavy and not designed for sport. This is true with most mass market motorcar companies. I have replaced the factory wheels on every ride I've owned. Have a set of 18" Enkie Raijin with the Potenza RE-11's for the TL. Lightweight and superfast summer only tires.
Sadly the Yoko's on the RDX are gone. Got a nail in the sidewall of one of them and decided to step up to the Michelins.
The Yoko's were lighter, but these are tighter.
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