It was finally time to replace my Michelin's and I was not about to pay nearly $300/tire for 235/45-18's. I found a set of 245/40-18 Michelin Pilot Sport A/S and pulled the trigger. It was an unbeatable deal.
Has anyone else plus-sized tires on the stock rims? I remember a thread a while ago about it having a minor percentile effect on speedo readouts... what do I have to look forward to? Good, bad?
Let me know your opinions. Oh and before anyone asks, $425 shipped for all 4 w/ 7-8 32nd's left. Not bad I think.
245/40-18 Tires on Stock Rims
Re: 245/40-18 Tires on Stock Rims (lswaidz)
I have had 245 45 18s and had no problems what so ever. In your case when you will be going 65.806 your speedo will read 64.204, so speed diffrence is negligible your tire height will drop .15 inches.
Modified by darcwun at 5:50 PM 10/13/2007
Modified by darcwun at 5:50 PM 10/13/2007
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maxnix
- Posts: 22627
- Joined: Mon Jul 22, 2002 8:11 pm
- Car: 1995 Infiniti Q45
1995 Infiniti Q45t
2000 Infiniti Q45
Re: 245/40-18 Tires on Stock Rims (lswaidz)
Let me ask you what other part of your car is in contact with the road? If everything else is alright, then the tires are the limiting factor in handling, braking, and dynamic safety performance.lswaidz wrote:It was finally time to replace my Michelin's and I was not about to pay nearly $300/tire for 235/45-18's. I found a set of 245/40-18 Michelin Pilot Sport A/S and pulled the trigger. It was an unbeatable deal.
Let me know your opinions. Oh and before anyone asks, $425 shipped for all 4 w/ 7-8 32nd's left. Not bad I think.
The PS Sports AS are 1.5 generations behind the PS2. But you will be changing them soon anyway as they are over half used for their life. It's not just miles, but exposure to ozone and UV also. Even Michelins are seriously degraded after 20K miles.
Personally, buying used tires is like wearing someone else's used underwear. Better the skid marks are my own.
Re: 245/40-18 Tires on Stock Rims (maxnix)
To be honest, these tires are a temporary fix until next summer. I'll be putting new wheels on my car once winter is over and these will be 4-5 month tires for me. I was prepared to spend $1500-$2000 on tires I'm only going to use for less than half of the year.
What concerns me, if you say they're half used? With a 400 tread rating should that equate to much more than 40,000 miles? Maybe I'm wrong. I got almost 57,000 miles out of the stock Michelins, and those have a lower tread rating.
Again, these are more of a stop gap measure for me, so I only anticipate putting 10-20k on them every year.
One other question... you guys that have put larger wheels on the car... how has that impacted your tire pressure monitoring systems? I'm running on my full size spare right now, and the car is very upset thinking it has a flat all the time... is that an interchangeable sensor on the rims?
What concerns me, if you say they're half used? With a 400 tread rating should that equate to much more than 40,000 miles? Maybe I'm wrong. I got almost 57,000 miles out of the stock Michelins, and those have a lower tread rating.
Again, these are more of a stop gap measure for me, so I only anticipate putting 10-20k on them every year.
One other question... you guys that have put larger wheels on the car... how has that impacted your tire pressure monitoring systems? I'm running on my full size spare right now, and the car is very upset thinking it has a flat all the time... is that an interchangeable sensor on the rims?
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maxnix
- Posts: 22627
- Joined: Mon Jul 22, 2002 8:11 pm
- Car: 1995 Infiniti Q45
1995 Infiniti Q45t
2000 Infiniti Q45
Re: 245/40-18 Tires on Stock Rims (lswaidz)
400 wear index (althouogh not comparable across brands) is way too hard.
Most performance tires are 220 and under. Billiard ball hard tires do not have good traction so they don't brake, corner, nor handle very well. Rain performace is scarey. But they will last.
Pay attention to traction ratings after speed and load indexes.
Most performance tires are 220 and under. Billiard ball hard tires do not have good traction so they don't brake, corner, nor handle very well. Rain performace is scarey. But they will last.
Pay attention to traction ratings after speed and load indexes.
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szh
- Posts: 15932
- Joined: Tue Jul 23, 2002 12:54 pm
- Car: 2018 Tesla Model 3.
Unfortunately, no longer a Nissan or Infiniti, but continuing here at NICO! - Location: San Jose, CA
Re: 245/40-18 Tires on Stock Rims (lswaidz)
My guidelines for tires, in no particular order, are as follows - some of these guidelines are specific for the M (with its heavier weight), of course:
1. Change the tires when you get to about 4/32" of tread depth. Yes, you can legally get to 2/32", but it had better not be raining in your neck of the woods when you are out there! Look at the video I have posted for the difference in wet weather braking with 2/32 and 4/32 tread depth ...
2. Buy a tread depth gauge (less than a few bucks at most auto parts, Sears, Walmart and Target stores). This is far more useful than the "quarter" (for 4/32") or "penny" (for 2/32") tricks. Heck, buy a few and put one in the glove compartments of all your cars!
2. For the M, make sure that the tire load index is at least 95 (preferably much higher), no matter what the actual diameter of tire/wheel. Anything less, and you are going to have internal tire damage (assuming no actual tire blowout) that will require frequent re-balancing, and lead to premature tire failure.
3. Set the tire inflation pressure to 36psi or higher. This gives you the actual load index performance measurement point. To compromise a bit on comfort, if you want to run at about 32 to 33 psi, get a load index tire of 100.
4. Never install or use tires past the 5 year mark from the date of manufacture (on the sidewall ... next to the "DOT" symbol). You could stretch this to 6 years, but I think you are asking for trouble. Change the tire, no matter what the mileage or tread depth if the tire is more than 5 years old from the date of manufacture (not the date of "first in service").
5. Make sure that you use summer tires for summer and change to snow tires for any snow conditions, or temperatures less than 34-35 degrees Fahrenheit.
6. Make sure that the speed rating is at least H (preferably higher, like V, W, Y or Z). Never think that the M can handle T or S rated tires - the internal construction strength of these tires is not good enough for the weight of this car.
7. Never exceed the speed for the rating for your tire. For H tires, this is 130mph.
8. Once the tire has been patched for any reason whatsoever (like a tire puncture), never exceed 100mph - for any rating tire. Period!
9. Never speed on unbalanced or underpressure tires.
10. Follow the minimum and maximum tire width specs for the wheels you have, although being off 0.5" on the allowed range of wheel width is probably not a serious concern (albeit, remember that the actual tire footprint is changed ... "wider" tires may actually have a smaller contact width). VIP guys like to "stretch" tires (usually too little a width) ... personally, I consider the look completely silly (but that is my opinion) and, regardless, it is unsafe at speed or while cornering.
11. Check and adjust your tire pressure often - every week preferably, but a minimum of two weeks apart. With an accurate gauge - analog or digital. Tire must be cold. So, do it early in the morning, in your garage, before the sun has had a chance to warm it up even a bit.
12. Lower aspect ratio tires need more frequent pressure checks ... less air in there, and thus, more of a pressure change from week to week.
13. The UTQG tread life measure number is not comparable between manufacturers - only within the same manufacturer. It is a guideline, not an exact spec.
14. For high performance cars, I would never consider getting a tire with less than "A A", with a preference for "AA A". Gives me better wet braking and handling characteristics.
15. For powerful cars, don't assume that you can drive "All Season" tires in snow - and, of course, summer tires in snow would be an accident looking for a place to happen! Buy a cheap set of wheels and snow tires - even the cheapest snow tires will be safer than running summer tires in snow!
16. My opinion: if you can afford it, spend your money on good to excellent tires - even if you have stock 18" or 19" wheels - do not waste it on larger diameter wheels and tires (unless you have money to burn). Many of those larger diameter tires do not have the right load index anyway!
Z
1. Change the tires when you get to about 4/32" of tread depth. Yes, you can legally get to 2/32", but it had better not be raining in your neck of the woods when you are out there! Look at the video I have posted for the difference in wet weather braking with 2/32 and 4/32 tread depth ...
2. Buy a tread depth gauge (less than a few bucks at most auto parts, Sears, Walmart and Target stores). This is far more useful than the "quarter" (for 4/32") or "penny" (for 2/32") tricks. Heck, buy a few and put one in the glove compartments of all your cars!
2. For the M, make sure that the tire load index is at least 95 (preferably much higher), no matter what the actual diameter of tire/wheel. Anything less, and you are going to have internal tire damage (assuming no actual tire blowout) that will require frequent re-balancing, and lead to premature tire failure.
3. Set the tire inflation pressure to 36psi or higher. This gives you the actual load index performance measurement point. To compromise a bit on comfort, if you want to run at about 32 to 33 psi, get a load index tire of 100.
4. Never install or use tires past the 5 year mark from the date of manufacture (on the sidewall ... next to the "DOT" symbol). You could stretch this to 6 years, but I think you are asking for trouble. Change the tire, no matter what the mileage or tread depth if the tire is more than 5 years old from the date of manufacture (not the date of "first in service").
5. Make sure that you use summer tires for summer and change to snow tires for any snow conditions, or temperatures less than 34-35 degrees Fahrenheit.
6. Make sure that the speed rating is at least H (preferably higher, like V, W, Y or Z). Never think that the M can handle T or S rated tires - the internal construction strength of these tires is not good enough for the weight of this car.
7. Never exceed the speed for the rating for your tire. For H tires, this is 130mph.
8. Once the tire has been patched for any reason whatsoever (like a tire puncture), never exceed 100mph - for any rating tire. Period!
9. Never speed on unbalanced or underpressure tires.
10. Follow the minimum and maximum tire width specs for the wheels you have, although being off 0.5" on the allowed range of wheel width is probably not a serious concern (albeit, remember that the actual tire footprint is changed ... "wider" tires may actually have a smaller contact width). VIP guys like to "stretch" tires (usually too little a width) ... personally, I consider the look completely silly (but that is my opinion) and, regardless, it is unsafe at speed or while cornering.
11. Check and adjust your tire pressure often - every week preferably, but a minimum of two weeks apart. With an accurate gauge - analog or digital. Tire must be cold. So, do it early in the morning, in your garage, before the sun has had a chance to warm it up even a bit.
12. Lower aspect ratio tires need more frequent pressure checks ... less air in there, and thus, more of a pressure change from week to week.
13. The UTQG tread life measure number is not comparable between manufacturers - only within the same manufacturer. It is a guideline, not an exact spec.
14. For high performance cars, I would never consider getting a tire with less than "A A", with a preference for "AA A". Gives me better wet braking and handling characteristics.
15. For powerful cars, don't assume that you can drive "All Season" tires in snow - and, of course, summer tires in snow would be an accident looking for a place to happen! Buy a cheap set of wheels and snow tires - even the cheapest snow tires will be safer than running summer tires in snow!
16. My opinion: if you can afford it, spend your money on good to excellent tires - even if you have stock 18" or 19" wheels - do not waste it on larger diameter wheels and tires (unless you have money to burn). Many of those larger diameter tires do not have the right load index anyway!
Z