i tried to do a search with no results.

our stock tires for the TLS are 215/50/17 right? now from what i have read and seen, we CAN change the fires to 225/45/17, but we CANNOT change them to 225/50/17.

why? i thought thicking sidewall will help, but what makes it impossible for us to install 50 and need to do 45?

 

There MIGHT be issues with rolling radius of the tires... there is a certain limit for it... and if the rolling radius of the tire is wrong, it would greatly impair speedometer accuracy as well as VSC sensor....

Andy Kuo

 

oh, so that means it has little to do with what our rims can take, but more on what our speedometer and vsa sensor?

 

I'm sure they would fit but it would look sooo gay. It would also hinder performance. I just put 45 series pirelli's on my car and it drives and rides so much nicer. They're even quieter. Go 225/45-17, Bridgestone Potenza S-03 pole position. IMO these are the best tires available.

 

I've been looking for new tires too. Check out this thread I started, I got a lot of good info from different folks on what to replace my tires with.

http://www.acura-tl.com/forum/showth...0&pagenumber=1

Marc

 

To me the issue is mostly the width of the wheels. The TL-S has 6.5" wide rims, and most tires (including 225/45R17) require at least a 7.5" wide rim.

 

I just installed Michelin Pilot Sport A/S in size 225/50/17. No problems with VSA as of yet (got to test it out a little in the snow today). The tires are sooooooo much better than the stock tires as far as I can tell, although I've only had them on for a couple of days. Handling is definitely better and the ride quality seems to be equal or better to that of the MXM4s.

Yeah, I would have liked to install 225/45/17 which would have kept the sidewall a little smaller, but find me a 225/45/17 tire where the manufacturer has approved the use of 6.5" rims.

 

umm, so that means i should get 225/50/17 rather than 225/45/17...

 

I forgot, you poor tl owners only have 6.5" wheels. cl-s comes w/ 7". And there are many cl-s owners running 225/45-17 w/ no problems.


rominl, I would suggest new wheels.

 

sniff sniff, only if i have the money now

 

Depending on the manufacturer 225/50 17 tires would be @ 25.9 inches tall and the 215/50 17s are @ 25.5 inches tall. That difference will result in a 1 mph higher reading on the speedo at 60 mph. So with the 225s the speedo would read 61 at the 215 speed of 60.

I have 235/45 17s on my TLS. Dunlop 5000s which I am thrilled with. They are supposedly 25.5 inchs tall. So they match the stock TLS Tire height. I also have a set of Michelin Pilot Sports in the 225/45 18 size which I used during the summer. I changed to the Dunlops and new rims last month preparing for winter and I really like them. They are much more quiet than the stock Michelins or the Pilots. They also handle almost as good as the Pilots. Pilots are only slightly better at the extreme while cornering.

As for the look, I think you'll like the look of the 45s better than the 50s. Additionally, my 235/45 17s ride much better than the 225/45 18s. The car was harsh with the 18s. Its much more compliant with teh 17s.

 

umm...... wait, i thought the speedo reading is calculated by the axle rotation?

if that's the case, having a tire of larger diameter will result in underestimated speedometer reading?

see, if the diameter is larger, the distance one rotation travel would be longer.

am i right?

 

OK, the concerns about speedo accuracy is irrelevant, since most speedos already contain gross errors to begin with. I wouldn't be surprised if a given speedo indicates 6-10 MPH fast at 50 MPH (they all indicate faster than actual speeds), so what's another 1 or 2 MPH error?

VSA and TCS would probably be completely unaffected by these minor changes, as they use gross differences in wheel velocities (slip) as well as the yaw/turn/steering wheel sensor (under/oversteer) to act, and not precise wheel speeds.

 

daverman, wow, you serious that the speedo is that way off? i mean, that's 20% off at 50mph!!!! that's not good.... @_@

 

I recall a Car and Driver test a while back that found that 225/45 was ideal for a 17" wheel on a sedan. 18's were worse than the 16's in terms of handling. I also think a 7" rim should be fine. Many OEM cars fit those tires to 7" width rims.

I am going to go with 225/45 when my Pirelli's wear out, which should be soon since they are as soft as bubble gum.

 

Rominl,

Your right I didn't quite say it right. What I meant is that with the larger tires you real speed at 60mph on the gauge would be almost 61mph.

If you're interested check out his link for calculating the speedo error a tire change would make.

http://www.4lo.com/4LoCalc.htm

I got this link from one of my 4x4 buddies. It's mostly for trucks and such, but a few of the calculators come in handy for my car stuff as well.

 

Sorry guys, I got confuse now. :o

So.. if I want to install 225/45/17 tires, I need to change rims?! For 225/50/17 tires, I don't need to change rims?!

Am I right?

 

Correct. You could PROBABLY get away with 225/45, but no tire manufacturers recommend that size on a 6.5" rim. 225/50 can usually be mounted on a 6-8" rim however.

The sidewall is a little taller than stock on a 225/50, but it doesn't look bad. If you want to see a 225/50 tire on a 17" rim, check out the 2002 Maxima SE.

 

KCHO2000,

I think either tire would be fine on a 7" wide rim. If your rims are only 6.5" wide, both tires will fit, but it probably isn't recommended by the manufacturer of the tire. You can check out their web sites and look for the model of tire you thinking about getting. In the specs on that tire it will recommend the minimim and maximum rim width.

Now with that said, you will probably be fine running both sizes with 6.5" rims if that is what you have. They will look like they are bulging out a little more than normal on the rim. It seems the 225/45 size is popular on the stock rims from what I can get from the list. The only real problem with doing this is that the tire won't look as wide as it should due to the narrower rim pulling the sidewall in and you'll also more than likely wear out the center of the tread faster than the shoulders due to the pinching the sidewall and the crowning effect it creates with the contact patch.

Personally, I wouldn't do it unless my rim was 7" wide, because I like the look of a wider tire on a wide rim but I don't think you'll have any problems.

 

Perhaps speedometers on older vehicles may have such gross errors, but if the reading on my GPS III+ is any indication, the TL-S speedo is just about dead-on at 50 mph and at 80 mph.

Sure, a consumer-grade GPS unit isn't totally accurate either but in the case of my III+, either both the TL-S speedo and the III+ are way off or the III+ is giving a reasonably accurate reading since both speedo and III+ display the same value at a given MPH.

Here's a counterpoint--if speedo accuracy concerns are irrelevant, why even bother with speedos in automobiles, DOT regulations/requirements notwithstanding? Because people need or like to know how fast they're going? If the speedo is supposedly giving out an incorrect reading, then they won't know how fast they're really going, thereby making it pointless to even have a speedometer to reference how fast they're going. But, one may say that if they knew the degree of accuracy (or inaccuracy, in this case) of the speedometer then they can properly determine how fast they are going. Therefore, speedo accuracy is not as irrelevant as one may think.

Don't take my reply as a slight; either that or I'm misunderstanding your take on the irrelevancy regarding the concerns of speedo accuracy.

Tony

P.S.: of course the above applies to consumers and consumer vehicles; IIRC vehicles in pro racing circuits (e.g., stock cars, race bikes) don't even have speedometers or have them disabled. Then again, race competitors usually are more interested in coming out on top, not how fast they were going...

 

Basically you are trying to aim as close as possible to a total radius of 25.7 inches:

215/50/17 : 25.5 inches
225/45/47 : 25.0 inches (too small IMHO)
225/50/17 : 25.9 inches
235/45/17 : 25.3 inches
245/45/17 : 25.7 inches

BTW I have 245/45/17 Firestone Firehawks on the stock 6.5" rims and they are great.

 

Thanks for the help.