|Topic Review (Newest First)|
|07-22-2019 01:01 PM|
I went from 27.30" 235 50R18 Goodyear tires to 27.70" 245 50R18 Michelins. The larger tires have only slightly taller 0.20" sidewalls or 0.40" + on the diameter if you like.
Even slight changes like the above have very definite repercussions in the speedometer/odometer settings along with the ABS/Traction-Control system.
My new tires changed the speedometer that read consistently @ 3MPH higher than actual to @ 0MPH higher on two "your speed is" signs in the area.
I could leave the speedo as is and be aware I didn't have a 3mph buffer in the Impala. However. The revs per mile change from 740 to 730 that caused the speedometer to be more accurate also made the odometer read lower miles than actual.
I changed the tire diameter in the PCM and the ABS as soon as I got home from the tire shop a few miles away so my displayed mileage is largely unaffected.
Vehicles that are commonly changed to much larger tires, like My pickup trucks, are likely much higher mile rigs than the odometer states even tho nobody has purposely tampered with the odometer.
You don't need to go to the manufacturer to get the nominal tire diameter and other specs based on common metric tire sizes. This little web widget will allow you to compare two different tire sizes.
This is how you fix your rig if you've changed your tire sizes...
|07-22-2019 06:20 AM|
Tirerack lists the diameters of all the tires they sell under the spec column in their listings. There won't be a lot of difference in overall diameter in all 3 rim sizes because the aspect ratio (sidewall height) decreases as the rim diameter increases. So, the speedometer won't be affected. What does change, is sidewall width (sidewall to sidewall).
The height of the sidewall will affect handling in curves. The shorter the sidewall, the less the car will lean when you turn, but the taller the sidewall, the more the tire will deflect when you hit a bump. I've driven Impalas with all 3 sizes, and owned an '08 LT with the 17's. I wouldn't recommend the 18's, but the 17's were a good mix of handling & comfort.
|07-21-2019 08:04 PM|
The speedometer isn't difficult to deal with. The tire size parameters are in two controllers the PCM or ECM&TCM and the ABS controller. HP Tuners or similar tuning tools will update the PCM or ECM&TCM tire size. A Tech 2 or MDI/GDS will deal with the ABS controller tire size parameter... It will make a difference in braking performance because the ABS controller also actively handles traction control and brake bias to the wheels among other functions.
18" tires and wheels run into trouble rubbing on the struts that aren't sized for them.
16" wheels and tires will likely run into trouble with the larger disc brake components on 2012 and later Impalas.
You can use 17" wheels and tires on 18" equipped cars but not always the other way around. Look for the FE3 suspension code on the SPID label if you intend to use the 18" wheels.
|07-18-2019 04:27 PM|
I just have a 2013 Impala Police version. The tire size is of 235 55 17 101W. The four tires are brand new on Police steel rims. I would not change the wheels (cannot afford anyway).
I live in the South, no snow. Then, it should be fine.
|07-18-2019 02:55 PM|
A coworker has a 9th gen with an 18 inch wheel i believe, 245 tires i think. He said in the northern Indiana snows his car just sucked, i convinced him to look up his tires on tire rack and he found others had big complaints about the snow too. I got him to buy a new set that had great reviews for the snow and rain, he was way happier with the car on icy and snowy roads. Moral of the story, 18s can be ok as long as you get a quality tire that's designed for snow travel.
Or keep your second set of rims for the winter months and throw snow tires on those.
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|07-18-2019 02:20 PM|
|RShea||Spoke recently with someone and they mentioned that the 17" tires may not do as good in snow. Well known that in really heavy snow sometimes the narrower the tire the better it does. Anyone have experience with the handling in heavy snow belt areas care to provide feedback?|
|07-17-2019 08:29 AM|
|AdamLyth||I agree with you...|
|07-12-2019 07:37 AM|
Originally Posted by sheila View Post
ETA: I have the VCX Nano with GM software and can go in and adjust tire size in less time than it takes my laptop to start up. And I know my 2012 came factory with 17’s and someone put the older style 16’s on it but there have been no clearance issues anywhere at all. Would love to find a set of originals for my car hate the way it looks with the 16’s on it.
|07-08-2019 10:37 AM|
Originally Posted by 12 lt View Post
I priced out the same tires I have in on R16 and R17 and while there are no promotions on them now (when I purchased mine there was a $60 rebate for 4 tires), they end up being about $20 to $25 per tire more on the R17's.
|07-08-2019 08:02 AM|
|sheila||Has anyone installed '16's on a '12+ LT? If so, any issues?|
|07-08-2019 06:07 AM|
i had the 16" steel wheels on my 2010 LS. the tires could be cheap but you get what you pay for. i'd stay with the 17's personally. less sidewall for a little less tire roll in the corners. the ride should be pretty decent still, i think i was looking into upgrading to 17's at one time and found the 17" tires to be reasonable about $125 all day long.
i paid 125 each for a set of bf goodrich advantage T/A Sports and loved them on the impala and the wifes cruze with 17 inch wheels.
ideally i'd have loved to get a set of the 18 inch double 5 spokes that came on the LTZ but then i would have had issues with the tires rubbing the rear struts potentially (LTZ came with a different strut package that had clearance for the bigger wheels).
|07-08-2019 05:42 AM|
Dunno about all the year models, but if I remember correctly the 2012 trim levels would in general give you 16's with the ls, 17's with the lt, and 18's on the ltz. We have an lt and the 17's. There is no shortage of GOOD options in tires for the 17's and in what searching I have done do not seem to be quite as expensive as 18's. I have not compared pricing to the 16's, but can tell you the last set of pirelli p4 plus tires I put on our car were very inexpensive.
With all that being said, some of the reading I have done right here suggests that there are some potential possible issues with moving to smaller sized wheels and disc clearance. And there also may be some issues with rubbing with moving up in size. I do not know first hand though as we have kept with the factory wheels.
|07-07-2019 09:54 PM|
Wheel sizes? 16 and 18 in some years, 17 inch also?
All the 8th Generation 2006- 2008 LT and LS that I have noticed have the 225/60/R16 then some of the newer years with the LT or LTZ have in some cases the 18 inch wheels. Anyway looking at a used 2010 LT that lists 17 inch aluminum wheels. 225/55/R17. Tires probably are a bit more expensive going to 17" and also not as popular of a size.
Can I easily switch to the 225/60/R16 wheels and tires (since both appear to be listed for the 2010 LT on most of the tire sites)? Any issues with speedometer in doing that (assume the lower 55 ratio number is to adjust for the rim diameter difference. I do not know the condition of the tires on the 2010 yet (will be asking about the thread and what tire brand and model is on the vehicle..) so if they are marginal, I may move my 80K warranty 16 inch tires over and of course the wheels off my '06
Finally any noticeable ride and/or handling differences that anyone has experienced with the 17 inch wheels?