255s on stock R-Spec rims??

[RSPEC429]

When the all-season Contis that are on there now wear out, I want to switch over to some summer tires. If 255s will fit on the stock rims, I'll spring for the Michelin Pilot Super Sports since they do not come in the factory size of 245. If not, I'll go with the Bridgestone Potenza S-04s.

 

[scottdk]

When the all-season Contis that are on there now wear out, I want to switch over to some summer tires. If 255s will fit on the stock rims, I'll spring for the Michelin Pilot Super Sports since they do not come in the factory size of 245. If not, I'll go with the Bridgestone Potenza S-04s.

They will fit WALLYMN is running a 255 summer tire (Conti DW's) on this 18" wheel. I think the RSpec wheel is a half inch wider then the 18" wheel also.

Another spring another set of new tires...

I liked the Conti Extreme contact dw so much I got them again, but this time I went wide. squeezed 255/45/18s on the stock rims...

Love them so far - about 200 miles on them.

I had spring fever, I know snow is likely for at least another month.

http://www.genesisowners.com/hyundai-genesis-forum/showthread.php?t=7135

 

[brfatal]

They will fit WALLYMN is running a 255 summer tire (Conti DW's) on this 18" wheel. I think the RSpec wheel is a half inch wider then the 18" wheel also.

Please don't advise if you don't know what you're talking about.

255s will NOT fit on either 4.6L 18x7.5 wheels nor on R-Spec 19x8 wheels.

For a 255/40/19 tire, manufacturer specs require a minimum 9" wide wheel. Running this tire on a narrower wheel will cause excessive sidewall flex and will completely void the manufacturer warranty.

For a 255/45/18, manufacturer specs require at least an 8" wide wheel. WALLYMN is running an incorrect tire size.

 

[Crusty Old Shellback]

Here you go, from the tire rack web site.

255/40 19 will fit a 8.5 to 10 inch rim width. The measured rim width is 9" which will give you a true 255 foot print of the tread.

http://www.tirerack.com/tires/tires...ehicleSearch=false&fromCompare1=yes&tab=Specs

On my old Pintiac G8, it came with 245's and when I replcaed them, I steped up to a 255 with no issues.

 

[RSPEC429]

According to Tire Rack, the Michelin Pilot Super Sports should fit on my 8" R-Spec rim...

http://www.tirerack.com/tires/tires.jsp?tireMake=Michelin&tireModel=Pilot+Super+Sport&partnum=545YR9PSSXL&vehicleSearch=false&fromCompare1=yes

 

[RSPEC429]

The 255 Pilot Super Sports have a rim width range of 8-9.5"

 

[RSPEC429]

Straight from the Michelin website:

http://www.michelinman.com/tire-selector/size/EMetric/255/45/19/OE/BNW/pilot-super-sport/tire-details

Guess I know what my next tire is going to be.

 

[brfatal]

According to Tire Rack, the Michelin Pilot Super Sports should fit on my 8" R-Spec rim...

http://www.tirerack.com/tires/tires.jsp?tireMake=Michelin&tireModel=Pilot+Super+Sport&partnum=545YR9PSSXL&vehicleSearch=false&fromCompare1=yes

You're looking at the wrong size tire.

255/40/19, not 255/45/19.

The shorter the sidewall, the wider the wheel has to be. The more the sidewall, the narrower the wheel. In SUV sizing, 255s can fit a 7" wheel.

 

[brfatal]

http://www.michelinman.com/tire-sel...5/40/19/OE/BNW/pilot-super-sport/tire-details

Rim Width Range
(Min/Max) 8.5" - 10"

 

[geoffc]

255/45/19 would mount up on stock R-Spec rims, but you'll be WAY off compared to original 235/45/19 on your speedo. Assuming handling will be off as well, you'll be physically running a larger diameter tire. If you want to go 255 width, 255/40/19 would be closest to stock size, but 255/40/19 is too wide for 8" R-Spec rims. 255/40/19 would get you 1% off stock size. Widest tire you can put on stock R-Spec rim is 245/45/19, with out messing up speedo/odo too badly.

here's chart on 235/45/19 OEM size, verses 255/45/19


Diameter inches (mm)

235/45/19 255/45/19 Difference

27.33 (694.1) 28.04 (712.1) 0.71 (18) 2.6%

Width inches (mm)

9.25 (235) 10.04 (255) 0.79 (20) 8.5%

Circum. inches (mm)

85.85 (2180.58) 88.08 (2237.13) 2.23 (56.55) 2.6%

Sidewall Height inches (mm)

4.16 (105.75) 4.52 (114.75) 0.35 (9) 8.5%

Revolutions per mile (km)

738.04 (458.59) 719.38 (447) -18.66 (-11.59) -2.5%

http://www.tacomaworld.com/forum/tirecalc.php is great for calculating tire sizes.

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[RSPEC429]

According to Tirerack:

Conti 235s:
Revs per mile - 761
Overall Diameter - 27.3"
http://www.tirerack.com/tires/tires.jsp?tireMake=Continental&tireModel=ContiProContact&partnum=345HR9CPC&vehicleSearch=true&fromCompare1=yes&autoMake=Hyundai&autoYear=2012&autoModel=Genesis%20Sedan&autoModClar=5.0%20R-Spec&tab=Specs

Bridgestone 245s:
Revs per mile - 753
Overall Diameter - 27.7"
http://www.tirerack.com/tires/tires.jsp?tireMake=Bridgestone&tireModel=Potenza+S-04+Pole+Position&partnum=445YR9S04PP&vehicleSearch=true&fromCompare1=yes&autoMake=Hyundai&autoYear=2012&autoModel=Genesis%20Sedan&autoModClar=5.0%20R-Spec&tab=Specs

Michelin 255s:
Revs per mile - 741
Overall Diameter - 28.1"
http://www.tirerack.com/tires/tires.jsp?tireMake=Michelin&tireModel=Pilot+Super+Sport&partnum=545YR9PSSXL&vehicleSearch=false&fromCompare1=yes&tab=Specs

 

[RSPEC429]

You're looking at the wrong size tire.

255/40/19, not 255/45/19.

The shorter the sidewall, the wider the wheel has to be. The more the sidewall, the narrower the wheel. In SUV sizing, 255s can fit a 7" wheel.

I'm not looking at the wrong tire size. I want 255/45/19s... You misunderstood me.

 

[RSPEC429]

http://www.1010tires.com/tiresizecalculator.asp?action=submit

According to that site, 255 will be 2.601% too slow; this is assuming that the Genesis is tuned for 235s. If it was originally tuned for 245s, the 235s actually read 1.317% too fast and 255s would read 1.266% too slow. I'm going to check the actual speed of the Genesis at 60mph against my GPS; it may already be off with the 235s on there.

 

[geoffc]

Stock tires are 235/45/19 for R-Spec, assuming it's speedo is tuned to it. With summer tire option, think it comes with 245/45/19 Bridgestones. 235/45/19 is uncommon size, verses 245/45/19.

No one's saying you can't mount 255/45/19 on stock 19"s, but you'll be adding sidewall height, overall larger tire, and being mounted on narrowest possible rim for that size tire, profile will be off.

 

[RSPEC429]

The question is whether or not the speedo on the R-Spec is tuned for the 235s or the 245s. If they're tuned for 235s, Hyundai offers a tire that throws off the profile to begin with. If they're tuned for 245s, the profile is off even with the 235s on there. Whenever I have a chance to verify speedometer indicated speed against GPS speed, I will let you all know.

 

[EXBMWGUY]

Minnesota roads were exciting today, as in rapid heartbeat and sweaty palms from observing other drivers going through red light intersections sideways. Roads were like grease. Prior Lake surface streets were a mess. No problems on the road with my stock R-Spec wheels/winter tires. My stupid driveway was another matter!

 

[RSPEC429]

I feel for ya! Luckily here in South Texas, I don't have to deal with those sorts of road conditions.

 

[geoffc]

The question is whether or not the speedo on the R-Spec is tuned for the 235s or the 245s. If they're tuned for 235s, Hyundai offers a tire that throws off the profile to begin with. If they're tuned for 245s, the profile is off even with the 235s on there. Whenever I have a chance to verify speedometer indicated speed against GPS speed, I will let you all know.

I'm guessing speedo is tuned for 4.6/5.0 base, which is 235/50/18, with 235/45/19 it's off by 0.3% with 245/45/19 it's off by 1.6%

255/45/19 Mich are off by 2.9%, which is quite a bit. If you mount these NOT on 8" R-spec rims, but some 9" wide wheels, difference will drop, since less sidewall height.

I'm running 225/55/18 as winter tires mounted on 8" rims which is max width for that tire, when comparing my GPS reading to actual speedo, it's dead on. According to tire calculator, I should be off by 1.5% but I'm not.

Besides speedo being off, adding physically larger tire diameter wise, and introducing more sidewall along with wider tire, can have negative handling effects.

Talk to an expert, call up Tirerack and see what they say. Usually if it's off by more than 2% from factory spec, their techs won't recommend it. I got into a good 10 min discussion with their techs when ordering my winter tire/rim combo since it was off by 1.5% and I had to call in to clear the hold on my online order.

 

[RSPEC429]

Calling them sounds like a good idea, thanks for the tip. Those Michelin Pilot Super Sports are just superb tires and I would love to have them on the Gennie.

 

[garner]

Just throwing in my opinion about the speedometer, if hyundai is like other car companies, they calibrate the certain car for the tires on it so the speedometer is correct. Like I have a 2012 ram and my speedometer is calibrated for the factory 275/60/20 tires, whereas my 2011 ram was calibrated for the factory 285/45/22 tires, and if the truck has the 17" wheels with 265/70/17 tires then the speedometer is calibrated for those tires. However if I was to swap wheels and tires on my current truck to the 285/45/22 I could go to the dealer and have my speedometer recalibrated for those tires