Wider tires on stock rims? (255 vs. 245?)
06-29-2008, 02:25 AM
#1
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Wider tires on stock rims? (255 vs. 245?)
I'm still running stock 17" 8.5" wheels on the back, and it's time for new tires.
I was thinking about moving up from 245/40R17 to 255/40R17. According to tirerack, for the Sumitomo HTR Z III, it will change the rotations/mile from 842 to 834, which I don't think is too big a deal.
I also imagine that 255s will fit with no issue (correct me if I'm wrong).
So here's my real question (again assuming there's no actual problem above): what is the downside/upside of using 255 instead of 245? Better/worse mileage, handling, ride, anything? If it's better with no downside, why doesn't Mercedes put it on from the factory?
And I guess the same goes for the fronts too - can't we use 235/45R17 with good results, instead of 225/45/R17?
(As a side note, my tires still vibrate and flat spot in the front, and I swear it must be the size of 225/45/R17 somehow over stressing the tires. I have Michelin PS2, and they should be really good about flat spotting, so I am thinking about putting my 245/40R17 on the front to give it more surface area to spread the weight.)
I was thinking about moving up from 245/40R17 to 255/40R17. According to tirerack, for the Sumitomo HTR Z III, it will change the rotations/mile from 842 to 834, which I don't think is too big a deal.
I also imagine that 255s will fit with no issue (correct me if I'm wrong).
So here's my real question (again assuming there's no actual problem above): what is the downside/upside of using 255 instead of 245? Better/worse mileage, handling, ride, anything? If it's better with no downside, why doesn't Mercedes put it on from the factory?
And I guess the same goes for the fronts too - can't we use 235/45R17 with good results, instead of 225/45/R17?
(As a side note, my tires still vibrate and flat spot in the front, and I swear it must be the size of 225/45/R17 somehow over stressing the tires. I have Michelin PS2, and they should be really good about flat spotting, so I am thinking about putting my 245/40R17 on the front to give it more surface area to spread the weight.)
Last edited by trikoid; 06-29-2008 at 02:30 AM.
07-03-2008, 12:17 AM
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Sold - CLK500
im no expert, but i have had the same idea as you.. but thinking about it, i belive it might make the car have more body roll... so decided not to bother trying. If you want to go wider go with a wider j on the rims.. 9.5" would be good on the rears.
07-03-2008, 12:17 PM
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W209 CLK
Yes 255 will fit no problem. Just be aware (from my experience) different manufacturers width are not the same for some reason.
For example: I've got 18R/35/265 in the rear with 10 wide rims. 265 Goodyear Eagle GSD3s are wider than 265 Pirelli Pzero Neros on the same rim...
For example: I've got 18R/35/265 in the rear with 10 wide rims. 265 Goodyear Eagle GSD3s are wider than 265 Pirelli Pzero Neros on the same rim...
07-03-2008, 09:15 PM
#5
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Under the spec from tirerack for the Sumitomo HTR Z III that I bought and now am now awaiting mounting:
Tire size Rotations/mile
225/45ZR17 834
245/40ZR17 842
255/40ZR17 834
Yes, that's right, the wider 255 will now match the front 225 size. In theory. I hope I don't get a ticket for going 1MPH over 80.
My neighbor who has a Boxster has 17" wheels with 225 on the front, and 255in the back. In fact, the wheels should be exchangable between the cars (that's what he says anyway).
Also, why would 255 cause more body roll? I was figuring for better handling and traction...
On a different note, because I'll need new tires for the winter anyway, I've been running my winter 245/40R17 tires on my front (they do clear), and OMG it handles so much better now! Steering response, etc. are all better, and even little bumps are better too. Seems more solid.
Now I'm trying to figure out whether I should put summer 245s on the front. It visually looks too wide for the car, but it works so well...
And on yet another note, I still get SO much flat spotting that my car shakes at 65 MPH and never stops. It only gets better when I put fresh front tires on that were sitting on their side. Does anyone else have this problem? I can't believe how bad it is!
Tire size Rotations/mile
225/45ZR17 834
245/40ZR17 842
255/40ZR17 834
Yes, that's right, the wider 255 will now match the front 225 size. In theory. I hope I don't get a ticket for going 1MPH over 80.
My neighbor who has a Boxster has 17" wheels with 225 on the front, and 255in the back. In fact, the wheels should be exchangable between the cars (that's what he says anyway).
Also, why would 255 cause more body roll? I was figuring for better handling and traction...
On a different note, because I'll need new tires for the winter anyway, I've been running my winter 245/40R17 tires on my front (they do clear), and OMG it handles so much better now! Steering response, etc. are all better, and even little bumps are better too. Seems more solid.
Now I'm trying to figure out whether I should put summer 245s on the front. It visually looks too wide for the car, but it works so well...
And on yet another note, I still get SO much flat spotting that my car shakes at 65 MPH and never stops. It only gets better when I put fresh front tires on that were sitting on their side. Does anyone else have this problem? I can't believe how bad it is!
Last edited by trikoid; 07-03-2008 at 09:18 PM.
07-13-2008, 03:05 AM
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Mercedes
Under the spec from tirerack for the Sumitomo HTR Z III that I bought and now am now awaiting mounting:
Tire size Rotations/mile
225/45ZR17 834
245/40ZR17 842
255/40ZR17 834
Yes, that's right, the wider 255 will now match the front 225 size. In theory. I hope I don't get a ticket for going 1MPH over 80.
My neighbor who has a Boxster has 17" wheels with 225 on the front, and 255in the back. In fact, the wheels should be exchangable between the cars (that's what he says anyway).
Also, why would 255 cause more body roll? I was figuring for better handling and traction...
On a different note, because I'll need new tires for the winter anyway, I've been running my winter 245/40R17 tires on my front (they do clear), and OMG it handles so much better now! Steering response, etc. are all better, and even little bumps are better too. Seems more solid.
Now I'm trying to figure out whether I should put summer 245s on the front. It visually looks too wide for the car, but it works so well...
And on yet another note, I still get SO much flat spotting that my car shakes at 65 MPH and never stops. It only gets better when I put fresh front tires on that were sitting on their side. Does anyone else have this problem? I can't believe how bad it is!
Tire size Rotations/mile
225/45ZR17 834
245/40ZR17 842
255/40ZR17 834
Yes, that's right, the wider 255 will now match the front 225 size. In theory. I hope I don't get a ticket for going 1MPH over 80.
My neighbor who has a Boxster has 17" wheels with 225 on the front, and 255in the back. In fact, the wheels should be exchangable between the cars (that's what he says anyway).
Also, why would 255 cause more body roll? I was figuring for better handling and traction...
On a different note, because I'll need new tires for the winter anyway, I've been running my winter 245/40R17 tires on my front (they do clear), and OMG it handles so much better now! Steering response, etc. are all better, and even little bumps are better too. Seems more solid.
Now I'm trying to figure out whether I should put summer 245s on the front. It visually looks too wide for the car, but it works so well...
And on yet another note, I still get SO much flat spotting that my car shakes at 65 MPH and never stops. It only gets better when I put fresh front tires on that were sitting on their side. Does anyone else have this problem? I can't believe how bad it is!
That flat spotting you have may not be flat spotting. You might have a bent rim. Pretty common with this car. I've bent 10 between my 2003 clk500 and this 2007 clk550 with the roads here in Chicago.
