klugey1

Hi Guys,
Has anyone calculated the widest or fattest (not "fastest") tire I can put on the stock R16 rims for an S430 (w220) without rubbing? I would like to try the 255/50/16. It looks like the ratio formula doesn't change the stock total diameter too much (stock total is 26.63" and would be going to a 26.04").

Any help, opinions, suggestions even yellings would be appreciated.
Klugey1

klugey1

I made the mistake when I traded in my stock alloys (R16"s) for the Chrome's and got R16's as well. (I know I should have gone up to R17's or R18's, but hindsight is always 20/20).

I've been doing quite a bit of research on Tires, and decided that the Yokohama's Avid V4s would be the best move. Some idiot at BigO talked me in to some Falkens at 17K about 2 years ago (so who is the real idiot here?). These Falkens lasted 16K and are now bald, so I want some "fat" tires that have excellent grip. I live in San Diego, so weather is a non-issue.

The guy at Discount Tire just put some 245/50 R16 Yokohama YK420 96V rated tires on, and so far they seem to handle corners extremely well. The stock size is 225/60 R16, so I've gone wider and a little lower profile. I just wanted to ask if anyone foresees any problems with this configuration before I've driven more than 200 miles on them. Thanks in advance!

bamberger_1

The thing here that calculations are theoretical only. All tires have slightly different dimensions and may or may not work on your car. To find out what is the maximum tire width before rubbing the fendors is to measure as follows. (Critical is only the rear axle, front is not critical, if not super extremly wide tires are planned.)
Drive ONE rear wheel on a 6-7 inch higher pedestal (or the curb). This is the maximum the rear wheel will move towards the fendors, (air matic in standard). Then have someone sit in the trunck and measure the distances to the fendor, the bumper, and the metal latch, the bumper is attached to the fendor. Then you know how much more the new tire can stick out w/o rolling the fendors and cutting the bumper plastics to give room. So for example if you measure 10 mm would still let the wheel run freely the tire could be 20mm wider than the one you have. (10mm each side, makes 20mm). Then you have to calculate the diameter or circumference to keep the odometer in tolerance. Generally diameter should not change much, because if it gets bigger the room between fendor and tire may decrease again. My guess is that you can go as far as 275/50 16" tires. The question is here whether or not the stock rims can safely take a 275mm tire, because they are only 7.5" which are 190mm, so the tire would "baloon out" 42 mm 1.67" each side.

klugey1

Many thanks for the suggestions & Advice. I have taken a few fast corners in the new 245/50/16's and it seems to grip very well. These Yokohamas YK420 96Vs are also very quiet at 80 MPH. The only thing that I've noticed is that, though they seem very responsive to slight turning of the steering wheel on a relatively straight road, the ride feels nice and cushioned but a little "spongy" or squishy.

Do you think this is because of the extra 20 MM of tire width over the stock 225/60/16's that I had on there before? Or is this just because these Yoko tires are softer (v rated) than my old H rated tires?

bamberger_1

If you increase the track the car the "responsiveness" to small movements of the steering wheel might increase. The softness maybe the individual spec of the different tires, and what I was saying earlier about the "Balooning" over the rims, may make the tire feeling "softer".

klugey1

Many Thanks again.
I like the way it feels so far, but is there any risk or downside to the extra "balooning" over the rims. If it is a 7.5" rim, then I calculated that the total width of the tire is about 9.5" (stock is 225 or 8.86"). So it looks like it is "balooning" about an inch on each side of the rim instead of about 1/2" using standard tire size.

In a nutshell, do you foresee any problems or issues that can arise from this? Should I keep a little axtra PSI in the tires or anything like that?

bamberger_1

I would suggest to ask a tire pro on that one.

klugey1

I checked with Yokohama, and they said that the 245/50/16 96V was rated too low, and that for safety reason I should put on the 255/50/16 99V. I'm guessing that this width will still work since I have seen many users with 275's on their S430's. Many of them have 18" rims, but 275 is 275 isn't it?

bamberger_1

They told you right 96V is not the suffivicient loading spec. the minimum is 97 or 98. So 99 is ok. 275 is 275 hmmm yes, but each brand has a certain tolerance, some come out wider some just match 275 and some may even be a little less. If you use 18", the tire comes out 2mm extra, since the offset is different between the 16" and 18" (16" is 46mm and the 18" have 44mm) The offset is the dimension which the mounting surface of the rim is off the centre of the rim.
44mm sticks out 2mm more than 46mm.

klugey1

They replaced the 245/50/16 with 255/50/16, and the width is fine in front and back (no rubbing). It seems to grip around corners very well, and they have the 99V load rating. Feels good so far, but I think if I still own the car at the next tire change I will change to 18" wheels for cosmetic reasons. Thanks for all the help.