Well, I'm going to need tires very soon. The wheels are 7.5" wide with 35mm offset. I'm thinking more towards 245/45/16 for the better contact patch.

Any opinions/suggestions?

Anton

 

I have 225/50/16s on 16x7.5" but I cant say much since I never tried 245's. I do love the 225s though and never had any traction problems with them yet.

 

The overall diameter of 245-45-16's is even smaller than 225-60's, which are already smaller than stock.

215-55-16 25.31 in
225-50-16 24.86 in
245-45-16 24.68 in

The difference is very small between 225 and 245's though. Gearing/speedo offset should be really close to what you have now. With 35 mm offset, you should be fine. The tires may stick out a hair in the front. 245's are 20mm or .75 in wider than 225's, which mean that 245's will stick out another 3/8 inch. Go out and take a look at your car to see how it might look. If you think it'll look okay, I'd say go for it. Not many people on this board (hell, none that I can think of) with 245-45-16's. Should look meaty.

 

I've got 225/50s Sumitomo HTRZs on my 16X7.5 K1s. Believe me, 225/50s are plenty wide for a Maxima. The tire itself is 9.5" wide. 245/50s is what I had my 94 Z28. Granted the wheels were 16X8, but the tire was 10.5" wide. This is too wide for a light 3000lb sedan. You'll hydroplane horribly in the rain. 9.5" is pushing it, IMO.

Remember, the size of the contact patch is always the same regardless of the width of the tire (car's weight stays the same). All you change by getting wider tires is the SHAPE of the contact patch. You're not "putting more rubber to the ground".


Dave

 

Remember, the size of the contact patch is always the same regardless of the width of the tire (car's weight stays the same). All you change by getting wider tires is the SHAPE of the contact patch. You're not "putting more rubber to the ground".


I don't get the logic behind this? With a wider tire, wouldn't you get more surface area? I'm sure tire presure has something to do with it, but with the same tire pressure, you should get more contact patch! Show me why not?

 

245/45/16 You're gonna kill yourself!

 

AND you're going to get rubbing on the passenger inner fenderwell. I have 225-50-16 Sumitomo HTR+ tires on my SE rims and I get a small amount of rubbing. Add effectively 3/8" more rubber on the inside and you may damage the inner edge of the tire through continued rubbing...unless your offset is greater than stock or you run spacers...

 

The contact patch area is dictated by the amount of weight placed on each tire. Assuming the car's weight stays the same, the area stays the same regardless of tire, but you can change the shape of the contact patch. Low profile and wide tires give great cornering ability because the contact patch is wide and narrow. A taller and thin tire has a long and wide contact patch.


Dave

 

This does not seem to be true. If the tire pressure is unchanged, there should be more contact patch with wider tires. The force exerted by the weight of the car to each tire does play a factor in the amount of surface area (contact patch), but it is not limited to the weight of the car. Look at the extreme. You mean to tell me that a 165 tire has the same amount of contact patch as a 345 tire? If this was not true, why would drag racing tires be so wide? The light racing cars actually has less contact patch than a steet car? I don't think this is so.They are not wide for there cornering ability.

 

I think what Dave is saying is a wider tire will exhibit a contact patch that is wider but not as deep (front-back) as a narrower tire that will have a narrower (sideways) but deeper patch. Basically a wider tire will have a more oval contact patch than a narrower tire that will have a more round patch.

I don't know if this is correct because I haven't researched it, but it sounds reasonable off the top of my head since the weight of the car will ultimately dictate the load on each tire. A wider tire will have less pressure applied to it due to the increased area and thus the contact patch will change shape accordingly.

 

I know that the load plays a part in it, but it's not the only factor. Tire pressure plays a big part in it too. I know the shape changes, but so does the total surface area. I also know what he means, but it's only partially correct. He's point is only true when the only variable is weight, not tire pressure nor tire size, although the tire pressure will change if weight is increased. With a wider tire, the only variable will be the amount of area that touches. If the pressure is the same, the wider tires should result in more cantact patch. Why bother with wider tires when drag racing, if it does not improve the contact patch?

 

Yes, 165 series tire will have a contact that is similiar to a 345 series assuming the same car. If you lower the pressure, the patch will begin to "cup" (bend inwards). Too much pressure and the patch gets narrower, but longer. Think about it, you can't pump a tire to the point that only a 1/2" cube of contact patch is on the ground. You'll make the tires ride harder or softer, but the general contact area stays the same.

Light racecars typically run fairly wide tires for thier size, but keep in mind a racecar (ie CART) generates a MASSIVE amount of downforce which in turn lets the car take more advantage of the tire size. They generate enough downforce to drive upsidedown on a ceiling at 120+mph.

Most street cars don't benefit from really large and wide drag tires. Most street cars run 6"-9" wide slicks. Drag tires are also typically mounted on 13"-15" rims with rather tall sidewalls. How many drag cars do you see running 40 series tires? 22" to 28" diameter tires are typical in terms of slicks. Real drag cars run very tall tires mounted on 15s. The tires can be along the lines of 2.5' wide, but keep in mind under full acceleration, the tire does shrink in width and grow in height. A 2.5' wide tire becomes a 1.7' wide tire under full acceleration.


Dave

 

It's true...my tires are beefy and I get really great traction with the 225/50 A520's. But whatever you do is eventually your own decision; the 225/45 and 225/50 are close. And, phenryiv1, I also get a teensy amount of rubbing with the wheels turned allll the way as well. With really wide tires in the front, you're asking for trouble, but in the back I suppose it doesn't matter.