18x8.5 Wheel/Tire Suggestion

Hi,

 

I am looking for some suggestions for an 18.8.5 Rota Grid. I currently have 17x7 aftermarket wheels. The car is an 05 LGT. Stock suspension. I live in an area with potholes.

 

I read in the wheel and tire sticky closest size to oem is 235/35/18. However I can't find many tires in that size. I am concerned with putting wheels that are not close to the original size. I don't want transmission or diff issues down the line.

 

Would I be closer with a 245/35 or a 235/35? I was looking at the Hankook V12 also.

 

I would prefer not to roll fenders but I will if necessary.

 

Any suggestions are appreciated.

 

Thanks

Have a look at this: http://rimsntires.com/specspro.jsp

More important than tire size is rim offset, make sure it is correct or there will be undue stress on your wheel bearings. Read the sticky That lists Subarus specified offset and get a wheel that is as close to that as possible.

You live in an area with pothholes, but you still want 35 series tires?!

You live in an area with pothholes, but you still want 35 series tires?!

 

There isn't potholes everywhere but I live in the northeast. NJ/NYC area and Upstate NY. The roads aren't the greatest down here. I was looking at a 35 because it would be closest to the original size.

Have a look at this: http://rimsntires.com/specspro.jsp

More important than tire size is rim offset, make sure it is correct or there will be undue stress on your wheel bearings. Read the sticky That lists Subarus specified offset and get a wheel that is as close to that as possible.

 

Thanks for the link. The stock offset is 55. The Rota Grid is 44. I used the link and this was the result. Is that too much of a difference?

 

 

Suspension clearance:Package 2 is 4 mm (0.2'') closer to suspension/brakes components. Acceptable for most cars.

 

Fenders clearance:Package 2 will stick out 26 mm (1'') farther. Make sure that you have enough room under the fender. If not, consider narrower tires or higher offset.

 

Wheelwells clearance: Will fill out the wheelwell by extra 2 mm. Almost no difference

 

SPEEDOMETER: When speedometer reads 60mph (96.6km/h) actual speed will be 60.3mph (97.1km/h): 0.5% faster.

You should be fine. Read this, it is a gold mine of information.

http://legacygt.com/forums/showthread.php/faq-offsets-sizes-rims-and-tires-gt-xenonk-version-4426.html

You should be fine. Read this, it is a gold mine of information.

http://legacygt.com/forums/showthread.php/faq-offsets-sizes-rims-and-tires-gt-xenonk-version-4426.html

 

Thanks for the link. Ive been reading that. So much info. So 245/35/18 is closer to the original 215/45/17 than a 235/40/18 right? Thanks.

It all depends on what you're looking at. The first number is the width of the tire in mm, and the second is the percentage of that number in mm. Take for example 245/35/18 The 245mm tire width has a sidewall height of 85.75mm (45% of 245). The third number is the innder dimeter of the center made to match the rim size. Here's the breakdown of your question:

215/45/17: 215mm width / 96.75mm sidewall height / 17 in rim.

245/35/18; 245mm width / 85.75mm sidewall height / 18 in rim.

235/40/18; 235mm width / 94.0 mm sidewall height / 18 in rim.

 

Based on that, the sidewall height of a 235/40 is closer to the sidewall height of a 215/45. However, due to the difference in rim size, the overall tire height is different. In that case, a 245/35/18 and a 215/45/17 are closer in size with the 215/45/17 being 3mm shorter (1.5mm on each side is an insignificant difference).

 

Does that make any sense?

I think I understand now. Thanks for being patient. So the 235/40 has the closest side well height to the 215/45/17 but the 245/35/18 is a closer overall diameter. So the 215/45 is only 1.5mm on the left and 1.5mm on the right sidewall shorter so I would be very close to the original size.

I think I understand now. Thanks for being patient. So the 235/40 has the closest side well height to the 215/45/17 but the 245/35/18 is a closer overall diameter. So the 215/45 is only 1.5mm on the left and 1.5mm on the right sidewall shorter so I would be very close to the original size.

 

1.5mm on the top and bottom on the same side of the tire.

 

I like this site to compare sizes because it shows a picture to compare.

 

http://www.tacomaworld.com/forum/tirecalc.php

Thanks for the link. The photos helped. So it would be better go with something that has the closest diameter to the original or one that has the closest sidewall to the original? Thanks!

Thanks for the link. The photos helped. So it would be better go with something that has the closest diameter to the original or one that has the closest sidewall to the original? Thanks!

 

1. The closest overall size will keep your speedo and gearing happy and closest to OEM specs.

 

2. The shorter the sidewall the higher the risk for potholes damaging the rims.

Idk bout your car, but both subarus i've had, the speedos actually read about 2mph faster than what you were actually going. IE you had to set the cruise at 72 to be going 70 (2 different gps verified). So if the overall diameter is a tad bit taller, then the speedo will be closer to true.

Also, short diameter will make you accelerate faster, and will result in less strain on the drivetrain, but you'll be turning more rpm's to go the same speed. Thus your mileage will go up faster.

 

A larger diameter, you'll accelerate a little slower, but you will turn less rpms to go the same speed. Your mileage will go up a little slower also.