ok ive done a search on what brand of tire to get so now my question is what size is best for the R, especially for street/drag races. ive noticed alot of people go to a 50 from the stock 55. so going with this formula, wouldnt that be, in effect, slowing your car down since the bigger the circumference of the tire, the further you will travel with each rotation of the tire, so going from a 195/55/15 to a 195/50/15 will slow you down but by how much? would the 55 be like 1/4 foot further traveled with each rotation?less more? even with a 1/4 foot, for every 4 rotations you would be 1 foot ahead of the guy running 50's, how many rotations in a 1/4 mile? but putting some stupid ugly extra tall tire on the car would hinder turning performance as well...so what would be the best tire size to use?

 

It's all about the torque. Torque is a force measured at a distance from the center of the wheel. Your engine puts out a specific torque, so changing wheel/tire size will change the amount of force you put to the ground. Example: 100 lb-ft from your engine to a 1-foot wheel (to make things easy) = 100lb of force. But 100lb-ft from the engine to a 2-foot wheel (bling bling!) = 50lb of force. It's like the difference between starting in 1st gear and starting in 3rd gear. So don't put 24's on your R Hope that isn't too confusing...

 

That part is correct. A tire with a bigger outer diameter (or circumference, which is diameter times 3.141592653589793) will go further with each engine revolution. It's like being in a higher gear. So acceleration will be slower.

No, it won't. The diameter of a 195/50-15 tire is smaller than that of a 195/55-15 tire.

The diameter of the tire is equal to the diameter of the wheel (15 inches) plus the sidewall height. The sidewall height is the tread width (195 mm) times the aspect ratio (50 percent or 55 percent). The sidewall height is smaller with a 195/50 tire than with a 195/55 tire.

There are lots of compromises and trade-offs in selecting a tire size. Up to a point, wider tread may give you better handling, but not always. Shorter sidewalls may give you better handling and response, but may make it easier to bend your wheels when you hit potholes. Smaller outer diameter may help you accelerate faster but may make your car handle worse.

On the Type R, with the stock 15" wheels, the stock size is 195/55-15 and that's a good size tire. There are a number of different tires available in that size, some better for traction, some last longer, some are more expensive than others. The stock RE010 is a great tire in a lot of ways but it's not inexpensive. Many folks here like the Falken Azenis. If the tire you want to use is available in 195/55-15 that's the size I would recommend.

Some folks use 205/50-15 tires because there are a lot more different kinds of tires available in that size. (It's virtually impossible to find R compound track tires in 195/55, for example.) The 205/50-15 is actually a slightly smaller outer diameter than 195/55-15. The 215/50-15 is about the same outer diameter as the stock size - which is a good thing - but they can rub in the fender wells - which is a bad thing. And there aren't a lot of tires available in 215/50-15.

I think the main reason some folks have been choosing 195/50-15 lately is only that the Bridgestone S03 is currently on sale at a bargain price, in that size only.

 

kewl thanks for the info! im runnin some yokohamas in the 205 50 size right now and was just wondering if i should stick with that size or if it was hurting my acceleration, i really like the SO3's but those falkens are pretty sweet too. BTW ive read alot of threads that give the tread life on those tires but like they said different man. numbers vary so its not a really good way to tell so from ya'lls experiences which has a longer life, the falkens or the S03's? thats probably whats going to determine which one i get

 

From what I have heard, the S-03 wear out pretty quick. Azenis will last you longer. I'm planning on getting the S-03's also but I just can't decided on wether I should get 205-50-15 or 195-55-15.

 

last question, where can i find the falkens online? tirerack doesnt seem to carry them?

 

http://tires.com (Discount Tire, http://www.discounttiredirect.com). If you do a search, you'll find that they are in short supply, with conflicting information about whether they're out of stock or not.

 

Most drivers, when they switch from the factory 195/55/15 to 50 usually they go with 205/50/15, not 195/50/15. Like someone said before, 195/55/15 is about equivalent to 205/50/15. Technically, the width compensates for the difference between the two side wall hights (55 and 50).

 

Here are the actual numbers. Remember, the objective in choosing a tire is usually to keep the outer diameter of the tire the same as stock:

195/55-15 (stock) - 23.44 inches
195/50-15 - 22.68 inches (3.27 percent smaller than stock)
205/50-15 - 23.07 inches (1.60 percent smaller than stock)
215/50-15 - 23.46 inches (0.08 percent larger than stock)

As I mentioned, 205/50-15 is sometimes chosen, mostly because a lot of tires come in that size and because it doesn't rub, not because its outer diameter is the closest to stock.

 

so after reading the posts above.. . I take it that your speedometer will be off a little with different tire sizes right?


tj

 

Yes, that's correct. It will be off by the same percentage.



[Modified by nsxtcjr, 11:14 AM 2/24/2002]

 

Your speedo's probably off anyway (stock).

On the Azenis -- 205/50/15 -- but visbly wider (stacked) than AVSi of the same size...
60 mph on the speedo showed 56 on the radar sign. You take it from there!

Ed -- who left behind a turbo supra last night!


[Modified by zygspeed, 11:49 AM 2/24/2002]

 

I love the S-03 in the 205/50-15 size, but I agree, the Falkens are apparently the big hit. I love the fact of the speedo reading 60 but radar only 56.....affected gas mileage, but the benefit of driving just a little faster is awesome. I have to say, I have been tempted to go back to the RE010's in the 195's. As a tire, they seem to manage the Type R's tossibility the best. I wish they lasted longer.

 

It doesn't affect your actual gas mileage*. If you're calculating mileage as indicated on the odometer, it may LOOK like you're getting a different number of miles per gallon (you should actually be getting MORE indicated miles per gallon), but if you adjust for the difference in the outer diameter, it should come out the same.

*The exception is if the smaller outer diameter, by giving you better acceleration, hurts your "effective gearing" to such an extent that it actually gives you worse gas mileage, and that's possible - but it shouldn't be by the full amount of the percentage difference in indicated miles.