Are 225/40-18s too big for the tC?
i was lookin at a tire sizing program -- http://members.aol.com/agspeed/tiresize.htm -- and it said that the tire height is off when ya go from 215/45-17s to 225/40-18s .. but its a size thats offered on the RS1.0 ... and other tCs that have 18s as the aftermarket package from the factory .. says that the stock tire height is 24.61 inches .. and the 225/40-18 tire height is 25.08 inches .. which to me seems like a lot off .. i did the calculating for the 215/40-18s and the tire height is a more comparable 24.77 inches .. which to me helps ya have a more correct speedometer .. so when i get 18s im gonna go w/ the 215/40-18s .. even tho i may loose a half inch on width .. ill be more correct on my speedometer .. and i guess if no one cares .. oh well .. i also heard that if u put taller tires on the car you actually loose a little in torque ..
I went with 225/40-18's on my new wheels. I'm putting them on this weekend I'll let ya know how big of a difference it makes. Here's is the info about going from 215/45/17 to 225/40/18 from the site I got my wheel/tire package from http://www.whalentire.com/tiresize.c...0&crn=0&alt=no
Originally Posted by utatc7218
yeah I have seen quater mile times with the tC on 17 and then to 18 and the car lost almost 2 tenths of a sec. Its a whole inertia thing... but who cares your ride will look nice.
reaction time, launch rpm's, engine temp, driver skill, the list is endless.
Something like a full second, I could see that, but 2/10ths....hell, many people wouldn't even be able to run back to back with only 2/10ths difference on the same car, same setup.
Originally Posted by sensay
instead of 225/40/18 get 225/35/18 DURR its almost perfect with stock
I understand what your saying but they had the same driver for each trial and they did more than 2 runs... It was done by some magazine and it showed a consistent range of about .2 slower than stock 17's.. just what I read... but it makes sense. I saw on speed channel when they upgraded this RSX's brakes to a big brake kit and even though the brakes were lighter they still lost horsepower. Its all physics bud...
I'd have to see the article, to truly believe it. But this post makes it sound a lot more believable than the first one you posted 
But yes, if you just took a larger diameter rim, then yes, you could see slower times.
However, when smart people upgrade rim sizes, they typically use a rim that *weighs* less, as well as move to a lower profile tire. This way, you get a lighter weight rim, better looking tire that also weighs less (lower profile tire) and same overall height. There fore, inertia is not an issue.

But yes, if you just took a larger diameter rim, then yes, you could see slower times.
However, when smart people upgrade rim sizes, they typically use a rim that *weighs* less, as well as move to a lower profile tire. This way, you get a lighter weight rim, better looking tire that also weighs less (lower profile tire) and same overall height. There fore, inertia is not an issue.
Just ordered 18's for my xb. They should be in by next week. I went with the 225/40/18 myself. My buddy works at a local Toyota dealer and he is ordering me the TRD springs. If anyone has any pictures of an xb dropped with TRD springs, that is sitting on 18's, I'd like to see it.
Originally Posted by TRDToaster
Just ordered 18's for my xb. They should be in by next week. I went with the 225/40/18 myself. My buddy works at a local Toyota dealer and he is ordering me the TRD springs. If anyone has any pictures of an xb dropped with TRD springs, that is sitting on 18's, I'd like to see it.
I have TRD springs with 225/40/18 and i havew no rubbing and the ride is a lot smoother that with 17's. I love this tire size its perfect. I live in an area with a lot of bad roads so i can use the extra tire....any smaller and i could be risking my rims being bent.
Originally Posted by phatfront
I'm running 235/40r18s.






