I am in the market for 18's for my 06 tC.

A few people told me that it can Lower your 1/4 Time, and all in all, slow your car down.

What is the facts behind this. Also, Will it affect the Odometer, or anything...

Please Tell my the Negative side of having 18" rims?
Although I am pretty Set on getting some!

Thanks.

I already have a TRD drop by the way.

 

Well the slower times and such would be if the wheels are heavier than the OEM ones. You'd be adding more weight... which will slow you down.

As for the odometer, as long as you keep the same rolling diameter, you'll be fine. I'm sure someone here knows how to do the conversions and can tell what would be equal to the OEM stuff.

 

i dont know if you want to take this into consideration, but on my xB i hve had both 18's and my current 17's and the 17's handle soooooo much better. just something to consider, just trying to help :D

 

Ride quality will likely be worse with 18s with the shorter tire sidewall as well. Tires are also generally more expensive.

 

true, i paid only $75 a piece for my falken ziex's

 

I have 18" FN01RC's on my tC. things to look for in wheels when upgrading are:

1) check the weight of the wheel, lighter is better.
2) the offset. Stock tC wheels are 17x7 with a +45 offset, you want to go like 18x7.5 with a +35 offset, or in that area.

3) also a lot of people like forged wheels, which are more expensive than cast, and multipiece is also more expensive than single-piece.

Some excellent wheels are: Gram Lights, Volk Racing, RH Evo, Racing Hart, 5Zigen, DPE Engineering, SSR, HRE (if you want to spend A LOT on wheels that is). Also Konig and ADR are inexpensive and popular.

if you get the right wheels, (and tires of course) your handling should definetly improve, but probably at the cost of ride comfort. Usually thats about all you are gonna sacrifice though. Just stay away from anything too heavy.

 

The Toyota 18's Upgrade are: {225 / 40 / 18}.
I Plan on getting the same specs on my aftermarket 18s.

I believe that will be the same Circumference as our stock 17's.

BTW, anyone know how much the STOCK rims and tires weight?

Thanks so far guys.

 

goin from 215/45-17s to 225/40-18s .. theres a height difference .. the stock tire size is 24.6" .. the upgrade size is 25.1" .. half an inch difference .. i think thats a moderate difference .. if you went from 215/45-17s (24.6") to 215/40-18s (24.8"), its more reasonable .. i dunno .. does it make that much of a difference? im not sure .. but when i upgrade to 18s .. im prolly gonna go w/ the 215's instead of 225's .. yeah i know they are slightly thinner .. it would help w/ the odometer/speedometer reading .. and well .. take care of the other issues .. hope i could be of some help

 

Ya, I am buying a Package through WheelMax.com, I'm a returning customer.

It looks like they will only offer me 225-40-18.

But my theory is that if Toyota offers this upgrade, it can't be that bad for the car....see what i'm sayin. I think it really comes down to the weight of the Rims/Tires.

 

NEW QUESTION: The Rims I want have a 45 Offset, what does this mean for me?

EDIT: They are also 18x7.5

 

the 45 offset will appear the same as stock .. a 35 offset will sit out more .. which is preferable .. if you upgrade .. you need to get a smaller offset to bring the rims out a bit more .. im most likely upgrading to a 18 X 7.5" rim w/ a 35mm offset .. and im most likely buying a set of Bronze Enkei RSV rims .. w/ Pirelli tires .. i like the pirellis i have now .. if they dont cost too much more then the tires they would offer in the wheel package .. im gonna go with them .. by the way .. the Pirelli PZero Neros are the upgrade option w/ the tC for the most part .. they also offer yokohamas too i guess ..

 

Checkout this handy site for tire measurement comparisons.
http://www.miata.net/garage/tirecalc.html

45mm offset is okay if your wheel is no wider than 7.5 inches. any wider and you risk rubbing the inside of the wheel/tire with the suspension.

 

I went with pretty much the widest tire I could come up with for my 18s. For tires I looked for the best wet and dry combination tire. For me that was the PZero Nero M+S... I am continually blown away how little sliding in the corners and how much stick there is going 3/4 throttle in the wet!

As for the weight of the wheel. It really only matters much during acceleration and stopping, and its not a ton. I read an article of a guy with light weight 15" race rims on his miata going around Laguna and lost control of his car and damaged a rim. Rather then waste the money he spent on the track day he tossed on his nice heavy 17" chome rims and went around the track. He fully expected there to be huge difference in his time, and there wasn't.

His main point, 90% of your time is the driver, the rest is the car. So buy what you like and just drive it.

 

hate to be off topic but i guess this is somehow part of the topic. does anybody know the disadvantages of having low-profile tires in the winter time?

 

i dont think profile of the tire....its the tread of the tire
an all season tread would probably be a little harder to find in lo pro's tho

 

The diameter of the 215/45/17's is 24.6 in but not all tires that size are that same diameter. It will also depend on tread depth. I've seen a 225/40/18 that was 24.6in but I forget what company but i found it on tire rack. Generally a 225/40/18 is 25 in. in diameter but your car will never notice the difference. You would have to be goin atleast 100mph to see any change. Then it would only be something like 2 mph.

Now you could try to go with a 215/40/18 but they're aren't wide enough for the rims. Yeah they'll go on but they aren't safe and you have a greater chance of damaging your new wheels. True light weight wheels are expensive. You can try looking into Volk's or maybe 5Zigen. Another thing you need to look for is tire weight as well. Not all tires that are the same size weigh the same.

If you are turely concerned about weight then go smaller. If you aren't taking your car to the track then I wouldn't really worry about it.

 

what is the weight of the OEM wheel by itself? anyone knows?
(if nobody knows, i will do it, but if somebody already did the job, please answer me)

 

the 17's are 19.5 lbs

the 18's are 20.5 lbs

 

well considering most new cars with the exception of most domestics are comming stock with 18"s and even 19"s and i dont think that is an issue with those. techinically you could say the Tc has 18" wheels stock even though its an option....if that makes sense

 

*whips out glasses and graphing calculator*

according to my calculations, if the stock tires are 24.6 inches in diameter and you're running tires 25.1 inches in diameter, then when your speedo reads 60 mph you'll actually be doing 61.2 mph. so basically the diff is negligible.

there would be a slight loss of accelleration. the weight thing isnt that big of a deal really, even if it is rotating mass, because the car is so heavy relative to the rims. but also, bigger tires basically means a higher gear ratio, so there'll be a little more resistance to accelleration. but, top speed would be improved a little (itd top out right around 130), and the larger contact patch will improve traction for better launches and better handling at the limits.

basically it might feel a little slower when your just driving around town, but it'll be quicker launching off the line and be able to turn harder without understeering.