Tire decisions: 235/45 or 245/40? I'm interested for the gearing.
 

I am currently running a 245/45 on the front. I know, I know that is a supremely stupid thing to do and I don't know what I was thinking when I was ordering. But here is the deal. My rediculously bad alignment and camber has chewed threw half of their life in less than 2K. I know I need to get the alignment fixed but I'm going to do that when the tranny swap is complete. I think I have a problem with the steering rods cause my steering wheel is cocked. But that is not the point of this thread.

I can't decide which tire size to go with. I want your opinions on what would be a good comprimise. There are two options that stand out in my mind that would still look suitable for a street car. They are 245/40 or the recommended 235/45. Which is best? The overall diameter of the 245 is 24.7". The overall diameter of the 235 is 25.3". What is the overall diameter stock? Is the 235 larger than stock? Would you guys think it would look alright to have a tire that was .6" smaller in the wheel well? Please keep in mind that I will be 5Spd, I have a 60Ibs system and I have Progress Springs which drop 1.7 front 1.5 rear. I don't want to be nose high.

The main reason that I'm looking into this is for the gearing. I want the better gearing that a smaller tire offers but only if it will look right. Also, do you think the added 10mm of tread will negate some, most or any of the acceleration gains? Also, how much would one estimate the top speed would be increased? Does anyone have experience with this size? Would the gas mileage be greatly decreased due to being higher in the RPM's during cruising.

Your kinda splitting hairs. You won't notice or see much of a difference at all. Remeber, a tire that is .5" taller will only be .25" taller on each side of the tire, so you will hardly be able to notice that.

Kind of veering a bit with this question, but it relates...

For 17" wheels, is there a preference b/w 7", 7.5", and 8" widths?

Funny, seems like the majority I notice are using 17 x 7.5's. Why then?

And cheap...

Thanks for the opinions. I'm fairly sure I'm going to move my current 245/45's to the rear and the 235's on the front. That way I can have a nice thick sidewall on the back to help the beam deal with uneven surfaces. When the 235's are dead I'll decide. I'm fairly set on 245/40. Does anyone have this size on a 5Spd with Progress? I really can't stand being nose high. I need to find the weights but I think I recall the 245/40 being lighter than 235/45. TopElement, what would the OD of the 245/40 be on the 8" rim?

Won't wheel damage be a likelihood with the 235's on 8" wheels?!?!? Seems like the wheel would darn near stick out past the tire.

I use a 235 on an 8" currently and there is enough tire to protect it from a slight grazing. Just be smart and you won't have an issue.

Also, the tire that I like and is cheap is the Kumho. In 235/45 it is 25Ibs. In 245/40 it is 26Ibs. A one pound difference isn't much but it would certainly negate most of the acceleration gains from the smaller OD.

If you're comparing OD, you should control one significant variable: different brands and types of tires will vary slightly! So just go and compare the ODs on the Kumho site which you obviously just visited. :)

http://www.kumhousa.com/Products/Ptn...ID=1&PtnID=712

Broaner, my opinion: go with 235/45. The extra pound probably negates the tiny difference in OD. I think 245/40s won't look as good either.

But TopElement is right your tire can never be too wide. I agree that it has the possibility of looking wrong. I still have to decide.

Any more input on this topic is welcome. I have my buddy's input as well as the opinion of the handling guru.

See that sticky above, in this forum, that says "Tire Calculator?" Check it out...

I have 245/40/18, Progress/Illuminas, and 5spd, and I think they tires look perfect. The drop is damn near even, but then again I have no system in the back. Pics on homepage.

18" rim diameter throws it all out of wack. Thanks though. Is 245/40 standard for the size your running. OD?

Thanks for the Tire Calculator but I also want the opinion of how the slightly smaller tire looks in the wheel well on a 5Spd car with Progress drop.

:tard: sorry, didn't see the 17" part. 245/40/18 is too big by a few %, but I cared more about having the extra sidewall than my speedo off by a MPH or two

But you get worse gearing with the taller tire.

Well to that end... extra sidewall cushion reduces the chances I'll bend a rim, which to me, is worth more than the extra .05 seconds I'll lose by going with a larger outside diameter setup. I mean if I'm really trying to go as fast as possible I'd find some super-light 15" or 16" wheels.

True true...