TSX Hokie

I am looking at getting 17" SSR Competition wheels. Tirerack recommends the 17x8 +48 offset, but for the RSX they recommend the 17x7.5 +42 offset. Both are 5x114 bolt pattern.

However, according to this calculator, the 17x7.5 +42 actually protrudes 1 mm LESS than the 17x8 +48. Wouldn't the +42 actually be a BETTER fit for our cars than what Tirerack recommends? The 7.5" width wheels would accomodate most 215, 225, and 235 width tires, whereas the 8" width wheels would be too wide for the stock tire width of 215mm. Plus the 7.5" width wheels are a half pound or so lighter.

Someone please correct me if I am wrong. I am close to buying the 17x7.5 +42 wheels.

Thanks

Dan Martin

You'll have no problem with either wheel setup.

Edit: The outer edge of the two different setups only varies by 0.35mm (14 thousandths of an inch). That's pretty close.

TSX Hokie

I emailed Gary at tirerack about why they recommend the 17x8 for our cars over the 17x7.5 I'll let everyone know what he tells me. Thanks Dan.

TSX Hokie

Gary says:

"The 17X7.5 ET 42 fits well and should be up on the site by early next
week. SSR often lists the most aggressive fitment as 'preferred' for
customers looking to push the limits a bit more. I don't necessarily
share that belief myself. "

LannyM

I think we can agree that for the RSX, the 7.5" 42 offset wheel is the optimum setup, as the 02-04 RSX uses a 6.5" 45 offset wheel stock.

I would think that 8" 48 offset rim would be preferred for the TSX, though, not because of the protusion issue, which is non existant, but for the fact that it's wider and still fits well, and would be a better match for a 235/45/17, which is very close to the factory diameter.....

Since youre not going up in size, and going with a very lightweight rim, I'm guessing this move is motivated more by performance than just looks. If that's the case, I'd want as much rubber on the road as possible......

mg7726

damn SSR competitions are like 15 lbs. damn that's light!!

TSX Hokie

Correct, I have chosen 17" SSR Comps for the improved acceleration, braking, and handling provided by a lightweight wheel. Going up to 18", even with a wheel as light as the Comps, would completely negate these benefits since the rotational inertia would increase so much. Not to mention the higher cost and rougher ride associated with lower-profile tires. Plus the Comps have a nice understated look (I don't want to draw attention).

I plan on using 215/50/17 or 225/45/17 tires over 235/45/17 for the following reasons:
1. Lighter
2. Cheaper
3. Better fuel economy (less rolling resistance)

I don't plan on doing any clutch dumps from a stop, so the extra traction 235 width tires would provide doesn't outweigh the reasons above. I do plan on using grippy summer tires (Toyo T1-R if they are released stateside by spring '05), so even 215 width tires should provide gobs more grip than an all-seasons with 235 width.

TSX Hokie

17x7.5 Comps are 13.6 lbs.....

LannyM

I was thinking 235 in a grippy summer tire .......

Lighter: I'll give you that, assuming the specs on Toyo's website for the T1-S (one of my favorite tires) are correct:

215/45ZR17 91WRD /7.0-8.0/20.1lb

225/45ZR17 94WRD/7.0-7.5-8.5/20.9lb

235/45ZR17 97W/7.5-8.0-9.0/23.8lb

215/50ZR17 91Y/6.0-7.0-7.5/22.9lb

Why does the 225/45 only weigh .8lb more than the 215/45, but the 235/45 is 3lb more than the 225/45? Does it require a lot more reinforcement at that width?

But look at the weight of the 215/50/17! And you really don't want to run a 215/45/17.

Price: The 235/45/17 T1-S is only $4.00 more than the 225/45/17 at bigwheels.net. The 215/50/17 is the same as the 225/45/17....

Gas Mileage: Doubt it would make a huge difference.....

I've always been amazed at the listed weight of the T1-S 225/45/17. It looks like the best bet for you considering all your criteria, on the lighter 7.5 rim. Assuming these specs carry over to the T1-R.

TSX Hokie

Yeah, the weights for the T1-S don't make alot of sense. The best prices I have found on the T1-S are at Tireswap

They have 225/45/17 for $135!

xizor

There's a tradeoff for the width/offset. The greater wideth will give more grip w/ a wider tire, but it'll also lead to more tramlining and more steering wheel pull when acclerating/braking. An offset that's farther out will give you a wider track, but also pull more on the steering wheel. I should probably go w/ 17x7.5 +48 if you can.

17" comps are too small for the TSX

kaikai114

will the 42mm offset one protrude more or the 48mm offset one?

xizor

42

LannyM

This is a great site for calculating tire diameter and offset effects:

Click here


In this case, the 8" rim with the 48 offset will actually stick out .013" more than a 7.5" 42 offset rim. Even though the 42 offset rim is mounted 6mm further out, the fact that the 48 offset rim is 8" wide means that there's 1/2"(12.7mm) of extra width that is basically distributed evenly both on the inside and the outside of the wheel. So that means that it's 1/4" futher out, which is 6.35mm, less the 6mm offset difference, so you end up .35mm or .013" further out....(not even enough to see.)

Sorry for the long winded explanation, just use the calculator......

But as a general rule, if two rims are the same width, then the lower offset number will stick further out.

vansterdam

That calculator link doesn't seem to work. Here's another wheel offset calculator