Steering feel w/ different offsets
 

Has anyone noticed a difference in steering feel with different offsets in the front? A lot of the wheel options for this car are +45, which is 2mm off -- looks tiny, but I have heard that kind of difference touted as a significant change in vehicle suspensions.

2mm off from what? yes when you get wider wheels and tires you will feel it.

Stock is +50 and 8" wide. 5mm is something you wouldn't feel. If you went with 10.5" +45 then that's actually way more than 5mm and you will feel the difference (especially with an appropriately wide tire).

I'm toying with the idea of swapping the big R3 19s for a lighter set of 17s or 18s, and it seems that there are very few options with the stock offset -- most seem to be +45mm. I'm not looking to go wider at this point. I've heard that different offsets can affect steering feel, so I wanted to see if/to what extent that happens on the S2.

Really? I thought read that stock for the R3 is +47...

Stock RX-8 R3 wheels are 19 x 8 +50.

Got it. Thanks!

Also, the R3 Forged BBS wheels are pretty light, I just helped ship a set for a buddy and they were around 20lbs IIRC, the boxes were big heavy boxes for 20" x 11" wheels and with packing, popcorn, and cardboard wrapped around them they were 38lbs shipping weight.

A typical 225/40-19 will weigh about 25lbs by itself.

Attachment 221767

Yeah, they are great rims for their size.

If I drop down to 18s with Michelin Pilot Super Sports, that'd drop 5-6 lbs per corner and add a bit of sidewall, and less of the mass would be so far out from the hub. Seems like it could be a worthwhile move, no?

I highly doubt you would shed much weight at all. An 18" Michelin is quite heavy typically. And the average 18" cast wheel will weigh as much as the R3 wheels. You can also look into a BBK for weight savings.

Wheels (example): Enkei Racing PF01, 18 lbs

http://www.tirerack.com/wheels/Wheel...nt&showRear=no


Tire: Michelin Pilot Super Sport, 22 lbs

http://www.tirerack.com/tires/tires....omCompare1=yes


Should be 40 lbs a corner, give or take.

Yeah, you could shave 4-5lbs per corner if you went with stock 18" wheel and tire specs. I'm not sure why that would be important to you though. Are you racing competitively?

Also that 18.0lb spec is not accurate from what I can see. But it's close.

Yeah, there are a few sizes for that model rim that are slightly different but all listed as the same product for some reason. The one I was looking at was 18x8 and +50 offset.

4-5 lbs per corner can make a big difference! I noticed it pretty easily on my last car...

I have had a few sets of varying sizes and never noticed a difference really. Spending $2000.00+ to save minimal weight on a street car seems silly. But I have done crazier things, :lol:

offset will actually change alignment. this changes feel. My tack tires make the car wider. (brain will not remember the different offsets. I seem to think stock is 50mm, and track wheels are 35mm. That moves the tire out, which increases the pressure on the spindle (greater leverage), which compresses the spring a bit more, which results in a little more negative camber and since they are compressed, it moves the center of the spindle out a tad, which gives a little bit of toe in because the steering is mounted in the front. This makes the car a bit twitchy, but it turns really nice. It is also one of the reasons I decided to take track tires to the track on a trailer instead of putting them on the car.

I think tire width makes less difference than moving the center point of the tire. But, pretty soon you start taking into account the pressure distribution across the tire that is influenced by the negative camber. I need beer for that discussion.

Or, yes, it makes a difference. Different offsets will re-align the car. Use it to your advantage.

Most of what you're saying makes sense, but shouldn't toe-in make the car LESS twitchy?

Maybe what you're feeling with the lower offset has to do with a change in scrub radius?

You wont notice a 5mm difference.......you would notice a wider tire more