hmm, auto-xing on 18" steel doughnuts would be interesting... :D

Actually there are no "friction plates" (i.e. clutch discs) in a Torsen LSD. Still not a good idea to have different overall tire diameters, though.

did the rx-7 have a full size or donut?

just for comparison....

the 350Z has a full size spare

I don't care if it's full size or a donut. Just please leave room for a full size. It sucks to get a flat, put on the donut, and realize the flat tire will not fit in the donut cavity.

It would also make it a little easier to transport racing tires. Or at least one.

Randy Chase
P.S. Hey jps...

How much is that fix a flat stuff, and how are when do you usually dent your rims? Why is it that with 18"'s you get more dents? Is it mearly the bigger surface area? Again, humour me. I'm not as experienced as you guys. Thanks!:confused:

It's been a while since I bought any of that aerosol stuff... it was about $15 a few years ago...

Don't know about dents in the rims... never had a car with 18" rims... anyone care to comment?

With 18's you'll seriously have to watch the curbs. Even a minor low-speed run into one can ding them pretty bad. May not damage the rim to the point where it's unusable, but it'll definitely make it look like shit.

That's the obvious bit I suppose... anyone comment about the chance of damaging them from a poor road surface??

A friend of mine managed to turn his 17's into a kinda pac-man shape... but that was a rather exceptional hole in the road.

yup, the deal with chipping big wheels easily is that there is less tyre to give way before solid hits solid...
and because the sidewall is so close to the ground, even small rocks and stuff (that you try to guide your tyres around) that the edge of the rim will catch on, and bend as the tyre rolls over it...
the bigger the rim (and smaller the sidewall), obviously, the more things this can happen with...

To Red_Base 95
 

Actually, the wheel/tires will be 225/45 18's.

Give me a donut - less expensive, less weight and more room in the trunk for my golf clubs. :D

you can fit two sets in there, so figure you still fit one with a donut, and that's enough for you to play golf :)

If they don't allow room for a full size spare, where do you put the regular tire when you have a flat and you are driving on your donut. I fdon't mind the donut at all. With good tires and the state of tire technology, it's been a long time since I have had a flat. I just want the room to put the regular tire. That way I can put a racing tire there, and then one in the trunk, and two in the back seat. :)

MMmmmm.... donuts.

Hurcules:

Start getting pissed off now so that you will be over it by the time your shiny new RX-8 is delivered.:D

Hehe, nawww I won't be mad actually.. but I would prefer the full size if not for anything else but safety. Though I must admit, I have a pretty good track record now for not busting tires :)

Do you guys actually use heal and toe shifting?

You don't? It's not only for racing, it's the only way to get a smooth downshift while braking.

P.S., how exactly does that fit in with this thread? Or was it just a random thought you had?

It's not the only way...

it's the simplest and least complicated way. I personally don't hee and toe because I've found a better method, but it's more work on a turn so there can be a tad bit of a slowdown if you don't do it fast. I've done it as long as I can remember, so fortunately I've got it down and I do it fast. Just ease up on the clutch as you throttle in, and on the turn you have a perfect turn-in and no 'jump' in the car.

Granted it's slower than heel and toeing IF you aren't used to it (which most people are not), so for me it's faster.. but I'm used to it :)

Michigan
 

I live in suburban Detroit, and our pot holes are caverns into hell out here. It's the fact that we have lots of salt mines so we use salt to tame the ice on our roads in the winter, come spring, it has eaten into the road and the heat expansion just open up the wounds more. So if you have 'rims' or a lowered car out here, you get used to being carefull and paying attention to faults in the roadway. I personally have used a donut for up to several days in these conditions and as long as you realize your driving with a dounut, it really isn't that bad on your ride, well you car anyways. So I think a donut will work just fine...It ain't that hard to get your tire fixed is it? Oh and for the record, Fix-A-Flat...Best shit since sliced bread if you need a new tire anyway.

I wondered the same thing.

But I disagree about it being the only way to downshift while braking, specially in competitive motorsports.

I don't think the 18" wheels are a problem on the roads since the profile is 45. However, anything less than that would be difficult to accept on real world roads.

How does easing up on the clutch help to rev match when downshifting? Heel/toe'ing is used when you are braking and need to downshift without letting up on the brakes. Without rev-matching, any downshift will be rough, but you can't rev-match normally in this scenario because your right foot is busy on the brake pedal.

I don't see how your description of events, or any other besides the standard, solves the problem. You need to be on the brakes, clutch, and throttle all at the same time. Unless you have a third leg or some kind of hand operated pedal, that means heel/toe'ing.

Let me explain it better. Heel and toeing is used with downshifting. I downshift like this:

First, you approach the turn, clutch in fully and shift from forth to second (this is for example).

As you approach the turn, you've slowed the car enough that you can start accellerating out of the turn, so you slowly clutch out and throttle in.

It's smooth and no jumps are involved. And you get optimal power exiting the turn as well as it being smooth.

Works for me :)

It's like letting the car cruise in neutral until you slow down (staying on the clutch), then downshift when the speed is low enough that it doesn't matter which gear you select.

It's kind of partial toe and heel, without the throttle blip to allow you to shift sooner.

At least, that's how I'm reading it.