Miscellaneous Questions
Alright, folks. You, my varied and fantabulous group of LJ friends, can come to the rescue of a horribly stuck-inside-his-box otterdoc. :)
I’m shopping very soon for tires and/or rims for my car with two things in mind ( Read more... )
I’m shopping very soon for tires and/or rims for my car with two things in mind ( Read more... )
Lets see, where to start... You have a good basis for your search, and unsprung weight and acceleration are what you have to consider on the performance side of things to start with.
Higher unsprung weight means the tires won't react as rapidly to rebound from the shocks, and the car will feel like it drops a little more speed in the corners, assuming you're cornering properly.
Higher rotational mass means you're trying to turn more weight, rather than using that force and putting it to the ground. Rotational mass has two specific characteristics that need to be reviewed. Overall weight, and location of said weight.
Going to 18" rims pushes the brunt of the weight of the wheels out by a half inch on the radius. While this is great for torque, you're not trying to tighten your crank bolt by spinning your drive wheel, or at least, I hope you're not. ;) Quite the opposite, since the wheel is going to need to spin on the axis, it will TAKE more torque to rotate it. Basic physics and so on.
As far as the staggered rim widths, it's typically done on rear-wheel-drive sports cars. The reasons for this are two fold, and I dare say on your car, serve one function. One is asthetics, some people like seeing the beefier tires in the rear, and it lends itself to a true sports car look. However, the other is keeping off-the-line traction high.
Assuming you switch to 8" rears and fronts, you'd be losing a half inch of track on the rear, which would facilitate the need to reduce the width of the tires accordingly, reducing the overall contact patch. The best soloution in this respect would be to go with 8" wide wheels all around, and while that may seem to state that you'd have a loss of traction in the rear, the balance overall will be MUCH better, and the tires will break free more evenly, along sweepers, and it will help avoid understeer by the possibility of plowing in at high speeds where your wide-tracked rears will keep grip, and the fronts give up.
For what tire to buy, I'd sugest these: https://secure3.nexternal.com/shared/StoreFront/default.asp?CS=bimmerworl&BusType=BtoC&Count1=86406886&Count2=3547310&ProductID=291&Target=products.asp
I've ALWAYS loved the TDR Pro Race 1's, and will be buying a set for myself, soon, maybe, just for asthetic wheels (My present wheels weigh 10 pounds, and are 15's, so... =) I figure I have room to wiggle in a set of 'pretty' wheels, since I do nearly nothing asthetic to my car.)
Optimally, this would all go in conjunction with proper suspension tuning, in the form of stiffer front and rear sway bars, springs, and struts, accordingly adjustable. But most important to your suspension is your selection of tire. I would suggest some very good tires, specifically the BFGoodridge G-Force Sports or Yokohama's Neova or AVS Sport series, which both combine daily drivability with maximum performance to life ratio. If you have the money, splurge on better wheels, like the BFG G-Force KD or the Goodyear Eagle F1 GS-D3 series. Size-wise, I'd stick with 235/40R17's, keeping the profile lower, but keeping the width reasonable. Assuming you get something of appropriate offset, I can't forsee any problems with rubbing, since you're within factory specs EASILY.
Anyway, if you have any othe questions, hit me up on AIM as EddieCoon, or find me on the MUCK or whatever... You can find me, no doubt. =)
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Honestly, by the sound of things, I'm not going to notice a major change if I go to 8" all around. I'm not cornering hard enough in general to notice a lot of understeer, and really, there's not going to be track time for this car, nor is there going to be in the immediate future any advance driving courses. What I'm aiming for is to keep the stock performance feel, which is quite enough for me at this point, without breaking the bank. I'm willing to spend a reasonable amount of money on this car, but that doesn't get up to $3500 for rims alone.
Stock tires on this car were Continental Contisport Contacts. Not the newest or best, I'm told, but they felt pretty good to me. Noise was the only issue, but the rears are very well worn, obviously. And, as I said, I've gotta get two rears like NOW, but the fronts are in great shape. No reason to replace them, and I don't think it's all that wise to have 2 different tire types on the car, is it? I'm not unhappy in general with the peroformance of the Contis.
Sizes currently for tires (which I like the look of): Front 225/45/ZR17, Rear 245/40/ZR17
Suspension has to wait for a need to replace. Again, I'm not unhappy with how it is now.
Thanks for the input!! I'll probably bother you more about this later today if I can find you. It's all effed up since you guys are now on Cali time. :) That link didn't work. Which rims?
-M.
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But remember, the BIGGEST difference you'll make to your car is good tires. Conti's I rate as 'fair', at best, and I, as well as a certain few other car drivers who's cars came with SportC's, that even the "lowly" AVS ES100's from Yokohama grip nearly twice as well. I would suggest you spend a good amount on tires that'll both last you a while, and grip like a MoFo. That car is no light pony car, but rather a weighty cornered GT car, so you'll be wanting some stiff-assed sidewalls, too, which shouldn't be a problem with 40 series tires.
Here's the actual link to those wheels:
http://www.bimmerworld.com/html/team-dynamics-pro-race-1---e3646.htm
They typically come in three color options: Silver, gold/bronze, and black. I can hunt around more closely, if you're interested in 'em. =)
- Eddie
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I'm with you on price, performance, size, etc. on those rims... just not the style. I'm not a fan of the long spokes. :P However, we'll see, and I'll be keeping an eye on that site for sure.
I think what I have to do (not what I WANT to do, as there are some BBS rims that are teh sex) is:
1) Replace the tires on the rear pronto. I'd get something different if it were OK to mix, but as it stands I'm going to stick with my fair contis for now -- OEM was good enough for me, basically -- and run that set through.
2) Come winter, I'll pick up a cheap set of rims and good winter tires. Keep these for yearly use.
3) Come spring, I'll probably replace the M68 OEM rims that are damaged with new ones and then decide about a whole new set of tires. I'll probably need brakes by then, which is about a $700 job, so I may well just keep the Contis on.
Not the most fun option, but I'm filing away the information you've provided for when I've got more cash flow next summer. If I get hyooge bonus this fall with the hospital being down to 2 docs for a while, well, we'll talk again! :)
Thanks again for all the tips!!
-M., better educated
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