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Sabin
provisional solo poster
40 Posts |
 Posted - 02/19/2010 : 20:59:13
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I was woundering about the tire height. The maximum tire size my car can fit w/o rubbing on suspension parts is:
215/45/17
215/55/16
215/65/15
and so on
The question i have to ask is how does the second number (sidewall height) impact the handling of the tire? From my understanding the sidewall flexes when under side load from cornering. I know a bigger sidewall will flex more than a thinner one and can cause less grip. I also know that if you go too thin, you can also loose grip because the sidewall is now stiffer and the side load on the contact patch of that tire is too much to keep traction. Right now I got lightweight 17" rims w/ Toyo Proxy 4's. They are a great tire for the street, rain or shine. I've been debating on putting my 16's back on for the track and this is the only thing I don't quite know enough about to make my decision.
95 Neon 12.1:1 Compression
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adambrouillard
novice poster
9 Posts |
Posted - 02/21/2010 : 08:42:29
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A shorter sidewall will increase transitional response of the vehicle, which most people consider good, and it will also reduce the peak slip angle so there is less tire scrub during cornering which is also good. You can also run somewhat less pressure and that will increase the contact patch, again also good. You can go too far, especially on a bumpy track because there is less compliance, but a 215/45 is plenty of sidewall. Just look to race series that allow any tire size and you will see how little sidewall they use. Stiffening up your tires also affects your overall wheel rates and can cause balance shifts, but unless your car is very,very stiffly sprung the difference will be negligible. Formula 1 cars actually often have more compliance in the tires than in the suspension and for them this is very important for setup.
www.howkartswork.com -Setup and Driving Tips
www.hollingsworthrg.com -Atlanta Property Management |
Edited by - adambrouillard on 02/21/2010 08:49:26 |
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JeremyGSU
Instructor poster
406 Posts |
Posted - 02/22/2010 : 16:43:42
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Since the tire sizes aren't any wider I would go with the 16" wheel if you have an extra set for costs reasons. 16's should be cheaper than 17's, possibly even lighter depending on the rims.
Jeremy
'06 Ford F-150
'04 Honda CBR F4i
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Sabin
provisional solo poster
40 Posts |
Posted - 03/01/2010 : 20:10:12
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actually, my 16's are heavier than my 17's. my 17's are lightweight aluminum, as for my 16's are chrome plated steel. I bought the lightweight rims cause the heavy chrome ones were making it extremely sluggish off the line. Now I can't floor it off the line anymore. Thanks for your knowledge on this topic and I'm sure others might find it useful too.
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dew-e
novice poster
9 Posts |
Posted - 03/08/2010 : 15:40:00
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If your question is what wheels, that I already own, should i use? The answer would be to use the wheel that is lighter as long as the tires that fit those wheels are in your price range.
I do have to ask why you think those are the only sizes you can run? Is that what tirerack has told you to use, or is that based on web forums from other people that track the model of car that you are using? Keep in mind that many online tire retailers use the concept of "plus sizing" tires so that your speedometer and other mileage stay pretty accurate. The sizes you have listed look like they are sized up to keep your speedo accurate.
How wide are your 17" rims? That is what should dictate how wide of a tire to run. For a 17" rim, a tire with a 40 profile is pretty standard. Some cars run much lower profile tires. I would probably avoid tracking any tire that has a huge sidewall, like a 55 or 65 series tire. I tracked a 235x45 before and the tires were very squirmy because the side wall was so large.
The direzza z1 comes in 215x40 and is the lightest 17" offering for that particular tire, that would be good for a 7" rim. If you have a 7.5" rim I wouldn't run the 225x45 because is is a much heavier tire, three pounds more. The 235x40 will run on an 8" rim and is also two pounds lighter than the 225x45. The 225x45 just has a huge sidewall, so it is a heaver tire. |
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Sabin
provisional solo poster
40 Posts |
Posted - 03/10/2010 : 20:03:15
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That is based on what maximum tire/wheel combination will fit on my car without rubbing on suspension parts.
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Sabin
provisional solo poster
40 Posts |
Posted - 03/10/2010 : 20:07:18
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I actually run a 205. the 215 scrubbs on the inner frame at full turn. and on the rear, i will eat an angle in the tread from my trailing arm . a 50 series on a 17" rim would not fit on the hub due to the spring seat on the shock will be in the way.
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215/45/17 tires or 215/55/16 series.
