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      08-15-2016, 01:31 PM   #1
AriuSen
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So, I have done a extensive research on why people would track with the 18s, and mainly what I heard from people is because of bbk clearance and because tire companies dont provide 17" tires in 35 for their size.

This weekend I tried his 17x9.5 et 35 on my car and they clearly clear my bbk (PFC). I am not sure the size of my bbk, but it also clears my friends bbk (brembos)

Running 17s, will save me $200.00 per set!!! that is amazing!

Also, I would like to verify this information. running with 17x9.5 with 275/35/17, my gears will be shorter....I would be shifting fast which is a good thing!

Lastly look at the sheet I made....you can save 20lbs of UNSPRUNG weight.....that is a lot of weight to consider if you go with 255/40/17. Note that by going 255 compared to 275, the difference in width is very small. is 10.5 vs 10.8

So before I make the purchase, I would like to know from you guys....should I go with 275/35/17 or 255/40/17 ?

Advantage of going 255/40/17 is to save 20lbs of unsprung weight.
advantage of going 275/35/17 is to save only 8lbs of unsprung weight, but gears will be shorter (not sure this is true)

The HACK could maybe confirm?

Btw, if I go 275/35/17, I will have no issue with clearance as it will sit lower than my spring perch.

update: my friend told me, that by going 17 my speedometer will be off by 5%? I dont really actually care, as I dont really look at my speedometer at the track.
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Last edited by AriuSen; 08-15-2016 at 01:42 PM.
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      08-15-2016, 05:00 PM   #2
The HACK
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Only laptime could tell. But I wouldn't be surprised if the 255 width 17" tires is faster than all the options available, especially if you're running stiffer springs/dampers.

The wider tires don't really give you more grip, it gives you more surface area to keep the tires cool. If you're not overwhelming your tires, running wider don't give you significant amount of grip advantage, ad as you've found, is detrimental in weight penalty. Especially for lighter cars.

The company that corner balanced my MZ4 Coupe, Tri-Point Engineering, was heavily into racing Miatas. They've found that in the 15" tire range, by going from a 225 to 245 width tire of the same compound, they actually LOST time.

Of course, a 2,200 lbs, 130hp on a good day car vs 3,1xx and 330hp...Different story. But I'm inclined to say that, if you've got the budget, test out all the different options available to you.

This also is dependent on your particular driving style too, and on which side of the grip you live on. If you tend to live on the right side of the grip curve, then wider tires will definitely help.
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      08-15-2016, 08:04 PM   #3
AriuSen
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Quote:
Originally Posted by The HACK View Post
Only laptime could tell. But I wouldn't be surprised if the 255 width 17" tires is faster than all the options available, especially if you're running stiffer springs/dampers.

The wider tires don't really give you more grip, it gives you more surface area to keep the tires cool. If you're not overwhelming your tires, running wider don't give you significant amount of grip advantage, ad as you've found, is detrimental in weight penalty. Especially for lighter cars.

The company that corner balanced my MZ4 Coupe, Tri-Point Engineering, was heavily into racing Miatas. They've found that in the 15" tire range, by going from a 225 to 245 width tire of the same compound, they actually LOST time.

Of course, a 2,200 lbs, 130hp on a good day car vs 3,1xx and 330hp...Different story. But I'm inclined to say that, if you've got the budget, test out all the different options available to you.

This also is dependent on your particular driving style too, and on which side of the grip you live on. If you tend to live on the right side of the grip curve, then wider tires will definitely help.

I think im gonna try the 255. the 275, i think will be harmful on slow turns.
Hope it works!
thanks will keep updated!
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