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Tires- 40vs 35

Would I notice a big difference in handling going to a 40 series tire on the back?, just not a fan on the look of no sidewall.
 
I have 40's and love them. I believe they do tolerate high G cornering better than low profile tires IMO. notice all the nasacars, scca gt1 class mega-cars run big sidewalls.

retro1.jpg
 

PeteInCT

#LS-378 - So many Porsche's, so little time....
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It depends upon the tire and your suspension. There is no 'right answer'. I run 35 front and rear. Based on my suspension, the width of the tires and the sidewall stiffness I get no rollover on the fronts at all.
 
Michelin Pilot Super Sports, stock suspension
they are 1.1" taller.


285/40-19 vs
285/35-19
 

GB899

NO REGRETS
430
323
Nebraska
NFSBOSS said:
If this is for street use I'd pass unless you have a need to go 270 MPH. ;) If you want a higher sidewall move down to 18" wheels and then get a 40 profile tire.

I have been debating the 19 vs 18 wheel thing for spares... what 18's would you recommend?
it is bone stock...
 
DGRacing said:
I have 40's and love them. I believe they do tolerate high G cornering better than low profile tires IMO. notice all the nasacars, scca gt1 class mega-cars run big sidewalls.

retro1.jpg

Like one poster said, it depends on the rest up the set-up, bars, springs rates. But from my experience, given a very stiff suspension, the taller tire allows some extra room to flex before the car goes into a drift as you mentioned. In T1 we did this on the back of the C5 Zo6's. On that car, we used a smaller rim to do it, it looked kinda funky, but it worked very well. Credit Phoenix Racing with the idea. Bottom line, is it pulled more G's with that set up, and could get the power down a bit earlier. That not to say a wider tire with a lower profile would not work equally as well, but we had only so much room to work with.

Curious, Are those the BBS Boss S 9.5 x 18's all the way around? and are those Hoosier 295/40/18's ?.

Great Looking Car, BTW. I think the 40's on your car also give it a more nostalgic stance, very cool.
 
Yep. 295/40/18 & the 302r 18x10 bbs wheels. You can tell I'm going for the old school look with the louvers as well. Thanks for the compliment and interesting info.
It sounds funny to say this but I see the tires (including choice of sidewall) as the most important part of the suspension! After all the tires suspend the car with air. :p
 
When I spoke with a guy at Rehagen about the 10" wide BBS he was trying to lean me toward the 9.5" BBS, mentioned that I may need a spacer, special 5/8" studs and Lugs nuts. Where the 9.5" were go to go as is and would fit their Conti scrubs well. There seams to be a lot of disclaimers on the Ford Racing site as well, he may have just been quoting them, not actual experience. Seamed knowledgable, but said he was not a tech.

Looks like the offset is pretty good, nothing seams to be sticking out either.

Did you need spacers, special, studs or lug nuts?. I was planning on the ARP studs anyway, but 1/2 by 20 not 5/8. That way I can swap street wheels on easier.
 
I have ARP studs but I had to ditch my camber plates and cutoff and grind down the sway bar end link bolts in the front struts which were a hair from the tire. Otherwise, no problems.
I saw on the ford site it says "spacers may be required", but who the heck knows with what car, suspension, ride height, etc. that applies to....seems out of place to me.

The problem for me now, is that there are no more 295/40/18 slicks on the market. Hoosier, for some bizarre reason, stop making them. The closest tire I could find is the Toyo Proxes RS1 in 285/680R18 which is actually .2" wider, but .6" shorter diameter....

If you know any comparable tires to the R6/A6 295/40/18's I'd love to know!
 

Domestic Product

Big fat tires and everything !
gsw166 said:
Would I notice a big difference in handling going to a 40 series tire on the back?, just not a fan on the look of no sidewall.

Yes and no. Are you running with the track key? If so tire size is important. I think you want to stay close to the overall size of the stock sizing no matter. If you change overall height by more then say a quarter inch, you will have your speedometer messed up. If you have the track key tire size is inputted into the tune as in stock sizing and if you change that too much it will mess up the tune. So as NFS says go to 18" rims and get some bigger side walls that are still close to the stock over all height. Vorshlag has a good write up on this tire wheel thing. I really like the look of DGs car and agree tires are the most important part of the suspension.
 
Thanks guys, guess I will just stay with the 35s, had bought a set of used wheels and tires off of Stevespo, so not going to 18s yet ;)
 

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