My flared six will have 9x16 Fuchs in the rear and 8x16 Fuchs in the front

How meaty of a tire can I get on the rear?

245/45/16?

According to Tire Rack, a couple of manufacturers make 255/50-16 tires

http://www.tirerack.com/tires/Compare1.jsp...ark=1&do=Search

Can I squeeze in some more meat on my backside? (Sorry, I coudln't resist wording it that way!)

Thanks!

Karl

if the offset of the wheels is right (might have to play with spacers) you'll be able to get a 285 under the back ...

if you have FG flares, make sure to shave off that inner lip at least around the top. it's usually way to big/wide ...

you want the tires to come out as far as possible.
here's a pic of my car, with engine and tranny in it, i can barely get my fingers between the fender and the tire.
i have 225 on 7" wheels with 1 1/2" spacers. still have lots of room on the inside, with the same offset, i could (and will eventually) run 9" with 285 tires ...

Andy

I think you'd be best off with a 245 even if bigger will fit. 245 is just right for a 9" wheel. If you want wider tires I'd get 10" wheels first. JMHO

-Ben M.

I had 245s on an 8 inch wheel....put a 1 inch spacer to fill the well and get a wider track.....

I'm using a 9.5 / 17 racing dymanics wheels from a 930 turbo car on a FG flared 914 with 255/40/17 . I had to trim the inside lip of the flare. This is the biggest tire that my car will take. When I replace these I think I'll use a 245/45

I have the 930 turbo 9x16 rears and the 944 8x16 fronts. I believe those are the correct offset combination for the application.

IMHO,

I had 16x6's with 225 rubber all around. From the charts on tire rack, 225's fit a 6inch rim. But the car felt funny in turns. The sidewalls are at angle with 225's on a 6 inch rim. It looked good (poseur) but gave crappy handling. Also, doing a DE last summer showed me that the 225 gave alot of tire deflection on that 6 inch rim (rear tire rubbed on the trailing arm and the inner fender on the passengers side in a 180 hairpin)

I just put some 16x6's with 205's in front and 16x7 with 225 for the rear (after a little rear fender massage...). Car feels completely different. It feel way more connected to the road that before.

I wouldn't go wider than 245 on 9's. It might look good with something wider, but you will loose on handling.

Marc-André

now wait a minute. you say 225x7 feels good (which i second!) and then you say don't go wider as 245 on a 9" ...

where are the 8" in your calculation?

245 seems like a very good fit for a 8" (which is what i'm gonna run in the front),
so what would be wrong with 285 on 9" ???

9 x 2.54 = 22.86 centimeters

285 x 9 = 28.5 cm on a 22.86 cm rim = 1.25 ratio
245 x 8 = 24.5 cm on a 20.32 cm rim = 1.21 ratio
225 x 7 = 22.5 cm on a 17.78 cm rim = 1.27 ratio


sooooo, the 285 x 9 is even a slightly "better" fit than the 225 x 7


Andy

It's certainly possible to "over-tire" a car.

Why go to monster meats on the rear?....the car will push like a pig....leaving power oversteer out of the equation for the moment.

Then there's un-sprung weight....tires as
suspension components (springs), keeping the tread
flat (or in contact with) on the ground as the suspension moves, ride height....it's an endless list.

Throwing on fat meats
may look nice to some. That's what the ricers do...they are fun to watch at the AXs.

I tend to agree with JP on this..

Wider track = better.


B

sooo, you think people do things like this just because they like RICE ?
hmmm, maybe you're right, after all, i'm the one who just got that Carbon Fiber Dashboard ...

So.... what is everyone saying?

Stick with the 245s in the back and 225s in the front?

no
i say, go 245x8 in the front and 285x9 in the back.

just my 2 cents of kraut & rice ...
Andy

How would I know?

I have 225/45 X 15 at both ends....but no flares to fill up and my needs are prolly different than yours.

Something to ponder.
The 914 came with the same size tires at both ends.
I think most will agree that it was well balanced.
More grip is what I'm after, whle maintaining decent balance. A touch of oversteer or understeer is easy to deal with.

When I get ulf out on a dry AX course with this new set-up, some of my ponders will have answers.

Since you already have the wheels it's not just a question of what's best for the car - it's what's best for the wheels AND the car. I have 245's on 8's and they are to wide for that wheel IMHO. On the front I have 225's on 7's. Again, to wide for the wheel IMHO. I think those tires would be just right on 8's and 9's.

-Ben M.

hmmm... this thread seems like a deja-vu

285's on 9"?
Not on 16" wheels I'd say. On 15" (very) maybe...

I've got 8x16 on the rear of my 911 now with 245/45/16 tires
They look better, but I think 225's would work/handle better

So, Karl, to answer your Q, yes... 225's on the 8 and 245's on the 9

Andy, we just have to agree that we disagree

cheers,

Jeroen

pas de probleme

"Rice" may have been too harsh of a term.

To my way of thinking, tires/wheels that detract from the handling are....what?...inelegant?

BTW, my first choice for my dash was carbon fiber, but I couldn't find what I wanted.

I mounted my new Hoosiers yesterday. Taped to the tire was my receipt from Tire Rack and a pamphlet from Hoosier, both with some good info. What's relevent to this thread is the receipt states that the 205/45/16 should go on a 7" to 8" rim, I put them on a 7", and the 245/45/16 should go on a 8.5" to 9.5" rim. I put them on a 8" and the side wall does have a very noticable bulge compared to the fronts that are pretty flat. I'm thinking of looking for some 8.5" rims or after these wear out going with 225/45/16 on the rear. Also the pamphlet shows the amount of air that should go into the Hoosiers as 31 to 36# cold. This is way more than I've been running.

yeah, but we all know that the Hoosiers are an inch wider than the number on them

205 Hoosiers are as wide as 225 "normal" tires ...

Andy

I've been running Michelin Pilot Sport Cup 225-245 on 7 & 8 X 16's on my semi tube 914. I have 19 track days last year and 8 days this year, somewhere around a 100 heat cycles. The tires are barely worn (they were not shaved). I've fooled with hot press from 31 to 36 and the tires ocassionally feel a little greasy on the hi and lo end. Take temps pretty religously and am lucky if I see 161-163 on a 95+ day. Tires generally read 161-156-150 on average.
I was ready to go to 225 on all corners when I finally found a Michelin tire guy.
Tire rep said that Michelin Cup is designed for European market where the Porsche are usually heavier and have stock suspension. Said my temps were low but were not the problem. Because of lite car I was not getting a flat foot print and I said what about tire temps across tire and he said the different pressures were making the tire work either slightly under or over inflated but it had to do with the way Michelin makes the tires. The sidewalls are not as stiff but the tred is stifffer than most R type tires.
His recommendation was to mount 225-245 on my spare set of 8 & 9 X 16 wheels so the sidewall is straighter that will allow the tred to sit flatter. Then start lowering the hot pressure and I could end up below 30 and that was OK, keep lowering pressures and checking temps. Said these tires will work on a lite car. Said this setup should work better than 225's on all corners.

Don; Thanks for the insight. That's pretty amazing the number of heat cycles you're getting with the Michelin's. I'm thinking of looking for some 9x16 Fuch's for my rear. Since my car handles the 245 on an 8" rim it should handle the same tire on a 9" unless the offset changes the position of the center of the tire. When you mount your 9's is the tire in the same position relative to the fender or does it move?

This is on my car, work for me. I had to shave the FG front flares some because the tire was catching the lip.


225/50 ZR 16 front
245/45 ZR 16 rear

255x50x16s are on the back of this steel flared 914-6. Very little freespace left.

Who's car? Any more pics?

what about on the inside? in your pic, there's approx. 1cm left on the outside so all you need for a 285 is 2 cm on the inside and wheels with the correct offset (or spacers).
i measured my car from the inside of the flares (lip) to the metal of the fender and i had enough space for 285's. but every flare is different i guess. after all, they are "handmade"

Andy

I am running 205/225 50's on 15 x 7 and 8" standard 911 offset wheels. I use a 1" spacer up front. There is no way I could get a 245 under the rear on an 8" wheel. My flares are fiberglass and do have a pretty godd size inner lip.

What is interesting is that I was one of the lucky ones who had no problem at all getting 205's on 2.0 Fuchs prior to flaring.

you need to shave off that lip. it's almost 1" ...
245 on 8" should be no problem at all with those flares.
given that the offset of the wheels is right or you used spacers to compensate.

in the pic below, you can see my 225 on 7" in the back.
i used spacers (1.5 ") to get the wheel all the way out to the fender lip.
i still have over 2" of space left on the inside ...

Drew, I can only talk specifically about the Michelin Cups. The glass fenders I'm running look more like they're pulled out instead of having the offset for the true flare look. These are not add on flares but full fenders mounted with dzus fasteners.
Everyone that makes fiberglass fenders does it a little different as to how much "extra" glass they leave for fitting purposes. When you mount them they will not be *exactly* the same even if you're careful.
No problem with 225f-245r. I have to use 1/4 spacer on front to clear the caliper in front and 1/2 in rear. All wheels are Fuchs, don't have offsets in front of me.
The Michelin's have about a 3/8-1/2 bead that protrudes from the sidewall where the tire meets the rim. Think it may be a standard Michelin tire design to protect the wheel when you start running 17-18 wheels with lower profiles.
This was not a problem for me because of the way the fender is made but could be for someone depending on how the wheel fits in the fender opening. When looking at the side of the car if the top of the fender opening is close to the top of the wheel. My fenders are bowed so it wasn't a problem.