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> Wide body wheel widths and offset
FastFroggy
post Jan 18 2016, 07:37 PM
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I was taking a break from the fiberglass repair and noticed on my car that the tires sit different front to rear. then I was surprised that the fronts are 9in and rears are 8in wide rims... then the final surprise was that the offsets were significantly different.

My car is a 5 bolt conversion 73 914-4 of unknown origin with wide body fenders.

Please explain the general convention on this.

Thanks
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campbellcj
post Jan 19 2016, 10:13 AM
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Well, a "reverse staggered" setup is NOT the convention... What type and how wide are the flares? GT style? I'm running 8's and 9's (F/R) but what is best for your car depends on a lot of things. Most guys with GT flares run 7's all around or 7 front 8 rear.
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Mueller
post Jan 19 2016, 10:23 AM
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QUOTE(FastFroggy @ Jan 18 2016, 05:37 PM) *

I was taking a break from the fiberglass repair and noticed on my car that the tires sit different front to rear. then I was surprised that the fronts are 9in and rears are 8in wide rims... then the final surprise was that the offsets were significantly different.

My car is a 5 bolt conversion 73 914-4 of unknown origin with wide body fenders.

Please explain the general convention on this.

Thanks


Too many beers by the previous owner?

Have you swapped them back so the wider wheels are in the back?

I'm guessing purchased the car like this, good chance wheels just thrown on there to get the car on the road or that the offsets are wrong or the previous owner was experimenting with how the fit to make a final decision and forgot to swap back.
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SirAndy
post Jan 19 2016, 04:06 PM
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QUOTE(campbellcj @ Jan 19 2016, 08:13 AM) *
Most guys with GT flares run 7's all around or 7 front 8 rear.

(IMG:style_emoticons/default/agree.gif)
7" all around with 10" slicks and spacers to fill out the flares ...
(IMG:style_emoticons/default/smile.gif)
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campbellcj
post Jan 19 2016, 06:19 PM
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QUOTE(FastFroggy @ Jan 18 2016, 05:37 PM) *

I was taking a break from the fiberglass repair and noticed on my car that the tires sit different front to rear. then I was surprised that the fronts are 9in and rears are 8in wide rims... then the final surprise was that the offsets were significantly different.

My car is a 5 bolt conversion 73 914-4 of unknown origin with wide body fenders.

Please explain the general convention on this.

Thanks


Pics of the car and a summary of what you have discovered so far would help us all give better tips from this point.

Are the wheels factory Fuchs or something else? You may have an incurable offset problem with those wheels, which could explain why the PO swapped them around. Obviously if they are too far inboard you can space them outwards...too far outboard though, and you are modifying fenders further or switching wheels which can be $$$$.
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FastFroggy
post Jan 20 2016, 11:48 AM
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Thanks for the replies, I figured to check if I had missed something. I have the feeling the seller just threw whatever the wheels he didn't want.

The funny part is he put the same width tire front to rear so it's over width on the rear and right sized for the front.

I have to take we more measurements and pictures. Will probably try swapping wheel, just have to wait for spring to test drive .

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Randal
post Jan 20 2016, 06:50 PM
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QUOTE(FastFroggy @ Jan 20 2016, 09:48 AM) *

Thanks for the replies, I figured to check if I had missed something. I have the feeling the seller just threw whatever the wheels he didn't want.

The funny part is he put the same width tire front to rear so it's over width on the rear and right sized for the front.

I have to take we more measurements and pictures. Will probably try swapping wheel, just have to wait for spring to test drive .


I like staggered setups on 914's race cars. Like 8"/rims and slicks in front and 11" rims and 10.5" slicks in back.

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wndsrfr
post Jan 20 2016, 08:45 PM
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When I got the "Cup" wheels for mine, which are 7's & 8's, the offsets worked out needing a 25mm spacer on the rear with the 7's there and a 5mm spacer on the front with the 8's there. Using 225/50/16's square setup. Hardly noticeable difference....Attached Image Attached Image
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john914somers
post Jan 21 2016, 08:20 AM
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I too am struggling a bit with the winter upgrades, I recently purchased some 17x10 and 17x11's. The 11's fill the rear flairs nicely but the 10's are a little too wide for my fronts. The wheels I am currently using are 17 x 7.5 and 9's with 1" spacers. So I have 3 options, I could buy some different inner barrels for my fronts and reduce the width down to something smaller that will easily fit, I was thinking 8.5" or I could modify my flairs or completely change them. Some reliable sources have told me that 8's and 11's are too much stagger and that the best set up is 10's and 12's. I'm leaning towards sticking with the 10's and 11's and trying to modify the flairs and if that doesn't work just changing them all together. Does anybody have any experience with too much under steal with 8's or 8.5's run with 11's. Sorry, I didn't mean to hijack this topic but my questions are of a similar nature. Thanks!
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Randal
post Jan 21 2016, 10:45 AM
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QUOTE(john914somers @ Jan 21 2016, 06:20 AM) *

Some reliable sources have told me that 8's and 11's are too much stagger and that the best set up is 10's and 12's. Thanks!


It all depends upon what events you are running and how wide you want the front tires. If you do the arithmetic and figure out stagger based upon weight balance there are situations where 8's and 11's are perfect.
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J P Stein
post Jan 22 2016, 11:24 AM
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The fact is the 914 front suspension ( & early 911) is limited.
I've tried 10 inch wide front wheels ( & fat slicks) for AX and they are a disaster.
8 inchers are about the upper limit if ya want to go around a tight corner. If you like a heap of understeer, they'll work. A bunch of steering effort goes along with em'.

It's a scrub radius issue. It was not for nothing that I got that fixed. You can take my word for it or go down that dead end.....it doan make no difference to me.
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campbellcj
post Jan 22 2016, 07:27 PM
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Along the lines of JP's comments, it would help to know the OP's intended application(s) for the car and more about its current build/setup.
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FastFroggy
post Jan 31 2016, 04:10 PM
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ok, finally had a few moments to get me info together.

My car is primarily intended for react use. ( Waterford, Grattan, MidOhio etc ) I am a low horse power car ( modified 1.7 )
(IMG:http://www.914world.com/bbs2/uploads_offsite/img.photobucket.com-19415-1454278252.1.jpg)

I was wrong on width in my original post. I have:
2 x 7Jx15 Fuchs 911.361.020.41
2 x 8JX15 Fuchs 911.361.020.42

I believe they are 23.3(7J) and 10.6(8J) mm offset respectively.

Front suspension
(IMG:http://www.914world.com/bbs2/uploads_offsite/img.photobucket.com-19415-1454278252.2.jpg)

Rear Suspension
(IMG:http://www.914world.com/bbs2/uploads_offsite/img.photobucket.com-19415-1454278298.1.jpg)

The tires look like they will do at least one season before replacing them. So I'll just use them to sort out the car, myself and see what I think of the balance. Just curious the conventional wisdom on this subject.

My gut feel right now would be to got to 205/50r15 front on the 7Js and 225/45r15 rear on the 8J. I know there are a lot of factors. But this is close to the tire width balance of the boxster/cayman... cannot be that far off.

Thanks for the help
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Randal
post Jan 31 2016, 07:46 PM
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QUOTE(FastFroggy @ Jan 31 2016, 02:10 PM) *

ok, finally had a few moments to get me info together.

My car is primarily intended for react use. ( Waterford, Grattan, MidOhio etc ) I am a low horse power car ( modified 1.7 )

I was wrong on width in my original post. I have:
2 x 7Jx15 Fuchs 911.361.020.41
2 x 8JX15 Fuchs 911.361.020.42

I believe they are 23.3(7J) and 10.6(8J) mm offset respectively.

Front suspension

Rear Suspension

The tires look like they will do at least one season before replacing them. So I'll just use them to sort out the car, myself and see what I think of the balance. Just curious the conventional wisdom on this subject.

My gut feel right now would be to got to 205/50r15 front on the 7Js and 225/45r15 rear on the 8J. I know there are a lot of factors. But this is close to the tire width balance of the boxster/cayman... cannot be that far off.

Thanks for the help


What is your front to rear weight figures off a corner balance?
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FastFroggy
post Feb 3 2016, 06:46 PM
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QUOTE(Randal @ Jan 31 2016, 08:46 PM) *

QUOTE(FastFroggy @ Jan 31 2016, 02:10 PM) *

ok, finally had a few moments to get me info together.

My car is primarily intended for react use. ( Waterford, Grattan, MidOhio etc ) I am a low horse power car ( modified 1.7 )

I was wrong on width in my original post. I have:
2 x 7Jx15 Fuchs 911.361.020.41
2 x 8JX15 Fuchs 911.361.020.42

I believe they are 23.3(7J) and 10.6(8J) mm offset respectively.

Front suspension

Rear Suspension

The tires look like they will do at least one season before replacing them. So I'll just use them to sort out the car, myself and see what I think of the balance. Just curious the conventional wisdom on this subject.

My gut feel right now would be to got to 205/50r15 front on the 7Js and 225/45r15 rear on the 8J. I know there are a lot of factors. But this is close to the tire width balance of the boxster/cayman... cannot be that far off.

Thanks for the help


What is your front to rear weight figures off a corner balance?


Great question, unfortunately I do not access to a scale system.
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Racer
post Feb 3 2016, 09:10 PM
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I've seen 205's run on 6 and 7" wheels. 225's on 7 and 8" wheels and even 245's on an 8" wheel over the years.

Some of the limits you will have tire wise are based on any class rules you need to meet, desired gearing changes, as well as who makes 15" tires in sizes that will fit!

Wheels are standard 911 and even early 944 fare.
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ge9146
post Mar 4 2017, 10:45 AM
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I just ran across a great saying for race car construction.
"Start with the tires you will use and build the car around them"

If your rules will allow it, BFG just released a new tire that could be very useful.
They now have a Rival S 1.5 that is sized 245/40x 15 that could work well on your 8x15 wheels. That is a 200 tread wear tire if you have to meet some class restriction. If you do not have any tread wear class restriction and you want something perhaps a bit stickier, the old standby TOYO RA-1 is a great long lasting track tire too. Tire Rack has it in a 225/45x15 or a 225/50x15. Of course Hoosiers are faster too but the are expensive and do not last very long. You get what you pay for.
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wndsrfr
post Mar 4 2017, 06:57 PM
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I've been on Toyo's for years--shaved RA1's and now RR's in 225/45/15 using 8 inch rims. They will fit on the 7 inch rims fine. If you stay with 225's on all 4 corners (square setup) then you can move the tires around, flip them, etc. With your 1.7 I don't think you need 245's for the rear. If you're going to street drive the car as well as track it, then get the RA1's and leave 8/32'nds of tread after shaving.
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campbellcj
post Mar 27 2017, 11:50 AM
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Ahhh... I just revisited this thread and it's good to see your suspension/wheel setup is actually quite conventional. I'd lean with the other comments about a square setup with some reasonable 225 DOT-R tires that'll enable you to further learn and setup the car and have fun without doing a monthly roto-rooter on your bank account.

I ran 205 Hoosiers on all 4 for many years until I dropped a stout 2.7-six in the car, and truly needed more rubber...
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