Question about wide wheels/tires

That One Guy · 03-17-2003, 02:27 PM

How wide a wheel/tire combo can one fit on the 914 before you really have to go to flared fenders? I'm not looking to put some gargantuan 13-in. wide wheels under there, I'm just wondering if say a 6.5-in or 7-in. wide wheel with around 215 section tires would fit.

Thanks.

mike mueller · 03-17-2003, 03:33 PM

Porsche was evil when they made the 914......

normally, without flaring you can run 8's on the front with 225's
and 7's on the rear with 205's ?!?!?

of course no one does this ( i did for a few weeks until I pulled out my rear fenders to swap the tires around)

so, basicly, 205's on 7's is considered the widest unless you roll/pull out the rear fenders.

each car is a little different and the brand tire makes a differance as well.

That One Guy · 03-17-2003, 04:31 PM

Groovy. Thanks.

Bruce Allert · 03-17-2003, 09:30 PM

Also, don't forget about the backset of the wheels you buy to put those wider tires on. The more the better, otherwise the tires won't go under the fender.
I bought my 914 from a guy in Albany. Best car I ever had!
bruce

Jim Smolka · 03-18-2003, 04:32 AM

I had a set of 225x7's Komo's V-700's all the way around. Now it was not easy to get those tires on the back. Lots of fender rolling

Dave at Pelican Parts · Dave at Pelican Parts's Garage

More backspacing (backset, whatever) is better, until you go overr about 5" worth. Then you start needing spacers so you don't rub on the inner fender!

"Backspacing" is the distance from the plane of the inner edge of the rim to the plane where the wheel mates with the hub.

--DD

That One Guy · 03-18-2003, 01:05 PM

Quote:

Originally posted by Bruce Allert
Also, don't forget about the backset of the wheels you buy to put those wider tires on. The more the better, otherwise the tires won't go under the fender.
I bought my 914 from a guy in Albany. Best car I ever had!
bruce

It's not a black 1.8 with the original fuel injection is it?

That One Guy · 03-18-2003, 01:06 PM

Quote:

Originally posted by Dave at Pelican Parts
More backspacing (backset, whatever) is better, until you go overr about 5" worth. Then you start needing spacers so you don't rub on the inner fender!

"Backspacing" is the distance from the plane of the inner edge of the rim to the plane where the wheel mates with the hub.

--DD

Yep, the amount of allowable backspacing was going to be my next question. Thanks.

Bruce Allert · 03-18-2003, 05:02 PM

Mine is Orange and it came from a guy by the name of Barlow (Barlow Trail) off Conser Rd. in Albany
bruce

Andyrew · Andyrew's Garage

Dave, are you saying that a 23mm offset should fit under the stock fender? (did a little calculating with that 5 in number, and i might get some wheels with that offset) and taking that into consideration, would 7 in wheels with 23mm offset work? if so what size tires would work? anyone done this? thanks

mike mueller · 03-18-2003, 07:04 PM

I had 16x7 Phonedials with 205/50/16's with the 23mm offset on my last 914...fit nice in the front...the rear required pulling out on the fender some....not a lot, but too much if your paint is perfect.

Andyrew · Andyrew's Garage

perfect paint, LOL. Thanks for the info mike, Im thinking of getting some cookie cutters, ill have to check the offsets, but I think that they should fit my purpose nicely. Thanks for your response.

Rog914 · 03-18-2003, 08:23 PM

I read the 914 alloy wheels have a backspacing of 120mm(almost 4-3/4"). 23mm offset is less than 1". Backspacing is measured like Dave said. Offset is where I get confused. Isn't offset measured from centerline of the rim to the plane where mates with the hub and is a positve or negative offset?
Anyway I was trying to find 7X17" rims to fit my 914. Found only one company that will custom backspace in the Porsche 4 or 5 bolt pattern (Forgeline). There RS wheel is nice looking but at over $500 per wheel it's a little on the expensive side.
As for backspacing it looks like 5" max up front & 5-3/4" max in rear. But don't my word for it. I'd like to put it on a ramp type lift to look under the wheel wells better.
Anybody know where you can get 7X17 4 bolt with correct backspace for a good price?
Ralph

74 2.0

Andyrew · Andyrew's Garage

Here is a quote from Danno's web sight (he's a 944 guy that hangs out on rennlist, Very smart guy)

"How to compute OFFSET (given OverallWidth and Backspacing)
Having measured the Overall Width and Backspacing, use the following formulae:

Offset = Backspacing - 0.5*(OverallWidth)

For example, let's say we have a 16x7" Fuchs wheel with a measured Overall Width of 7.625" and Backspacing of 4.75", what is the Offset?

Offset = 4.75" - 0.5*(7.625") = 0.94" (23.8mm)

which is pretty close to the actual offset of 23.3mm stamped on the wheel.

How to compute BACKSPACING (given OverallWidth and Offset)
Backspacing = 0.5*(OverallWidth) + Offset

So let's take that 16x7" Fuchs wheel again where we measured a 7.625" Overall Width. Also given the 23.3mm offset stamped on the rim, what is the Backspacing?

Backspacing = 0.5*(7.625") + 23.3mm = 3.81" + 0.92" = 4.73"

which matches closely with the 4.75" that we actually measured for the Backspacing."

http://members.rennlist.com/951_racerx/

is danno's web sight,

So using his method,
4.73 - .5 (7.625) = .9175 or 23.3mm
4.75 is the desired backspacing. and 7.625 is the overall width of a 7 in wheel. so am i think i am right when saying taht about 23mm is the desired offset. Did I do this right? (I know the math is correct, hehe)

Ralf, Good luck finding 17 in 4 lug wheels, I dont think anyone has found them. your best bet would be to go to 5 lug, cheaper, easyer, and a common practice.

Peter_Hinkle · 03-18-2003, 08:56 PM

If you are running four lug fuchs, you can run a 215/50/15 on the rear without pulling the fenders if you get a quarter inch wheel shim/spacer to go under the rear wheels. If you can find a longer lug bolt than the alloy units, you could potentially run a 225 in the rear with a half inch spacer. I measured it and it works but the 225's are a theory whereas the 215's are a fact on my car...peter

mike mueller · 03-18-2003, 08:59 PM

Ralph......these are about $240 a piece......17x7 with a 35mm offset...even better than the 23mm offset for the rear of the car.
(no it's not my car) and they make 'em in our bolt pattern

Revolution Wheels

Andyrew · Andyrew's Garage

Those look sweet, i knew revolution had em, but it didnt know the web sight.

Barry2 · 03-18-2003, 09:45 PM

Here is a URL for a webpage showing the size, weight, offset, backspacing and part numbers for Fuchs, other Porsche rims, and some aftermarket rims:

http://members.rennlist.org/911pcars/WheelWts.html

Hope it helps,

Barry

'97 Supercharged XJR
'89 XJ6
'81 RX-7
'73 914 FI 2.0 Liter
'71 & '74 TR-6
'68 XKE FHC
'65 Catalina

Dave at Pelican Parts · Dave at Pelican Parts's Garage

Quote:

Originally posted by Peter_Hinkle
If you are running four lug fuchs, you can run a 215/50/15 on the rear without pulling the fenders if you get a quarter inch wheel shim/spacer to go under the rear wheels.

Yet another illustration that all 914s are different. On most of our cars, a 215-width tire on a stock four-bolt wheel will hit the outer fender. (On one side.) Adding a spacer will make this problem worse.

--DD