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> Wheel tracking, Front 2" narrower than back - Why?
tracks914
post Nov 3 2005, 04:09 PM
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Wider is better for cornering, everyone knows that.
If that's the case, why did Porsche engineers leave so much usable room under the front fenders?
Was it because they adapted some other cars geometry to the 914?
I have seen wheel spacers for our cars, have many of you used them to widen the track of the front end?
I don't race my car and it would just be for esthetic value but I have considered putting spacers in to "fill out the front fenders" but was wondering if it would screw up some other front end geometry.
What do you think? (IMG:http://www.914world.com/bbs2/html/emoticons/confused24.gif)
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Midtowner
post Nov 3 2005, 04:29 PM
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I've been wondering about the same thing! (IMG:http://www.914world.com/bbs2/html/emoticons/biggrin.gif)
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davep
post Nov 3 2005, 04:35 PM
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Front suspension is pure 911 design, hence the two can be interchanged between 1969 and late 70's. The 914/6 was a 911 suspension.

The rear is unique to the 914 and had to fit around the engine and transmission.
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Root_Werks
post Nov 3 2005, 04:42 PM
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QUOTE (tracks914 @ Nov 3 2005, 02:09 PM)

If that's the case, why did Porsche engineers leave so much usable room under the front fenders?

Space your front wheels out to the edge just like the rears. Then go start taking corners really fast and you'll see why. (IMG:http://www.914world.com/bbs2/html/emoticons/wink.gif)
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Root_Werks
post Nov 3 2005, 04:44 PM
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Wait, that was a retarded answer on my part.

When you turn your wheels and take a corner at the limit of the car (Compressed susp) the tire will either get chewed up by the fender or the tire will kick the fender lip out.
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SirAndy
post Nov 3 2005, 05:02 PM
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QUOTE (Root_Werks @ Nov 3 2005, 03:44 PM)
When you turn your wheels and take a corner at the limit of the car (Compressed susp) the tire will either get chewed up by the fender or the tire will kick the fender lip out.

naaa, think about that again ...

i run spacers in the front, about a (fat) fingers worth of space between the fender and the tires, car lowered. many, many AX runs, and i never had the tires rub on the fender ...
(IMG:http://www.914world.com/bbs2/html/emoticons/driving.gif) Andy
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Mueller
post Nov 3 2005, 05:09 PM
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I'd have to say one reason could be safety....an understeering* car is generally safer for the "regular" public

*front end pushes instead of the rear swinging out
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SirAndy
post Nov 3 2005, 05:11 PM
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QUOTE (Mueller @ Nov 3 2005, 04:09 PM)
an understeering* car is generally safer for the "regular" public

(IMG:http://www.914world.com/bbs2/html/emoticons/agree.gif) "normal" drivers tend to let off the gas when they encounter loosing grip.
in a understeer situation, this will result in gaining control of the car again, in an oversteer situation this will result in a spin ...

(IMG:http://www.914world.com/bbs2/html/emoticons/driving.gif) Andy
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Demick
post Nov 3 2005, 05:28 PM
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QUOTE (tracks914 @ Nov 3 2005, 03:09 PM)
If that's the case, why did Porsche engineers leave so much usable room under the front fenders?

It's really very simple. The front wheels turn. The rears do not. The extra room is to allow the front wheels to turn.
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SirAndy
post Nov 3 2005, 05:32 PM
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QUOTE (Demick @ Nov 3 2005, 04:28 PM)
It's really very simple. The front wheels turn. The rears do not. The extra room is to allow the front wheels to turn.

i run a 1 1/4" spacer in the front and my wheels still turn ...

(IMG:http://www.914world.com/bbs2/html/emoticons/wink.gif) Andy
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fiid
post Nov 3 2005, 05:34 PM
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QUOTE (Demick @ Nov 3 2005, 03:28 PM)
QUOTE (tracks914 @ Nov 3 2005, 03:09 PM)
If that's the case, why did Porsche engineers leave so much usable  room under the front fenders?

It's really very simple. The front wheels turn. The rears do not. The extra room is to allow the front wheels to turn.

Your rear wheels don't turn? Is that cos the car is on jackstands???

lmao

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blabla914
post Nov 3 2005, 05:45 PM
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I agree with Andy. I run a 205-50 on a 7" 911 offset wheel with 911 struts and 1/2" spacers under stock fenders. My ride height is 4" under the frame rail. I autocross quite a bit and set decent times on Khumos. Wheels turn just fine, but will rub if you hit a large bump while turning tightly. Not enough rub to even leave marks on the tires, but enough to leave black marks on the insides of my fenders.

Kelly
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blabla914
post Nov 3 2005, 05:49 PM
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Slight thread hi-jack.

Andy, are you using a 27mm+1/4" (4mm) spacer to get 1 1/4" (31.75mm) spacer? What length studs are you using? I'm looking to put flares on my car so I can run 8's on the rear and then space the fronts. Is my only option for studs to buy 100mm's and then trim them down?

Kelly
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tracks914
post Nov 3 2005, 06:37 PM
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Can you put a 3/4" or 1" spacer on the stock hub with stock Mahles and not hit/rub the fenders?
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lapuwali
post Nov 3 2005, 07:25 PM
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Depends on your fenders. These cars weren't all the same when they left Karmann, and they're certainly not the same now 30-35 years later. The rear fenders show wide variation from side to side and car to car, and there's no reason to think the front fenders are any different. On my first 914, I could fit my pinky between the tire and rear fender lip on one side, but my first two fingers fit fine on the other side, and there was no evidence the car had been hit, and this didn't change with a good alignment. My second 914 shows a smaller variation, but the wide fender is on the other side.
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tracks914
post Nov 3 2005, 09:11 PM
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My rear fenders are the same way. I can only (barely) get my pinky inbetween on the driver side but almost 2 fingers on the PS.
The fronts seem a little more equal but I can almost get 3 fingers in on both sides. (the fenders that is) (IMG:http://www.914world.com/bbs2/html/emoticons/biggrin.gif)
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Brett W
post Nov 3 2005, 09:55 PM
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As mentioned before a car with a narrower front track will be safer for most of the population. Many front wheel drive cars can spin should you lift of the throttle in a heavily loaded corner as well as under trail braking. OUr cars can do the same if you exceed the traction limits while coasting or under braking. Next time you are out run around a nice cloverleaf on ramp and play with speed and braking to see how your chassis reacts to different inputs.

When you go adding spacers to your hubs you increase the scrub radius. Increasing the scrub radius will make the car do some weird things. The contact patch will tend to move in bump, rotational torques will increase in single wheel bumps, bump steer can increase. Increasing the scrub radius can also lead to roll understeer.

Now increasing the front track is very benefical. It decreases weight transfer from side to side. It can also increase later acceleration (grip). The proper way to increase front track is to lengthen the a-arms and move the upper strut mounts outward. This will require some fab work.
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SirAndy
post Nov 4 2005, 02:53 AM
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QUOTE (blabla914 @ Nov 3 2005, 04:49 PM)
Andy, are you using a 27mm+1/4" (4mm) spacer to get 1 1/4" (31.75mm) spacer?

100mm studs in the rear, 74(?) mm studs in the front, spacer in the front is 1" + 1/4 " ...

(IMG:http://www.914world.com/bbs2/html/emoticons/wink.gif) Andy
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maf914
post Nov 4 2005, 08:25 AM
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QUOTE (Brett W @ Nov 3 2005, 07:55 PM)
When you go adding spacers to your hubs you increase the scrub radius. Increasing the scrub radius will make the car do some weird things. The contact patch will tend to move in bump, rotational torques will increase in single wheel bumps, bump steer can increase. Increasing the scrub radius can also lead to roll understeer.

Now increasing the front track is very benefical. It decreases weight transfer from side to side. It can also increase later acceleration (grip). The proper way to increase front track is to lengthen the a-arms and move the upper strut mounts outward. This will require some fab work.

How much does increasing the front track with spacers, therefore changing the original scrub radius, affect steering effort? When going from the stock 5.5" wide wheel, to a 7.0" or 8.0" wheel or to spacers you're moving the wheel ceneter line further away from the steering axis which is going to require more steering effort. I'm just curious how much it increases. (IMG:http://www.914world.com/bbs2/html/emoticons/idea.gif)
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dsmeyer
post Nov 4 2005, 09:07 AM
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It's all about costs. $$$

The 914/6 uses 911 hubs and brakes which result in a wider
front track, just as the designers and engineers wanted.

The lower cost 914/4 (4) lug uses VW parts bin brakes and
rotors which result in the narrower track.

It's just that simple.
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