if running spacers on the front wheels, how does it effect handling??? |
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if running spacers on the front wheels, how does it effect handling??? |
pete-stevers |
Jul 23 2008, 11:05 PM
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#1
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saved from fire! Group: Members Posts: 2,641 Joined: 10-October 04 From: Abbotsford,BC, Canada Member No.: 2,914 Region Association: Pacific Northwest |
on a flared car, do spaced wheels adversly effect handling
why do guys run no spacers in ax but run spacers on the street i am planning to run 16x7s up front with 225s with flares, and looking ahead this will be my winter project i am lookin for the low down on running spacers and handling issues for street use |
brant |
Jul 23 2008, 11:37 PM
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#2
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914 Wizard Group: Members Posts: 11,625 Joined: 30-December 02 From: Colorado Member No.: 47 Region Association: Rocky Mountains |
I had a conversation with my race shop in which I was told that they fine tune cars by adding spacers to one end or the other.
I believe that as the track widened on that axle it added traction to that axle. so front spacers should add front grip. I am only passing along what I've been told (and I'm not 100% I'm remebering correctly about adding grip with track) I haven't used it as a tuning technique myself as I've been learing roll bars, spring rates, diffs, and tire pressures... enough for my amateur level without changing track. brant |
messix |
Jul 23 2008, 11:39 PM
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#3
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AKA "CLUTCH KILLER"! Group: Members Posts: 6,995 Joined: 14-April 05 From: between shit kickers and pinky lifters/ puget sound wa.north of Seattle south of Canada Member No.: 3,931 Region Association: Pacific Northwest |
more steering effort. and a larger scrub radius.
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TimT |
Jul 23 2008, 11:46 PM
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#4
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retired Group: Members Posts: 4,033 Joined: 18-February 03 From: Wantagh, NY Member No.: 313 |
QUOTE more steering effort. and a larger scrub radius. Yeap! |
messix |
Jul 23 2008, 11:57 PM
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#5
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AKA "CLUTCH KILLER"! Group: Members Posts: 6,995 Joined: 14-April 05 From: between shit kickers and pinky lifters/ puget sound wa.north of Seattle south of Canada Member No.: 3,931 Region Association: Pacific Northwest |
and you might have to add more toe in to counter the leverage effect of the spacers.
funny thing is that your steering effort a stand still or low speed might be easier, 'cause the tire will roll along an arc instead of twisting on the tread. and the steering feed-back might be more sensitive. |
Tom |
Jul 24 2008, 12:05 AM
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#6
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Advanced Member Group: Members Posts: 2,139 Joined: 21-August 05 From: Port Orchard, WA 98367 Member No.: 4,626 Region Association: None |
Just guessing, but, without spacers use on the street would probably cause a lot of inner wheel rub due to full lock steering inputs in parking lots, etc. ?
Tom |
TC 914-8 |
Jul 24 2008, 01:22 AM
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#7
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Senior Member Group: Members Posts: 809 Joined: 23-May 08 From: Sequim, WA Member No.: 9,090 Region Association: Pacific Northwest |
I asked the same question at the WCR08
and got the same answer from the same guys. The Scrub Radius becomes affected, if your on the street and want to fill out the flairs, go ahead and add the spacers. On the track it will have an adverse effect from when the alignment and geometry was set up. Troy is " the man" he didn't Kill my clutch but came close, He and a few of the guys all said the same thing, try it and see what, and how it performs. Until I can put the 8's in front and 9's in the rear, spacers will have to be. Tony |
messix |
Jul 24 2008, 01:47 AM
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#8
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AKA "CLUTCH KILLER"! Group: Members Posts: 6,995 Joined: 14-April 05 From: between shit kickers and pinky lifters/ puget sound wa.north of Seattle south of Canada Member No.: 3,931 Region Association: Pacific Northwest |
that clutch had it's work cut out for it, puutin along 'bout 60mph in 4th gear and nail'n the throttle to 'bout what 120 ish rpm were 5,800 last i looked, and all that happened in a couple of heart beats.
oh and the top was off! i'm gonna have to build one! (IMG:style_emoticons/default/happy11.gif) |
Brett W |
Jul 24 2008, 02:05 AM
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#9
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Advanced Member Group: Members Posts: 2,856 Joined: 17-September 03 From: huntsville, al Member No.: 1,169 Region Association: None |
Adding front spacers will help widen the track. This will in turn reduce the amount of weight transferred in a turn. It will however on a strut car increase the scrub radius which can increase steering effort. You can increase the caster to counteract the effects a little, but going to far will make the steering floppy.
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bondo |
Jul 24 2008, 02:06 AM
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#10
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Practicing my perpendicular parking Group: Members Posts: 4,277 Joined: 19-April 03 From: Los Osos, CA Member No.: 587 Region Association: Central California |
I'm running 9's front and rear. I notice more bump steer (but not much more) and it takes some grunt to parallel park, even with the big stock wheel. With a tiny wheel it might become nearly impossible to turn the wheels while stopped. If I had a choice I'd have narrower wheels in the front, but I got a deal on the wheels and that's how they came. (thanks markb!)
Edit: Well, the real question was about spacers, and I forgot to mention that yes, I needed 1" spacers to get the wheel to not hit the strut. I can turn full lock to lock, but they do still rub on the inside at full lock. It's amazing how much room there is for wheel in there with GT flares. |
PeeGreen 914 |
Jul 24 2008, 03:23 AM
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#11
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Just when you think you're done...wait, there is more..lol Group: Members Posts: 10,219 Joined: 21-September 06 From: Seattle, WA... actually Everett Member No.: 6,884 Region Association: Pacific Northwest |
At an AX you do not want them as it will have an effect on the steering input. Your times will be slower.... I know this from experience. PUshing the wheels out in the rear widens the track for greater stability but in the front it is mostly for looks... On the track I take them off as your pivot point on the wheels is now different and throws things off.
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neo914-6 |
Jul 24 2008, 04:00 AM
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#12
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neo life Group: Members Posts: 5,086 Joined: 16-January 03 From: Willow Glen (San Jose) Member No.: 159 |
wow, lot's of you "old timers" posting. Just like the old days... (IMG:style_emoticons/default/bye1.gif)
yeah I know, I haven't been around for awhile |
J P Stein |
Jul 24 2008, 09:07 AM
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#13
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Irrelevant old fart Group: Members Posts: 8,797 Joined: 30-December 02 From: Vancouver, WA Member No.: 45 Region Association: None |
I've run up to 10 inch wide front wheels up front. The result was very high steering effort & an unfixable push in your average AX turn. A rough calculation was a scrub radius of 3.5 inches. Large/moderate steering inputs cause the tires to "shuffle" sideways rather than roll in a smooth arc. Live & learn.
To keep it simple, I found that a standard offset (with about 5 inch backspace) 8 inch wide Fuch is as wide as I can go. A 7 inch wide Fuch has the same backspace as the 8. A one inch spacer on a 7 would give the same scrub radius as an 8 inch wheel. This set up is tunable from a handling set up aspect but the steering effort is higher. Edit. Make that a .5 inch spacer. |
SirAndy |
Jul 24 2008, 12:10 PM
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#14
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Resident German Group: Admin Posts: 41,651 Joined: 21-January 03 From: Oakland, Kalifornia Member No.: 179 Region Association: Northern California |
on the street, i run 7x15 cookie cutters with 225 tires and 1 1/4" spacers.
on the track, i run 7x15 cookie cutters with 9" GoodYear racing slicks and 1" spacers. funny thing, steering is actually *easier* with the goodyear slicks! i had the car perfectly balanced with the old 1.7L motor. now that i added the 3.6L, i'm having a lot of understeer in slow corners. i'm currently working on dialing that out. (IMG:style_emoticons/default/smash.gif) Andy |
pete-stevers |
Jul 24 2008, 12:26 PM
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#15
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saved from fire! Group: Members Posts: 2,641 Joined: 10-October 04 From: Abbotsford,BC, Canada Member No.: 2,914 Region Association: Pacific Northwest |
andy what sway bar do you run up front?
so i guesse i will be looking at a understeer with 11/4 spacers up front how does this effect a high speed corner, is there still a push? |
SirAndy |
Jul 24 2008, 12:43 PM
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#16
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Resident German Group: Admin Posts: 41,651 Joined: 21-January 03 From: Oakland, Kalifornia Member No.: 179 Region Association: Northern California |
andy what sway bar do you run up front? so i guesse i will be looking at a understeer with 11/4 spacers up front how does this effect a high speed corner, is there still a push? not really. wider track means better grip, so that should give you more grip in the front, not understeer ... i've got understeer now because the added weight of the /6 motor gives it more grip in the rear and in tight corners, when you hit the gas coming out of them, you're moving even more weight to the rear, so the front gets light = understeer. i run the 22mm tarett bar up front and the stock bar in the rear, 911 carrera torsion bars up front, 250lbs springs in the rear. koni adjustable shocks all around ... (IMG:style_emoticons/default/bye1.gif) Andy |
messix |
Jul 24 2008, 01:00 PM
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#17
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AKA "CLUTCH KILLER"! Group: Members Posts: 6,995 Joined: 14-April 05 From: between shit kickers and pinky lifters/ puget sound wa.north of Seattle south of Canada Member No.: 3,931 Region Association: Pacific Northwest |
have you tried running with out the rear bar? or do you need it at higher speed?
tough to balance a car when you get so much weight transfer to the rear on accelaration |
jmill |
Jul 24 2008, 01:44 PM
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#18
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Green Hornet Group: Members Posts: 2,449 Joined: 9-May 08 From: Racine, Wisconsin Member No.: 9,038 Region Association: Upper MidWest |
Removing the rear bar would make it worse. You want to soften the front and stiffen the rear to correct understeer.
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Richard Casto |
Jul 24 2008, 02:35 PM
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#19
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Blue Sky Motorsports, LLC Group: Members Posts: 1,465 Joined: 2-August 05 From: Durham, NC Member No.: 4,523 Region Association: South East States |
Ok, this is a good topic. I had been planning on buying a set of the Rota Fox wheels. These seems to be sold as 17x7.5 +35ET for the front and 17x9 +16ET for the rear. I like the idea of running the same wheel and tire size all around to allow for more rotation options. I "think" you can buy the rota as a set of four 17x9 instead of the mixed sizes. So this bring up the topic of "what is the impact of running 17x9 both front and rear". I don't know what to do. Here is what is important to me in priority order...
1. Handling at track 2. Handling at autocross 3. Tire wear/rotation options 4. Ease of low speed turning The car is going to have a full cage, 3.2 six for power, 911 front end and stock 911 torsion bars. Tarrett front swap bar, most likely no rear bar, but will have mounts for the rear. Koni all around and whatever rear spring rate that make sense. Basically similar to Andy, but with a slightly smaller motor. What should I do? |
andys |
Jul 24 2008, 03:06 PM
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#20
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Advanced Member Group: Members Posts: 2,165 Joined: 21-May 03 From: Valencia, CA Member No.: 721 Region Association: None |
Adding front spacers will help widen the track. This will in turn reduce the amount of weight transferred in a turn. It will however on a strut car increase the scrub radius which can increase steering effort. You can increase the caster to counteract the effects a little, but going to far will make the steering floppy. Shunning a debate, my experience has shown quite a different result in general terms. Increasing the scrub radius (track) also increases the gain from caster which increases (cross) weight transfer (the inside tire will droop more). Adding yet more caster will amplify the effect. That's how it has worked for me. Andys |
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