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shorter than stock IRS wheelbase?

Posted: Mon Aug 22, 2011 5:27 pm
by adjunog
I was thinking about a shorter wheelbase for my IRS '69 fasty to get tires tucked in more as opposed to cambering.
I need some suggestions.

Re: shorter than stock IRS wheelbase?

Posted: Mon Aug 22, 2011 5:36 pm
by Marc
The term you're looking for is "track width" ("wheelbase" is the measurement from the front to the rear axle).
It can be/has been done, but it's an ambitious undertaking. How wide of a tire/wheel are you trying to get under the fender? How much clearance is there now between the inner sidewall and the control arm/control arm-to-springplate bolts? The upper shock pad can be trimmed easily, and some clearance can be gained by altering the control arm hardware. This may be enough, if you select a wheel with more backspace.

If that still doesn't do it, you've got to narrow the control arm and use offset springplates and shorter axle shafts.
RickS wrote:...What you do to narrow the arms is cut the bearing housing free from the arm, cut the arm back, set it up square in a jig and reweld. Bruce Tweddle wrote a How-To article in Hot Vws back in the early 90's. Another way to go would be to buy some tubular narrowed control arms from either aircooled.net or Blind Chicken racing. The AC.net ones are 1 1/2" narrowed and blind chicken will make whatever you want.

Re: shorter than stock IRS wheelbase?

Posted: Mon Aug 22, 2011 9:00 pm
by adjunog
That's right. I'm at stock right now using the empi 8 spokes. I wanna get a good 3" of tuck to get some cool looking dish rims.

Re: shorter than stock IRS wheelbase?

Posted: Mon Aug 22, 2011 9:15 pm
by Marc
IMO that's way too much work just for cosmetics. There's no cheap/easy way to do it.
With the Type III rear drums/hubs it's not too hard to redrill/stud for other bolt patterns which offer more choices in rims. My son & I have done 5x130, 4x100, even 4x4¼" (to match Mustang front rotors on a race car). You'll still need enough offset to keep under the fenders so nothing really deep will work, but you might look around to see if there's something you could live with in any of those patterns (or anything else between 100 and 130mm).

Re: shorter than stock IRS wheelbase?

Posted: Mon Aug 22, 2011 9:27 pm
by adjunog
Yeah. If I go with disk brakes conversion I think there's kits out there that get 1 5/8" narrowed. If anyone has pics of disk conversions Please post. Thanks

Re: shorter than stock IRS wheelbase?

Posted: Mon Aug 22, 2011 9:37 pm
by Piledriver
There's a great thread over on TOS that covers what combos/offsets will fit T3s... More than one person running 17x7s with LP tires.

There's 2 different "narrow" setups...
1) Narrow track--- These are the bolt on TAs that narrow the track and let you run that special set of Fuchs you love under stock fenders.
With coil overs and the right pivot setup (replaces the spring plate) it MAY give you some more room for wheel/tire on the inside.
(See the Mendeola rear suspension setup)

2) Narrowed torsion... This actually provides more room.

Like Marc said, It's expensive... Before I figured it out, I looked into getting a set of ACN arms not too long ago and the ~1K for the last set in existence just wasn't worth it, especially as it doesn't really provide significantly more room for more meat, the spring plate is in the same place.

If you aren't "in love" with a particular set of rims, there's essentially no advantage to just narrowing the track.

To really get serious tire underneath out back, the torsion needs narrowed and custom trailing arms are needed, and a bit of wheel tub will probably be required, depending on how far you need to go.(might be able to get some tubular TAs in "kit" form so you can make them as needed if you can)

At least on a T3 you can yank the rear suspension as a unit and not have to fight with the car as much.

Re: shorter than stock IRS wheelbase?

Posted: Tue Aug 23, 2011 3:46 am
by adjunog
I don't think im gonna go over 16s. Do you think you can post a link. I'm having difficulty searching it. Thanks pile.

Re: shorter than stock IRS wheelbase?

Posted: Tue Aug 23, 2011 1:46 pm
by Piledriver