Twincam Rear Toe

[JeffBatt]

I’m trying to rough in the rear toe on my special.

Spec seems to be 1/8” to 1/4”. Can anyone confirm if this is per wheel, or total?

Thanks!  (Seems like I need to used a ton of spacers. Seems wrong…)

[BDA]

Those specs in the workshop manual are for the total toe. A lot of guys here have tended to use a toe toward the smaller toe measurement.

[JeffBatt]

So, spec is 1/4” total max for a twincam? (i.e. 1/8” per wheel)

Thanks!

[BDA]

Right.

[JeffBatt]

Thank you!

[Fotog]

Having just gotten new bushings for the trailing arms, and needing to reduce my toe from a recently measured 5/16 total, I would be interested to hear how much of a difference a single pair of "normal" washers would make to the toe.
I unfortunately don't have the washers here to measure.  I'd like to minimize the number of iterations required to complete this.
Thx!...Vince

[Bryan Boyle]

Having just gotten new bushings for the trailing arms, and needing to reduce my toe from a recently measured 5/16 total, I would be interested to hear how much of a difference a single pair of "normal" washers would make to the toe.
I unfortunately don't have the washers here to measure.  I'd like to minimize the number of iterations required to complete this.
Thx!...Vince

I'm thinking that you'll need 2 iterations; frequently toe on the rear is reduced when new bushings are installed, in my experience, since the bushings have a tendency to sag inward as they age.  Bolt up with what you have, take the reading, and you'll know where you need to either leave alone, add, or remove.  But, predicting beforehand is hard without knowing your starting point with fresh metalastic units in place. 

Just a suggestion.

[BDA]

I would say there really is no “normal” washer thickness. AN washers come in two thicknesses in that size bolt (0.032” and 0.062”). Alignment shims which should be available at parts houses or even Harbor Freight have specified thicknesses and are handy because you don’t have to unbolt the joint to put them in.

I think in the past, someone has posted the change in toe from a certain sized washer. Maybe he can remind us again.

[MRN I J]

1/4" seems excessive, I would have thought 1/8" total toe in, 3/16" absolute max, so 1/16" per wheel, 3/32" per wheel max

[jbcollier]

I'd be cautious as you really don't want it to go to toe-out during cornering.  You have track time to dial it in?  Great!  Setting up for the road?  I'd keep to at least the minimum spec.  Also, don't forget to check your rear thrust angle.

As an aside, Tim Engel checked with the factory back in the day and was told the rear toe spec was not across the axle but for each individual wheel.  Certainly the S1/2 spec seems that way. The TC/S spec less so.

[Fotog]

Thanks for the advice.  I'll check the manual, and then ask some expert(s) before finalizing things.
I did my very first run over 60mph the other day.  70 for a short period, then 75 briefly. There was a truck in front of me.  I didn't really want to pass him. One step at a time, if you catch my drift.
I didn't sense that there was really anything wrong, but just going straight certainly demanded my attention.
I'm not exactly sure what's to be expected, but some reading tells me that handling could be very sensitive.
-V

I'd be cautious as you really don't want it to go to toe-out during cornering.  You have track time to dial it in?  Great!  Setting up for the road?  I'd keep to at least the minimum spec.  Also, don't forget to check your rear thrust angle.

As an aside, Tim Engel checked with the factory back in the day and was told the rear toe spec was not across the axle but for each individual wheel.  Certainly the S1/2 spec seems that way. The TC/S spec less so.

[JeffBatt]

I’m going to need about 12-15mm of spacers per side to even hit 1/4” total toe-in.

Bought some of the Esprit spacers because I don’t want to stack that many washers. I also have some very thin shim washers from McMaster, but I’m not sure if I’ll need to fine tune quite that much.

[JeffBatt]

1/8 - 1/4” per wheel for a TC, measured at the wheel (not tire)? Wonder if I should start there rather than total..

This kinda makes sense in that I’m shocked how many spacers I need to hit spec.

I'd be cautious as you really don't want it to go to toe-out during cornering.  You have track time to dial it in?  Great!  Setting up for the road?  I'd keep to at least the minimum spec.  Also, don't forget to check your rear thrust angle.

As an aside, Tim Engel checked with the factory back in the day and was told the rear toe spec was not across the axle but for each individual wheel.  Certainly the S1/2 spec seems that way. The TC/S spec less so.

[RonPNW]

I have heard, in the foggy past, that occasionally the front bushing is mounted inside out. That is, mounted such that the attachment is sifted inboard by the thickness of the bushing witch is around 15 cm. Could this be the issue?

Ron

[JeffBatt]

I have the bushings bolted to the outside of the frame, with the thick rubber sections facing inward.

I think this is how they’re supposed to be? With the thick rubber section facing out, I’m not sure if there would much room for adjustment?