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Mk Indy Rear Toe Shims
Matt21 - 26/2/17 at 05:25 PM

Last time I got my MK set up I was told that one of the rear wheels had more toe in than the other side.

I'm not looking to add some shims to get them balanced out.
I'll be making up a load of shims myself to add/remove to get it right, can anyone give me a rough idea on how thick big they would have to be?

I cant remember the figures, but lets say I have 2degrees toe in and want to get to 1degree.

Also, are the rear hub bolts 10mm or 12mm? (I'm away from home so cant check myself, I have a feeling theyre 12mm)


procomp - 26/2/17 at 06:03 PM

Hi. Remember its not just the toe setting you need set but also thrust alignment measured at front axle.
The 4 hub bolts are 10mm.

Matt


Banana - 26/2/17 at 06:37 PM

How do you adjust thrust angle with IRS?


Matt21 - 27/2/17 at 08:00 AM

Thanks Matt,

How would I go about adjusting and measuring the thrust angle?


mikeb - 27/2/17 at 09:30 AM

This might help.
We bought a set for our caterham a few seasons back to adjust the rear toe in and camber.

Shims[/url ] by [url=https://www.flickr.com/photos/62740914@N04/]mjb22001, on Flickr

These are for DeDeon but from recollection the interface between the dedeon ear and the rear hubs is the same as our standard seirra rear hub to upright so they should work.

[Edited on 27/2/17 by mikeb]


loggyboy - 27/2/17 at 09:44 AM

Surely being an 'Indy' it will have independent rear.
Are there not adjustments on the wishbones for geometry? or is it a more fine tuning needed than a half rotation on a tie rod will give?


[Edited on 27-2-17 by loggyboy]


SJ - 27/2/17 at 10:01 AM

quote:

Surely being an 'Indy' it will have independent rear.
Are there not adjustments on the wishbones for geometry? or is it a more fine tuning needed than a half rotation on a tie rod will give?



With Standard wishbones there is no adjustment for rear toe.


Banana - 27/2/17 at 10:42 AM

You can shim the rear for toe.

I can't figure how you'd adjust thrust angle satisfactorily though, with IRS.


loggyboy - 27/2/17 at 11:47 AM

Surely by doing this the thrust angle will be corrected, thats the whole point of correcting/balancing the rear toe? (assuming the adjustment is based on a 4 point geometry check)
The thrust alignment will come from re-aligning front tracking to suit.

[Edited on 27-2-17 by loggyboy]


procomp - 27/2/17 at 02:30 PM

The rear toe is non adjustable via wishbones as such hence the need for shims between the fabricated upright and the Sierra bolt on hub to align the rear toe.

My comments re Thrust is that most people only look at the toe as a single item IE its been adjusted and now has the correct toe of say 1mm toe in. However with cars of this type the toe needs to be pointing evenly down the center line. As little as 4mm of center at front axle line can cause problems on our loverly British roads.
So although the toe at moment may suggest that only one side needs shimming to get correct toe setting it may need a minor amount on one side and lot more on the other side to get the thrust to fall within an acceptable tolerance.

Cheers Matt


Banana - 27/2/17 at 02:49 PM

Hi Matt, for the amateur at home, would a center line created between wishbone/chassis mounting points be acceptable as a ref point?


procomp - 27/2/17 at 03:01 PM

Yes. We have to assume the left and right wishbones are within a small tolerance so working from chassis pickup points to create a center point to measure from rather than chassis tubes is idea. just make sure you can gain access with a steel rule etc to String / line / laser being projected forwards from rear wheels/ tyres.