template for rack mount shim

[LaikaTheDog]

hi, does anyone have the dimensions or a template for an Elan Plus2 Rack mount Shim ?

[JonB]

Hi Laika

It's just a rectangle of sheet metal, galvanised, with two holes in it that match the rack brackets. No complex shape. The thickness is what's important as I am sure you know.

Cheers

[geni]

explain to us how to know the thickness to be inserted under the rack?

[Frogelan]

G?rard,

The thickness of the shims is determined by calculations explained in Brian Buckland's book. Do you have this?

L'?paisseur est d?termin? par de savants calculs qui sont expliqu?s dans le livre de Brian Buckland. As tu ce livre ?


Andrew

[LaikaTheDog]

I just didn't want to go out in the cold to remove my rad and rack mounts if someone already had the dimensions!

[geni]

I am in trouble but the book is lent to a friend at 500kms so if a charitable soul would like to copy!

[LaikaTheDog]

Shim dimensions in mm

img_20191029_113227.jpg (30.86 KiB) Viewed 1340 times

Just in case someone somewhere someday has the same question...

[nmauduit]

I use a slightly different version of the shim by opening the holes towards the nearest side, so that I can add/remove some without taking the whole rack away.

As for the thickness of the shims, I adjust them a bit at a time for bump steer minimization (using a small laser pointer attached to the hub), required accuracy being about 1/10mm requiring a set of shims of various thcknesses so that the combinations would cover the required target (e.g. cut from 0.5mm 0.8mm 1.0mm 1.2mm sheet stock) to avoid spending time grinding off small thin pieces.

[baileyman]

There is an angular range of near linear movement in the geometry that I think people call "neutral bump steer". The shims move the range up or down. I chose to put my range into the bump, supposing toe changes on droop were not so important. Once on the road, though, I'll know for sure.

John