Front Wheel Alignment

[Oddball]

Morning All

I need some help understanding an aspect of front wheel alignment. Many year ago I decided I wanted a little more negative camber on the front wheels of my 6.I therefore fitted more shims to the lower wishbones. I can’t be sure how many but as I have four shims both sides front and back I think it was just one extra all round. I now intend to remove one shim from all four locations, however I can’t understand how by doing that it will affect the alignment. Obviously the camber will be less negative, however how is the toe in, toe out changed.

Thanks

Cameron

[RogerH]

Hi Cameron,

imagine that the steering rack and its parts are a single stiff rod across the car.

The front and the rear wish bones are also effectively stiff rods.

If you shorten the wish bone 'rods then the unchanged steering rack 'rod' will cause more 'toe-out'

You effectively bring the centre of the wheel inwards while leaving the forward edge of the wheel where it was - thus giving toe-out.

 

Roger

[Oddball]

Thanks Roger, that makes perfect sense,I’ll get my stands and fishing line out and get it sorted.

Slàinte mhath

Cameron

 

[TriumphV8]

Buy a Gunsons Trakrite and set the wheels properly.

That is a really good help to get things in limits for our cars.

 

Also a digital scale used on a flat ground is perfect to set camber.

[Oddball]

Strange you should suggest that,I ordered one last night from Amazon, should be here tomorrow.

Cameron

[Rogcastle]

I thought  the other day that  the camber on the rear of my tr6 looked a bit negative so I used my iphone which has a level measurement on it which can be used on the vertical. I used a straight edge on the outside of the tyre with the phone and the readings  were rear 1degree neg and front 0 degree on both sides. I know its not very accurate and only shows steps of one degree,  but it made me happy. It only took a minute. Maybe useful for a quick check.

Roger

[Oddball]

I’ve been using an android app to measure camber in the same way, it’s called Clinometer and measures to tenths of a degree

[ChrisP]

Would it be better to straight edge off the rim as the tyre must bulge at the bottom I think this would make a big difference to the reading. Chris.

[RobH]

A mobile phone may indicate to tenths of a degree but the accuracy depends on the resolution and calibration of the sensor and its alignment to the case of the phone. Just because it's digital and shows 'n' places of decimals you shouldn't necessarily believe what it is telling you. (The same thing goes for ANY digital readout by the way).

[Oddball]

I’m not so concerned about it’s accuracy, it’s the precision that I’m interested in. I have found using the same straight edge, rim to rim, with the car in the same location and no phone case I get very repeatable results. May not be particularly accurate but the precision is good. 

Cameron

[Waldi]

No matter what method you use, it is best to measure at 2 positions, the wheel rotated 180 degrees further and then take the average of these results. This eliminates the wheel imperfections.

Regards,

Waldi