simon's learning what to do with the polo thread

[Sydneykid]

Just make sure that you bend it high enough on the plate that the flat part of the plate will sit high enough on the outside face of the tyre that it wont be kicked out at the bottom by the tyre balloon down at the road surface.

OK Sam, you got me, why is that a problem?

Mine are copy of the NASCAR ones I saw at SEMA about 15 years ago, I just used steel right angle bases as they are heavy enough not to move in the wind when working outside;


The height of the slot is determined by what's needed for clearance under the car. The higher the better (up to the wheel centre) but make sure nothing is going to get in the way of the tape measures.

Cheers
Gary

[sambb]

When I first made mine and you sat it against the outside face of the tyre, I found that where the tyre was bulged between the road surface and the rim was pushing into the base of the plate so that along the bottom of the tyre the plate wouldn't sit flush. It would however be flush across the tyre along the top edge of the plate. I had a look at the commercially available ones and most seemed to have the bend set much higher than mine so I figured they had done it that way to avoid what I was seeing. I do have 55 profile tyres though. I jus figured you want the plate to have flush contact around its whole circumference. By moving the bend higher I could get the plate to sit flush against the outer edges of the tyre on the plates bottom edge without the tyres bulge interfering with how it sat.

[Sydneykid]

I was more curious about using a distance measurement that will only be correct at a specific distance from the hub - unless you have the right distance you can't trust it

How is your high school trigonometry, bit of Pythagoras to help pass the time

Changing the length of the toe plates by 100 mm (say from 750 mm to 650 mm) would make less than 0.5 mm difference in the toe measurement. That has some importance in one of our F3's, with its carbon fibre monocoque and control arms, rose joints and fabricated alloy uprights etc. But in a road car, with lots of chassis flex when new, let alone after a few thousands k's, elastomeric bushings etc it's not likely to be an issue.

The bottom line is repeatability, consistency, what they read in absolute terms doesn't matter.


Cheers
Gary

[Sydneykid]

When I first made mine and you sat it against the outside face of the tyre, I found that where the tyre was bulged between the road surface and the rim was pushing into the base of the plate so that along the bottom of the tyre the plate wouldn't sit flush. It would however be flush across the tyre along the top edge of the plate. I had a look at the commercially available ones and most seemed to have the bend set much higher than mine so I figured they had done it that way to avoid what I was seeing. I do have 55 profile tyres though. I jus figured you want the plate to have flush contact around its whole circumference. By moving the bend higher I could get the plate to sit flush against the outer edges of the tyre on the plates bottom edge without the tyres bulge interfering with how it sat.

As long as the tape measures, at their height, are measuring flush across the tyre (ie; above the bulge) it doesn't really matter what the bottom of the toe plate is doing. Kicking it out at the bottom shouldn't change the measurements.

Cheers
Gary

[sambb]

ha ha. cool just didn't look right that the plate was being interfered with. Over thinking as usual I was.

[simon k]

Changing the length of the toe plates by 100 mm (say from 750 mm to 650 mm) would make less than 0.5 mm difference in the toe measurement.

yeah, fair call, I just saw that there was room for error, I didn't stop to actually quantify it... consider the back of my head slapped

As long as the tape measures, at their height, are measuring flush across the tyre (ie; above the bulge) it doesn't really matter what the bottom of the toe plate is doing. Kicking it out at the bottom shouldn't change the measurements.

Cheers
Gary

except that the plate is only touching the tyre along the top edge rather than with its back face flat against it - so if you're not careful and have one corner of the plate kicked out a little bit you wouldn't notice... but then you might get 0.25mm error?

... owww, *****, that one hurt!

[sambb]

actually I remember now why I was so anal about not having it kicked out at the bottom. I was measuring camber with them too. I'd gotten one of those cheap little digital angle finders off ebay and was using it to check my camber and didn't want to get exaggerated readings by the base of the plates sitting proud of the tyres edges by being pushed out a little at the bottom.

[Sydneykid]

actually I remember now why I was so anal about not having it kicked out at the bottom. I was measuring camber with them too. I'd gotten one of those cheap little digital angle finders off ebay and was using it to check my camber and didn't want to get exaggerated readings by the base of the plates sitting proud of the tyres edges by being pushed out a little at the bottom.

I have been known to use the spirit level app on my iPhone, works great for wing angles, it's just the right length.

Cheers
Gary

[Sydneykid]

yeah, fair call, I just saw that there was room for error, I didn't stop to actually quantify it... consider the back of my head slapped
except that the plate is only touching the tyre along the top edge rather than with its back face flat against it - so if you're not careful and have one corner of the plate kicked out a little bit you wouldn't notice... but then you might get 0.25mm error?
... owww, *****, that one hurt!

Don't worry I even had one guy say my toe measurements weren't any good because of the writing on the tyre sidewall.

Cheers
Gary

[simon k]

clutch paranoia is setting in... 16yo learner behind the wheel giving it a bit of a hard time. I might need to buy a clutch and have it sitting ready to go in

saving link to handy info here - PARTS where to get these: Clutch and pressure plate upgrade maybe lightened flywheel

the manual says to take the gearbox out and leave the engine in the car, but it seems like it'd be cleaner to take it out as a unit... what is everyones preference?