simon's learning what to do with the polo thread

[simon k]

time for a rollcage... REALLY stiffen it up

[simon k]

here's what I was thinking of doing for a rear stub axle spacer - would tap a thread in the holes that line up with the original caliper mounts and put a bolt through or a locating pin - a locating pin would allow the use of toe/camber shims. The caliper is mounted to the plate and is rotated around the stub axle's axis a bit.

Could line the holes in the spacer plate up with the original mounts and use a longer bolt, but doing it this way gives some freedom with toe/camber shims



seem reasonable?

[sambb]

yep for sure. The whiteline ones were similar but ran further forward so the stub axle had spacer meat under it in all places. Not sure if the whiteline shim had the caliper through bolted through it though. Basically looks a goer to me. Possibly a fast track method to working out the thicknesses could be to order a pair of the eibach shims. They could be put in their various camber/toe configurations and their thicknesses measured off as a guide to what you need to generate. Various toe's at 2 degrees neg camber would be good. I'll take a couple of pairs once you start knocking them out!

[simon k]

The whiteline ones were similar but ran further forward so the stub axle had spacer meat under it in all places.

ahh, yep, that'd make sense... I should probably make them round and the same diameter as the stub axle so they look like they're meant to be there

They could be put in their various camber/toe configurations and their thicknesses measured off as a guide to what you need to generate.

I was just going to cut them out flat and put the plastic shims behind them, but are you suggesting pre-machining them at set toe/camber angles?

I guess that'd be easy enough. I'd have to make a jig to sit on the mill. Jig would have 4 pegs aligned with the mount holes. Sit the plate on the jig with the right shims under each peg, bolt it down (countersunk centre hole) and then mill it flat... sounds like it'd work OK

might need to wait until July though

[sambb]

yeah either way would work. I suppose the problem of making up angled spacers is that you'd need to make so many variations that it'd be impractical. Yeah doing them as a straight spacer and then running them over the top of the adjustable shims would be the cost effective way to do it. I do worry about my wheel bearings at et20 at the back.

[Sydneykid]

My 20 cents ............. I'd cut the brake caliper mounts off the original flange and bolt the caliper to the spacer plate, that way any camber or toe change (from original) won't affect the relationship between the caliper and rotor ie. they will always be in line. I'd also make the spacer out of alloy to save weight and hellicoil the caliper bolts. By not using longer (through) bolts, removing the dust cover and cutting off the original cast caliper brackets there may not be much unsprung (evil) weight increase.

In a FWD car I don't change the rear toe or camber settings very often, I find that the rear swaybar is the best handling balance tuning method. That and the rear shock damper settings. Rear spring changes are really only for the extremes of tracks, Philip Island for example needs a spring rate increase due to its long, high speed (lat G) corners.

In comparison I do change the front camber and toe settings depending on the track, including biasing of the camber for clockwise or anti clockwise tracks.


Cheers
Gary

[simon k]

My 20 cents ............. I'd cut the brake caliper mounts off the original flange and bolt the caliper to the spacer plate, that way any camber or toe change (from original) won't affect the relationship between the caliper and rotor ie. they will always be in line. I'd also make the spacer out of alloy to save weight and hellicoil the caliper bolts. By not using longer (through) bolts, removing the dust cover and cutting off the original cast caliper brackets there may not be much unsprung (evil) weight increase.

thanks Gary - was retaining the caliper mounts and putting a locating pin (not a bolt) in them because I was scared that the stub axle bolts would have too much load on them. I was going to make it out of steel, but we do have a lovely piece of 10 or 12mm aluminium plate sitting in the workshop - I must resist working on Polo this week - too much other car work to do...

I'm booked in for tyres Wednesday morning, Bridgestone RE003 205/55/16 @ $121 each with the buy 4 pay for 3 deal - they might not be the best thing out there, but should be a reasonable compromise and better than what's on there now

[Sydneykid]

Compared to the impact loadings on the stub axle, rotational loading due to braking would be minuscule.

Cheers
Gary

[simon k]

Compared to the impact loadings on the stub axle, rotational loading due to braking would be minuscule.

Cheers
Gary

excellent - I can take that out of my design considerations, should make it easier because handbrake cable, brake lines etc. can stay where they are.

If anyone wants some plates they can either cut the original lugs off if they want to use shims, or leave the lugs there and use longer bolts...

I'm getting my tyres done tomorrow morning and a wheel alignment so I have a baseline - how much toe-out should I get them to put on?

[sambb]

I'm in on a pair @ 15mm thick. I'd go at least 2mm toe out total minimum. I have 3 and a bit mm total and commute 80km a day and its never phased me with tramlining etc but does handle better that way for my car.

[simon k]

I'm in on a pair @ 15mm thick. I'd go at least 2mm toe out total minimum. I have 3 and a bit mm total and commute 80km a day and its never phased me with tramlining etc but does handle better that way for my car.

kewl... I'll go with that - always confuses me though... 2mm at what point? the wheel rim? the tread? centre of the sidewall? it's all different

[sambb]

You'd measure rim inner lip across to the opposite rim inner lip - leading edge of rim versus the same thing on the trailing edge. 2, 3 or 4mm wider on the front measurement. Go for a drive a check for wheel straightness. If not centred then drive back into your alignment surface with the wheel dead centre, work out which way both wheels are pointing, and then take an equal amount out of each track rod ie 1/2 turn in on one side, 1/2 a turn out on the other till you are re centred, and then maybe check your total toe again to be sure it hasn't changed. In practice though thats very hard to do due to the underbody forcing you to measure in less than ideal positions on the rim. I did mine with those toe plates that I made about 20 posts back in my thread and they make it so easy. They measure tyre outer, to tyre outer and negate the need to stuff around lying under the car with tape measures. You'll need them for measuring your before and after rear toes when you go to do the shims/spacers too. They only measure total toe so as I said above you may need to do a couple o road tests to get it so that you are equally out on both sides.

[Sydneykid]

My toe plates are 750 mm long (tape position to tape tape position) and I have used them on all wheel diameters from 13" to 19". So the measurements are consistent regardless what sized tyre is on the car at the time. In fact I can measure toe without any wheels/tyres if I wanted, just rest them on the hubs. At 750 mm I run a minimum of 4 mm toe out and often 6 mm, occasionally 8 mm. With a lot of toe out (more than 4 mm) some drivers don't like the squirrelly feel from the rear end under brakes, that's about the only real negative.

Cheers
Gary

[sambb]

They are easy to make Simon. The commercial ones have a bend in the base. 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. I just fit bolts to mine. Use thick enough aluminium so that when you tension the tape measures you are not going to deflect the plate and skew the measurement. And the slits that you cut for the tape measures to sit in, make sure they are cut fat enough that the concave ends of a tape measure can slide in side ways.

[simon k]

thanks guys - I did see your plates Sam - I'll knock some up when I find a bit of scrap. I've done it with string before, but it's too easy to bump out of place...

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

My new tyres are on - the tyre bloke and I were both curious about how much clearance they'd have to the guard liners... I can just get my fingers between the tyre and the guard liner at full lock on both sides. So, as per Louis, I now have tyres that really fill out the mudguards, looks a bit tonka truck-ish, but good to at have decent rubber.

My speedo is now 100% accurate - 60kph on the speedo is 60kph on the satnav, 100kph on the speedo is now 100kph on the satnav

They did a wheel alignment - must've been a dead easy alignment job, the before and after toe numbers are almost identical. My car has had a very easy life, until now