The short of it is i've bought new tyres for the front and had control arms with poly bushings fitted (thanks Dann). The two upper arms on the fronts had offset bushes.
- I've known the camber on my rear used to be massively out from a poorly calibrated wheel alignment setup. This had been "officially" calibrated every 6 months by the operator's main office, with incorrect settings. The rear left on the alignment system would always report 1deg camber when in reality it was closer to 2.0-2.2deg - easily seen, visually, with your own eyes on the car.. Front left would have odd castor despite the alignment computer screen saying otherwise. The roadster always pulled to the left and very noticeably so on many backroads near home, and on highway driving, i'd be aiming the wheel offcenter right to try and maintain a straight line.
Clearly either the hoist's 'level' and or the left hand wheel modules were out of whack somewhere...
The other major annoyance was the machine's resolution was one reading per 6 minutes of a degree. Enough to have toe settings be annoying and unsettling.
with the bad road tracking, i ended up toeing in the front left and centering the wheel after an amount of pfaffing about. I eventually got it pretty much where i wanted it but knew full well this had thrown out the 'alignment' it had. I left it for 8 months as other projects took hold.
So with this week's lavish purchases, i ended the week having my alignment done at Jax Tyres Bendigo.. I'd given them forewarning that i'd be providing a personalised spec sheet of my settings and Glen, the alignmentologist had no problems with being issued it. I had readings in mm, degrees and decimal degrees as i wasn't sure what their systems would be giving readings in, and 1.4 degrees is different to 1˚40' ..
What i also did based on my last alignment suggest if their alignment readings weren't precise or high resolution enough-
Knowing toe out on the front is preferred over toe in:
I suggested when doing the toe adjustments to move the toe out positive then slowly adjust until just hitting the zero value then backing off a smidge, with the opposite for the rears.
That way if the resolution of value is below 6minutes/degree, the actual to would likely be in positive (near as makes not much difference for zero) for the fronts, and negative (-zero??) for the rears.
The alignmentologist was ok with this too. Then he tells me that the toe in resolution is 0.1mm and the degree resolution is in minutes but that the idea i presented was sound for a lower resolution alignment system.
I sat in the drivers seat while this alignment was done. I forgot to drive/empty one third of my tank beforehand and essentially had 38 litres of fuel for these readings.
Adjustments were made over the next hour and a half, adjusting a few times (as the first time the driver side front alignment wheel hanger dooby had nicked the front bar during the initial front wheel steering procedure) giving odd readings for the castor and camber. I asked if a range of readings could be given for each corner, so i know what range of camber/toe/castor i can play with for future choices. Glen the alignmentologist gave me readings each corner he completed and then for the front and rears together. Basically thinking aloud, which kept me in the loop and kept me happy.
Based on numerous wide ranging suggestions of from folk from forums all over, i decided to go my own way on camber (too wide a range of suggestions from 0.5 to 2.0 degrees) but followed the advice to go with castor and toe settings.
Castor left at 5˚52 (5.86degrees) and right at 5˚09 (5.15degrees). This was as much as could be dialed in on the left with the right nearly at 0˚42' (0.71degrees) less. I ideally wanted the right being 0˚30 (0.5degrees) less but it was getting late at the workshop and i was much more concerned with toe and camber being spot on.
Front camber is 1˚33 (1.55degrees) both sides
Rear camber is 1˚40 (1.66degrees) both sides.
Toe was set to zero on all corners.
I wanted to get the cambers closer together as what i'd read on here and other forums suggests less understeer and more likelyhood to oversteer, which i need practice with controlling. So with these settings, i can practice on a mate's property.
Looking at the car, clearly the cambers are equal left and right unlike my previous alignment shop's best attempt..
I'd also got before/after printouts - but the before was kinda moot as the control arms were fitted and wonky - awaiting the alignment.
The best part of this process, is it's cost $66 and i've found a bloke who's happy to put in time to make me happy. I'll be back for regular tweaks at that price and the rest of the crew at the store were friendly and approachable and didn't look at me as if i was a twat when i presented my ideas.
Driving experience:
(keep in mind, i haven't really had a proper aligned Roadster before so this 'correctly aligned' RWD handling is a bit new to me)
I've noticed the slow speed steering is noticeably heavier and that's with power steering. I like that. I don't mind it light but i'm loving it heavier.
Driving tracks straight ahead on straight roads (was thinking the slightly larger castor L/R difference would have it track right) at 60, 80, and 100kph.
A quick squirt up a short narrow bumpy mountain road i was able to do easily 10kph faster without effort, offering much more stability: no sliding, no loss of traction, and felt that all wheels maintained much better contact with the road compared with previous trips. (yep, it's a pretty bumpy road)
Confidence in handling has increased dramatically, previously this road required much more manhandling the steering wheel and heaps of concentration.
I had a crisis by the time i arrived at the peak.
I can hear the sound of my 40 slotted rotors as i brake normally. (I've always loved that sound - previously only heard when i stamped the brakes to a stop). Gentle braking, the sound is pretty much absent.
NVH
Vibration - I can feel the road much better through the seat and steering. I'd say it's communicative now. Not annoying.
This was on the bumpy rough mountain road and is definitely not a deterrent over the oem rubber bushings.
Noise - it *is noticeably quieter* then with my previous bushes. Road noise sounds filtered to a muffled bass rumble instead of a previous "white noise" (this noise was noticeably louder pre-bush and post-tyres replacement) If anything - the noise frequency range is shifted down to lower frequencies then with the oem bushes. There is definitely less treble harshness in the cabin, no ifs buts or maybes.
There are quiet cabin noises (plastic creaking) associated with the 'road communication vibrations' but this is very negligible over oem bushes.
Harshness - The roadster feels more raw due to feeling the road. It feels firmer, yet not harsh at all. You know you're driving on a rough or smooth surface, but it's not jarring. not crashing in the cabin - *at all*
This is with Bridgestone RE002 205/50/r15s (Jax Tyres $165 each inc balance/fitment)
Oh yeah - big huge happy thumbs up to Glen the alignmentologist at Jax Tyres Bendigo for the alignment.. He did a very thorough job for me and i'd recommend him if you're in the area, and Benn Doherty Mechanical for fitting the control arms for me while i was at work.
It's true what they say - an alignment can change your life.. The bushings have made a big impact too.
