Is Suspension Tuning Backwards? - A Test with RX-8

[rk]

Could you explain this again? If you're adding the SAME amount to both springs, shouldn't it do exactly as it did before, but just, you know, stiffer?

Exactly. That is why the step is part of my basic procedure, as is presetting the brake tension (I just cant tune on 3) and adjusting the ride height to where I have learned leaves just enough room for suspension compression travel. I have found that 5kgt/mm is pretty close (relatively speaking) to whatever spring tension I end up prefering; occasionally I have to fish around, but not often. Since the procedure is innocouous enough, it takes 5 minutes or less to complete, and has held consistent results for every car I have applied it to, I decided it was valid enough to post for review. Now that I think of it, I basically learned this formula because of this thread so "Thanks" tuning is fun again.

 

[sukerkin]

Nice to hear that you've worked things through to your satisfaction Aarque 👍.

I've done a little spannering myself (at last!) this weekend and have reached a similar conclusion in principle to M-Spec i.e. that the character of the car is much more influnced by driving style than spring rates.

The test cars were TVR's (V8-S and Cerbera) on which I tried an array of rates (within a band stretching to 50% of the softest default rate) and ran a multitude of laps to discover that, as with GT3, the Spring Rate is a relatively insensitive tool, in-game, for tuning of turning balance.

I could get understeer or oversteer behaviour at will with almost all the spring rate combinations with very little variation in lap times.

Generally speaking tho', I found that with softer rear rates you get more noticeable steady-state acceleration understeer on corner exit and that with stiffer rear rates you got more noticeable corner entry oversteer as you come off the brakes. I also got the feeling that acceleartion response was more lively with stiffer rear rates whilst braking power was lessened but that could possibly be my imagination .

Those impressions are only slight however and on the whole I would've been hard pressed to say what the spring rate relationship was on any of the runs without knowing beforehand. It could just be that I haven't played enough with GT4 yet to be fully aware of it's nuances but I've a feeling that my old tuning ways will serve well enough for now and not dump me off the track too often .

 

[Maturin]

Well, Sukerkin, good to know.

Therefore, could you tell me how to do the following in the game?

The Supra RZ's default settings are:

Springs: 12/7
Shocks: 8/8


This car oversteers, in all situations, like mad. What would be a *first* guess of what the spring setting should be to correct this?

 

[sukerkin]

Mmm ... haven't really tuned one of those since GT2 (not a Japanese fanboy I'm afraid) .

I'll have a look to see if I have anything worked out for it but I would suggest that you're looking in the wrong place trying to control the behaviour of the car with the spring rates. You'd be much better off trying other areas of the suspension.

However, it may be that the Supra is one of those vehicles whose real world stats don't 'fit' the physics model in the game and it could be losing rear grip because of insufficient weight at the rear. Hence, your approach of increasing the rear springs to match the front might just be the cure .

My gut feeling is that the Bound rates are too high by quite a way - soften them to 5 or 4 (with the rear higher than the front to give exit understeer).

Drop the Rebound a notch to 7/7 to increase entry and exit understeer (tho' this may actually make mid-corner oversteer worse so take care).

Increase the rear camber to about 2.

Put some toe on, say -0.5 at the front and +1.5 at the rear.

Drop the Ride Height as much as you can too to reduce weight transfer effects (and hopefully improve grip).

Stiffen up the Front Stabaliser and Soften the Rear. Front 5 Rear 3 is what I'd recommend in GT3 (the general default bars seem very stiff in GT4 - they're obviously following Japanese style tuning rules (which are a bit idiosyncratic to say the least)). Or you could try to "go with the flow" and attempt to control the oversteer rather than quell it by using Front 3 and Rear 5.

I'm sure tho' from hints that you've made before that you already know this stuff. Give it a go anyhow; experimentation is frequently the only way that knowledge is expanded.

 

[Pontiac Le Mans]

Here I'm back, with the setup for the Nissan Skyline GT R N1 (91) I promised last week on this post (unfortunately, I couldn't yet do the RX-8).

Some preliminary comments: I applied exactly what I did when I played GT3 (adapting the measuring system for downforce and toe). The car get's very controllable, rather neutral (somewhere inthe middle between a Lancer (understeer) and an Alpine (oversteer). What a nice car! I could make it oversteer, but that was a bad idea: I lost 2 or 3 seconds on a lap.

So here is my setup: (race transmission, full race suspension, LSD, VCD, Rigidity+, Wing (no power upgrade))

-308 HP
- tyres: S2 /S2
- ride height: f100/r105
- springs: f8,5/r13
- bound: f4/r6
- rebound: f4/r6
- camber: f3,0/r2,0
- toe: f-2/r0
-stabiliser: f3/r5
- brakes: f14/r11
- downforce: f30/r18
- lsd: 5 for all values (behaves better like this than without adjustable LSD)
- TCS: 3
- other driving assistences: OFF (off course)
- VCD: 10
- gears:
1: 3,204
2: 2,291
3: 1,946
4: 1,602
5: 1,289
6: 1,028
Final: 4,111
Auto 7 (gearbox setup for 0-1000m, works also on Midfiels; other tracks: adjust final)

So, that's is, don't hesitate to send your comments.



- spr

 

[rk]

I've done a little spannering myself (at last!)

Congratulations on your swift recovery.

 

[sukerkin]

Cheers Aarque - fingers still a bit stiff but they work well enough without too much pain. I can even type properly now (not that you can probably tell that of course but I've been able to stop two-finger-pecking (that sounds a bit rude actually ) and am back up to speed ).

 

[Maturin]

However, it may be that the Supra is one of those vehicles whose real world stats don't 'fit' the physics model in the game and it could be losing rear grip because of insufficient weight at the rear.

...

 

[Duke]

Could you explain this again? If you're adding the SAME amount to both springs, shouldn't it do exactly as it did before, but just, you know, stiffer?

No, not by adding the same absolute number (say, 5kg) to each end, because 5 kg represents a differing proportion of the base spring rate for each end.

However, if you're adding, say, 5% (as a ratio rather than an absolute number) you would expect the balance to remain the same. Not to say that the car's handling would stay the same overall, just the balance.

 

[rk]

No, not by adding the same absolute number (say, 5kg) to each end, because 5 kg represents a differing proportion of the base spring rate for each end.

However, if you're adding, say, 5% (as a ratio rather than an absolute number) you would expect the balance to remain the same. Not to say that the car's handling would stay the same overall, just the balance.

Interseting point you mention there, Duke. I have been noticing that while dialing in the springs, a one click increase at the rear does increase my noticeable oversteer, while a one click decrease in the front does not produce a similar change, it is usually more effective to raise the rear 2 clicks and the front only one if I want a reduction in front spring rate as relates to the rear. So, the explanation is, my one click reduction is a different proportion of the overall front spring tension than my one click increase is a proportion of the overall rear spring tension.

 

[Duke]

Correct! Some cars have relatively equal spring rates from front to rear; but most are fairly different and some are quite substantially different.

 

[sukerkin]

Maturin ... never mind ... I have a headache right now and am likely to say things I'll regret. Suffice it to say that you asked me a question, I answered it in good faith and if all I get is back then I shan't bother again.

EDIT: Some painkillers later I'm feeling more human and reasonable once more. If you didn't mean anything personally snide by your post then I apologise for snapping. Normally I have more tolerance than that ... honest .

 

[Natural Newbie]

Wait, there is yet hope, and no offense DrBiggly, thanks for your excellent comparitive analysis- do I HAVE to doubt you to see your racecar, btw? This is an important consideration when comparing data or measuring systems. All values must be of the same unit measurement to derive any useful meaning from comparing data. It is concievable that real world tuners can use thier hard learned numbers for ride height and spring rates, two very important factor in suspension dynamics. But is anyone outside of the Polyphony crowd able to define a shock compression value of 5? And is that 5 half of 10 or, like on the Richter scale, could it be half of 6? And are these values absolute- 1 has a specific number in any application, on any car, or are they relative- 1 is the lowest of 10 values you could use specific to this particular application (car). Then there are the sway bars; a value of 3 would be, um 3 inches? Perhaps 3 mm? Or it is measured in strength, so 3 would be 3 times stronger than 1...or maybe it is 3 arm wrestles stronger than 1...3 horsepower?
You can, of course, see how these "nuances" might affect MrBigglys game WRX. For every unnasigned value he must take his real world number and convert it into every possible unit of measurement and try each one and each combination of "re"assigned numbers while he is at it. In other words, if a number applies to a torque value, he must convert it to lbs/inch, lbs/ft, newtons, joules/kg, etc. Until he has done this he can learn nothing aside from the fact that the programmers use a different (and perhaps alien) measuring scale.
Personally, I prefer the empircal school of tuning, real world theory is an good basis to understand what the programmers were trying to accomplish, but there is no way they could have factored every variable into their equations. In the final distillation, when you use real world values, you are comparing mathematics to mechanics and you mustn't get lost in translation.

I read all 12 pages and I think that sums it up best.

Also since we dont have tire pressures and temperatues, we have no idea how good (or bad ) the tire model is. Individual tire pressures and tire temperatures (inner, middle, outer) would help us set up the cars since we don't know what units (or even the ratio's/relative'ness) of all the adjustments. As aarque said, just by testing and making small adjustments is going to get you the farthest.



It would probably be best to make another thread. But since we already have some good minds watching this, I'm going to throw this into the equation.

(make note I have all driving aids turned off at all times, and I am referring to a FR car, with a LSD)

You can't do a donut (tight radius, or even pivoting about one of the front wheels), or drift style figure 8 in GT4 as you could in RL. The car just pushes (understeers) with both rear tires spinning. As if the front tires are almost completely unloaded. (seems the physics engine thinks the acceleration is so great, transferring almost all the weight to the back wheels)

Now once you built up some speed (30mph ish...) the car will finally spin around. (seems the physics engine thinks that the acceleration is less, transferffing weight back to the front wheels, allowing the car to rotate and spin)

In GT3 you could could do donuts and drift style figure 8s, just as you can in real life.

And what's with not being able to lift a tire during corning. Makes me want to smash the GT4 cd with my Nascar Racing 3 CD. Someone call me an idiot, or reply to my findings, or discuss. Whichever.


EDIT: Bored at work. Freshening up on some physics. Found this article on the net and it's worth a read. http://www.smithees-racetech.com.au/theory/wttrans.html

 

[Bad760]

I just took my newly won TVR Speed12 to the skid pan the other night and I also found that doing a donut was impossible.

Came to a dead stop, full right lock punch the gas and instead of flicking round wildly I just smoked both rear tyres round slowly in about a 6-7m radius like it was a single spinner.

Something strange is definitely happening here

 

[Natural Newbie]

I have been doing some reasearch. With the dual shock 2 controller, the computer helps you (in regards to not letting you go full lock-to-lock). I have a dual shock 2

Can anyone try donuts with one of the fancy shmansy wheels (from what I've read, when using them the computer does't help you with your turning).

 

[Dodge_Barger]

You can't do a donut (tight radius, or even pivoting about one of the front wheels), or drift style figure 8 in GT4 as you could in RL. The car just pushes (understeers) with both rear tires spinning. As if the front tires are almost completely unloaded. (seems the physics engine thinks the acceleration is so great, transferring almost all the weight to the back wheels)

Hello, I am new to this forum but I had to join you all because this thread was so interesting. Spent an extra couple of hours at work ust to read it last night (imagine that).

I had been struggling to set up cars on GT4 and had been looking round the net for guides. I read Greyout's and Mspec's explanations on how things worked in real life and they made complete sense to me. A big thank you to you guys for that. They helped me understand what I had not quite sussed for years.

After reading this thread I was like wtf, no wonder I can't seem to set anything up. Anyways I did some experimenting myself last night when I should have gone to sleep.

I was experimenting with a speed 6 (with no aids) and came to the same conclusion that stiffer suspension = more grip (especially where weight was beeing transfered from the back to the front of the car during lift off). Initially I thought hang on that aint right! However, I remeber reading in M-Spec's guide that more load on the tyres icreased grip to a certain point until the tyres gave up. I also remember reading in Greyout's and Mspec's guide that stiffer suspension increased loading to that wheel. Therefore is it no so that as long as the tyres do not become over loaded then we will gain increased grip from stiffer suspension and vice versa and this effect is increased where weight transition is involved? Maybe the tyres are not reaching overload?

I have also noticed that I can get cars with less rubber on the back wheels (older cars generally) to handle more how I like. It seems I can transfer weight to the back wheels under power and seemingly overload them to oversteer (in a progressive manner). However, when using cars with lots of rubber on the back such as the speed 6 this technique seems to increase grip at the rear and give me lots of push understeer (which I can't abide). I therefore am unable to overload the tyres at any point and would therfore be unable to do dougnuts

Anyways for me the notes written by Greyout and Mspec still kind of fit with what I am experiencing but Is it possible that when we say that hard suspension equals less grip we are assuming the tyres will get overloaded?

 

[sukerkin]

Welcome to Natural Newbie and Dodge Barger. I'm glad that you've found this thread enlightening and that you're thinking about how things actually work (which makes you stand apart form the "Gimme settings for my 1000HP Skyline" crowd).

I see that NN has found the Smithees site - a most excellent place for quite succinct explainations of suspension and driving physics and behaviours. There are a large number of places where you can learn these things but Smithees have the knack of keeping it simple so you don't have to dig through a trough of equations to come up with something you can use.

The good news is that, in the main, if you knew how to tune in GT3 then you still can in GT4. There are a few wrinkles that are apparent more to some than others (such as the "Spring Rate Changes Act In Reverse" school of thought) but Real World techniques seem to work well enough. Something to bear in mind tho' is that the changes in tyre grip level do appear to have a more marked influence in GT4 than previously. Increasing the softness of tyre compound in GT3 was a matter of degree. Switching from Sports to Racing is a change in kind - this is something M-Spec was trying to get across earlier in the thread I think i.e. that percieved car behaviour changes quite radically when you switch tyre 'group'.

Nice insight into grip behaviour by the way Bad760. As you say, that's not quite right !

Anyhow, as ever, got to get on with work. Hope to hear more from the new 'minds' soon.

 

[rk]

Something to bear in mind tho' is that the changes in tyre grip level do appear to have a more marked influence in GT4 than previously. Increasing the softness of tyre compound in GT3 was a matter of degree. Switching from Sports to Racing is a change in kind - this is something M-Spec was trying to get across earlier in the thread I think i.e. that percieved car behaviour changes quite radically when you switch tyre 'group'.

Tire compounds are not linear in their grip or wear, and the differences are significant, even within the same group. Not only do harder tires appear to slip more throughout their wear cycle, than their softer siblings; a car tuned on super soft tires will have different oversteer/understeer characteristics when fitted with a harder compound. I am assuming Polyphony kept it simple by affecting only one suspension characteristic- making it necessary to adjust only one setting when switching compounds, but until I discover that relationship (it seems logical to assume the programmers "functionalized" many of the things they considered too trivial to digitally map, like the difference in grip of mediums to softs on any given car besides the original "test/map" car(s)); It is more efficient for me to do a third lap to qualify on warm hard tires than drive soft tires on a chassis tuned for hards. Also tires can't be just superficially layered or staggered like was possible before. If you tune your Viper for racing mediums then slap some racing hards on the rear, thinking that you will suffer through the greasiness to get longer useable life, you are in for a surprise because the greasiness does not go away, ever, from blue to orange...it might however, be a really good way for those drifters to get their doughnuts.

 

[sukerkin]

Nice elaboration Aarque 👍.

I'm heartened that such a number are making intelligent inputs in the area of tuning at present. It used to seem something of a 'mission' to bring 'real world' into the virtual arena. Now I'm just one small voice amongst many - excellent.

 

[Dodge_Barger]

Thanks for the welcome Superkin! Nice to find other people that want to understand how to setup cars and make sure that games physics match reality as close as possible.

In my last post I was trying to explain why I thought it might be possible that the the harder = more grip scenario might in reality be a possibility in the real world and that PD may have not got this aspect wrong.

Greyout and Mspec gave this as an example as to why a harder setup at the rear of the car should improve grip at the front.


F1. 900 500 F2. 850 650
R1. 900 500 R2. 1000 400

Example 2 shows what happens to tyre loads going round a right hand bend where we have a harder rear suspension set up as opposed to example 1 which shows equal spring rates front and rear. Because there is a more equal spread of load on the front tyres in example 2 it is was argued that grip is increased at the front of the car and reduced at the back (which makes sense). However, this assumes that tyres grip is increased in a linear relationship to load. Mspec stated: "because a modern performance tire will produce more grip as you increase the amount of weight you put on it" So if in the above examples the tyres used are designed to perform optimally at a load of 1000 could it be possible that we have most grip at the rear in example 2 because the rear end of the car is being supported by one tyre that is working optimally rather then 2 working at less than optimum? Also the above examples do not seem to add front and rear weight shift into the equation. Most understeer and oversteer I encounter happens when I am off or on the power. Anything untoward happening mid corner feels to me to be a lot to do with which direction that heavy lump of iron wants to go due to inertia (and I know that is likely to affect tyre loads as well).

It seems to me that tyres can be underloaded and produce less grip or overloaded and produce less grip. I think so far I can almost feel both situations in the game. To my way of thinking (which granted is quite likely to be wrong) I can't help thinking that the "Maturin" effect is down to under loaded rear tyres during front to rear weight transitions and vice versa.

 

[Natural Newbie]

Thanks for the welcome!

That does sound correct. And from experience it is true. Obviously I've never put SUPER SUPER soft springs on the back of my race car ('85 RX-7, race in the SCCA) and see what happens (because that would be a pricey experiment, one for the springs, and two me being in the barrier or upside down in the grass). But it makes sence.

Along with a few others, I have tried that on my R/C car. (I race them competatively, so not to sound like a prick, but I know what I'm doing). And when I say (under slight power coming out of the corner), that is steady enough where my damping (bounce and rebound) wont have a noticeable affect on handing, but the spring rate's will.

It would be neurtral handling (under slight power coming out of the corner), with the correct setup. (which happened to have slightly stiffer front springs, as opposed to the example above with slightly stiffer rear springs)

A little less spring tension in the rear had it push a tad (under slight power coming out of the corner).

A little more spring tension in the rear and it the rear would start to come out a little (under slight power coming out of the corner).

Super soft springs in the rear, made it seem like the rear tires weren't even there (under slight power coming out of the corner).

Super hard spring in the rear, made the rear end squirly but controllable(under slight power coming out of the corner).

Now I bet people are getting the stiffer in the rear is more grip in the rear with racing tires. Try it with N2 or N3 tires and I bet the car will be tail happy. Also as said before, since the spring rate has no units, we don't know if the range is 0-1000 kg/mm or 300-900 kg/mm, or if it's relative to the car's mass (or make/model and available springs), or relative to the current damping, or relative to the ride height. Soo many unknowns.

 

[Maturin]

Now I bet people are getting the stiffer in the rear is more grip in the rear with racing tires. Try it with N2 or N3 tires and I bet the car will be tail happy.

I've noticed this concerning the N2's while on Nurburgring. I now run essentially nothing but hotlaps on the Ring, with N2s, in order to "rank" completely stock cars. The shocks, particularly, work this way. The springs still seem a bit backwards, imo.

 

[Maturin]

Maturin ... never mind ... I have a headache right now and am likely to say things I'll regret. Suffice it to say that you asked me a question, I answered it in good faith and if all I get is back then I shan't bother again.

EDIT: Some painkillers later I'm feeling more human and reasonable once more. If you didn't mean anything personally snide by your post then I apologise for snapping. Normally I have more tolerance than that ... honest .

I'm just frustrated with the tuning on some cars. And the inconsistency in the cars ("this one is tunable, this other one requires a PhD in weight transfer") drive me nuts.

 

[rk]

Thanks for the welcome!

That does sound correct. And from experience it is true. Obviously I've never put SUPER SUPER soft springs on the back of my race car ('85 RX-7, race in the SCCA) and see what happens (because that would be a pricey experiment, one for the springs, and two me being in the barrier or upside down in the grass). But it makes sence.

Along with a few others, I have tried that on my R/C car. (I race them competatively, so not to sound like a prick, but I know what I'm doing). And when I say (under slight power coming out of the corner), that is steady enough where my damping (bounce and rebound) wont have a noticeable affect on handing, but the spring rate's will.

It would be neurtral handling (under slight power coming out of the corner), with the correct setup. (which happened to have slightly stiffer front springs, as opposed to the example above with slightly stiffer rear springs)

A little less spring tension in the rear had it push a tad (under slight power coming out of the corner).

A little more spring tension in the rear and it the rear would start to come out a little (under slight power coming out of the corner).

Super soft springs in the rear, made it seem like the rear tires weren't even there (under slight power coming out of the corner).

Super hard spring in the rear, made the rear end squirly but controllable(under slight power coming out of the corner).

I am sorry to sound pedantic, but when you say "a little more tension" are you ratcheting in pre-load, or are you actually swapping out springs. pre-load mainly affects ride height or more accurately, which part of the suspension travel is devoted to initial bound, the remainder going to initial rebound. "A little more tension" should actually be a slightly stiffer spring to accutateiy reflect the action on the tuning screen, correct?

 

[Natural Newbie]

I am sorry to sound pedantic, but when you say "a little more tension" are you ratcheting in pre-load, or are you actually swapping out springs. pre-load mainly affects ride height or more accurately, which part of the suspension travel is devoted to initial bound, the remainder going to initial rebound. "A little more tension" should actually be a slightly stiffer spring to accutateiy reflect the action on the tuning screen, correct?

Sorry should have clarified. Preload is stayed the same, as well as ride height. The only adjustment I made were swapping rear springs, so it is a different spring rate. (I have over 60 different pairs of springs, ya, I know it's probably overkill).

 

[sukerkin]

Good posts from DB and NN there (sorry for the abbrevs {} chaps but I have no time today ... then I just took the time to explain so I could've typed your names in full ... .

I particularly agree that you can get both understeer and oversteer from tyre loading - I too have seen that, depending on how I handle a car into and through a corner, I can generate both effects practically at will and with reasonable variations in the spring rates seeming to make a big difference sometimes and none at all (or reversed effects) at others ... .

Nice to get some 'real world', '3D', 'hands-on' annecdotes too. As an engineer, I find it's always good to get some tactile evidence to reassure you that the mathematics actually are working .

I'm currently slogging away on Golding my licences so spanner time is limited. Nonetheless, I shall hopefully have some things to contribute (apart from "Good Point" and "I agree" ) next week.

 

[Greyout]

Greyout and Mspec gave this as an example as to why a harder setup at the rear of the car should improve grip at the front.


F1. 900 500 F2. 850 650
R1. 900 500 R2. 1000 400

Example 2 shows what happens to tyre loads going round a right hand bend where we have a harder rear suspension set up as opposed to example 1 which shows equal spring rates front and rear. Because there is a more equal spread of load on the front tyres in example 2 it is was argued that grip is increased at the front of the car and reduced at the back (which makes sense). However, this assumes that tyres grip is increased in a linear relationship to load. Mspec stated: "because a modern performance tire will produce more grip as you increase the amount of weight you put on it".

grip is continually increased as downforce increases, just not at the same rate. Its not really a case of traction increasing to a point - anything other then a perfect balance is less then optimal. Look at the following graph. Input the numbers you listed above and you will see why. The grip units are made up, but that doesn't really matter, you can input whatever value you want.

the blue line is the theoretical 1:1 increase of friction as weight increases, which is not atainable. The red line is the actual graph of available grip vs. downforce on tire.

the green lines on top of eachother show an example where there is no weight transfer (car is driving straight). The car has 11 "units" of traction available.

the purple lines show a turn in which 200 lbs is shifted from one side to the other ( not really that signifcant...). The dark purple line is one tire, the light purple line is the other. The combined traction available is 10.6 "units", or about 4% less total grip.

These numbers are purely pulled out of thin air, but their relationship is accurate. It shows how the more weight you transfer, the less total grip you have.

This is true no matter how much weight is transfered - even 5 lbs shifted is less grip (albeit, much less then 1% loss).

 

[Greyout]

And I must say it is really hard to stay interested in GT4 now... with such an inconsistant array of setting adjustments, its just not fun, and DEFINATELY not an imersive sim.

 

[Dodge_Barger]

Thanks for the explanation and the graph greyout!

It was just an idea which I suspected wasn't actually reality because I don't have enough experience of race car setup etc. What I thought was a possiblity would mean on your graph that the red max grip line would be a lot steeper rising to a peak and then drop off sharply when the tyre was overloaded. You are assuming that grip per unit of load tails off and is slightly less than a 1:1 relationship. I wondered if it was possible that this relationship differed from this. I understand that it probably doesn't unfortunately and that I am clutching at straws in the hope GT4 has an acurate physics engine.

Natural Newbies RC experience also sounded interesting where the supersoft springs seemed to give next to no traction.

I share your disapointment greyout if as we suspect they have got it completely wrong

Papy's GPL/Nascar2003/4 was generally regarded as having an excellent physics engine. Did that follow the lines of the harder = less grip angle?

If we could understand how PD had interpreted reality it would be half as painful!

 

[Dodge_Barger]

currently slogging away on Golding my licences so spanner time is limited. Nonetheless, I shall hopefully have some things to contribute (apart from "Good Point" and "I agree" ) next week.

That might take a while! I was tempted as I like to get the tedious stuff out the way first. You going to gold the special too?