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Some Technical Notes: Tyres, Engines, Whatever.

Today, 02:14 PM

Hi chaps:

I'm pretty sure that almost everyone of you knows the amount of work that is required to make a good quality mod: the very existence of this platform is in itself a proof of that.
The very issue of making such mods is the amount of research one (or a team) must do in order to give the best possible quality in the final product: we all know that perfect realism is impossible - whoever says the opposite is a madman and shouldn't be trusted - but we work and toil to have at least the best apporximation that we're able to do.

So, the idea of this thread is to collect the various notes, scripts, references and such that could be useful to any future modder, in order to make the research a little bit easier. Everyone can contribute, obviously: the more the info, the better it will be.

As far as I've worked out, most of the info I got comes from Costin, Berthon, Nye, Forghieri and Benzing.



This is specifically about the size and slip angles, more than anything: as reported by https://en.wikipedia.../wiki/Tire_code in "Historical Tyre Codes" (and as confirmed by Costin's "Racing & Sports Car Chassis Design"), tyres pre-1965 were made with a fixed 90% ratio: this allowed to write them as rim diameter by widest part of the tyre, for example 7,00"x16.
From the same source, tyre pressure followed this kind of range:

- Normal: 25-30 psi
- Fast circuits: 40-45 psi
- Heavy cars (Le Mans, for example) : 60+ psi
- Raining: -10% to -15% normal pressure.

According to Berthon, Nye and Benzing (especially the latter in his "Dall'Aerodinamica alla potenza in Formula 1"), Cross-Ply tyres had from 10° to 15° of slip angle, depending on how tight was the steel frame inside the rubber.


Even in the 1960's the suspension stiffness didn't change much since the very early '30s: according to Costin, one should've always looked for 70 cycles per minute in front and 80 in the rear, but this often proved difficult to achieve because of the steel used, what was then-called EN45A: the modern equivalent is the AISI 9260. Always according to Costin and Forghieri, at the time they used to calculate the stiffness of the suspensions by using an equivalent semi-cantilever leaf spring (a leaf spring that is free to swing at just one of the edges) and usually they counted a leaf thickness of half a centimeter. This explains why the cars were often very soft when compared to modern solutions.

When designing them, the designer had to account 3.5 inches of bump and maximum 3 inches of droop.

Castor/Caster usually is between 3° to 8°.

Braking ratios should go from around (Rear:Front) 40%:60% in a front-engined car to a 45:55 on a mid-engined one.


According to Costin and Benzing, in order to have a good road-holding the car's weight distibution with no driver and all fluids (full fuel included) must aim for a 45% front and 55% rear, give or take a 5% more on the rear.


About the eternal dispute between Italian horsepower and DIN/HP horsepower: before the introduction of the Kilowatt (1978) the CUNA (Commissione tecnica UNificazione dell' Autoveicolo, http://www.cuna-tech...strastoria.html ) used a measuring system that was even more barebones than the SAE Gross: the SAE Gross method measures the car with only the stuff it requires to actually run (so no filters and such), while the CUNA system allowed the engine to be measured without almost anything deemed useless like exhaust pipes, filters, radiator fans, dynamos... this allowed for a 15% power increase than the DIN standard and a 5% increase on the SAE Gross.

  19 Views · 1 Replies ( Last reply by Iestyn16 )


Green Track In Mirrors

22 Sep 2018

I've just been driving at Kyalami with the V2 1967 Historic Mod, Carset 1. In my mirrors the track looks dark green.

I'm sure I've seen this mentioned before but can't find it now. Any ideas?


  105 Views · 3 Replies ( Last reply by tjc )


Re: Win10 And Auto-Running Of "defender"

21 Sep 2018

I've gotten annoyed at this 'defender' scan happening it seems when it wants. i thought i had it set to run in my 'off' hours....
now i wonder if has anything to do with screen freezes or disco's that occur while online racing!

The location of the Automatic Maintenance settings actually did change in Windows 10:

So this is where you have to go now to change the schedule for the Windows Defender Scheduled Scan task: Right-click on the Start button and choose Control Panel > Security and Maintenance > Maintenance > Change maintenance settings.

It’s been 3 years now, and there are still way too many people (including Microsoft documentation authors) who just can’t quite seem to get a grip on how this works. The fact that the controls for the scheduled scan went missing in the new Windows Defender user interface doesn’t mean that the feature was dropped and that you’ve been left to your own devices – it means that the scheduled scan was reengineered so that it now runs reliably without any user configuration. It’s now fully automatic just like the definition updates. So you don’t have to change any settings at all to get the scan up and running; and you certainly don’t need to add a trigger, or otherwise reconfigure the Windows Defender Scheduled Scan task. This is a system task, and you would be well advised to just leave it alone. Full Scans don’t need to be scheduled, but if that’s something that you really want to do, you can use the Create Basic Task Wizard.

  189 Views · 6 Replies ( Last reply by Michkov )


Again Problem With Fairshift

21 Sep 2018

I use Fairshift with wheel and pedals Fanatec.The problem is the clutch.The clutch,without "anable clutch" activated,work only with the first gear.I use this to start but for the other gear i can do without it.If i anable the clutch i hear the clutch that don't allow to engage the gear,the car remain always in neutral.Someone know the problem?

  189 Views · 4 Replies ( Last reply by francesco )


Gplracer 55 Fun Cup Tuesday 18.09.2018 Aintree

17 Sep 2018

Posted by paul skingley in GPL-"Hey, anyone need a racer?"
Hello RACER!

This Tuesday 18th September GPLRACER 1955 Fun Cup continues with race 8 Aintree


- 18.09.2018
- 20:30 CET
- 19.30 UK
- 24 Runden [laps] -> ca. 45 min.
- Int/long mode (free use of Shift-R without penalty)
- iGOR Chatroom: #GPLRACER

36 fps server

More info

Good Luck and Fun

  124 Views · 0 Replies

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