New version of DG patch is installed on the server

[André Jahren]

Hi,

Olaf as made a new version of the DG patch( DG 85) that should be more down to tire wear then of the track related.

Please test and report back what you think. I loved it!

Br
André

[snafu]

I ran a full length simulation at Dijon as I already had data available.

I have to say I like it a lot. I ran off track a few times towards the end and while tyre wear and reduced grip was still evident the additional wear was much less, the reduced grip (For about a lap) seemed to me more manageable.

The biggest thing I noticed was the car remained more "Balanced" as the tyre wear increased, a lot more sliding towards the end but not "tail happy" like before. The increased tyre wear on the fronts is presumably responsible for this.

So, initial tests for me are excellent. I really like this new version so far.

TTFN
John.

[Olaf Lehmann]

Hi John,

glad to hear your initial conclusion sounds good.
It's very time-consuming to test, as every driver drives differently (I seem to have the most wear of all) and every car is different...
So my question, John: Did you also drive with v813 at Dijon?
If so, how did the values compared with v85? Especially at the rear.

BR Olaf

[snafu]

I was using the previous version of the patch for the Dijon race. (813 - Dated 14/01/2025).

My overall tyre wear over race distance felt slightly lower, although a few off track excursions late in the session pushed it up a bit. One thing I did notice was wear off the start seemed a lot less, so wheel spin on cold tyres didn't seem to cause as much concern for me as it did with previous versions. This gave me a longer period of near optimal grip before I noticed the grip was reducing.

Apart from the increased wear on the fronts which definitely helped with car balance later in the race I didn't notice much difference in the wear rate of the rears between 813 & 85 once the tyres had warmed up although the rate of wear seemed to slow down towards the end of the session. (This may have been because I wasn't pushing so hard).

I didn't take a note of the actual wear figures. I'll try to find time to run a back to back test of both versions in the coming days.

TTFN
John.

[Olaf Lehmann]

Perhaps the background to the wear calculations:

In version 81. and earlier versions (we raced the first two races 2025 and 2018 to 2023 in HIES and also earlier in EOLC) wear is determined exclusively by wheelspin - more precisely wheelspin² (if you generate twice as much wheelspin, you generate four times as much wear).

In version 84 (which we rode last year), the calculation is more complex. Essentially, the formula is wheelspin³ * contact pressure * average tyre temperatures. Because of the tyre temperatures, wear is minimal at the start with cold tyres. Later in race the wear on the outer front wheel increases because it usually gets hotter than the others (the aim was to put more load on the front tyres).

In version 85 the tyre temperatures are no longer used. Therefore, the start has a stronger effect than in v84.
The rest of the formula is the same as in v84, i.e. wheelspin³ * contact pressure, but wear effect for the front tyres is increased and there is a maximum limit. The very extreme effects that sometimes occurred beyond the tarmac can therefore no longer take place.

I'm looking forward to your tests, John.

BR Olaf

[Seb Gore]

Hi Guys,

I'm using the normal link at the top of Olaf's Dirtgear News, but I keep getting the old 42 and 813 versions. Please can someone tell me where to find the correct link?

Sorry, 'Keyboard to chair interface' problem.......

Thanks,
Seb.

[snafu]

Sorry, 'Keyboard to chair interface' problem.......

Alternatively known as PICNIC (Problem In Chair Not In Computer). (Been there so many times)......

Ok, Decided to start testing at Imola as I need the practice. Contrary to what I felt I was seeing when testing at Dijon making actual notes at Imola so far I am seeing the following.

Cold start, flooring the throttle off the line.
85
0 0 F
9 10 R

813
0 0 F
6 5 R

After 10 laps (Ignoring lap 1, times between 1:34.8 1:33.7 - Both DG versions)
85
3 2 F
35 23 R

813
1 0 F
33 24 R

So, not what I thought was happening. Balance still though feels better with 85 compared with 813 once tyre wear kicks in.

Off Track testing.
Slow out lap, (Tyre wear both versions)
0 0 F
1 1 R

Run onto Grass roll to a stop (No brakes or throttle)
Accelerate on Grass - 2 seconds.
85
0 0 F
13 13 R

813
0 0 F
12 13 R

So again, not what I thought I was feeling in the initial tests at Dijon.

There appears to be no appreciable difference in tyre wear between the versions when you run off track.

Are these the type of figures you would expect?

TTFN
John.

[Olaf Lehmann]

Thank you for your values.
You have very low values at the front. However, as they are even lower in v813 and the ballance back/rear differs greatly for different routes, the ballance should be OK. Perhaps you could drive on a track with hard braking zones and see if the difference is less there.

Now to your concerns off the track:
I would like extremely spinning tyres to produce a clearly noticeable amount of wear. The driving style should have a significant effect on tyre wear.
It is practically impossible to allow more wear on the tarmac than off the track. The patch simply cannot differentiate between the two.
However, sometimes in unusual situations (which usually take place off the track) an incredibly high level of wear occurs, which virtually destroys the tyres. (Values from 0 to 200 and more). These extreme cases should no longer occur in v85.
I made three short movies with Fraps. WITH v85, v842 and v813.
There you can see how values go extremely high in v842 (last year's version), but moderate in the other versions.

http://race.eolc.de/Olaf_Lehmann/dg.mp4

All in all, I think two seconds of strong throttle with spinning tyres can generate values of 13.

BR Olaf

[snafu]

Regarding the lack of expected tyre wear on the fronts. I think we can probably put that down to my driving style. I tend to favor quite close ratios for the 3rd, 4th & 5th. So I brake a lot earlier than most people but use the engine to slow down, finally using the brakes for the final phase into a corner. So I put very little load on the fronts until I've slowed the car down quite a lot. Even at tracks where hard braking would be expected I tend to "Ride" the gear changes to get the car into a window where I feel happy to brake harder. For me it works well with the DG patches.

TTFN
John.