Formula Student Germany 2013

[mech5496]

I agree that there is possibly too much water on the wetpad, but I am surprised that you think it is wetter that the 2011 enduro, where the track was basically a lake! (I am also surprised that Delft was allowed to run in intermediates; AFAIK once the track is declared "wet" you are forced to use your rain tires.) Nevertheless, a minor change on the watering system could be made in order to pour less water on the track...

[JulianH]

There are no "real Intermediates" in FS. You have dry or wet.
Delft choose cutted Slicks as their rain tire and therefore had to run with them in the Lake Hockenheim 2011 The Goodyear rain tires are basically also Intermediates and they are fast as hell in these conditions.

[mech5496]

My bad, I wasn't aware that you are allowed to run carved slicks in wet conditions, I thought you are only allowed to run them in "damp" track. If those were their "rain" tires, they were also using them in wetpad, and poor water evacuation might be the problem....

[Markus]

JulianH: About that 5kg deviation, the rules say that all the scrutineerings are done with dry tires. So even if you run 13" wets and 10" drys there should be no weight problems in case of rainy endurance.

[JulianH]

JulianH: About that 5kg deviation, the rules say that all the scrutineerings are done with dry tires. So even if you run 13" wets and 10" drys there should be no weight problems in case of rainy endurance.

Really?
I think to remember a Rules Clarification about one year ago and they said "the car must be within 5kg in every dynamic event, even with rain tires". The German Organisers also check the "Tennis Ball Rule" with rain tires although it says "dry tires" in the rules.

Even if the 5kg rule is not a problem. Running with 13inch Rims in Endurance on a 10inch car is probably not too much fun.

[Markus]

Well, now that you mentioned I'm not completely sure. I wouldn't be surprised if FSG did it differently to other comps, and the FSG rules state that in any dynamic event. So I guess you must be within 5kg always.

I don't see a big problem here though: 13" Goodyears are pretty light and I'm pretty confident to claim they are lighter than 10" Hoosiers (about 1kg per tire!). That's easily enough to balance the wheel weight difference.

At least Akron's 13" wheels are light enough to be within 5kg with wets, I'd estimate they're very close to same weight with them actually.

And I don't think there's a problem for these teams to run 13" wheels in the rain, the difference in dynamic radius of the tires in question is quite small (~5-7mm?) and it's probably possible to swap to wets without any setup changes. To think of it the difference in dynamic radius between 13" dry and wet Hoosiers might be bigger...

[Thrainer]

I don't know about fsg but at fsuk the scales are designed for about at least a ton (1k kg) of weight (as it is a standard truck/car weighing station). Putting a 150kg car on that thing should give a discrepancy.

In 2010 we had to weigh our car three times within the first two days of comp. Without modifications, the measured weight changed 5 kg. I am quite sure the officials know their scales.

If you weigh the cars after scrutineering, you have lots of cars in Design with no official weight, even on Friday.

I remember suggesting to use 13" GY intermediates for wetpad, it is nice to see it works.

[mech5496]

Well, wet 10" Hoosiers are 4.5kg each (dry are 4.2), Goodyears are about the same if I can recall correctly. Also Hoosiers are 500mm dia., while Goodyears are 510mm dia. As you see the differences are negligible, and you simply cannot gain 5kg from 4 wheels, if they are to similar spec with your 10's...

[Markus]

Hoosier website states 10" slicks to weigh about the same as 13" slicks, which is around 5,0-5,5kg new and 13" Goodyears are about 4,5kg new. By general rule 10" wheels weight 66% of 13" wheels if done by same team and with similar manufacturing method (unsurprisingly as this is the about difference in volume). Takes the worst cases to around ~2,5kg weight difference (heavy or ultralight wheels, both rare occasions) and a normal team running 3-piece alloy wheels to around +-0kg, so no problemo to run them.

[JulianH]

Well ok, I translated our "problem" to different teams.

When we did our calculations:
10 inch CFRP rims: 4*850g
10 inch LC0: 4*3.2kg

> 10 inch setting: 16,2kg

13 inch Alu rims: 4*2kg
13 inch Goodyear: 4*4,5kg

> 13 inch setting: 26.8kg

But that shouldn't be the issue right here. Ok, maybe it is possible to use the Goodyear in rainy conditions (sadly the Goodyear is not manufactured anymore).
Still, my issue is, that the tire alone seems to dictate the outcome of one event. That should not be the case in my opinion. But maybe I am alone here.