Where does all the rear weight come from?

[Shagaliscious]

Originally Posted by fistpoint

Really? If true, that explains why I keep seeing both set of numbers mentioned.

Then I read this reply:



So who is right or are we still in the assumption phase?

I am pretty sure fatoni is correct in saying the #'s are with & without people.

I was the one assuming, that just because I read 55/45 on the Subaru site, that's what the BRZ was.

[SpeedR]

50/50 split is not that big a deal by its self.

[denverizzles]

Can you really tell the difference between a 53/47 and a 50/50 split? i dont think unless you're doing some hard core tracking that you'll notice the difference.

[ML]

Do you think it would be worth relocating the battery to the trunk?

[ashtray]

Pop the hood. Look at where the front suspension points are, now notice the engine sits BEHIND that point. That means some of that engine weight is supported by the rear wheels. Now look where the transmission is - closer to the center of the car, so a bunch of its weight is carried by the rear as well.

It's percentages, not all or nothing. You don't split the car in half and say anything in the front half is supported by the front tires and vice versa.

[Nevermore]

The real question here is, with this nearly even weight, will it need weight in the trunk in the winter?

[Bristecom]

Originally Posted by Nevermore

The real question here is, with this nearly even weight, will it need weight in the trunk in the winter?

I'd just give it a full tank of gas and maybe put a sandbag on the rear seats or right behind the front seats for more rear traction without upsetting the balance.

[Miniata]

Originally Posted by ML

Do you think it would be worth relocating the battery to the trunk?

No. Moving the stock battery to the trunk means adding even more weight with cables and a box. A better solution (unless running a big stereo) is putting a small lightweight battery in the stock location. Save 20+ lbs over the front end with few downsides. I have a 2 lb lithium battery for my Miata for autocrossing, and my normal street battery for the Miata is a 7 lb AGM battery.

[ML]

Originally Posted by Bristecom

I'd just give it a full tank of gas and maybe put a sandbag on the rear seats or right behind the front seats for more rear traction without upsetting the balance.

This would be negligible compared to winter tires(or chains!), and under inflation.

[Bristecom]

Originally Posted by ML

This would be negligible compared to winter tires(or chains!), and under inflation.

Well yeah, I was assuming he already knew to get winter tires. But I question underinflation... I think it's only good for getting out of deep snow. But for grip and traction on hardpack snow and ice, you want normal inflation so that there is more pressure pushing into the ground. But the pressures are already pretty high on these cars so maybe dropping a psi or two for a little extra sidewall flex would be OK.

Now underinflating the stock or summer tires is a good idea so that they can try to build some heat into them. But obviously that's only if it's just cold tarmac and there is no snow. Tires are not going to warm up on snow and if anything, they'll just get a bit colder. But they'll probably get underinflated by the cold anyway. You lose about 1 psi per every 10 degrees F. If you want an accurate reading though, check your pressures after the car sits out in the cold.

[DaJo]

Lol... Snow tires aren't warmer... Snow tires are built super soft, so in cold freezing weather it takes more to harden the tire.

We all should know... Hard tires means hard rubber = no sticky on the road.
Also, deflating the tires help expands its surface area... for better grip.

Adding the two together; they work VERY well on snow... You'd be surprised how much of a difference just the tires can make alone.

[Bristecom]

Originally Posted by DaJoian

Lol... Snow tires aren't warmer... Snow tires are built super soft, so in cold freezing weather it takes more to harden the tire.

We all should know... Hard tires means hard rubber = no sticky on the road.
Also, deflating the tires help expands its surface area... for better grip.

Adding the two together; they work VERY well on snow... You'd be surprised how much of a difference just the tires can make alone.

But it's all about how much pressure is on the contact patch per square inch. More pressure means the tire can bite into the snow and ice harder. Why do you think rally cars run narrow, knobby tires with high pressures on snow? It's because less contact patch means that more weight and pressure is put on the tread. But if you wanna try telling the rally drivers that they need wider tires with lower pressures for their snow rallies, good luck. My advice is to experiment with this first hand. I'm sure you will find that higher pressures give more grip and control on hardpack snow vs lower pressures which can cause it to glide across the surface more easily.

This reminds me of that episode of Top Gear where Richard Hammond goes to the salt flats in Utah and tries to meet a target speed and some guy who had been going there for many years told him he needed the lowest possible pressures for his tires. Well it turned out that was the reason he was so slow and when he tried the opposite and increased his tire pressures, he met his target speed. But you must admit, tires are a difficult beast to understand.

[carbonBLUE]

Originally Posted by ahausheer

This car has a pretty good weight distribution, as we all know. But when I picture things in my head I see an engine and a transmission with their weight almost completely supported by the front suspension. In the back is the diff and fuel tank (not so heavy). How does this car achieve a near 50 50 weight distribution with almost all of the heavy stuff at or in front of the front wheels? Where does the weight supported by the rear suspension come from?

most of the weight is structural in the rear
even though the engine and transmission are mounted up front
the engine and transmission is mostly alloy, other than the gears/clutch and a few other mis things, here's the corner weight of the frs/brz/gt86

Originally Posted by jdrxb9

Saw this on the scca forums - original thread with pics is at sub---brzf----

LF 746 RF 765
LR 621 RR 591

Total 2723

Limited
Preproduction
No driver
"Tank was prob' about half full given where the car came from."

with that being said 1511lbs in the front 1212 lbs in the rear
55.49% front and 44.51% rear

rounded to the closest % its 55% and 45%

[regal]

The weight split discussion has to include wheel base. Ever been on a teeter-totter when you were a kid? Same physics.