Where does all the rear weight come from? - Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community

ahausheer · 09-20-2012, 04:09 PM

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?

Carban · 09-20-2012, 04:52 PM

well, first of all, the engine and tranny sit VERY low and VERY far back. Then u have the big driveshaft coming from the tranny to ur LSD diff, rear axles, then finally gas tank, spare tire (and tools), rear seats, muffler, etc.
The center of gravity on this car is a few inches behind the shift knob.

Laika · 09-20-2012, 04:57 PM

Quote:

Originally Posted by Carban

The center of gravity on this car is a few inches behind the shift knob.

I guess this could be calculated pretty easily but do you have a source for this? Not doubting it, just curious.

Also, the fuel tank might not be that heavy but I believe the weight distribution is listed as being a wet weight (with fluids). 13 gallons of gas at 6 pounds/gallon = 88 pounds or about 7% of the rear weight.

SkAsphalt · 09-20-2012, 05:06 PM

There is a lot more "body" and "structure" to the rear I would argue. cabin, trunk, crash protection for the passengers, etc

Carban · 09-20-2012, 05:13 PM

@Laika, saw a diagram on some website. been searching for it but cant find it anywhere. it was legit. ill keep searching for it and post up when i find

SUB-FT86 · 09-20-2012, 05:16 PM

Its not nowhere near 50/50. It is 55/45 with nobody in the car.

ML · 09-20-2012, 05:21 PM

Quote:

Originally Posted by SUB-FT86

Its not nowhere near 50/50. It is 55/45 with nobody in the car.

I heard from multiple sources that it was 53/47

Shagaliscious · 09-20-2012, 06:17 PM

Quote:

Originally Posted by SUB-FT86

Its not nowhere near 50/50. It is 55/45 with nobody in the car.

BRZ is 55/45. FR-S is 53/47.

ahausheer · 09-20-2012, 06:34 PM

It just seems that the motor and tranny are the vast majority of the weight. From a mass perspective there just seems to be a lot less stuff in the rear. How much does a drive shaft and diff weigh compared to an engine block and tranny? The weight distribution is just hard for me to visualize.

russv · 09-20-2012, 06:56 PM

Quote:

Originally Posted by Shagaliscious

BRZ is 55/45. FR-S is 53/47.

Why the difference between the 2 cars?

fatoni · 09-20-2012, 07:15 PM

Quote:

Originally Posted by Shagaliscious

BRZ is 55/45. FR-S is 53/47.

that strikes me as odd since the brz should have more amenities in the cabin. ive heard that the cars were 53/47 with people in the car and 55/45 without. was that what you were thinking of? otherwise, youre talking about a 50 lb shift in nearly identical cars

CBR600RR · 09-20-2012, 07:37 PM

50L of fuel is in the back too. That's over 100 pounds.

ahausheer · 09-20-2012, 07:49 PM

Thats BS, few will have people in the back, a spare tire, and a full tank of fuel when things get twisty. Ill bet these cars are more like 60/40 real world.

roddy · 09-20-2012, 07:56 PM

Quote:

Originally Posted by russv

Why the difference between the 2 cars?

Big 'ol nasty mustache...

09-20-2012, 04:09 PM	#1
ahausheer Re-member Join Date: Nov 2011 Drives: Toyota camry Location: S. Cali Posts: 1,001 Thanks: 98 Thanked 292 Times in 152 Posts Mentioned: 2 Post(s) Tagged: 0 Thread(s)	Where does all the rear weight come from? 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? __________________ Nothing decays like progress, and nothing preserves like neglect.

09-20-2012, 04:52 PM	#2
Carban Grease Monkey Join Date: Apr 2011 Drives: Whiteout FR-S Location: OC, CA Posts: 114 Thanks: 63 Thanked 52 Times in 24 Posts Mentioned: 1 Post(s) Tagged: 0 Thread(s)	well, first of all, the engine and tranny sit VERY low and VERY far back. Then u have the big driveshaft coming from the tranny to ur LSD diff, rear axles, then finally gas tank, spare tire (and tools), rear seats, muffler, etc. The center of gravity on this car is a few inches behind the shift knob. __________________ R.I.P. '92 Honda Prelude you will be missed

09-20-2012, 05:13 PM	#5
Carban Grease Monkey Join Date: Apr 2011 Drives: Whiteout FR-S Location: OC, CA Posts: 114 Thanks: 63 Thanked 52 Times in 24 Posts Mentioned: 1 Post(s) Tagged: 0 Thread(s)	@Laika, saw a diagram on some website. been searching for it but cant find it anywhere. it was legit. ill keep searching for it and post up when i find __________________ R.I.P. '92 Honda Prelude you will be missed

09-20-2012, 06:34 PM	#9
ahausheer Re-member Join Date: Nov 2011 Drives: Toyota camry Location: S. Cali Posts: 1,001 Thanks: 98 Thanked 292 Times in 152 Posts Mentioned: 2 Post(s) Tagged: 0 Thread(s)	It just seems that the motor and tranny are the vast majority of the weight. From a mass perspective there just seems to be a lot less stuff in the rear. How much does a drive shaft and diff weigh compared to an engine block and tranny? The weight distribution is just hard for me to visualize. __________________ Nothing decays like progress, and nothing preserves like neglect.

09-20-2012, 07:49 PM	#13
ahausheer Re-member Join Date: Nov 2011 Drives: Toyota camry Location: S. Cali Posts: 1,001 Thanks: 98 Thanked 292 Times in 152 Posts Mentioned: 2 Post(s) Tagged: 0 Thread(s)	Thats BS, few will have people in the back, a spare tire, and a full tank of fuel when things get twisty. Ill bet these cars are more like 60/40 real world. __________________ Nothing decays like progress, and nothing preserves like neglect.

09-20-2012, 05:16 PM	#6
SUB-FT86 86 Member Join Date: Dec 2010 Drives: 2013 Toyota 86 2.0T (Asphalt) Location: Atlanta, Ga Posts: 3,129 Thanks: 126 Thanked 527 Times in 296 Posts Mentioned: 2 Post(s) Tagged: 2 Thread(s)	Its not nowhere near 50/50. It is 55/45 with nobody in the car.

09-20-2012, 07:37 PM	#12
CBR600RR Senior Member Join Date: Jul 2012 Drives: Raven Black Location: Ottawa, Canada Posts: 1,343 Thanks: 451 Thanked 563 Times in 276 Posts Mentioned: 5 Post(s) Tagged: 0 Thread(s)	50L of fuel is in the back too. That's over 100 pounds.

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