WHAT DID YOU DO TO YOUR FRS TODAY?

[guybo]

I put it in the back. Even without a jack, I'll keep the spare so that I won't need a tow should I get a blow out.

One thing that confuses me though.... people in this thread are saying to take out the spare that may come in really handy... but keep the rear seats that won't fit a full size adult..... OK, well, I choose to do it the other way.

As for raising the COG of the car, I think it'll even out and the COG won't move. There are several things that I deleted besides the seats and they were up near the roof and have some heft. Plus the side plastic panels. The seat back has some weight and that is fairly high as well.

I'm really tempted to delete the headliner and carpet- but then wind/rain/road noise will be bad.

[Tcoat]

Originally Posted by guybo

I put it in the back. Even without a jack, I'll keep the spare so that I won't need a tow should I get a blow out.

One thing that confuses me though.... people in this thread are saying to take out the spare that may come in really handy... but keep the rear seats that won't fit a full size adult..... OK, well, I choose to do it the other way.

As for raising the COG of the car, I think it'll even out and the COG won't move. There are several things that I deleted besides the seats and they were up near the roof and have some heft. Plus the side plastic panels. The seat back has some weight and that is fairly high as well.

I'm really tempted to delete the headliner and carpet- but then wind/rain/road noise will be bad.

http://www.ft86club.com/forums/showthread.php?t=42284

[johan]

Originally Posted by Tcoat

http://www.ft86club.com/forums/showthread.php?t=42284

[guybo]

[Tcoat]

Originally Posted by guybo

I put it in the back.

Oh crap I just realized that I "won" on the internet!

[Spuds]

Originally Posted by guybo

Weight balance in a car is about a lot more than the division of weight. the 55/45 number is easy to quote and easy to understand but it really doesn't matter for much. What's more important is HOW that weight is distributed. If there's a lot of weight far out from the longitudinal COG, the car will be slower to respond. If the weight is centered, the car will be very quick to respond. The more mass that can be moved toward the center of the car, the shorter the moment of inertia of that mass becomes and the quicker the handling of the car becomes. This is one of the big reasons that the battery in a lot of new cars is going up close to the firewall. It's a big chunk of heavy materials inside a plastic case that creates a huge moment of inertia when mounted up front of the engine bay- and that prevents the car from wanting to turn.

Grab a gallon of milk. Hold it close to your body and pivot. Hold it out at arm's length and pivot. Which way is easier to pivot?

I'm an engineer, I understand the physics. What I was trying to point out is that you are moving that cg forward (by a very small amount). When you do this, the car wants to rotate around a point further forward if it we're floating in space. Now, if you are looking to make it more tail happy, that's great. But in reality the car is rotating about a point to the left or right of it when turning. Since the front wheels travel a larger arc than the rears, you are actually increasing the moment of inertia by moving the cg forward.

This is the reason Porsche continue to contend that rear engine cars are the ideal design. Moving the cg back makes it easier to rotate the car.

[humfrz]

Originally Posted by Tcoat

Oh crap I just realized that I "won" on the internet!

Maybe he just gave up .......

(I can't see your picture .. ??)


humfrz

[humfrz]

Originally Posted by Spuds

I'm an engineer, ............

I should have known ........




humfrz

[humfrz]

Originally Posted by Teseo

3rd law of Newton?

The humfrz 1st law of backing up. Just ask @Tcoat ,which way his head wanted to go, when I backed into that pillar ......


humfrz

[Dadhawk]

Originally Posted by guybo

One thing that confuses me though.... people in this thread are saying to take out the spare that may come in really handy... but keep the rear seats that won't fit a full size adult..... OK, well, I choose to do it the other way.

I guess it depends on your goal. If the goal was to make the car lighter, then removing all of it makes sense. Your decision to keep the tire/not keep the tire is a trade-off against weight.

If my goal was weight reduction, I'd remove the tire and leave the seats, just because it looks better and accomplishes the same thing (more or less).

If your goal is to move the center of gravity forward (not sure why you would want to do that), then removing the tire and leaving the seats is the better option. The tire is further out on the arm for weight and balance, so removing that mass from the rear has more impact than removing the seats. Removing the seats and moving the tire forward probably has the same impact (again more or less) as removing the tire only letting you keep the tire.

Removing the seats has minimal impact on CG but does impact weight. Leaving the tire in has no impact on weight (obvious) but moving it or not moving it does impact CG.

So, given all that into consideration:

If my goal was to remove weight, I would remove the tire, and leave the seats. I'd rather have a clean cabin and no spare than a spare and no interior (but this is my DD, not my racecar)

If my goal was to impact CG (move it forward) I would remove the tire and leave the seats for the same reason.

If I was building a racecar, well all bets are off.

[ermax]

I'm 41 now and in all my years of driving and all my cars I have never once needed a spare. I have picked up nails plenty of times but if you pay attention to your tires you will spot the problem way before the tire comes flying apart. I carry plugs and most of the time I plug at the house. Only once did I have to install a plug in dress cloths while out to lunch. I suspect anyone driving an FRS is going to be very aware of tire pressures. Especially with TPMS. If you are the type that ignores a nail and rolls around at 10psi regularly or like to drive on corded tires then yeah.. you need the spare.

[stevesnj]

Sidewall damage would be another issue. Unless there is a a sidewall repair solution out there.

[Tcoat]

Originally Posted by ermax

I'm 41 now and in all my years of driving and all my cars I have never once needed a spare. I have picked up nails plenty of times but if you pay attention to your tires you will spot the problem way before the tire comes flying apart. I carry plugs and most of the time I plug at the house. Only once did I have to install a plug in dress cloths while out to lunch. I suspect anyone driving an FRS is going to be very aware of tire pressures. Especially with TPMS. If you are the type that ignores a nail and rolls around at 10psi regularly or like to drive on corded tires then yeah.. you need the spare.

You are lucky then. I have had several tires suddenly and catastrophically shredded, cut or torn beyond repair where a spare was the only answer. Nails are not the only hazard out there.

[Cole]

Originally Posted by ermax

I'm 41 now and in all my years of driving and all my cars I have never once needed a spare. I have picked up nails plenty of times but if you pay attention to your tires you will spot the problem way before the tire comes flying apart. I carry plugs and most of the time I plug at the house. Only once did I have to install a plug in dress cloths while out to lunch. I suspect anyone driving an FRS is going to be very aware of tire pressures. Especially with TPMS. If you are the type that ignores a nail and rolls around at 10psi regularly or like to drive on corded tires then yeah.. you need the spare.

Sounds as though you probably don't drive enough. In this year alone, I've had to get 6 or 7 patches on my tires, plus I had to replace a wheel and a tire with 3000km on it after the wheel bent, tire debeaded and I had to drive 11km to where I knew I could get cell service