spare tire?
 

i want to get a donut style spare tire for my 89 supra to replace the stock heavy one. i found a tire for a 2003 and up corolla that has the 5 bolt pattern. will this work, if not, what will?

What are the dimensions and offset and what is the load limit? You'll need to make sure it'll clear both the front and rear brakes.

Unless it is a 16" rim, it will not clear the front calipers. I tried to put some donuts on a parts car for it's last trip to the salvage yard, and a 16" donut with minimual offset managed to fit. A 15" or smaller didn't clear the brake caliper. I managed to fit that one 15" on the rear, tho.

BTW, I hate those donuts. They will limit your car by speed and agility, and it flat out sucks to have to drive 50 mph on the interstate with trucks blowing by at 70. Trust me, it only happened once with me, and I'll never do it again. Every car I bought after that with a donut got a full sized spare immediately.

Sometime 16"s don't even fit (they hit the outer face of the caliper)... If possible it would be best to try to arrange a time to test fit them.

thanks i had found one but it didnt fit in the space where the previous spare had been lol

To be honest, the only reason you could have for wanting a donut spare is for weight saving right? I certainly hope you ain't going on looks! :crazy2:

Anyway, for the amount of weight you'll save over a full sized alloy wheel & the limitations (some would say danger) caused by the narrow tyre style, I'd say you'd be much better off just carrying 2 or 3 cans of tyre foam (it's called tyreweld here in the UK, think it's fix-a-flat in the US?) and/or a footpump.

At the end of the day, unless you're really unlucky you're not going to have more than say 1 or 2 flats every couple of years & most times just pumping them up will get you to a garage. It's up to you really, but I'd say either stick with a "proper" spare or if weight's that much of an issue don't have one at all.

EDIT-: if you wanted I suppose you could offset the weight of a proper spare by running only enough fuel in the tank for the journey you're doing, after all if you're concerned about a few lbs you're more likely doing short runs round a track or strip rather than the daily commute I'd guess...

Yea your right i wont sacrifice safety for only a lil bit. Ill focus on power first and weight as my second priority

i seem a carbon fiber hatch if i get that along with a CF hood wud the weight distrubition be right? Would it be too light?

The only CF hatch I've ever seen was a custom, one-off piece that a guy paid a lot for. if you've got that kind of cash then worry more about building the engine for more power and less about losing the weight. Reducing weight from the MKIII is not an easy feat. the hood and hatch weight a lot less (relatively) than you may think.... the hatch glass (which you'll still have in a CF hatch) is the heavy part of that piece and you'll loose more weight than you would from swapping the hood by simply replacing the drive shaft with a lightweight, one piece DS.... AND it's a reduction in rotating mass AND it's central. Lighter rims; again even weight reduction AND it's rotating mass.

Oh, and if your car is a targa top... trade it in for a hard top... they're lighter too. ;)

As for the spare... get a AAA membership and ditch it except for when you're going on long trips. Hell, the last time I needed to use a spare it was dry rotted to hell and had no air from lack of use. I do still carry one, but only becuase I don't have anywhere to store it outside of the car.

yes but where do i find a one piece lighter drive shaft? im proud to say that mines is a hard top,frankly, i think ill just modified whats under the hood and deal with the rotating mass as well. the car really is a true classic in Japanese muscle car history. anytime i drive theres at least 5 people tell me how they amaze to see it in original mint condition.

im planning on getting 18in rims with low profile tires...as for whats under the hood i want to rebuild and modified the 7m engine get a bigger turbo, electric fan, lighter pulleys, lighter and bigger intercooler as well as the radiator, as well as replace some the stock tubing with some aluminum ones merly for engine dress up. as for suspension i seen some tokico shocks that work nicely with TEMS and some eibach pro kit lowering springs. i will get a complete exhaust system straight pipe no cat(its illegal but i got my hook ups ;)

any recommendations?

Have one built at a GOOD drive shaft shop? Just a thought.... There are a few places that sell them online, they're also made to order as you have to measure for a precise fit.

I had these guys build me one: http://www.jawsgear.com/ It's superbly balanced!

I'm not fond of 18's on MKIIIs with lowered suspension... too rough of a ride on Colorado roads for my tastes. They do look good though.

Electric fans aren't much of an upgrade (if any). They add just as much resistance to the alternator as the stocker does to the water pump.... If you want to lighten the load get a flexible aluminum fan (and of course the proper fan clutch, a stock fan clutch would spin it so fast the new fan would explode). The flex fans flatten out the faster they spin and thus there's less resistance, that combined with the fan clutch at highway speeds you're barely using any power to keep it moving and it's really just the oncoming air that's cooling the rad.

Performance aluminum radiators aren't any lighter in the end... a lot of the time they weigh more due to the extra coolant capacity. The extra coolant capacity and additional area for heat transfer is the reason you run one, no weight. ;) An aluminum OEM replacement would be a weight reducer, but there's no other benefit.

That jawsgear website really came in handy. Much apperciated. I will definatly invest in the lighter drive shaft. As far as modifying the engine, what should i consider and of course any good websites will help.

Add a DS loop or cage or whatever you want to call it... if it grenades you don't want it hitting the ground and tossing the ass of the car 3' in the air or, worse yet, have the broken DS cone up through the rear floorboard. I recommend steel over aluminum. The saving from either is HUGE over the stocker but between those two it's only a couple pounds and the steel is more resilient to the type of stresses a drive shaft goes through.

If steel is better with durablity then why is aluminum more expensive and why even put aluminum as an option for the track?

Expense is because aluminum is more expensive to produce (Did you know it takes 10 tons of boxite to produce 1 ton of aluminum? Also, aluminum doesn't naturally form in our atmospheric pressure, so giant pressurized smelter are required for production.) and it is harder to work (This is due to the metal not having much of a liquid range in our atmosphere... It's not much harder to work with, but it's enough to raise the price.).

The reason it is so popular is that it is strong and light. It's popularity in race vehicles is because it's a sport where every single ounce must be cut in order to move the car faster... less inertia to over come. Very high end cars may even have a thinner walled drive shaft which can't be used more a a hundred times or so before.

Steel has a much higher elasticity. As such it is far better suited to the centrifugal stresses which a drive shaft sees. There is a mathematical equation for how much stress a drive shaft can take, at what speeds it is most likely to fail and serves as a guide as to how long you can expect to run it before needing to replace it (PRIOR to failure)... it has to do with the type of metal, the length of the actual shaft, the offset angle of the differential and transmission, the diameter of the shaft and the wall thickness.

If you look around, you'll find more people who've had aluminum drive shafts fail at the track than steel. There's also the unending string of complaints about all the vibration which in inherant in aluminum and even CF drive shafts.

For a daily driver, steel is the most comfortable and longer lasting bet... for a track only car, aluminum is a great choice... I just assumed your car is a daily driver, so if that's incorrect then I apologize for the false assumption.


EDIT: Ever wonder why everyone isn't making aluminum crank shafts? ;)

Im more of a weekend driver but ill go with the steel DS and yes you made me realized why they only make cracnkshafts in steel. How big of a gain will i feelwith lightweight rims with low profile tires and a 1 piece steel DS from jawsgear?

It's been so long that I really can't remember how big the difference was... I know I was rather surprised by it. Reducing rotating mass has a bigger effect, pound for pound, than other weight reduction.

There is a lot you can do to lighten the MKIII:
Remove the power seats.
Replace the stock baffled muffler and resonator with free flowing resonance based muffler and resonator.
Tubular intake manifold.
Replace the heavy stock noise matting with modern noise liner.
Delete the A/C system.
Convert to a manual steering rack.
Delete the rear seats (and do NOT replace them with a wooden or reinforced fiberglass box).
Do NOT add a subwoofer.
Remove the spare tire.
Run a rebuilt W58 transmission as opposed to the R154 (if your car has a R154); This one isn't as recommended on a high power build, the W58 is not as durable... I prefer the W58 though as it is lighter and smoother.
Lightweight flywheel.
Lightweight driveshaft.
Lightweight wheels (weigh the rims and the tires.... sometimes a smaller rim with a bigger tire is lighter and sometimes it is the opposite, it depends on how they are built).
Drive with less fuel in the tank... :P
Replace the charcoal canister with a smaller unit off of a newer Toyota or other import; One from a Toyota is recommended as the plumbing will more than likely be the same and require no modification. The CC from the Tercel is about 1/2 the size and weight of that in the USDM 7M MKIII.

et cetera, et cetera.....

i dont want to modify the interior or exterior look of the supra i want to keep that classic untouched look. im spoiled i need ac in the summer and the ladies love it. the ac in total weighs about 30 pounds i rather get light weight pulleys than sweat my ass off in a heat wave..the noise matting i can do because im lookin to get a new carpeting to restore the interior, rear seats are staying merly for looks or just in case sum1 is small enough to fit bak there...manual steering rack is too much of a pain in the ass(what is the weight difference?)....i got two 12in subwoofers with a 350w amp screw the weight of that i like blasting music :drool:...im going to get a complete exhaust system eliminate manifold cover or any other cover nd go cat less...

you know where i can buy a CC from a tercel?

Let's move this to another thread specifically about weight loss.. it'll make it easier to keep track of and easier for future users to locate.