bwhitaker

I need a donut tire to fit into the tire well in the trunk of my 2002 SC430. I hope someone has come up with an alternative for the tire and mat for the trunk floor

Update 3.8.17:
I bought a 145/70/17 compact spare tire and rim from After Market Auto Parts ( on line - .https://www.am-autoparts.com/ - about $375). Lexus wanted almost $700. They had the whole kit, but did not fit my budget. I am going to cut out a duplicate of the floor using 1/4 plywood, then cut out where the tire sits for the new floor. I will paint it grey or put carpet on it. The rug with the Lexus logo will fit up to the tire - not exactly but enough to look good. This idea came from one of the followers of our club Lexus. The tire fits my trunk, have not put it on the car to test it yet, but holding it up beside my old tire and rim that I took off when we replaced the rims and tires, it seems to be the same height, just skinnier.

Now I feel like a real convertible owner!

Bgw70

yes sir, please click, search this forum and type, spare tire
you will find plenty of info.

Bgw70

Go here
https://www.clublexus.com/forums/sc4...-2001-2010-63/

now look for, search this forum

then type, spare tire

Bgw70

did you find the answer to your question?

Jabberwock

After I got my SC430, I used the search function read the various spare tire options on this forum. I ended up going with the Mazda RX8 spare (purchased on ebay). Per on of the threads posted, I installed the spare at an angle (pulling out the plastic tool tray, installing new carpet piece, putting tools in bag under the spare, etc) rather than standard vertical position for the spare on the SC so I have a little more "easy to use" space in the trunk when the top is down. System works fine and having regular tires on the car makes it ride and handle so much better. No way I'd ever go back to run flats (aka fork lift tires).

DshngDaryl

My car came with 20 Inch tires. If I were to look for a spare, can I still use the RX8 spare?

Jabberwock

The RX8 17" wheel and high profile spacer saver spare will work with the OEM 18s and factory spec'd tire size/profile. Running that same spare with significantly larger than OEM standard diameter wheels/tires would likely stress the differential in the rear, not sure about running it in front, but likely not recommended.

Bgw70

seems to me you would want to know the outermost diameter of your 20s vs the spare. If not that much different, it may be safe for a short distance.
if I recall, many times, the donut spare is smaller than the regular tire on a car.

tire size calculator
https://tiresize.com/calculator/

the OEM spare is
145-70-17
25"

oem tire size
245-40-18
25.7"

RX8 spare
125-70-17
23.9"

DshngDaryl

Thanks BGW. I know spare tires are smaller than standard tires and was wondering how far you could push the limit.

If I read your specs right, people using the RX-8 tire push the limit to 1 3/4 inches.

The OEM spare is about 3/4 of an inch shorter than an everyday tire. The RX8 tire will work, but it is really 1 3/4 inches shorter than the other tires.

So If I find an 18 spare tire, I can use the tire calculator to figure out how big the tire has to be to be, to be within 1 3/4 inches of my low profile tires. 1.75 seems like a lot to me, but I would be no worse off then many on this board.

Finding an 18 inch rim, seems much more feasible than trying to find a 20 inch spare.

jzdulexus

Out of curiosity is there any guideline as to how much the maximum difference between spare tire and regular tire diameter can be? I imagine there has to be some limit to how much smaller the spare tire can be even if it can clear the brakes. Would one corner of SC430 sitting much below the others pose a big safety concern at 50mile/hr?

DshngDaryl

Wow, how weird. It turns out an 18 inch spare tire off a RX350 is too big in diameter for any of the 20 inch tires on the plus 2 size chart at tires.com (255/30/20 235/35/20, 245/35/30)
https://phoenix.craigslist.org/evl/wto/6021949862.html

165/90/18 = 29.7 Diameter
255/30/20 = 26
245/35/20 = 26.8
235/35/20 = 26.5

But am OEM SC430 17 inch spare is within range

Guess those engineers really know what they are doing when they spec this stuff out

jzdulexus

Tire diameter is not just the rim size, its tire wall height plus the rim diameter. The wall height for 165/90/18 is 165mmX90%=148.5mm. So if you want to match the other tires' diameter you have to do the math to make sure the wall height comes close to compensate the rim diameter difference.
So, to choose the correct spare tire, first make sure the rim clears the front and rear brake (front is the larger of the two on OEM) and second perform the tire wall height calculation.

DshngDaryl

Good to know. I am assuming that the OEM spare will clear the OEM calipers, but that is good info to know if I go with a spare from another Toyota. (like the Sienna)

jzdulexus

For SC weather floor mats I have another simple alternative that is cheap and works OK. I bought the ebay set three months ago and in rainy days like we had in Ca this winter and at sandy beaches they come handy. They do NOT fit completely as the seller claims. On the front mats, they miss some corners. But for $16 they serve some purpose. Here are some pictures:

Coleroad

another option to keep your carpet and floor mats looking great, 303 fabric protectant . I've used it for years now. The protection is way better than scotchguard . Vacuum weekly and keep it protected. I use it about every three months. Kept my sc 430 floor looking great it was an 03. Here is a video of it being used.