nlt999

Hi!
The spare tire is included in the TPI system, which is a good thing.... lets you know when any tire is low, INCLUDING the spare. However, airing-up the spare is a pain because you have to lower it down to get to the valve stem, which is on the upper side since the spare is stored with the outside of the wheel facing upward. I wanted to make it so I could check and air-up the spare if necessary from the trunk, without having to crawl under the car and lower the spare each time.
I bought a pair of valve stem extenders from Amazon:
(Click on this link to see the item on Amazon)
I removed the clamps, nuts, and washers from the pair, then screwed one into the other to make a total length of about 19 inches, tightening the connections securely using pliers. (You can remove the core from the middle valve stem to allow air to flow more easily, if desired) Then proceed as follows, referring to the attached photos:
(1) Remove the round dress-up cover from the bottom of the spare by rotating it counter-clockwise to release the catches.
(2) Open the tailgate and all three floor hatches. Find the chrome hex wrench and angled handle in the tool compartment under the front hatch.
(3) Remove the round black plastic cover over the lowering nut at the right side of the right-rearmost compartment.
(4) Turn the nut counter-clockwise to lower the spare tire to the ground.
(5) Remove the spare tire valve-stem cap and attach the extension securely to the valve stem.
(6) In the trunk again, find and pry out the two plastic retainers, one at each side of the black plastic bin under the two rear hatches. Remove the bin.
(7) Find and remove the round rubber plug in the center of the floor under where the bin was. Just squeeze it and work it out of the hole.
(8) Push an awl or other pointed tool down through the middle of the hole where the plug was. I will go down through the weather seal & you can see it underneath.
(9) Temporarily reinstall the black plastic bin and drill upward thru the hole where the plug was to make a hole in the bottom of the bin, then remove the bin again.
(10) Get a pair of flat washers that will fit over the valve stem at the end of the extension.
(11) Cut the weather seal from around the hole underneath so you can fit a flat washer and stem up through the hole, put the other washer & a nut on the top side.
(You can put some weather sealer around the flat washers and extension valve stem to seal out water, if you like)
(12) Rotate the spare so the valve stem is toward the front of the car.
(13) You want the extension to be between the Left-hand flat surface that stops the tire in the 'up' position, and the center rib of the trunk floor.
(14) Mark the tire and the plastic 'tub' underneath that it sits in under the center of the rear bumper.
(15 Keeping the mark under the center of the bumper, raise the spare carefully, watching that the extension stays between the LH flat stop surface and the center rib.
(16) Tighten the raising-nut so that the spare won't bang around on when driving on bumps.
(17) Tighten the nut on the top-side of the valve stem in the floor. Also, make SURE that the valve core is TIGHT inside the valve stem!
(18) I used dish-soap & water mixture around all the various connections of the extension to be sure there were no leaks! (I replaced the valve core in my trunk valve)

Removing the RH retainer for the black plastic bin

Rubber plug in trunk floor

Rubber plug removed

Bottom view of plug removed & weather seal cut away

Extension stem inserted through flat washer into hole up into trunk floor. You can put weather sealer around the washer and extension if you like.

Extension positioned between LH tire stop and center rib of trunk floor by rotating tire

Tire marked with extension in correct position. Also make a mark on the plastic 'tub' that the tire sits in, so you can watch it while raising the tire.

Raising the tire with extension maintaining correct position for clearance

Extension valve stem secured in trunk floor. You can put weather sealer around the washer up here too if you like.

Black plastic bin back in position with large hole around extension valve stem for access.

(19) Cut the hole in the bottom of the black plastic bin so you have good clearance around the valve stem in the floor.
(20) Reinstall the black plastic bin using the 2 plastic plugs removed earlier.
(21) Put away the tools, replace the black plastic plug over the lowering-nut at the right of the black plastic bin.
(22) If you want to hide the valve stem, you could get a black plastic plug to fit the hole you made in the black plastic bin (at the local hardware store)

Monitor your Tire-pressure indicator light in the dashboard to make sure the spare maintains its pressure.

Hope someone finds this helpful! Nick

DennisMik

Very ingenious! What gave you the idea to do this?

nlt999

Just seemed like a logical solution to the problem Dennis. Climbing up and down and under the car to lower the spare tire, then the awkward position to check pressure and air it up if necessary is not fun when you are 77 and have had 3 spinal surgeries, plus a bad heart, Arthritis, etc, etc. I just hope the extension is durable and doesn't leak with time. If it holds up, it will have been worth the effort one time to avoid future gymnastics!

Nick

DennisMik

Being 73 myself, I can understand your reasoning. I am considering doing your mod, but I would prefer for the valve stem to not be in the spot you recommend. Have to think about where I would want it and how feasible/possible that would be.

But you still did a great job. Thanks.

nlt999

Let me know what you decide Dennis! I was just lazy and used the hole already there in the trunk floor. Also figured it made it easy to get to... just open the tailgate and raise the spring-up hatches.

edwardh11

A LOT OF WORK. good job. i may just check it once a year tho

nlt999

UPDATE: So far, so good as of 10/15/2018.... still no indication from the TPI system. I haven't been checking the spare with a tire gauge because you lose a little air each time you do that.

Also, I added a cover for the valve stem in the floor to protect it. Just a 1/2" PVC pipe cap shortened just a bit with the grinder. I trimmed the hole out slightly so the cap just slides down over the stem. (see photo)

edwardh11

what is the light blue material in pix 7-- some type of sound insulation?
plenty of room for more

nlt999

The blue is just some sort of paint or coating they put on after applying the sound-deadening 'pads' to the metal floor.

mandyfig

Very clever idea, nice work. Fortunately-unfortunately I do not have the TPMS on my RX, my model used a different method on sensing if the tire was running low on air or flat through the wheel hub. Also to help with fuel consumption, I have removed my spare, figure maybe 50 lbs? I have had the spare for many years and in fact I have upgraded my rims to the newer RX and could not use the old spare set (it sits in storage with the original set of tire - 5 spoke wheel). Instead I keep a tire repair kit in case of a flat, it includes a compressor. Knock on wood. For preventive maintenance, I check the condition of the tires weekly, pressure included. Get it rotated every 6K miles myself and if needing balancing, I take it to Costco. Tires are the most neglected component in the car and yet if they are not maintained, it can get you in a tough spot and maybe even in danger. Low tire pressures waste gas. Worn tires are more susceptible to tear and therefore accidents. We spend less money on tires than anything that requires maintenance.

edwardh11

really bad design by Lexus- are all suv s like this?