MTFCA Forum

Using my rim spreader, I successfully got one of my 21” tire sets mounted on the rim. After I released the rim spreader and spread the rim back out, I noticed that the rubber tire stem is a little crooked. Looking at it from the side, it is at about 1:00. Not bad, but I don’t like it. What is the best way to straighten a crooked stem to an upright position? I have not added air yet so the tube and flap have no pressure on them. Is there a way you can bounce the tire in a certain direction in order to cause the tube to rotate in the tire to the correct position? I used baby powder in the tire and on the flap and tube, so they should be slick. Thank you. Jim Patrick

I did the same thing on my 24 Coupe 21” tires. The valve stem was off just a little. Before the tire was aired up I used a rubber hammer and bumped the rim around by bumping on the rim lug. If it seems to be to tight to move use some liquid soap and squirt it around the bead to get the rim to slip. Your not moving the tire or the tube but moving the rim. That’s how I did it.

I have bounced the whole wheel on the floor at sort of an angle and gotten the tire/tube and stem to move enough to be straight. I think by mounting the wheel on the car jacked up it could be turned some also.
Rich

With the core still out. Pull & hold stem @11:00. Inflate & deflate. Repeat as needed until stem is @ 12:00.
No need to move the tire. The inflation/deflation will move the tube internally.

I start the stem cocked the other direction and as the rim is expanded the stem straightens up. As you discovered, if you start with the stem straight, it will be cocked when you are done expanding the rim.

This is very helpful. Thankyou. Do you think that on the next ones, if I clamp a set of vice grip locking pliers to the base of the stem close to the rim, it will keep the stem straight throughout the process? Jim Patrick

jiminbartow wrote: ↑

Fri Mar 04, 2022 8:08 pm

This is very helpful. Thankyou. Do you think that on the next ones, if I clamp a set of vice grip locking pliers to the base of the stem close to the rim, it will keep the stem straight throughout the process? Jim Patrick

No. If you have rubber stems, the vise grip will most likely cut through the rubber and cause a leak. Either way, when the rim moves during expansion, it tugs on the stem, causing it to be crooked. It sometimes helps if you can start with the stem purposely crooked in the opposite direction, then when the rim is expanded it brings the stem back to straight.

The tube is free to float within the tyre. Just air it up a couple of times, core out makes it quicker, and it will settle where it is comfortable.
Or, you could grab the tyre in a big vice, and use a brass drift to engage on a lug , and mash hammer to drive the rim around the tyre a bit.
Allan from down under.

I always dust powder or corn starch in the tire casing before the tube goes in. The tube will slide easily in the casing so you can line up the stem before inflating the tube.

I have seen some reproduction split rims for the 1926 had the Valve Stem hole on the wrong side of the latch. This made
assembly very difficult. From memory, the section with hole is stationary and the other half is collapsed.
Alan in Western Australia

Thank you all for your help. I have found that when the tire is mounted on the split rim, after the rim is closed and locked and before the tube is inflated, the stem can be straightened by hitting the lug that the stem in angled toward, in the opposite direction with a rubber (not steel) mallet until the stem is straight up and down. The baby powder allows the tube and tire to slide on the rim. After the tube has been inflated, it applies outward pressure to the beads on each side of the rim, locking the tire in place. Jim Patrick