FOBO T-Stem Fail - How to Install?

[dcarver]

Months ago bought 4 FOBOS T-stems for both FJR's.

Today attempted install - epic fail.

Here's how FOBO says they install...



Problem is that the rim ID is 9.4mm and the widest point, OD, of 'Rubber Grommet 1' (RG1) is 14 mm.

No way does the threaded portion of the valve stem pass through RG1 without splaying too far out, preventing even partial insertion into rim hole.

Interestingly enough, RG1 fits better when inserted upside down, e.g. 'backwards' from inside of rim poking up to the outside world.

So I gave up and used a new 90 degree metal stem instead of the trick T-Stem.

Has anyone had success with FOBO T-stem?

If so, what am I missing?

[griff]

Interesting. I have these T-stems yet to install. What say you NTXFJR and Bill Lumberg? I know you guys have installed these.

[raYzerman]

Sum ting wong..... measured a spare T-stem I have here, OD of the metal threaded part is ~10mm, and the smaller stepped (you show tapered) part of the rubber grommet is the required 11.3mm, which is the same size as the hole in the rim, i.e., a line to line fit. I usually use Ru-Glyde (rubber or tire install lube), insert (finagle) it into the hole, or if it doesn't go, insert the grommet into the hole first, then the stem.

[bill lumberg]

I’ve used the ones from wingstuff, and the ones from Fobo. Both fit. Both, at first, looked like they weren’t going to seat. Both sets seated fine and sealed well when tightened. I had to replace a gasket on one of the wingstuff ones at around 70,000 miles due to a slow leak. Just took the rubber out of a pack of conventional metal stems. No issues thus far with the fobo t stems at about 24,000 miles since install. Fobo is very responsive to email questions. They may be able to help.

[dcarver]

Sum ting wong..... measured a spare T-stem I have here, OD of the metal threaded part is ~10mm, and the smaller stepped (you show tapered) part of the rubber grommet is the required 11.3mm, which is the same size as the hole in the rim, i.e., a line to line fit. I usually use Ru-Glyde (rubber or tire install lube), insert (finagle) it into the hole, or if it doesn't go, insert the grommet into the hole first, then the stem.

I'll measure my RG1 in a bit. I could get RG1 to *almost* fully seat into the rim w/o the stem. Put the stem in and RG1 'swells' out, pooches out, where only the skinny part of the tapered RG1 is into the rim. This is working from hub side to 'inside' of rim e.g. where tire pressure is.

Other sandbox comments have been that I'm installing RG1 upside down.. that it should insert from the inside of rim e.g. inside tire beads, poking out towards atmosphere?

Geesh. This should be simple!

[raYzerman]

I now you see rim ID was 9.4..... that's a bit odd..

[dcarver]

I now you see rim ID was 9.4..... that's a bit odd..

I'm going to leave what I have on for now.. 90 degree metal ASSuming it sealed. 40 psi last night will check this morning. The other one was leaking.

A nice member sent me this FOBO install link which indicates I'm trying to install correctly.
https://my-fobo.com/uploads/fobobike/T_ ... nGuide.pdf

Will look at the rear rim next. New tire already on front rim..

Wonder if back in 2006 the rim hole ID was smaller?

[raYzerman]

I don't believe the hole has changed since day one. Mine (I got from tpms.ca) does not have a tapered grommet or the second grommet.
I don't think it will matter which way you install, inside or outside, it will seal with two grommets. Has to.

[escapefjrtist]

Sum ting wong..... measured a spare T-stem I have here, OD of the metal threaded part is ~10mm, and the smaller stepped (you show tapered) part of the rubber grommet is the required 11.3mm, which is the same size as the hole in the rim, i.e., a line to line fit. I usually use Ru-Glyde (rubber or tire install lube), insert (finagle) it into the hole, or if it doesn't go, insert the grommet into the hole first, then the stem.

Agreeing with Ray with his install method. Used this method on every Ariete 90 degree stem I've installed. Once you get RG1 seated in the rim, make sure it stays seated on the rim as you insert the T stem.

~G

[dcarver]

Well, something is weird. My ID is only 9.4 mm not 11.3 and I am chicken s#$#t to drill it larger.

Continued to rear tire as front was mounted and balanced and I'm too lazy to break it down again.

Then forgot all about testing the rear stem id..

So now have a blue 90 degree on front and silver 90 degree on back tire.

Until next tire change the mystery remains..

Thanks to everyone for help.

Off to Zombie Thread Land.

[wheatonFJR]

Well, something is weird. My ID is only 9.4 mm not 11.3 and I am chicken s#$#t to drill it larger.

Continued to rear tire as front was mounted and balanced and I'm too lazy to break it down again.

Then forgot all about testing the rear stem id..

So now have a blue 90 degree on front and silver 90 degree on back tire.

Until next tire change the mystery remains..

Thanks to everyone for help.

Off to Zombie Thread Land.

We don't do zombies here. Yours is active!

[dcarver]

Update - installed the FOBO successfully on the rear rim of the 2013 FJR. Hmmm.