Update on Falken GRB FK-451 failure: it might not be entirely the tire's fault...

akula-ssh · 09-07-2005, 08:10 AM

Finally my T1R's have arrived so it's time to pay the tire shop a visit for mounting them. As it turns out both my failed tires have failed valve stems too. The tire shop says rubber stems are good for 40psi; when my tires failed I had 40psi "cold" pressure, which the tire shop said ought to be perfectly fine.

So there is only one thing I can perhaps fault the tires: that for whatever reason the tires weren't dissipating heat properly so that the "hot" pressure went way too high.

By the way, I now have steel stem valves, good for a ridiculous overkill of 100+psi.

qfrog@work · 09-07-2005, 08:21 AM

the listing of audis that accept that wheel valve is um... pretty much all of em.

Many of those cars have factory suggested tire pressures of over 40psi.

akula-ssh · 09-07-2005, 08:43 AM

For what I can see, the tire shop said rubber ones are only good for 40psi, and both failed tires have failed stems, so I thought 1+1=2 and their claim of pressure threshold seems right...

That, or perhaps I should always get OEM valves and bring them in when mounting tires (that require new valves)

Bob Petruska · 09-07-2005, 04:47 PM

Especially the ones in the trunks of black cars in Arizona where the the temps get to 130 degrees! I would say the tire pressure would be greater than 70 psi at that temp if the tire was originally inflated to 65 psi at 80 degrees. Same rubber valve stem used here as on standard tire rims.

The dealer was trying to make a fast buck on steel stems!

Chris not @ Toyo now · 09-07-2005, 05:03 PM

rubber valve stems can withstand a lot more pressure than 40lbs....think about it, the tires are usually max pressure of 45-50 depending on the tire, so the valve needs to hold a lot more than 40lbs. Probably the valves were old and that is why they failed......oh well enjoy the T1Rs

09-07-2005, 08:10 AM	#1
akula-ssh Member Account #: 70933 Join Date: Mar 2004 Posts: 4,699	Update on Falken GRB FK-451 failure: it might not be entirely the tire's fault... Finally my T1R's have arrived so it's time to pay the tire shop a visit for mounting them. As it turns out both my failed tires have failed valve stems too. The tire shop says rubber stems are good for 40psi; when my tires failed I had 40psi "cold" pressure, which the tire shop said ought to be perfectly fine. So there is only one thing I can perhaps fault the tires: that for whatever reason the tires weren't dissipating heat properly so that the "hot" pressure went way too high. By the way, I now have steel stem valves, good for a ridiculous overkill of 100+psi. __________________ List of 3.0 owners on AW compiled by A4AdMan <big>2002 Audi A4 Avant 3.0 Quattro Tiptronic</big> Premium package, sport package, xenon headlights Modifications to date: Neuspeed Sport springs Koni shocks (50% all around) H-Sport anti-roll bars custom stainless steel rear upper spring seat spacer Silver OZ Superleggera 18x8 Sumitomo HTR Z III 235/40-18 95Y XL (current summer) Toyo T1R 235/40-18 95Y (previous summer) Falken GRB FK-451 235/40-18 91Y (previous summer) Dunlop SP WinterSport M2 235/45-17 94H (winter) Supersprint resonator and mufflers (quick video clip here) BMC CDA intake Alcon B Type calipers Coleman Racing 13x1.25" 2-piece rotors Carbotech XP8 brake pads aluminum interior trim black bumper grill opened driver side foglight grill (from 1.8T) auto-dimming blind-spot Euro side mirrors bi-xenon E-code headlights Ultraleds (ultraleds.co.uk) 1W LED H6W bulbs Sylvania SilverStar H7 (high beams) Stealth blinker bulbs 7507 (front and rear) Hüper Optik Ceramic 60 and Sech (metal) tint My alignment specs Writeup on load equalizers mounted inside e-code housing

09-07-2005, 08:21 AM	#2
qfrog@work Senior Member Account #: 71421 Join Date: Mar 2004 Posts: 5,389	eh.... everything from the A4 to RS6 takes 281-601-361 rubber valves the listing of audis that accept that wheel valve is um... pretty much all of em. Many of those cars have factory suggested tire pressures of over 40psi.

09-07-2005, 08:43 AM	#3
akula-ssh Member Account #: 70933 Join Date: Mar 2004 Posts: 4,699	Any chance you know what the pressure threshold is for that particular part? For what I can see, the tire shop said rubber ones are only good for 40psi, and both failed tires have failed stems, so I thought 1+1=2 and their claim of pressure threshold seems right... That, or perhaps I should always get OEM valves and bring them in when mounting tires (that require new valves) __________________ List of 3.0 owners on AW compiled by A4AdMan <big>2002 Audi A4 Avant 3.0 Quattro Tiptronic</big> Premium package, sport package, xenon headlights Modifications to date: Neuspeed Sport springs Koni shocks (50% all around) H-Sport anti-roll bars custom stainless steel rear upper spring seat spacer Silver OZ Superleggera 18x8 Sumitomo HTR Z III 235/40-18 95Y XL (current summer) Toyo T1R 235/40-18 95Y (previous summer) Falken GRB FK-451 235/40-18 91Y (previous summer) Dunlop SP WinterSport M2 235/45-17 94H (winter) Supersprint resonator and mufflers (quick video clip here) BMC CDA intake Alcon B Type calipers Coleman Racing 13x1.25" 2-piece rotors Carbotech XP8 brake pads aluminum interior trim black bumper grill opened driver side foglight grill (from 1.8T) auto-dimming blind-spot Euro side mirrors bi-xenon E-code headlights Ultraleds (ultraleds.co.uk) 1W LED H6W bulbs Sylvania SilverStar H7 (high beams) Stealth blinker bulbs 7507 (front and rear) Hüper Optik Ceramic 60 and Sech (metal) tint My alignment specs Writeup on load equalizers mounted inside e-code housing

09-07-2005, 04:47 PM	#4
Bob Petruska Member Account #: 430 Join Date: Mar 2000 Posts: 3,644	Then all space saver spares @>65 psi with rubber valve stems should have stem pop! Especially the ones in the trunks of black cars in Arizona where the the temps get to 130 degrees! I would say the tire pressure would be greater than 70 psi at that temp if the tire was originally inflated to 65 psi at 80 degrees. Same rubber valve stem used here as on standard tire rims. The dealer was trying to make a fast buck on steel stems!

09-07-2005, 05:03 PM	#5
Chris not @ Toyo now Member Account #: 40471 Join Date: Jul 2002 Posts: 2,163	I don't think the valve failed rather it probably was pinched or cut.... rubber valve stems can withstand a lot more pressure than 40lbs....think about it, the tires are usually max pressure of 45-50 depending on the tire, so the valve needs to hold a lot more than 40lbs. Probably the valves were old and that is why they failed......oh well enjoy the T1Rs

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