X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Mon, 13 Feb 2006 20:16:21 -0500 Message-ID: X-Original-Return-Path: Received: from imo-m21.mx.aol.com ([64.12.137.2] verified) by logan.com (CommuniGate Pro SMTP 5.0.8) with ESMTP id 983802 for lml@lancaironline.net; Mon, 13 Feb 2006 19:24:30 -0500 Received-SPF: pass receiver=logan.com; client-ip=64.12.137.2; envelope-from=Sky2high@aol.com Received: from Sky2high@aol.com by imo-m21.mx.aol.com (mail_out_v38_r7.3.) id q.2d1.34ec73a (3932) for ; Mon, 13 Feb 2006 19:23:44 -0500 (EST) From: Sky2high@aol.com X-Original-Message-ID: <2d1.34ec73a.31227d10@aol.com> X-Original-Date: Mon, 13 Feb 2006 19:23:44 EST Subject: Re: [LML] Re: 235 tires X-Original-To: lml@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="-----------------------------1139876624" X-Mailer: 9.0 Security Edition for Windows sub 5300 X-Spam-Flag: NO -------------------------------1139876624 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit In a message dated 2/13/2006 12:50:43 P.M. Central Standard Time, lcfitt@sbcglobal.net writes: A question, What is causing the flats - what is found after inspecting the tube / tire. The reason for the question is that in some experimantals calling for tubeless tires, guys are inserting tubes for the belts and suspenders thing and flats become quite common. The culprit is sheared valve stems due to tire spin on the rim. The talk of underinflated tires failing suggests to me that underinflation might be the root cause and spinning of the tire resulting in valve stem damage might be the actual cause of the failure. Lowell, There have been very few instances of sheared stems. The usual consequence of extended use with an underinflated tire is excessive sidewall flex and tube wear along the side. This weakens the tube and most often produces pinhole leaks in the weakened areas or just outright tube side failures. The 235, 320/360 wheels and Legacy nose wheels are not designed for tubeless tires. It could very well be that Lancair's inflation recommendation is on the low side since underinflation is a relative term. Dan's 25 psi is definitely underinflated and perhaps the 42 psi for a 320/360 may also result in underinflation. At 55 psi and 1800# gross weight, about 600# per main, a main tire patch is about 11 square inches. At 35 psi that patch increases to 17 sq. inches. Thus, with a fixed tire width, the sidewall flexing is quite pronounced as the design tire profile has collapsed significantly. Scott Krueger AKA Grayhawk Lancair N92EX IO320 SB 89/96 Aurora, IL (KARR) -------------------------------1139876624 Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable
In a message dated 2/13/2006 12:50:43 P.M. Central Standard Time,=20 lcfitt@sbcglobal.net writes:
<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size= =3D2>A=20 question,  What is causing the flats - what is found after inspecting= the=20
tube / tire.

The reason for the question is that in some=20 experimantals calling for
tubeless tires,  guys are inserting tub= es=20 for the belts and suspenders thing
and flats become quite common. = ;=20 The culprit is sheared valve stems due to
tire spin on the rim.
The=20 talk of underinflated tires failing suggests to me that underinflation=20
might be the root cause and spinning of the tire resulting in valve st= em=20
damage might be the actual cause of the=20 failure.
Lowell,
 
There have been very few instances of sheared stems.  The usu= al=20 consequence of extended use with an underinflated tire is excessive=20 sidewall flex and tube wear along the side.  This weakens the tube and=20= most=20 often produces pinhole leaks in the weakened areas or just outright tube sid= e=20 failures. 
 
The 235, 320/360 wheels and Legacy nose wheels are not designed fo= r=20 tubeless tires.
 
It could very well be that Lancair's inflation recommendation is on the= low=20 side since underinflation is a relative term.  Dan's 25 psi is definite= ly=20 underinflated and perhaps the 42 psi for a 320/360 may also result in=20 underinflation.  At 55 psi and 1800# gross weight, about 600# per=20 main, a main tire patch is about 11 square inches. At 35 psi=20= that=20 patch increases to 17 sq. inches. Thus, with a fixed tire width, t= he=20 sidewall flexing is quite pronounced as the design tire profile ha= s=20 collapsed significantly.=20
 
Scott Krueger=20 AKA Grayhawk
Lancair N92EX IO320 SB 89/96
Aurora, IL (KARR)
 
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