Re: [CR] Alloy Stem bolt and wedge for Cinelli--safe to use?

(Example: Events:Cirque du Cyclisme)

From: "Brian Samson" <brsamson@telus.net>
To: Classic Rendezvous <Classicrendezvous@bikelist.org>
In-Reply-To: <4AAC6A05.9070302@aol.com>
Date: Sat, 12 Sep 2009 21:00:50 -0700
References: <897585.64977.qm@web55405.mail.re4.yahoo.com>
Subject: Re: [CR] Alloy Stem bolt and wedge for Cinelli--safe to use?


But I thought some of the 1R stems came with an alloy bolt and I don't recall anyone mentioning that they were prone to failure. Just creaking and slipping of the bars. Certainly a steel bolt will withstand over-tightening better than an aluminum one, so in that regard they would be safer.

Brian Samson Vancouver, BC, Canada

On 12-Sep-09, at 8:41 PM, verktyg wrote:
> Robert,
>
> I wouldn't recommend using the aluminum bolt. The wedge is probably
> OK.
>
> At most you might save a few grams weight but you're replacing a
> critical component on your bike with one that has less than half the
> the strength. Assuming that the bolt is made of a high strength
> aluminum alloy that's been properly heat threated, it's never going
> to have the strength of a Cinelli hardened steel expander bolt.
>
> Aluminum stretches a lot more than alloy steel and the point of
> failure is a lot lower than for steel.
>
> Some might say that once the wedge has expanded the base of the
> quill inside the steering tube the expander bolt has done it's job.
> But think of how much stress and vibration is transmitted through
> the stem. It may eventually work loose or fail unexpectedly.
>
> Those things are for world record attempts on a smooth track surface
> not casual TTs!
>
> One less beer or cookie or whatever will benefit you far more than
> the few grams weight savings from an alloy stem bolt.
>
> I quit weighing my bikes years ago. If I know how much a bike weighs
> then that will be on my mind on every hill I climb. I just ride them.
>
> In the mid 70s I got carried away with all the weight weenie crap
> and got my steel framed bike down to under 19 Lbs. using HiE wheels,
> 250g sewups, Huret Jubilee derailleurs and all of the alloy bolts I
> could get for my components.
>
> I rode 1 TT on that bike and immediately switched every thing back
> to more reliable components! Yes, I broke 60 min for 25 miles but I
> attribute that to a strong tail wind on the return leg.
>
> Aside from light weight wheels, hill climbing is about the only
> place where weight savings matter.
>
> Chas. Colerich
> Oakland, CA USA
>
> Charlotte Bronte wrote:
>> Looking for advice about this weight saving part. I acquired both
>> an alloy bolt and wedge for a Cinelli 1A stem, and am wondering if
>> anyone has had problems with this setup. I am considering this mod
>> for a TT bike I'm building up.
>> Any advice welcome.
>> Robert Aguirre
>> Windsor, ON