quattro Digest, Vol 7, Issue 42 - Opinions Requested - Chrome Pla ted vs Stainless Lug Bolts

[l.leung at juno.com]

Trying the bottom post again, feels weird....


Date: Mon, 10 May 2004 02:45:58 -0400
From: Ameer Antar <antar at comcast.net>
Subject: Re: Opinions Requested - Chrome Plated vs Stainless Lug Bolts
To: quattro at audifans.com
Message-ID: <20040510064554.40B3BF14F1 at audifans.com>
Content-Type: text/plain; format=flowed; charset="iso-8859-1"

>From: "Richard Hoffman" <billzcat1 at hotmail.com>

>Stainless Steel is far softer than mild steel.  Go for the chrome-plated as

I think the correct term should be weaker rather than softer. Stainless is usually harder than mild steel, but has a lower tensile strength, which means it takes less force to stretch/break apart a stainless fastener by pulling than mild steel. Hardness is a relative scale used to describe how easy it is to scratch one material with another... which is useful when selecting material for a cutting tool. Hardness is not a huge issue for fasteners, but it is for stuff like cutting tools or knives. Generally you can make metal stronger, but at the same time, you make it softer. The opposite is also true. That's why extremely hardened material can become weak/brittle. 

You'd be surprised, but there are some stainless steels that are STRONGER than mild steel. There's probably know way of knowing for sure what alloy they use for these bolts, but if they're a reputable source, I'm sure they've taken into account the appropriate calculations to sell a safe product. The idea that stainless is weaker than mild steel fasteners is b/c stainless nuts/bolts aren't graded and are probably weaker since there's no need to meet a rated strength. Between the two, I personally would go for stainless hardware b/c coatings never last, esp. on fasteners. Chroming also reduces the strength of the hardware. Just make sure you're getting these from a reputable source, not just off the shelf from a hardware store.

-Ameer

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Thanks to all that replied. I had been leaning the way of plated bolts, but Ameer seems to support what I had recalled about SS in my former life as a Mech Eng. There are a NUMBER of SS alloys that actually have a greater tensile strength than Mild Steel, but they tend to be expensive, and as Ameer notes, bolts don't tend to get graded. And, as he notes, plating does (mildly, mind you) weaken the base metal, but then again, so does rust. The SS hardware is being marketed by TireRack, whom has a large enough market base and has enough risk factors that I'd venture a guess that they aren't taking chances vending the SS bolts. At this point, I don't know of any precautions on the uses of their bolts such as "Not for racing or off-road use" that would make me hesitant to use them. I was simply searching for additional opinions, as I do believe the SS hardware will be rust free (and hopefully bind free) forever, whilst chrome eventually pits and gives up in the wheel/brake dust environment. Of course there are other
solutions for the binding issue, but I don't want to start THAT thread all over again.... In the meantime, I'm still searching for the P.O's
OEM lugs for the winter Avus wheels, if I don't find them, I think it's time for the stud conversion (the car) rather than buying two sets of bolts. Of course then I'll have to spend money on twice the nuts....

Thanks everyone, 

LL - NY