SCC cable chains on Avalanche--no!

[brmiller]

There have been a few threads recently regarding chain use, snow driving tips, winter weather driving laws, etc.  Of specific interest to me is the comment in the Avalanche owner's manual against using chains.

 

Since the "letter of the law" here is that 4WD vehicles must (among other things) carry chains, I thought I would investigate the possibility of using SCC's cable chain product on the rear wheels of the Avalanche.  I have used their products on my RWD Nissan, and they worked great.

 

And the verdict is--NOT!

 

Exhibit A:

 

Where the two connectors link up on the inside of the tire, there is a lot of metal in one spot.  The connectors come awful close to the brake line, but do not make contact.

 

Exhibit B:

 

Again, same shot, but tire rotated a little more.  The connecting link doesn't make contact, but is within millimeters.

 

Exhibit C:

 

A slightly different angle.  Still no contact, but too close for comfort.

 

Exhibit D:

 

This is a real problem.  The cable is actually deformed (stretched) the contact with the brake line.  Not a good idea.

 

Exhibit E:

 

On this section, the connector actually makes contact with the brake line.

 

Exhibit F:

 

Another instance where the cable comes in contact when tangent to the brake line.

 

 

And for those with high bandwidth (or patience inversely proportional to connection speed), here is a Quicktime (AVI) movie showing the full rotation of the tire from the same vantage point as the preceding pictures.  You'll need at least QuickTime 4 to view it.

 

Watch the wheel go 'round!

 

 

Conclusion:

 

The contact and pressure of the cable and cable connectors on the brake linec is just not something you want to risk even if you are only driving 20-30mph.  I would be worried that the cable would cut through the brake line, or worse, what if one of those connectors snagged it?  Uh-uh.

 

If you were able to watch the video, you can see that there are several points where the perimeter cable is far enough away from the brake line to be tolerable.  It is, therefore, theoretically possible to get the perimeter cable centered exactly about the tire with all connectors equidistant from the axis of rotation and maximize individual clearance with the brake line.  Practically speaking, this is highly unlikely.  It was difficult enough to get the chains lashed on with the truck jacked up in my garage.  I have a hard time picturing myself getting it perfectly lined up laying in the snow or ice on the side of a mountain pass.

 

Chevy was right--there just isn't enough clearance.  And I never expected it to be with the brake line.  There is another point of "close call" on the other side of the wheel, but I found it tolerable all the way around.  It's just too bad they designed it this way.

 

For my snow/ice travels (which aren't that many yet), I will throw the chains in the back so I meet the "carry chains" requirement.  I talked earlier about "the letter of the law".  What's really important is the "spirit of the law" which is "If you ain't got traction, get some, or turn around."  It's the dummies who can't figure this out that need the extensive chain laws and 6-point criteria.  If I carry chains that fit, as I read the law, I should be exempt from the chain requirements when operating my Avalanche in 4WD.  But if conditions provoke unsafe driving conditions, or if a highway safety official tells me to put the chains on anyway, I'll turn around.  As someone here said, it's just not worth risking life and truck.

 

Hope this blurb was useful to someone.  I had a good time putting it together.

 

Brendan

[chevy4x4trucks]

Wow, thanks for the pics, it sure will save a lot of AVY owners headaches if they ever feel the urge to put chains on their truck.

[Matts U.A.V.]

Great Post....I hadnt even seen that in the manual. Alot of times here in Cali when you go to the mountains having them in your truck isn't good enough. They make you have them on even if you have a 4x4.

 

thanks for the info..very helpful

[TxDoc]

What size tire/wheel do you have and what cable chain producct # are you using?

[chevy4x4trucks]

What size tire/wheel do you have and what cable chain producct # are you using?

Goodyear Wrangler AT/S 265/70R17 on Factory 17" Alloy Rims

[WS6Y2K]

Ok this is with the 17" wheels and with the  shur grip Z chains right. Would a 16" wheel help? I have a non 4x4 and was looking at these chains just the other day. My tire are the stock 265/70-16. It looks like the Z-chain has more clearance than the shur grip Z. Looking at 2 picture from the web page. www.scc-chain.com/products.htm

 

I was up in Redosio, NM this past week and I saw a few trucks with chains on them. We did not go up to far in the montains so I did not need them. I would really like to have them just in case.

 

I have a new set of chains that I got for my old 96 Z71 that I never got to use. I had 285/75-16 tires. They are the quik grip QG 3229. They are way too big for my Av. Let me know if someone needs them. I think I paid like 50 bucks a couple of years ago. Make me a offer.

[brmiller]

As chevy4x4 said, I have the 265/70R17, and I was using the "Super Z LT" chain, part no. ZT747.  The 265/70R16 that you have would be a smaller tire, so the problem could be even worse (with this chain) as you would have even more slack in the chain.  You might try the ZT741 to see if it fits.  What I actually need is smaller chains, so that the cable on the inside rides up higher--along the tire bead--so as to stay out of the way of the brake line.  The ZT741 might work out on my tires too, so longs as they will wrap around.

 

I don't know if you can trust the drawings on their product page to give a realistic view of how much slack you have.  There wasn't much slack in the chain I was using, so having even less might be hard to get them on.  It seems like the only way is by trial and error.

 

If you're serious about chains on your Avalanch, here's what is needed.  Take your wheel off and lay it on the ground face down.  Measure the perimeter circumference of your wheel where the tire bead mounts on it (or use the diameter * pi).  This is how long the inside loop of the chains can be--no longer or they will interfere with the brake line.

 

I'll look to see if I can find some Shur Grip Z in the same size, but I'm doubtful.  The QG chain you mention is a Quik-Grip chain with actual steel chainlinks.  These will definitely not fit, because the chain links will stick out too far and start rubbing on other stuff.  The beauty of the cable chain concept is that they lie pretty flat against the tire.

 

Brendan

[TxDoc]

I am forwarding your pics and size and product info to them and your problem.  I have two sets for my trucks and think they are great. I can start and stop on ice (we usually get ice and sleet or freezing rain and have no equipment to clear it-so you are on your own to go mobile) with no problem and it has made it possible for me to go to the hospital for emergencies when the conditions were horrible. I would like to see you get a positive resolution so you can use your cable chains and not damgae your truck.  I do remember that the slack is essentially non existent, though.

[brmiller]

Great!  Thanks, TxDoc...

 

Let me just add that one reason I bought these chains "hoping" they would work, was that they are listed in the SCC fitment guide at the store I bought them from under Avalanche.  I was kind of surprised to find anything listed for the Avalanche (since it is a new model), and given the warning in the manual.

 

But I bought them anyway, wondering at the same time, "Did SCC actually try these on the Av, or are they recommending them because of the Av's tire size?"  While I ran into clearance with the brake line, they fit the tires great!

 

Brendan