twisting the buckle stalk...

sb518 · Nov 7, 2007

I know it's mentioned a lot here and stated that it is okay, but I was thinking today and was wondering who/when/where was this tested and deemed safe?

Thanks

Victorious4 · Nov 7, 2007

It's in the curriculum, I've seen it in a manual (don't remember which one, sorry) & SafeRideNews has published it as a recommendation: Subaru specifically has released an announcement that they allow it.

UlrikeDG · Nov 7, 2007

http://carseat.org/Technical/tech_update.htm#twistedvehbelt

SusanMae · Nov 7, 2007

If I remember correctly from last week in class---it was IMMI that did the test---and they're the ones who make belts(right?).

Susan

crunchierthanthou · Nov 7, 2007

Twisting the buckle stalk has been independetly tested by IMMI. There is a known reduction in strength of the webbing with each twist. That is why no more than 3 complete twists are allowed.

the initial letter from IMMI is in the appendix of theCPS manual- page 237 of the manual / page 27 of the pdf.

from carseat.org-
Vehicle belt webbing is extremely strong and can withstand pull tests of over 6000 lb. This is 3 to 4 times the strength needed to restrain a 60-lb child in a severe crash. Laboratory tests conducted by IMMI Child Restraints in 1998-99 found that the average strength of vehicle belt webbing, pulled until failure, gradually reduced depending on the number of full twists: 1=6%, 2=11%, 3=20%, 6=40%. Some of the webbing had been soaked in apple juice or cola, which resulted in slightly more degradation than untreated webbing. When other samples were twisted and later untwisted, the webbing returned to its normal strength. These data indicate that up to three full twists in belt webbing will not reduce its strength enough to risk failure when restraining a child.

shauburg · Nov 8, 2007

My vehicle owners manual specifically states that if you have trouble tightening the belt to "disconnect the latch plate from the buckle, twist the short buckle-end belt several times to shorten it and insert the latch plate into the buckle with the release button facing out". It's a 2001 Chrysler/Dodge Neon. I was actually really impressed with their instructions for installing child restraints - really detailed and helpful with all of the possible problems you might encounter:thumbsup:

bombedier · Nov 8, 2007

Yup - IMMI tested it and came out with the max recommendation of three twists.

sb518 · Nov 9, 2007

cool thanks. I wonder now if you could twist the crotch strap on a car seat to bring it lower if needed, with a belly pad behind it??

joolsplus3 · Nov 9, 2007

No way. Seatbelt webbing is designed to hold like 6000 pounds of force and turning it only reduces the strength by like 40%...but a crotch strap is much thinner, designed for much less weight...you don't want to take 40% of it's strength away. And there's no need to, honestly, harnesses are designed the way they are for a reason...

twisting the buckle stalk...

sb518

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