Let's Discuss Non-Standard LATCH Spacing

LISmama810 · Jul 27, 2009

So...some cars allow borrowing LATCH in the center position.

And some car seat manufacturers allow you to use LATCH in those positions, usually (always?) if the spacing is between 11-20 inches.

But at a tech update I went to a while back, the Chicco rep said they don't allow non-standard spacing because the test bench has spacing of 11 inches, and therefore there's no way to test a seat with any other spacing.

With that in mind, how comfortable are you with non-standard spacing?

For manufacturers who allow non-standard spacing, what are they basing that on? Why 20 inches as a cutoff?

At the same time, seatbelt configurations come in a lot of different shapes and sizes, but there's no restriction on that. (Well, except for belts that ARE restricted, but not based on spacing...)

Does anyone have more insight on this?

LISmama810 · Jul 27, 2009

No one?

NannyMom · Jul 27, 2009

I'm interested in the answers. But I have none for you.

jess71903 · Jul 27, 2009

No insight, but I'm interested. It seems to me that there are lots of things that aren't standardized (seatbelts, seat slope, squishiness of the seats, RF tether locations, etc.) and I wonder how many of them affect the seats performance. This one seems to be pretty important and I would wonder if a few inches one way or another would make much difference.

Pixels · Jul 27, 2009

As long as it's allowed by both car and carseat, I'm fine with it.

The standard test bench only has standard spacing, but there's no real reason that they couldn't do due diligence testing on a bench with non-standard spacing.

Why 20 inches as a cutoff? Maybe because double the standard spacing is 22 inches, and they didn't want someone skipping over a LATCH anchor in order to borrow. I'm thinking of vehicles with 5 anchors across the bench seat, where one anchor is "shared" between center and one of the outboard positions.

LISmama810 · Jul 27, 2009

pixels99 said:
As long as it's allowed by both car and carseat, I'm fine with it.

The standard test bench only has standard spacing, but there's no real reason that they couldn't do due diligence testing on a bench with non-standard spacing.

But IS there another bench? The Chicco rep seemed baffled that any car seat manufacturer would allow non-standard spacing, because it sounded like there ISN'T any way to test it (short of creating an entirely new bench, which, perhaps, some companies have done).

NannyMom · Jul 27, 2009

LISmama810 said:
But IS there another bench? The Chicco rep seemed baffled that any car seat manufacturer would allow non-standard spacing, because it sounded like there ISN'T any way to test it (short of creating an entirely new bench, which, perhaps, some companies have done).

That may be the key. Maybe they use their own bench. Maybe they use benches from other countries as well? Just because it has to pass on ours doesn't mean they can't do additional testing on others

carseatcoach · Jul 27, 2009

I'm not super-comfortable with it, but that's at least in part because I think it's almost never necessary. There are very few seats that can't be installed with seatbelts just fine.

BookMama · Jul 27, 2009

I attended a CEU event last year where someone from UMTRI presented about a study they did regarding the effects of irregularly spaced lower LATCH anchors. They tested on several regular vehicle seats. Here are the notes I took:

LATCH anchor loads and the effect of irregularly spaced lower anchors (tests run w/o top tether)

No installation issues
No structural failure issues with the child restraints
No unusual ATD kinematics or accelerations - but small changes, usually w/no clear tendency

Rear-facing
Over rotation of CRS was the same or reduced with wider lower anchor system

Forward-facing
Head excursion movement was somewhat reduced in 2 cases and slightly increased in the third
Knee excursion was moderately reduced in 2 cases and slightly increased in the 3rd
Chest acceleration was slightly increased in one case and decreased or stayed the same in others

No drastic changes in performance!

Other changes in response variables were typically small.

southpawboston · Jul 27, 2009

interesting question. i'm not surprised that the test results don't differ much from standard spacing, at least from a physics perspective. i do think that the belt sustains higher tensile forces the farther apart the anchor points are. but again, the test results show no significant difference in seat performance, so that's moot.

however, i wonder what the effect of wider LATCH spacing would be in a side impact. physics would dictate that sideways rotation about the LATCH belt would be easier the farther apart the points of contact are with the immobile structure (the car). meaning, the seat could rotate left or right more easily when the LATCH connections are farther away from the seat. the seat could also slide left and right more than with narrower anchor points. whether or not it would be significant or not-- only testing could tell for sure.

Let's Discuss Non-Standard LATCH Spacing

LISmama810

Admin - CPS Technician

LISmama810

Admin - CPS Technician

NannyMom

Well-known member

jess71903

Ambassador

Pixels

New member

LISmama810

Admin - CPS Technician

NannyMom

Well-known member

carseatcoach

Carseat Crankypants

BookMama

Senior Community Member

southpawboston

New member

Car-Seat.Org Facebook Group

Sponsors

Forum statistics