Totally agree.
Look at mech33’s post history, he complains about everything. Nothing new. Let’s move on.

Anyways, if you opt for the eyelets, they rattle. I’ve had them. I’ve also had a straight top bar and partly curved top bar in my cars. The curved may give you and extra 1 cm of view, but really there is no big difference. To say there is a “major” block is hyperbole.

Ive had the CMS in my gt4 and will be going with them again in my 991.2 GT3RS

Stronger bar+view+phenomenal customer service makes me a repeat customer.

Some things for the OP to consider when looking at shoulder belt attachments on potential roll bars:

Eyelets are a trade-off. The belt snap rattles against the eyelet when it is dangling free when not being used, but they also make it easy to unsnap the belts from the bar and slide them through the seat openings to remove the shoulder portions between track days. When the belts aren’t snapped in, there is no rattle from the eyelets (unless the eyelts aren’t installed properly and not torqued down).

With a permanent wrap of the belts around the bar, you have to keep the belts dangling in the back somewhere. If the shoulder belts are permanently wrapped around the far rear horizontal bar (similar to the OEM Porsche Clubsport package setup), then the shoulder belts are long and the metal adjuster portions can rest down on the floor behind the seat when not in use (though they may slide around a bit in turns).

If the permanent belt wrap is sprung a horizontal bar in the closer main hoop section, then the belts are shorter and the metal adjuster brackets may be hanging and not fully on the floor when not in use, so some more care is needed to condigure they in some way so that they don’t whack into the back of the seat when driving / braking on the street.

If you run Schroth HANS belts, getting the 3” section compressed and pushed through the top openings on the LWB seats without scratching the metal adjuster against the plastic is tricky but do-able. If you don’t do that, you are stuck with the belts dangling right off the seat and the belt adjusters bump the carbon seat and door while driving (at least it didn’t on my car).

One nice byproduct of eyelets is when you unclip then from the rear, you can pull the narrower 2” section directly out through the seat quickly (rather than try and force the 3” section through the other direction).

Not everyone would notice and care about details like this when they’re actually using a bar, so keep that in mind.

More data for the OP: for reference, here is the view out the rear window of a 991.1 GT3 with a Cantrell roll bar that I snapped last weekend at the track. (I placed the phone right at my eye position while sitting, and took a photo looking through the rear view mirror).



I do like the Cantrell bar in general. Things I like:
- it has built-in belt loop capture (little wire loops around the bar at the belt positions) which keeps the belts from sliding around along the mounting bar
- they push the bar right up against the headliner (almost touching in the center, and almost touching at the edges), though it just has a single main hoop bar kink in the center, helping with visibility
- the sides of the main hoop are mostly vertical

Things I personally don't like about the Cantrell:
- you have to cut holes in the side panels (because the main hoop sides are more vertical, they intersect the side trim panels rather than clear them)
- the diagonals are pretty visible in the rear view on the left and right sides. I would prefer there to be pushed further out towards the edges to clear the view a bit.

Chris, fair points all. As an FYI we raised the rear cross bar to eliminate that issue. Having the rear cross bar low on the kickers allows it to most effectively reinforce the rear strut towers.

Also, be mindful that with a kicker-mounted harness cross bar (further from the driver), you should be using harnesses designed for that application. The shoulder straps will have a different elongation rate than the standard ones you’ll get if you buy “regular” harnesses.

Regarding the rear mounted harnesses, Schroth provides the standard GT3 harness set with shoulder belts long enough reach the rear kicker area, and the OEM Clubsport bar mounts them this way. Based on your comments, you’re suggesting that Schroth GT3 belts must be designed with the stretch appropriate for rear bar mounting (not close mounting like the CMS bar), since Porsche + Schroth together must be doing what’s right for the OEM Clubsport config.

So then if the Schroth GT3 belts aren’t the right belts for the CMS bar from a safety perspective, what belts do you typically sell with your bar for these shorter belt applications?

You have that backwards. Standard “off the shelf” harnesses, including the Schroth Profi II GT3, are designed for the shoulder straps to be mounted about 8” behind the driver. Its not a question of whether the straps will reach; it has to do with the rate and amount of elongation of the webbing in the event of an impact. Schroth and others do make harnesses with shoulder straps designed for mounting further back, as in Porsche’s race cars, and those are what PMNA uses in their factory race cars. They’re not unavailable to the general public, you just have to ask for them specifically. If you just buy “harnesses”, they’re designed for close mounting because that’s how the vast majority of race cars are designed.

As for the “GT3” version of Schroth harnesses, that has to do with mounting hardware that attaches to LWB OEM seat belt mounts instead of clip in-clip out. It has nothing to do with the harness material itself. Those are our most popular for the GT3/GT4 because of the hardware.

Also, make sure if you are using hard shoulder-mounting points to pay attention to how far apart they should be based on the distance of the driver’s shoulders (peak of the HANS) from the harness bar and his/her shoulder width. We don’t typically recommend the clip-in/clip-out shoulder straps. They’re easier to put in/take out for sure, but a roll bar manufacturer needs to be sure to get those measurements right for each driver so they’re in the right place.

I don’t understand why the Schroth “GT3” belts (which Porsche supplies for their OEM Clubsport package cars) come with shoulder belts so long and able to reach rear mounting points if they are not designed to do so safely.

If you have any data to back this up I’d love to red about it. In the Schroth manuals it just recommends certain lengths as ideal but to just cross the belts if you have to go longer.