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If a non-triangulated rear diagonal is good enough for the OEM Porsche GT3 Clubsport and GT2RS Weissach titanium designs, it's good enough for me!
For me personally, it was more important to have the bar hug the headliner so that the bar would start "working" in preventing a roof collapse before too much had crunched down towards my head.
But that's the great thing about having options: each customer can choose what's important to them.
Well put Mech33!
We chose to adopt the guidelines set for roll cages by the FIA for our LMS and WEC models. I think stating it in this thread will be helpful to those who are trying to weigh out their options, and what they like in a roll bar!
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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.
I contacted Schroth USA to inquire about the 8" rule as most bars don't allow for that. They said the manual is a bit misleading in wording. You can have more than 8", shorter the better. But if you have more than 8" than you need to bring the belts straight out the seats from your shoulders and cross wrap them, doesn't matter which side is on top or bottom. Also said just don't go crazy with more than 20-24" distance. The greater the distance the bigger exposure to potential web flex/stretch.
I contacted Schroth USA to inquire about the 8" rule as most bars don't allow for that. They said the manual is a bit misleading in wording. You can have more than 8", shorter the better. But if you have more than 8" than you need to bring the belts straight out the seats from your shoulders and cross wrap them, doesn't matter which side is on top or bottom. Also said just don't go crazy with more than 20-24" distance.
Thank you for this post. It does not seem like GMG or the other manufacturers are doing the cross wrap as their belt to bar length is very long. The shorter, the better on the strap length to the bar makes sense. Appreciate you contacting Schroth.
Happy Thanksgiving tomorrow to all of those in the USA! We just wanted to stop in and thank all of our existing customers here on RL for all of the past business. To show our appreciation, lets run a sale and save you some $$$ on a roll bar. Who doesn't like a deal for Black Friday while digesting all of the Turkey and other Thanksgiving goodies? We have been approached by fellow RL members asking about a sale on the CMS roll bars. Ask and you shall receive . Now thru Monday, use RL15 coupon code on our new website to save 15% on your new roll bar for your 991.
Just saw this post. Thanks for sharing the FIA rules! It helps confirm that in general most all of these aftermarket roll bars meet this rear diagonal criteria. As it says in the docs:
"The upper end of the diagonal must join the main roll bar no more than 100 mm from its junction with the backstay, or the backstay no more than 100 mm from its junction with the main roll bar."
I measured my BBi bar, and the rear diagonal junction is at the absolute worst case ~83 mm (~3.25") from the backstay junction with the main roll bar. Per the specific measurement spec, in reality it is closer to ~50 mm (2") since you measure the closest distance from the backstay to main hoop contact.
Originally Posted by gmgracing
Well put Mech33!
We chose to adopt the guidelines set for roll cages by the FIA for our LMS and WEC models. I think stating it in this thread will be helpful to those who are trying to weigh out their options, and what they like in a roll bar!
Happy Thanksgiving tomorrow to all of those in the USA! We just wanted to stop in and thank all of our existing customers here on RL for all of the past business. To show our appreciation, lets run a sale and save you some $$$ on a roll bar. Who doesn't like a deal for Black Friday while digesting all of the Turkey and other Thanksgiving goodies? We have been approached by fellow RL members asking about a sale on the CMS roll bars. Ask and you shall receive . Now thru Monday, use RL15 coupon code on our new website to save 15% on your new roll bar for your 991.
Had your bar in my gt4 and looking forward to putting one in my 991.2 gt3rs.
Does anybody know if all harnesses need a sub bracket for 991.2 GT3 w/LWB?
I'm looking at Schroth Flexi 2x2.
5 pt and 6 pt yes. 4 pt no.
edit: also- you’d need to cut the carbon on the passenger seat to run a 5/6 pt. The driver side is pre cut from the factory. Many folks run a 6 pt on the drivers and a 4 pt in the passenger because of this...I did the same as I didn’t want to cut the seat.
edit: also- you’d need to cut the carbon on the passenger seat to run a 5/6 pt. The driver side is pre cut from the factory. Many folks run a 6 pt on the drivers and a 4 pt in the passenger because of this...I did the same as I didn’t want to cut the seat.
Ah, I read about cutting. Yes I don't want to cut the seat. So a 4 point will work on passenger with no cutting. Our local PCA seems to have a rule that the passenger (instructor) should have the same safety gear the driver is using available.
CMS says the Flexi 2x2 has a special bolt in attachment to use factory mounting points for the sub. I would think they know, but is that not correct?
Ah, I read about cutting. Yes I don't want to cut the seat. So a 4 point will work on passenger with no cutting. Our local PCA seems to have a rule that the passenger (instructor) should have the same safety gear the driver is using available.
CMS says the Flexi 2x2 has a special bolt in attachment to use factory mounting points for the sub. I would think they know, but is that not correct?
Our PCA has the same rule and our local track has a ban on 4 pt. I took the harness out for PCA events.
I found it a bit silly...but PCA has always been a bit silly. When testing to run solo in the past my chief instructor WANTED me to take more risks in the run group, not later braking, early power exit ect. But running up on cars in front, corner diving, ect. Things I later learned through actual track driving schools as poor form. So I take PCA in general with a grain a salt and I recommend my friends do the same.
Cant help you on the flexi 2x2, no experience with that.
Ah, I read about cutting. Yes I don't want to cut the seat. So a 4 point will work on passenger with no cutting. Our local PCA seems to have a rule that the passenger (instructor) should have the same safety gear the driver is using available.
CMS says the Flexi 2x2 has a special bolt in attachment to use factory mounting points for the sub. I would think they know, but is that not correct?
They must mean factory attachment points for the lap belt. All of the "GT3" series Schroth belts have a special lap belt bracket that attaches easily to the OEM LWB seats, but you'll need a sub strap bar to run 6-point on the drivers side.
Personally, I prefer the Cantrell sub strap bar design.
They must mean factory attachment points for the lap belt. All of the "GT3" series Schroth belts have a special lap belt bracket that attaches easily to the OEM LWB seats, but you'll need a sub strap bar to run 6-point on the drivers side.
Personally, I prefer the Cantrell sub strap bar design.
Yeah after a bunch of reading I think CMS is thinking lap belt. I did ask about sub brackets though.
Do you know if the passenger seat cut is a notched section of the seat? As in factory marked for cutting.
Yeah after a bunch of reading I think CMS is thinking lap belt. I did ask about sub brackets though.
Do you know if the passenger seat cut is a notched section of the seat? As in factory marked for cutting.
No, it’s flat carbon where it needs to be cut. Though the felt cover stuck to the carbon does have an opening in it like the drivers side roughly outlining where the cut would go.
10-12-2018, 08:07 AM
Per the specific measurement spec, in reality it is closer to ~50 mm (2") since you measure the closest distance from the backstay to main hoop contact.
PM for info
