I'm sure most of you know the old seatbelt trick that many of us who don't have racing seats/harnesses use while on track:

Recline seat about 8 inches from normal driving position, yank seatbelt forward quickly to engage intertia lock, while holding it in lock position move seatback forward. This keeps the factory 3-pt harness locked on your body until you release it.

I have a question though. Do you think repeated use of the factory seatbelt in this way has a potentially dangerous outcome of wearing out the inertia lock? Car is under warranty, so I'm sure BMW would replace if it broke...however I would hate to find out my seatbelt lock broke the hard way (if god forbid i got into an accident on the road!). Any thoughts?

 

If your instinct tells you it's not a good idea, than you are probably correct. On the other hand, their is a simple device that can be purchased that does the same thing, but locks the lap belt only I believe. Bimmer Performance Store sells them, and if they don't, they are easy to find and fairly cheap. As for their safety, I am not sure either.

 

http://www.cg-lock.com/

 

Right. Am aware of CG lock. It just doesn't lock across shoulder.

 

The CG Lcok works very very well. I use it all the time. On the track I set my seat where it needs to be and then just tighten up the CG Lock but I still lean the seat back and give the shoulder belt a quick tug to lock it in place and then just lean the seat forward....works perfectly.
I'd love to have a roll bar or harness bar but my car is a weekly driver so that is not going to happen.

 

Right, but it's the 'quick tug to lock it in place' that i'm asking about. Securing the shoulder portion of the belt in this fashion no doubtedly puts wear/strain on the seat belt locking mechanism. I'm just curious if anybody has had problems with their seat belt locking after doing this several times.

 

if locking the belt would break it, i'd be worried of having it save your life. i'd think it's over engineered and well tested. it's not like you are abusing it...

 

I just got a Schroth Ralley 4 harness, It is a quick release harness and is street legal. When I dont want it, I simply un-click it and lay it behind the driver seat. It works great.

 

dont worry about using up the inertia lock...child seats use that lock all the time and you dont hear to much about people breaking or damaging them

 

PCA will not allow 4-pt harnesses for their events, otherwise I would consider the Schroth harness.

 

How does this Schroth harness work with the stock seats and belts? Do you need a harness or roll bar?

 

No harness or bar. See the link below. 4-pt has no anti-sub strap, and is not allowed in many club organized HPDE events. So it's pretty much useless unless you want to look really 'cool' driving around town in a harness.

http://www.schrothracing.com/products/Tuning

 

Actually the Schroth harness has and anti-sub device. The inner shoulder belt has about 8 inches of extra fabric folded up inside of a plastic retainer that give away in the event of a crash and acts like a 3 point. I also wear the factory belt along with the Schroth. The scroth is mainly inly to hold me in the seat during turn, not protection during a crash. It is also allowed by SCCA so it works great for track days and autocross's.

 

How do you still use the factory 3-pt while using the schroth 4-pt? The quick-fit pro system clicks into the factory 3-pt harness points. And the 8" of extra material may very well prevent submarining, but it's still not considered an anti-sub device.

PCA and several BMWCCA do not allow 4-pt harnesses...period.

 

Mine is not the quick-fit system. It is bolted into the factory seat belt point and is complete independent of the stock three point system.

And i dont have a Porsche or BMW so i am set. I am using it mainly for test-n-tune days and autocrosses, which on done on a road race track, not a parking lot?