DrJupeman

As the thread topic, indicates, I'm wondering if there is a safety advantage to a carbon kevlar seat, such as the Recaro SPA seats vs. fiberglass, such as the Recaro SPG seats. Is the carbon kevlar stronger or just lighter? (or given the huge price difference, maybe they are the panacea of stronger AND lighter)



(I tried a search figuring this might have been asked before but couldn't find any similar question...)

DanR

a comparison on material properties I would say there is little argument that like for like carbon kevlar is stronger than fiberglass. I would have thought that this translates into stronger seats.

DrJupeman

That's my thought, as well, but I'm wondering if these seats are made to minimally, or at least equally, pass standards (FIA, etc) and therefore the carbon kevlar is made to be simply lighter but not stronger.

Note that the weight savings on a % basis is very notable, the Recaro Hans Pro Racer XL SPA weighs only 45% as much as the Recaro Hans Pro Racer XL SPG.

RedlineMan

Hey;

Glasfiber is very easy to work with, has a pretty decent strength to weight ratio, and is cheap, not only in and of itself, but because it is used with fairly inexpensive and easy to use vinyl or polyester resin. Carbon is a good bit lighter, and much stronger, but is very much more expensive because it is used with more expensive and "difficult" epoxy resin, and because the necessary "layup" process is much more involved. The one thing that carbon is not - in relative terms - is tough. It is actually fairly brittle (much more so than glasfiber). That is where Kevlar comes in. It is not very strong at all (it is actually quite wippy), but is outrageously tough. So tough in fact that it requires special shears to cut it. It will ruin the best conventional scissors in only a few cuts.

You can't beat the strength and light weight of a carbon kevlar seat in any category but price. They are incredibly light and very strong. A glas seat will do a good job, but there is not really much comparison in the extreme. In the last few percent of need when things go wrong, you might wish you had C/K. For your purposes, Charely, I don't think there is much of a question as to which to choose.

RedlineMan

ummm...

I'd say this; I don't know if they "build them down" to the standard or not, but at the least there are probably many more severe stress cycles available to you in a C/K seat than a glas one, and certainly far higher, all things being equal.

paradisenb

The question is a very good one and I would like to know the correct answer.

If the 2 seats have the same specs there would no reason to buy C/K other than throwing money away in order to brag about having C/K seats or to save weight.

If the safety bar is raised in C/K then they are 'probably' worth the extra $$. Assuming a significate difference.

Cory M

Carbon/kevlar is significantly stronger than fiberglass and if it has been optimized (both design and build) it should also be significantly lighter, simply because it requires less material to make a part of equal or greater strength. All of the FIA approved seats meet or exceed the same specs, however I would assume the carbon/kevlar seats exceed the standard by a greater margin.

mglobe

OK, I'll play devil's advocate here. How many accidents do we know of where an FIA seat failure was the cause of an injury? Is any possible increased strength benefit from a CF seat REALLY a legitimate reason to buy one, or we just rationalizing? Personally, I would just decide if I wanted to spend the extra money to save weight.

IcemanG17

I would say any new modern FIA certified race seat is plenty safe....the benefit of the far more costly carbon-Kevlar seats if lighter weight and possibly stronger? Ihave racetechs 4009WHR and love them....not many wide hans seats out there under 20lbs (18.6)

fatbillybob

Here is another point of view. New FIA seats are not designed to be used with a back brace and not tested for one, with the exception of the racetechs 4009WHR which has back support built into the seat and mounting points on the back. It is pretty conclusive and done in NASCAR that seats are integral connected at many points to the cage not the car. Those seats are also almost always metal. So if we accept the idea that the full containment nascar style seat integral with the cage is the best there is then choosing unsupported C/K or fiberglass really is not much of a choice. But that's just another seat hollywar. The reality is 90% of drivers keep their plastic seats past the 5 yr. FIA legal point in clubracing and will retrofit a back brace. I would buy the Racetech seat with the integral back anchors because that seat is designed and tested to be used with a back brace.

J richard

Charlie,

I spent some time looking into this before buying a Fiberglas Recaro SPG Pro Hans, the bottom line is saving weight (about 7 lbs lighter) for the CF seat. They both seem to have about the same rigidity, if you grab the halo and twist they give about the same, the weight of the CF seat makes it feel fragile by comparison to the glass peice but CF is always suprisingly light. Pretty pricey for a few pounds imho...

kurt M

This is the conclusion I came up with after looking into the various systems. The CF/ FG thing is splitting fibers when you look at the leap you get with a multi point mount full containment system. I do not want to be held in place by something that flexes and displaces in relation to the belt mounting points. CF and FG base mounted seats noticeably flex when stressed even under normal driving conditions not to mention when you load one up with 50+ Gs. The car is the impact energy absorption system, not the seat. My reading lead me to conclude that the seat and belts work best when they hold you as immobile as posable.

Granted you can't mount a full NASCAR type alloy multi mount point containment seat in a DD Porsche but adding support to the back might help and using a seat tested and built for this even better I would conclude.

DrJupeman

Btw, the SPA (11#) vs. SPG (24.3#) in XL size is a 13# difference. But I'm interested in the safety difference, really.

Veloce Raptor

+1






Professional Racing and Driving Coach

chrisp

I would say that the C/K should be able to handle a greater number of severe cycles while the FG seat is more of a one-time use thing. Where this comes into play is an off track excursion where you get 2+ hard hits in the same incident...the most severe of which would be a big shunt into a wall followed by another car hitting you as a stationary object.

All this being said, the metal seats have the lowest yield (easily and permanently deform) follwed by FG and then by C/K.