TR6 Rollcage / bar safety

[barkerwilliams]

TR6 driver & passenger safety.

 

I have a TR6 without a roll cage / bar and common sense tells me I should consider fitting one. But what is the best way to go?

A roll cage is obviously stronger in certain scenarios, a bar looks like it may be deformed in a big impact.

So what does TR6 accident history show?

Have there been many accidents in which serious damage occurred to the occupants that a bar might have mitigated?

Have there been many accidents in which a simple bar “failed”.

 

Does the TR Insurance hold actuarial information of roll cage / bar performance?

​

I know all accidents have a downside and I don’t intend stir any bad memories for members, I would just like to protect my loved ones in my car.

 

Alan

​

[Alec Pringle]

Cage is OTT for a road car, but a decent roll over bar which goes down to the floor, twin backstays and preferably a diagonal, will make a very substantial difference in a major impact - it's not so much the rolling over, not so common a happening, as the much more common side impact T-bone situation where it really makes a difference.

 

Whilst you're at it, get a firewall installed behind the rear trim panel, to keep fuel in the boot in a severe impact.

 

Need I add, both the rollover bar and the firewall significantly improve stiffness, therefore handling, and also tend to reduce rattles and bangs . . . . .

 

Cheers

 

Alec

[Peter Cobbold]

Alan,

A cage exposes the sides of the skull to steel tubes and the foam protection needed to dampen skull/tube impacts may well be excessive. Racers rely upon helmets to lessen the risk.

A roll bar can be more easily covered, but some form of head rest is still a good idea to lessen the risk of the back of the head hitting a steel tube.

My Aleybar hs four mountings, the front ones go down the floor and bolt to the inner wing near the seat belt anchorage, and do limit rearward seat adjustment. But it is 35years old, the latest devices may well be better.

Peter

[Motorsport Mickey]

+1 with Alec.

 

Having raced a number of years it's never ceased to amaze me how when a car has spun or left the track at speed and it looks to have recovered, yet in the final throes of sideways motion at lowly speeds of maybe 20 or 30 miles an hour a wheel digs into a soft verge and the car rolls in seeming slow motion with only just enough energy to complete a revolution and with no injury to the driver.

Yet in a similar incident on the public roads caused by a swerve or other manoeuvre and with many more likely obstacles to trip the car the same low speed roll would likely kill or severely injure the occupants. The windscreen frame folds very easily and cannot offer help to the occupants, and even the best safety belts or harnesses only hold the unfortunate victims in place whilst a ton of car smears them into the road.

Also Alec mentions the fitment of a rear of cockpit alloy firescreen, this fits between the fuel tank and the cockpit with the original fibre board in front of it, unseen to all but offering greater safety in the event of the above mentioned car roll or a heavy impact from the side which causes the cockpit to lozenge and with it the frame holding the fuel tank which ruptures it allowing 10 gallons of fuel through into the cockpit and occupants. It will cost about £60 ish pounds to buy a pre cut alloy firewall from one of the TR specialists, (sold by all of them who prepare completion cars) and take you probably a couple of hours to rivet it into position with a tumescent sealer behind it, probably the most cost effective safety measure you can spend on a TR.

 

Mick Richards

[john.r.davies]

All good advice above, Alan.

 

Mickey makes the point that the most experience of accidents and the protection afforded by roll over bars (they are now "Roll Over Protection Systems"! ROPS!) is from motorsport, and the best guidance on design and construction is in the Motor Sport Association's Yearbook. Section K Safety gives every specification and approved design from a simple hoop, all that is needed for a road car IMHO, to a full cross-braced cage.

 

The design feature that is most often omitted is the diagonal tube, which IMHO is the most important part. That is what prevents the 'lozenging' that Mickey refers to, by transforming the reinforcement into a set of rigid triangles.

The backstays have a similar role (!), and without them a bar is just bling!

 

See the MSA's SEction K: https://www.msauk.org/assets/153191commonregulationsforcompetitorssafetyk.pdf

This provides you with all the questions you need to ask a supplier.

 

John

Edited November 26, 2015 by john.r.davies

[Marc R]

Hi John,

 

Thanks' for the document, if I well understand for an open car we must consider the drawing 60 (i) and 60 (ii) on page 190. Is it correct?

 

Regards

Edited November 26, 2015 by Marc R

[john.r.davies]

Thank you, Marc!

Yes, when reviewing my post above, I meant to refer to those and the height (P.60(ii)).

If a bar that fits under your soft top/roof will not let your head clear that line, then suggest lower seats?

 

Kirkey seats are about the closest to the floor. They look like mediaeval instruments of torture, but are amazingly comfortable, even without any padding at all!

Here they are in a GT6: http://www.britishracecar.com/ScottJanzen-Triumph-GT6.htm

And you can get thin padding for them if you must: http://www.britishracecar.com/PatRyan-Triumph-Spitfire.htm

 

I know people will say - these are pure racing cars, but Binman and I drove the old Club Triumph 10CR (Ten Countries around Europe in three days) in his SuperSix that has the minimally padded Kirkeys, and I can tell you they are comfy!

 

John

[Marc R]

Hi John,

Superb, I may also forward this information to some triumph's enthusiasts via the Triumph Club de France Forum.

Regards

Edited November 26, 2015 by Marc R