Roll bar clearance for L7C track days

[tomlil01]

Hi, all,

 

I am hoping someone might be able to assist. I am booked up for three L7C track days later this year, after getting my first Caterham and joining the club in December, and I am just trying to understand the requirements around roll bar clearance.

 

I have an R300 SV with standard floors, tillet seats and an FIA roll bar. I am 6 feet tall. I have read the article about safety requirements for the L7C track days, and understand that I need at least 5cm clearance between the top of my crash helmet and the line between the rollbar and top of the bonnet.

 

Sitting in the car today wearing a crash helmet just for testing, I found that my head was pushing up the half-hood quite considerably, and therefore would be above even the line between the rollbar and windscreen, never mind the line between the roll bar and the top of the bonnet.

 

I appreciate that I can get a lowered seat, but I had some questions before going ahead with this:

 

1) Would you expect that at 6 feet I would need lowered floors? I don't consider myself particularly tall and I understand that the tillet seats already put me relatively low compared to the leather padded seats. Have any of you of similar height needed to lower your seat to achieve the required headroom for the L7C track days?

 

2) is there a risk that even with a lowered seat I would not be eligible for the track days. I am concerned that I only get about 5cm lower with the lowered seat, and I feel like I'm way off at the moment.

 

3) I was sitting with my back flat against the seat when measuring my height today. Obviously I could get much lower by sliding forward in the seat. Is that "the trick" to achieving the required headroom?

 

Any advice very much appreciated.

 

Thanks

Lee

[SLR No.77]

Are your seats bolted directly to the floor without spacers?  I don't ask this with a thought of removing spacers, but it's possible to add more spacers to the front mounts (between the seat and the runner) to enable the seat to be reclined a little. My front seat mounts have around 25mm of additional spacers compared to the rear which makes a big difference to how high you sit in the car, it's quite surprising how much is gained for a relatively small adjustment.

Im 5'11" but long in the body, roll bar height was always an issue but having fitted lowered floors and reclined the seats I now look through the middle of the screen rather than near the top of the frame. I did think all SV's had lowered floors but obviously not!

Stu.

[SM25T]

It all depends on if your height is in your body or legs.

[Wrightpayne]

Taller FIA bars are an option though your full hood, possibly half hood and boot cover wont fit.

I'm 6'1" in an S3 and have a lowered floor and find it creates a lot of extra cabin room for knees and feet. Not so much of an issue in an SV. I also feel I sit in it rather than on it.

I also have a tall cage fitted so am well below / clear of the tubes.

Ian

[tomlil01]

Thanks, Stu. Think I had heard about tilting the seat with spacers, but had forgotten about that option. My only concern with that is that I'm potentially tilting my knees onto the steering wheel.

[Shortshift]

Lee

Just to clarify, the Club's trackday rules (TSRR - on this site under 'Trackdays' in the blue menu bar) specify the requirement for clearance as follows:

No mention of 5cm...

James

[tomlil01]

Aha, thanks, James. That is very helpful.

 

I was looking at the PDF "Roll Bars and Roll Cages", and that mentions 5cm. However, I just re-read it and it says "for motorsport", so I assume not relevant for L7C track days.

[GulfSeven]

When I specced my 310R I got the trackday roll bar (similar to the FIA roll bar) and lowered floors for exactly this reason. I'm 5'11"...

[tomlil01]

Thanks for the info. I don't think I'll go down that route, as I don't want to have to replace or stop using my hoods and covers etc. Hoping the lowered floor, possibly with a bit of tilt on the seat will be enough.

[Golf Juliet Tango]

You found a simple and quick way to test clearance (if any) even if it is a bit rough and ready.

This article from the archives illustrates things.

http://lowflying.lotus7.club/2016/2016_03_05_Rollbars.pdf

also: http://lowflying.lotus7.club/2016/2016_04_09_Rollbars.pdf

You probably understand the harness but here is a reminder: http://lowflying.lotus7.club/2015/2015_09_02_Harness.pdf
 

[tomlil01]

Thanks, all, for the advice. Very much appreciated.

 

Just to clarify, I noticed that the TSRR does actually mention the 50mm clearance, but in section (5) "Recommended further safety measures", so it is recommended but not mandatory.

 

I've now booked my car in to get the floor lowered before my first track day, and I will sit in a car with a lowered floor beforehand to see whether I also need the seat tilted backwards a bit as well.

 

Out of interest, does anyone know where I can obtain spacers to tilt the seat back?

[Shortshift]

"Just to clarify, I noticed that the TSRR does actually mention the 50mm clearance, but in section (5) "Recommended further safety measures", so it is recommended but not mandatory."

James

 

[SLR No.77]

Spacers: https://www.ebay.co.uk/itm/Tillett-Kart-Genuine-Nylon-Seat-Washers-Spacers-2mm-x-51mm-Pack-of-20/142175888276?hash=item211a57e394:g:xqIAAOSwakteeyU9

These are 2mm think but Tillett do a 4mm (IIRC) thick version also. In practice any oversize washers in hard plastic or metal will be fine, I have some machined aluminium cylinders to give 25mm extra height at the front plus plastic spacers at the rear to accommodate the angle, I now see they have a rubber version available which might be better at the rear.

Caterham used to sell the thicker Tillett spacers but they don't appear to be on the parts website, it might be worth calling them.

Stu.

[Red Line Components]

Lee

The spacers have been added to your Lowered floor order, 

many thanks

[tomlil01]

Thanks, Chris!