There are basically three options for seating yourself in an Academy race car - ensuring you are perfectly positioned, securely seated and below the 5cm regulation are the ultimate goals... Here are the options:-
First job is to remove the drivers seat - I got the shoulder belts out of the way, but was undecided about removing the lap and crotch straps, so thinking the fit would be more 'snug' if the seat was moulded around them - I left them in.
Next step is to prepare the 'bead bag' for a dry fit and to do so you need to lay it out on the floor, ensure the beads are evenly distributed and then using the hand pump vacuum out the air until there is an orange peel effect.
Here's a picture of the hand pump attached to the bead bag. The clear tubing needs a little bit of heating with a heat gun so that it goes around the valve nozzle on the bead bag, but then this gives it a really good fit. Also when you start to pump the air out the top button on the bag valve needs to be depressed.
With the bead bag removed of it's air, carefully insert the bag into the car ensuring the bag is pushed into all the corners.
Then carefully get into the car - I thought it best to do so with all the gear on for a prefect fit. Wiggle around until you get your driving position correct and get your 'assistant' to pack the beads behind you properly and to measure that the top of your helmet is lower than 5cm below the top of the roll cage.
Once you've got your dry fit position correct, you need to (roughly) remember this and carefully remove the bead bag from the car, so that you can add the resin. As the resin containers looked unusual it was time to get the instructions out - but the instructions are very clear which means the containers are straight forward to use to mix the resin and hardener.
It's recommended to give each container fifty clockwise pumps to fully mix the resin with the hardener. It's fairly thick stuff, so you'll probably get a sweat on - I certainly did!
With all the resin mixed, you remove the valve from the bead bag, and then using the plunger with the resin container squeeze the mixture on top of the beads in the bag - trying not to get any on the edges of the bag or the valve neck. With all four bottles of resin now in the bead bag, you'll need your 'assistant' to help you knead the bag for around ten to fifteen minutes to thoroughly mix everything.
As the resin mixture is black and the beads are white you'll see when the resin has thoroughly covered all the beads as the bag takes on a grey colour as per the picture below.
Now vacuum out the air to give the bag the orange peel effect and then carefully put the bag into the car, again pushing the bag into all the corners.
I thought it best to put all the gear on again (but in hindsight, had the bag ripped and covered my suit this would've been an expensive mistake, so maybe not recommended) I got my driving position right, Charlotte put plenty of material behind me and packed the lower spine area out which helped get a super snug and very well supported position. Happy with the driving position, I used the hand pump to ensure there was a good vacuum.
One of the benefits of a DIY bead seat is a beer (light of course - I'm a racing driver! ☺) while you wait half an hour for the resin to go off...
After the required half an hour elapsed, I could feel that the seat was much firmer, but still very carefully removed myself from the car trying not to dislodge any of the beads. The seat was then left to fully cure overnight.
Before I left for work the next morning, I had to give the bag a prod - it had definitely cured that's for sure... When I got home it was time to try and get the seat out... Using the hot wire foam cutter (which is extremely satisfying to use) I started to cut the excess material off the seat - trying to not cut too much off, then got back in the car, checked how much more I can cut off and so on - this took around three hours.
Charlotte and I thought enough material was cut off, so tried to get the seat out - but managed to get it wedged, which tool some effort to get back in to the car.
We carried on trimming the edges off the seat, made the holes for the lap and crotch straps and eventually it looked something (half) decent... The main things to consider when cutting the seat are the area behind your shoulders, the front edge (ahead of the chassis cross member) and also if I done it again it'd be worth putting some cardboard (or other stiff material) next to the transmission tunnel to flatten off the 'lip' the tunnel cover makes, but on this occasion I'll just trim off some of the seat material instead.
- Use the supplied Tillet seats (filling void behind seat with foam)
- Make a two part expanding foam seat - which can be made at home for around £50 / £60 (also known as a bag seat)
- Or... Invest in an bead seat (professionally made 'start' at £900!)
As I'm used to the standard Tillet seats from driving in the R500 over the last few years I feel they are an 'ok' fit for me, but I still move around in them a little... Having measured up I'm just under the 5cm height below the top of the roll cage, so I could use the Tillets, but I wanted a more snug fit.... The bag seats (although extremely cheap) are prone to shrinkage, so like a magpie to shiny things - I've decided to go down the bead seat route.
A professionally made bead seat 'starts' from £900 (plus finishing!) but I found that you can buy a Real Essentials DIY bead seat kit for around £300 from Demon Tweeks - you'll also need to buy the £45 hand pump and to spend another £100 for an Engel hot wire foam cutter, but I'm sure a decent hacksaw would suffice if you don't want to buy the cutter... At the above costs, I worked out I can c0ck it up at least once and still be quids in, but without buying the hot knife cutter (albeit expensive) you technically could c0ck it up twice...
Onto my attempt at making my own bead seat
If using this blog post as a 'guide'... A bit of a disclaimer - it's worth reading everything in this post before you 'have a go' yourself.
Demon Tweeks advised a 90 litre kit would be the right size for a Caterham, as it's always worth having more material than less, so I went with their advice. (I'm 6ft and around 11 stone 10 - so you can get an idea of my size)... I personally think I could've got away with a 70 litre kit, but have read reports of some 'larger gents' only needing a 50 litre kit...
This is what is supplied in the kit...
- A 90 litre 'bead bag' with a vacuum attachment
- Sufficient containers of unmixed resin and hardener - 4 are supplied with the 90 litre kit
- Two decent sized sheets of covering material (enough to cover the whole seat)
- Spray adhesive for covering
- Instructions ☺
|90 litre Real Essentials DIY Bead Seat Kit|
|Drivers Seat Removed|
|Bead Bag Laid out and Flattened|
|Hand pump used to vacuum air out of bead bag prior to dry fitting|
|Dry fit bead seat inserted into car|
|Bead Seat dry fit - wearing all the gear...|
|Bead bag removed, time to read the instructions... Again!|
|Mixing the four bottles of supplied resin and hardener|
|Kneading the resin mixture and beads takes around ten to fifteen minutes|
|Beads and resin now well mixed and vacuumed ready for final fitting|
|Now it's time for the final moulding / fitting and the bead bag goes into the car|
|All the gear (again!) and using the hand pump to vaccum out the air|
|The benefits of a DIY bead seat - a (light) beer (of course) while you wait half an hour for the resin to go off|
|Half an hour later you can get out and leave it to completely cure overnight|
|Trimming the excess off the seat using an Engel Hot Knife|
|Bead seat got wedged in one of the removal attempts - need to remove more material!|
|With a bit more trimming and the belt holes opened up it's beginning to look half decent|
I'm extremely fortunate to be able to go to Spa this weekend for back-to-back track days with Book-a-Track, so I'll use the seat in it's current state and will take some 'adjustment tools' with me (a rubber mallet) and will adjust the seat if any areas are uncomfortable or need modifying.
Granted this isn't a 100% professional job, and there are some things I'd do differently next time given the experience I have now. It took around six hours in total to get to this stage - three hours for the seat fitting and another three hours for the cutting / trimming, so for the £900 it'd cost to get a 'professional' job it's probably not a bad deal - time is money and all that!
Once I return from Spa and as long as I'm happy with the seat I'll then fit the covering material and the seat will be finished.