Widening a rear tub?

[adrianreeve]

I've just realised from HandyAndy's recent thread that having the bottom rear tube that the fuel tank straps weld to in the 'book' place means the fibreglass rear end won't fit. It's too late to change that for me now, as my roll bar rear stays are attached to the corners of this tube, and I've just cut off the beautifully tigged on rear curved tubes that came with my chassis in preperation for the rear tub!

How hard would it be to take one of fabby's rear ends, slice it, and add 40mm to it to make it fitt the book dimensions?

If Saturn are listening, is it something you may consider in the future,a s it would make things that bit easier, and also mean you could use a book fuel tank, along with a little bit more luggage space!

Cheers

Adrian

Would mean a new plug and a new mould and not as easy as it sounds. Just adding 40mm to an existing panel would leave a join line in the wrong place and would be hard to hide it.

[spud69]

As Mark says it would mean an awful lot of work to make a new rear plug and mould for the rear end. In consolation i made my chassis the same way as yours then realised that the rear end i got from Mark wouldn't fit so i added an extra piece above each wheel arch to lengthen the rear end. It doesn't look too obvious but i would have rather known in advance to make the chassis to fit the rear panel. Would have been easier to.

you don't loose all that much from fuel tank and boot space and may be something that we can look at in the future.

Regards.....Andrew

[HandyAndy]

Hi Adrian,

sorry , i m not sure i understand what you mean
do you mean the round tube at the bottom ?

are your back stays welded into the bottom corners or bolted?

when i got my rear tub i basically placed it into position & built my rear chassis in conjunction of the tub shape/dimensions,

unless i,m getting too old & losing my memory i used some photos that you posted as a guide to what i did, i,m confused

ahh, is the prob with your new chassis? ( i think the penny has just dropped into place) not meaning the chassis is a prob,
cheers
andy

[adrianreeve]

Cheers for the replies guys. My problem is that the roll bar rear stays are bolted to plates welded to the rear tube, and obviously fully welded at the roll bar end, so they cannot be moved now, Ithink the easiest thing to do may be to put the curved rear tubes back on and do the rear end in Ali, sprayed black.

Ho hum, the joys of car building!

Cheers

Adrian

[HandyAndy]

are the plates welded into the corners of the round tube? or if welded into more central position, maybe unbolt the backstays & fabricate new plates to re attach the back stays into the new square tube needed for the grp tub,
just a thought.

cheers
andy

I don't see what the rear stays are going to do sat on top of the rear hoop, to be of any use in the event of turning turtle they would be better running down to the diff area where the chassis is stronger.

As for the back panel, well it was never intended to be used with the set up in the book....The Haynes isn't a "bolt together kit car" so having to make the odd bracket or change a few things is no real drama and doesn't affect your warranty as you don't get one if you built the car yourself

[adrianreeve]

Andy

No they're welded into the corners. I've had a eureka moment though.... I'm going to do the rear and side panels in Ali, then get them painted black, once on the car, at the Caterham factory (their body man is a friend of my brother in law, and owes him a few favours!). It'll be more work, but save me about £200, so every cloud etc!!!

Cheers

Adrian

[adrianreeve]

Fabby

Obviously didn't explain it very well. The rear stays go from the top of the rollbar to the bottom of the chassis at the rear, and are tied into the rear suspension structure. I used some stress analysis software to ensure that the design was sound (my first job after uni was as a design engineer).

I'm totally happy to make it up as I go along, I agree that's the fun. If I didn't want to, I'd have bought a kit. I was just trying to work out the best way of remedying my current situation, as I have a completed 'book' chassis that I was loath to cut into again.

Hope your shoulder feels beter soon.

Cheers

Adrian

[frankie boy]

Hi Adrian

I am in the processed of making bucks and moulds for the roadster. My back panel will go over the rear tubes as the book. The side panels will have the curved section and will come up to the nose cone with a curved to the bottom. I’m looking to get them ready for detling kit car show next year if all goes well.