biasbilt

Don't forget that the nose of the diff will rise slightly under torque which will increase the angle between the 2 flanges (ooer missus). Should really be down by a couple of degrees or so they are parallel when driving

You'll need to give a bit more info on how you're planning to mount them. I'm pretty sure 2.5s won't fit through the coil platform and provide clearance at all axle positions plus bush compliance. To get them on, you'll need to mount them out side of the coil and fabricate top and bottom mounts to suit. Let me know if you want any more advice. Cheers, Toby

44mm tubing is not MSA approved for cross country events. You do not need to use CDS for cross country events as pipe to EN10255 ('blue band') is allowed. The key advantage of going to CDS is the increased material strength allows a thinner wall thickness to achieve equivalent strength with a the consequent weight reduction. Unless you are going for speed events, this probably not a key consideration. The pipe allowed has the following dimensions for mandatory members: 42.3x3.2mm for vehicles below 1000kg and 48.3x3.2 for vehicles above 1000kg. The cage needs to be made to an approved design (as per the blue book) and optional members can be of 30x3.2mm pipe. Hope this helps and you haven't already started. As said previously, the cage needs to be done properly if it is to perform as designed in the event of a roll. Cheers, Toby

I converted a set of old arms to take these bushes and after 2 years and probably 8-10 events, they are still in perfect condition. As far as I'm concerned, they're evirtually fit and forget, unlike the axle end bushes which need replacing every couple of events. Highly recommended! Toby

You want to chat to Falkners, as they will design and custom wind any spring for you, at very reasonable prices. I have just order 8 springs for the racer, and was very impressed with the service and price. I haven't received the springs yet, but the order is being turned around very quickly (2 weeks for a custom designed and manufactured product). Assuming the springs are as good as the service, I will have no hesitation in using them again. Other friends who have used them have been more than happy with the product. For info, they supply springs to Milners, Prodrive, Prolinx, White Power, Demon Tweeks and other high profile motorsport supplier. D. Faulkner Springs LLP, Greensleeves, Northfields Lane, Westergate, Chichester, West Sussex, PO20 3UH ENGLAND. +44 (0)1243 543049 +44 (0)1243 542133 sales@dfaulknersprings.com And you want to speak to Peter! Hope that helps, Toby

Many thanks. I'm up for a meeting on 30 Aug, so will be in touch nearer the time.

Hi Warthog, Can I claim those bad boys, they'll work out well for a set off road rims for my old 4-runner on spare diamond tyres. I'm not in Swindon until the end of August, but could collect them then, if you're in no hurry to get rid of them. Thanks, Toby

The other thing you have to take into acount, is that although you have done what appears to be an okay weld, you are weldin 6mm to 3mm, so the potential failure is going to be tearing the weld out of the chassis (before the 6mm plate fails). Some extra gussets underneath, tying down the insdie of the chassi would definitely be beneficial. Toby

I can recommend Nigel from HJ Chard (builders merchants, but their propshaft workshp is very specialised), who are in Bristol. They are local enough for you to take the car to (which means no mistakes in measurement/misinterpretation of your measuremnts), and he is very knowledgable. He built the driveshaft for the 4x4 Aston and Jag used in the James Bond film a while back. H J Chard & Sons Address 1 Cole Road Town City/County Bristol Post Code BS2 0UG Tel 0117 977 7681 Fax 0117 971 9802

Put a beadlock on your 7" rims, which'll bring the new width out to about 8". This will then give you the rim width you need plus the advantage of beadlocks - easy!

I cut the ends off the axle and rotated them to give more castor, to help turn in ( I think to about 6 degrees negative) on my comp safari racer. Due to the design of my frame, the radius arms are horizontal at ride height, so diff pinion angles weren't an issue. I built a jig, cut the flanges off with a very thin slitting disc where they have been welded on, took the case out of the jig, and did the weld prep on both peices, so that I had a good V, and then put the case back in the jig, rotated it to were I wanted it, tacked the flanges back on and then fully welded with a root and then 2 capping runs. Since you've already cut the mounts for radius arms etc off, it will be even easier to get the diff pointing in the right direction, and still get some caster on the swivels. Including the time to strip the axle and rebuild it, including hosing it out to clear any grinding dust etc, the whole job only took a morning, and I'd do it on any lifted vehicle to keep the handling okay. The only thing to watch is the relative positions of the panhard rod and the drag link to ensure that you don't start introducing bump steer (keep them parallel) as the wheel end of the drag link will effectively be lifted on the end of it's arm, which buggers things up nicely (ask me how I found out ) Hope that helps, Toby

In my opinion, the best way is to turn up the wire speed a little so that you can move a little quicker, avoiding concentratibng the arc in one place for too long. I also like to concentrate the arc towards the underside of the horizontal piece of metal or edge if it is the lower edge of a plate - ranging in thickness (from 3-20mm depending on who you are ), rather than directly into the corner, so that as the molten metal flows, it drops under gravity to form the weld properly, rather than having a large bulbous weld hanging down. It also lets you keep the heat up to ensure good penetation. As said previously, short welds and allow the weld pool to cool slightly, (back to dark red through the mask, rather than fully molten) before starting again. As you improve, you will learn the effect of different actions, in what ever position, which will allow you to master the more difficult positions. Toby

Having read what others have to say and given it a bit of thought in the past, it fairly obvious in my opinion. Forget thinking about axles and wheels/tyres for a moment - work with me here, you'll se where this going soon, and consider the half shaft to be a transmitter of torque and the wheel/tyre combo to be a lever. Obviously, a bigger diameter equates to a bigger lever. The amount of resitance that lever is able to exert is a result of the friction between the tyre and the ground. Finally, your engine, gearbox, transferbox, diff combo will supply a orque o the driveshaft. Asuming that there is enough friction, when torque is applied to the halfshaft, it is transmitted to the lever, which drives the vehicle forward. If the rolling diameter is small, the lever is unable to place a huge torque on the axle (equal and opposite reaction and all that good stuff), so it doesn't break, which is why comp safari cars (which generally run 205R16s as a fairly standard size, can put big power on to the ground and not break bits all the time. As the rolling diameter gets bigger, the lever gets bigger and can exert a greater amount of torque on the halfshaft. Equally, as the tyre gets bigger, it weighs more and has a bigger contact patch which gives greater amount of friction, and these two allow the amount of torque holding the end of the halfshaft still to be that much greater. If the torque applied by the transmission and that applied by the wheel in the opposite direction are greater than the capacity of the halfshaft to transmit torque then it will snap. If the vehicle is on flat hard ground with a low rolling resistance, there will not be enough force applied to the wheel end of the halfshaft, so ther are unlikely to be breakages, which is why poser trucks survive wit big whels and tyres and standard halfshafts. Conversely, offroad, up hill, axle deep in the mud equates to a huge rolling resistance so the torque the wheekl is able to resist with is huge, which equals carnage! To conclude, bigger equals heavier, so more likely to break. Go light, and you can get away with smaller everything, but you have to compromise between tiny wheels and tyres with no grip that won't exert any force on your halfshafts, cos they're always spinning or off the ground due to your negligible round clearance, versus lot of grip, ground clearance and strength which means upgrades. From this, perhaps the way forward is fairly small, but wide flotation tyres, to reduce the length of the lever, but still give grip and reduce ground pressure. Independant suspension to give good ground clearance under the diffs, or perhaps a curved beam axle running an independant diff with halfshafts driven by UJs/CVs at both ends (could be a lattice type structure to be lighter than a traditional enclosed beam axle), and a very light drive train (transverse engine with auto box driving straight into the diffs - nice low ratio and very simple) and spaceframe chassis, to continue the light weight theme. Hope it all makes sense, it's late and I can't be bothered to reread it.

Come on, Al'll be waiting, it's been over half an hour, and you haven't answered his quesion yet! I'm sure he's poised ready to make his keyboard smoke once he knows what you want to know.....

An upstand is fabricated off the chassis with a flat plate on top of it, which sits up against the underside of the floor. The roll hoop (and rear braces) have matching plates on the bottom of it, whch allows you to bolt the two together, sandwiching the floor. This means the hoop is removable, allowing you to take the tub off if required. If you are really clever, the nuts on the bottom are captive so that you can unbolt without even needign to go under the vehicle. Unfortunately, I haven't any photos of one which I did years ago in a Series 1, but I'm sure HfH's thread on rollcages has a picture in the ALRC section (fom memory of when I was in C&DLRC). The other alternative is to weld straight to the chassis, but that means big holes in your tub to weld through, or unbolting it to lift it up, which is always a hassle. It will also mean that you can't remove the tub. Hope that answers your question, Toby