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Winter Projects…2015…Spoked Wheels

by

Bill Davies (a.k.a.Crozier3)

The first project for this winter is the manufacture of new spoked wheels for the front of my trike, why? Well having been to the 23rd German Drierad Treffen last year and viewed a fair selection of trikes it became apparent that the original 2CV wheels make the car look front heavy… IMHO. They are also fitted with a heavy section tyre that adds to the look. The rear wheel and the spare will remain standard 2CV.

There were some very nice shiney ones manufactured from an aluminium billet… a lot of machining and waste but a very nice finish. So I consulted with my welder friend and discussed the use of pipe fittings to manufacture a set of hubs. It is possible to buy un-drilled flanges of a size to be determined by me and concentric pipe reducers.

The plot was hatched, so I ordered a set of 200mm and 150mm flanges and a set of reducers 100mm to 50mm diameter to give an asthetically pleasing design. These duly arrived a week later and were brought to my workshop for drilling. The centre was found( approximate as the finished diameter will be machined to size at a later stage) and the spoke circumference was marked on. Using the same radius the circumference was divided into six and the centres popped. Then a line was drawn between a pair of these centres and this was divided into three, a line was scribed through the wheel centre and the two marks to give an extension to the circumference. These two points were then popped and then using the original radius these were then struck around the circumference. I now had 18 centres marked on the disc, and now the process was repeated on the other three discs. The design was to have 36 spokes, 18 on both the outer flange and 18 on the inner one, a standard in wire wheels.

Now the drilling commences, start with a 2mm drill to get a good fit to the pop and then open out to 4.5mm. The holes are then countersunk on alternative sides( mark with a marker pen before countersinking as it is easy to get carried away and countersink adjacent holes). The depth was to give a finished thickness of 3mm at the spoke holes. As I intend to have them interchangeable with the 2CV hubs I also drilled and countersunk the stud holes, also needed to buy new wheel nuts to suit, and these need to be machined for taper match. The centres were opened out using a hole saw and gently pressure on the drill and lots of oil to clean the teeth. It is necessary to lift the drill frequently to wash off the swarf. This process was repeated for the four plate flanges, and took approx one day, marking, drilling, and countersinking.

Now a change of location to my pals workshop to use his big lathe and machine the bores to size for the taper pieces and preparation for welding. My pals although retired was a coded welder so I let him weld up the assemblies, the tapers were held off the table by approx 2mm(thick washers) to give a good weld penetration. After cooling I returned the following day to machine to size, first the small flange then change the hub to do the second one's small flange, The chuck is four jaw so by alternating it saves changing the jaw settings, But always centred on scribed marks. A stop for size measurement gave me a chance to observe my work… bloody hell…a crack extended half way round the weld. An examination of the other hub identified that a similar crack was present on it also. We do not know what caused the problem, but we believe the flanges were cut from bright plate and not mild steel. My friend had had a similar problem in the past, again with bright plate.

They say practise makes perfect so it was back to the shop for new plates and tapers(£75 down the pan…but that's a development cost). Then marking out and drilling and countersinking all over again. Then primary machining and then welding, then on with the final sizing. This time inspection was at all stages to search for a crack…none…job well done.

Back home and a clean up took place to smooth off all edges and holes etc, then a trial fit on the stub axle only to find one fitted fine but the other needed a little more off the inside…so back to my pals for a shot on the big lathe.

Then painted up to match the car's chassis principal colour…Hammerite Blue…it looks close to the French shade. Now it was time to take to the wheel builder for assembly. In a previous life I built up wheels for motorcycle restorations but at that time I knew the size of the spokes…ie length and could buy to order. I needed new spokes and rims so it was easier to give it to the man. Following on from Tom's experience with steel spokes and nipples I went for galvanised spokes with brass nipples, to stop corrosion problems welding the two together. I spoke to a friend regarding stainless versions and he advised against as they can fire up on tightening before they are under load…not a good plot.

New tyres are the order of the day and I went for 4.00 x 18 as their diameter is similar to the existing wheels so they will give similar loading to the drive train, and the speedo should remain within accepted limits, about 10% faster than normal.. I do not believe it anyway and use the SAT NAV as a check. Another way is to observe the grass as it bends down as you pass, if lying flat your going too fast.

First fit revealed that the studs were too short so had to order new long studs for a Subaro M14.3 spline…M12 x 1.25, these fall through the existing holes(16mm dia) in the hub backplate so had to source material and manufacture top-hat washers to suit. A bit of a torque to pull them through but now they are IN and not coming out. A small worry that was in the back of my mind…could I get my big paws through the spokes to fit the wheel nuts and then be able to tighten them…no problems there was plenty clearance and there is a nice line for the wheel wrench.

Other problems to sort out include moving the centre line of the mudguards as the track has increased as has the turning lock so that needs checking for contact and the stops adjusted. Well I decided to buy the new mudguards and checked the internet…none…all sites are showing "due in the summer". However I eventually found a pair in Germany(the last two in Europe!!!) and awaited with baited breath for there arrival. DPD were a problem but they arrived intact and were a good fit to the tyre so went ahead and fitted them. The brackets that I had made showed that the tyres was very close to the guard. The first run to the vintage motorcycle club resulted in stopping twice to stretch the curve to get more clearance, otherwise all ok and a nice drive…no shakes up to 60mph. Back home and the mounting holes were slotted to give a further 5mm clearance and all is well.

Well am I pleased…they say that beauty is in the eye of the beholder…and I am happy, and so is my bank account. Now need to get some miles under my belt to prove them and develop their handling characteristics.


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