Just a thought and possibly a dangerous one. Has anyone thought about or tried to make the rear wheel look like the front wheel. The front wheel is a collection of twelve flat spokes, for want of a technical description. The rear wheel is six U shaped spokes. Would it be possible to machine out the flat surface thus creating a wheel similar to the front one?
The front wheel does cope with all the loading of braking, the rear copes with engine torque/horsepower. Most bikes have similar looking wheels, some actually have the same size front and rear. Any ideas ?

I wouldn't. The braking torque isn't transmitted through the spokes on the front wheel however the drive and braking torque is transmitted through the spokes on the rear.

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08 Specialized Langster

The front can be built so light because of the rim brake. The braking / tyre friction forces stay within the rim and don't get transmitted through the spokes to the the hub as with a standard hub mounted disc. But the rear gets it's power transmitted via the hub mounted pulley through the spokes to the rim mounted tyre. Imagine the torque transmitted through the spokes when a wheelie is being pulled, thats the weight of the bike and rider all rotating around the pulley through the spokes to the tyre. I doubt a rear wheel machined to mimic the front would last long before stress fractures would see it collapse.

This looks interesting

http://m.youtube.com/watch?v=XlUwdpwf2fM

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The sound of a V-twin engine braking is music to my ears!!

Thought I would do it before Maz .

front wheel how do the braking / retatation forces get from the brake disc/ wheel rim /tyre to the wheel hub / forks if not by the spokes

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Buell Ulysses XB12X 06/08

I've always thought that was bollocks as well it's not just the wheel that you have to stop.

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2001 X1 2009 1125CR 2006 Uly X3 2010 Uly a fully Maz'd S1 and a 1991 RS1200 Westwind.

Draw a wheel and a pair of forks, side view. Or look at a side pic of any conventionally braked bike.
Imagine the pads clamped solidly to the disc (ie front wheel locked-up) and draw the 'load-path' from the tyre contact-patch up to the rest of the bike via the head bearings:
Tyre. Wheel-rim. Spokes. Hub. Disc bolts. Disc. Pads. Caliper. Caliper bolts. Fork leg. Yokes.
Now do it again for a rim mounted disc (psst, the clue is in there...)
You should have:
Tyre. Wheel rim. Disc bolts. Disc. Pads. Caliper. Caliper bolts. Fork leg. Yokes.
What was missed out?
The spokes have only to support the 'weight' of the bike, not transmit any braking force.

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'98 M2 Razorback, it's a keeper.

ok rik understand now

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Buell Ulysses XB12X 06/08

So a tuber has to teach those with a can!

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The sound of a V-twin engine braking is music to my ears!!

It is actually a good sense design as the hub is not trying to torsionally rip itself out of the centre of the wheel, but the disc's large diameter does carry the potential for increased run out, hence the importance of freely floating moutings.
It's no different in principle to a rim & caliper type bicycle brake... which begs the question of how much stronger they have to make the spokes on a bicycle that has hub mounted disc brakes...
Any of you road lice care to comment?

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'98 M2 Razorback, it's a keeper.

Spoke lacing is key to resistance of torque on a bicycle wheel

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08 Specialized Langster

From my point of view this is extremely interesting, educational and informative, thanks guys.
What is the most forceful ? Going from 0 to 60/80 MPH as quickly as possible or emergency braking from 60/80 MPH to 0 ?
Front and rear wheels used to be interchangeable, a long time ago. The ones shown on the nice blue bike look similar but I am sure the rear one will be stronger than the front one, they just share to twelve spoke pattern. The same applies to the Buell wheels, the front 12 spokes are more or less the same thickness from hub to rim. The rear 6 spokes are much wider at the hub and taper towards the rim. Still thinking about it .

If you give it a go ,i would not go to crazy with removing material from the hub and spokes.

And i don't know how good the casting of these xb rims are ,some other alu parts of the xb serie have a lot of air holes in them.

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The sound of a V-twin engine braking is music to my ears!!

0 to 60 /80 the back wheel is doing all the work. 60 / 80 to 0 the front wheel is doing MOST of the work.....Simples