View Full Version : Cheap drivelines for Rorty buggies.

09-11-2006, 11:24 PM
When going hard over really rough and rutted terrain, there's no substitute for plenty of droop in the suspension. To that end, it’s imperative to locate the CV joints as low in the chassis as possible and also as close together as possible to maximise axle length and therefore downward wheel travel.

Then, as now, there’s no suitable non-diff product for bike-powered buggies on the market, and, in the spirit of my DIY buggy manuals, I devised the cassette drive system for the R6 and R8 buggies using as many off-the-shelf parts as I could.

There are plenty of driveline solutions for bike-engined buggies (some with reverse built in), but they’re all expensive and all of them place the CVs quite far apart, though most of them do place the CVs quite low down.

OK, not everyone has the dollars or the need for huge amounts of droop, and a wider drive centre located higher in the chassis would suit them adequately. The current fashion for ultra long travel suspension, fuelled by the big racing buggies and truggies, isn’t unnecessary if all you want to do is thrash around in the dunes and occasionally do a bit of trail bashing.

I have seen plenty of suggestions for cheap/basic drive centres, usually along the lines of “Why not change this and machine two of those and put this here and that there”. The result is usually a more expensive and less functional unit.

I have been criticised for the potential cost of the cassette, well unfortunately, if you want fully inboard CVs with the associated wheel travel, there’s no alternative. The bearings that the CVs fit inside are expensive. Period!

I would hate duners to miss out on the experience of one of my buggies only because of the cost of a race-oriented driveline, so, I’m looking into designing two alternative drivelines for the R82s and R6 buggies; a very basic drive centre with chain adjustment, but without a disc brake - and a drive centre with brake and reverse which will be about mid way (technically and cost-wise) between the basic drive centre and the current cassette.

When finished, I will offer copies of the updates to all existing customers and include them as options in all future manuals.

I will post details of developments here as they occur.

09-12-2006, 05:26 AM
hey rorty, carn't wait for some more details of your rear drives you got planned. especially the reverse, spent countless nights trying to design a cassete with reverse (and trying to keep it under budget.)


P.s> have a copy of your R82s plans.

09-16-2006, 08:57 PM
It seems most people either don't want to machine custom parts, or they don't want to spend big dollars buying parts, so I'm going to endeavour to go halfway with the new drive centres.

From my point of view, all the parts would be made to my design, thereby everything would be optimally sized, compact and light weight, however, I know that's not realistic.

I've looked at using ag parts (splined shafts, weld hubs etc.), but they're on the heavy side and tolerances aren't brilliant. The CV flanges and weld hubs would still require machining and welding and then possibly re-machining.

So, I think I'll go with off the shelf 930 trans flanges and a custom made splined shaft which I hope to persuade one of the gear and trans crowd to produce to order from my drawings.
I'm just gathering dimensions and data at the moment.

Generally speaking, which is cheaper/more readily available in the US (for plate/flat bar), laser cutting or milling?

09-16-2006, 09:00 PM
nothing is cheap, but gene has a link to e very inexpensive laser cutter, so that probbaly is the best bet, laser/waterjet.... 8)

09-16-2006, 10:22 PM
bob, your plans are kick aarse, i have only one little complaint, the bend radius is metric, very hard to find probbaly not at all the bend radius you have drawn in, maybe if you are updating to a us version for us guys across the pond, maybe do little modification to the bend radius, i myself have 1 1/4" on 4 1/2" radius die, thats is really common set, cant remember what the plans were but seems like it figured out at 3.90 inches or something, without looking i am not posatively sure.... 8)

09-17-2006, 01:09 AM
I think it may be time for v1.02.

09-17-2006, 08:14 AM
This must be read with a snobby, high class, slightly nasal, English accent, whilst holding a cup of tea, with the little finger extended outward for full effect 8)

Come on, Bob - We Cro-magnons need plans with fractions, decimals to three places and the likes...

Non of that Proper Metric stuff... :roll:

09-17-2006, 09:05 AM
lol, nothing wrong with the metric stuff, actually it is easier to read, just the radius of the die is a bit challenging.... 8)

09-17-2006, 11:30 AM
I had GK Machine in Donald Oregon laser cut and bend the rear bearing carrier components for my car. Cost for cutting, bending and the metal - which is 3/16 A-572 - cost less than $50 US for each carrier. TIG welding took about 4 hours and MIG would have been very quick - but I want what I want.

Cutting precision on the million $ machine is .003. Cutting time is $280 per hour and the charge by the second. It's very fast.

Give them good CAD files for what you want made. They program the machine and literally moments later your stuff is cut. I did not watch the bending process but it must be very efficient or my pieces would have been more expensive.

I'm having shock tower components cut and probably a few custom tabs, hopefully this coming week.

I'll update cost in my project when I get the parts.

09-17-2006, 02:57 PM
Thanks Gene. Laser cutting is definitely quicker and hence cheaper than milling and suits this purpose well, I was just unsure of costs and availability in the US.

I'll continue to spec laser cut parts then. 8)

11-02-2006, 01:04 PM
Bob, I just sent you a private message on this topic...

11-04-2006, 10:30 PM
Nice looking work there- It looks like a cnc bender to huh- Jess

11-05-2006, 11:49 AM
Yes, the bender is computer controlled.

GK Machine is top notch. They have a ton of equipment, much of it computer controlled.