Inquiry for Morgan

[NevoBMW320i]

The newest Morgan three-wheeler was the subject of a "How Do They Do It?" episode. Unmentioned in the remark was the fact that the short propshaft and final drive of 90-degree bevel gears led to a motorcycle-style toothed drive belt attached to the rear wheel. How well do they fit? How? Why? If not, which one does it have if any?
 

[johnmayerrr]

Memories of last year's visit of Malvern link are hazy at best.

The need to construct vehicles with both left and right hand drive added an extra layer of difficulty. (But I don't recall the specific reason why.)

The single wheel is driven by a 4 cm toothed Kevlar belt, which is transmitted from the Ford 1.5 via the Mx5 gearbox (the finest in the industry), and then back through the short prop-shaft.

(It may be worth your time to see Jonny's Late Brake Show segment on this. Perhaps only he could have provided further information about the vehicle.

Coolest gadgets ever. I really hope the new Venture Capital owners don't ruin this family firm where most of the employees have been with Morgan since they were Nippers and who have known each other for decades. At least the three-wheeler's frame isn't made of wood anymore, which is excellent news.

[CyberMage]

Look up "Morgan 3-wheel bevel gearbox" on YouTube; the rear wheel is driven by a toothed belt from the gearbox's output.
Morgan, P.G.Bleazey Improved gearbox for tricycles
With the bevel box unsprung/fixed, the rear drive wheel may presumably be rotated vertically.
A toothed belt drive? I thought BMW motorcycles used to have such.

[CyberMage]

Three-wheeled P.G.Blazey Morgan

[nicebubby8]

Those things mentioned up above. Putting the bevel box on the hub would significantly increase the unsprung weight. Torque tubes predict that this would also cause a torque response, which, under acceleration/load, would cause the back of the vehicle to rise.
Belt drive was standard on the 800cc parallel twins that powered the motorcycles. Since the crank and gearbox shafts were perpendicular to one other, a simple belt was used instead.

[NevoBMW320i]

I appreciate the feedback. I just got a brilliant idea. Like many bikes, I figured the propshaft with bevel drive secured the rear wheel on a single side swinging arm. I now believe I was incorrect. The short propshaft with bevel box, as far as I can see, terminates short of the wheel and just serves to rotate the drive through ninety degrees before sending it on to the wheel through the toothed belt.

As always, your gratitude is much appreciated. Interestingly, manufacturing of the model with the two-liter S&S V-twin engine stopped in 2021, but the company's website promises that "the three wheeler will return!"

[nicebubby8]

Correct. In addition, the belt pulley will be located as closely to the swing arm pivot as feasible (if not concentric with) in order to reduce belt tension shifts over the range of suspension movement.

[vitessear3]

BMW isn't the only company to employ a toothed belt; Harley Davidson and Kawasaki are two examples. Chains, particularly exposed chains, are a pain, thus I don't see why they aren't more popular. Since my BMW uses shaft drive, I've been spared the hassle of maintaining a chain for the last 15 years. Final drives using shafts are the most durable and low-maintenance option, but they are also the heaviest and least efficient. Instead of a grimy chain, I believe a toothed belt would be the ideal compromise, since it would last longer and be more efficient.

[trikey]

Just like you, I've frequently pondered the question of why a toothed belt is preferable than a chain.
How often do belts break?

If belts were so much better, you'd think they'd be standard equipment on Moto GP motorcycles.

[NevoBMW320i]

Belt drives may be more compact, but the size reduction at the expense of power transfer is significant. They're too bulky to fit on a race bike. Compared to a Moto GP bike, this Harley Davidson belt drive isn't quite as powerful.

[vitessear3]

You make a good argument, and it does seem there is no difference when using a brand fresh chain and sprockets, as will be the case with the Moto GP bike at every race. When compared to the dusty and worn chain seen on many road cycles, a belt drive begins to seem like the better option.

Conclusions drawn from a practical comparison of chain and belt drive on a bicycle:

In terms of watts, the variations are negligible. About 5% of the life of a chain may be expected to be lost while switching to a new belt. However, the belt soon becomes more effective when both drivetrains are utilized and worn. When compared with a similarly worn belt drive, a chain drive is around 4% less efficient. When comparing the effectiveness of a worn belt or chain, tests demonstrate that Gates Carbon Drive belts come out on top.

ttps://www.bike-eu.com/39298/redefining-drivetrain-efficiency-that-matters-to-everyday-cyclists

[CyberMage]

A entire generation of Ferrari engines, it seems (they've since switched back to chains), required an engine replacement every 30,000 miles since they employed toothed belts instead of engine timing chains. When you're in a Ferrari dealership, you're looking at four digits.
See an illustration here.

[CyberMage]

SKF

[vitessear3]

I think timing belts are superior and would love to have one installed on my M271 engine. You need to make them readily customizable, unlike Ferrari. Belts were all the rage back in the '80s, and I've replaced them on a number of vehicles since then. If your automobile had a longitudinal engine, installing it was easy and inexpensive. In the M271 engine, for example, we have single-row chains and sprockets constructed of low-quality steel because chains were revived, but this time they were designed to minimize frictional losses rather than last. I'd rather have a belt that's simple to adjust than to be ignorant.

[CyberMage]

The OM607, a Renault-derived engine used in early A-class Mercedes cars, was the last Mercedes engine to use a timing belt.

[BENZE220AMG]

Unless it's on a BMW GS, it's useless. 😁

 

[CyberMage]

Logic behind the Morgan Super 3 EV | Autocar.

Several years ago, they even built an electric model!