Grubee 4g belt drive

[abikerider]

Hi, I'm shopping for the best 4 stroke tranny and found that the Grubee site has more info and pictures of the 4g belt drive here http://www.grubeeinc.com/USA/To See Whats Coming.htm It looks like it uses a timing belt drive belt and centrifigal clutch which would be a sweet setup. I talked to the guy at bicycle-engines.com and he said it probably won't be available till the fall. Anyone here have any more definitive information about when these will be available?

 

[azbill]

he would probably have the info before anyone else
Josh has been his biggest guy for quite a while

 

[Silvaire]

This does indeed look like a sweet setup, and I've been waiting to see it too.

As usual, the devil is in the details, and in this case I am suspcious of the size and configuration of the components used. Looking at the picture of the open belt and pulleys (on the right, midway down the page), there appear to be few very belt teeth in full contact with the engine pulley teeth. This condition occurs when there is a large differance in the size of the pulleys when there is a short distance between them, and can cause early belt failure. Based on this condition and the size of the belt, I'd be concerned about short belt life and the need for very critical belt tension ajustment.

Just my $.02...

 

[ocscully]

The folks at bicycle-engines are the US distributor for Grubee so when they say the Fall you can be pretty sure it will be the Fall. They seem to get just one shipment of kits from China each year. Their latest shipment of 4-stroke kits arrived in late Sept. early Oct. 2008 I believe. You might be able to find one thru a European distributor or maybe the dealer in Australia might have them sooner. The video at the link you provided seems to indicate that MBB Imports in Australia already has them?

ocscully

 

[fetor56]

"Available with or without engager".....good that finally we have the choice.
Provided it's PERFECTED & working flawlessly i'de also be interested in the price....i was keen on another tranny but at AU$500(delivered) it's out of my reach.

 

[fetor56]

The folks at bicycle-engines are the US distributor for Grubee so when they say the Fall you can be pretty sure it will be the Fall. They seem to get just one shipment of kits from China each year. Their latest shipment of 4-stroke kits arrived in late Sept. early Oct. 2008 I believe. You might be able to find one thru a European distributor or maybe the dealer in Australia might have them sooner. The video at the link you provided seems to indicate that MBB Imports in Australia already has them?

ocscully

Phoned George from MBB & he'll be getting them in approx 3 mths.....price AU$150-200.

 

[abikerider]

This does indeed look like a sweet setup, and I've been waiting to see it too.

As usual, the devil is in the details, and in this case I am suspcious of the size and configuration of the components used. Looking at the picture of the open belt and pulleys (on the right, midway down the page), there appear to be few very belt teeth in full contact with the engine pulley teeth. This condition occurs when there is a large differance in the size of the pulleys when there is a short distance between them, and can cause early belt failure. Based on this condition and the size of the belt, I'd be concerned about short belt life and the need for very critical belt tension ajustment.

Just my $.02...

Good observation. It looks like only about 1/4 of the pulley teeth are in contact with the belt. Does anybody know what forces such a belt can normally handle? The Honda engine puts out a maximum torque of 2 ft-lbs and the small pulley looks to be about 2 inches or .16 ft so the the engine is only pulling with 2ft-lbs /.16ft = 12.5 lbs of force on the belt which doesn't seem like much to me. Of course you have to consider that it might experience higher forces when the clutch first engages or if the engine or rear wheels stops suddenly. If the clutch engages smoothly I would think the belt could easily handle it but thats just my engineering intuition. Those Gates belts that drive the rear wheels of Harley Davidsons handle waaaay more force than that but of course are wider and are premium quality. Just my 2 cents.

 

[Silvaire]

I should probably wait until this unit is on the market and in use, and has shown its reliability (or lack thereof) before critiquing it.

However, I do have some experience with toothed drive belt systems and am a big fan of them. They have an excellent record for many reasons. If you look at the most common use of this type of drive system - the timing drive on most every small auto engine - you will see that they are always designed with a large number of teeth in contact with any driving or driven pulley. They typically use two (and sometimes more) idler pulleys to wrap the belt more fully around the toothed pulleys.

The soon-to-be-released Grubee unit could do the same if those designing and marketing it chose to add an idler pulley near the engine pulley on the slack side.

 

[duivendyk]

These cogged belts are quite durable,in your car thay are good for 75 k miles driving the camshaft,hardly a nice steady load !.I'm not worried at all about the potential durability however substandard component quality,more than inherent design flaws have plagued some Chinese products.The dimensional stability of these belts has proven to be excellent too.I think this is a very welcome development.

 

[HoughMade]

When it is on the market and I have heard some reports, I may go for this...but I'll take my chances and run it without the cover.