Gruber Assist: 100W in the seat tube

Haha... electrically adjusted seatpost with memory :))))))

On the Gruber... I will be moving to Dubai in 2012, so will be selling the Gruber bike at some point. The bike will come with 20ah battery, Topeak battery bag and large-screen Cycle Analyst.

I will be asking for 50% of the new price.
 
Dont put anything past those engineers at shimano....those boys really know what they are doing....some of the best bicycle engineers on the planet.

Usually dont waste their time on frivolous endeavors either....hmm i wonder what they are up to?

And how is miles able to pull links like that out of his hat?
 
Finally the (huge screen :lol: ) Cycle Analyst arrived... and perfectly setted on the bar.
I was right, this thing is very efficient - free spinning of the rear wheel in the air takes 10W :)
 
Wow. 10w. At what speeds?

I have tested a range of RC Motors for my friction drive and the no load power are all up around 35-60w just to spin the motor.

10watts seems very low for motor losses, bevel gears, chain, and wheel rotation air drag losses. Even though the drive line is under very light load.
 
10W was at 80rpm on the crank and high gear on the deraileulers. Though, I have pretty good crank (Shimano XT Hollowtech) and rear hub (Mavic).
Will test the real-world figures under full load tomorrow.
 
Finally... Topeak Mondopack with 8x4S Lipos, connecting wires and CA shunt inside.
Weight is exactly 4 kilos.

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VSkudarnov said:
Finally... Topeak Mondopack with 8x4S Lipos, connecting wires and CA shunt inside.
Weight is exactly 4 kilos.
Looks good!
 
I do not need it...
Actually, I quite like the logic of Gruber controller - the lower the rpm, the lower is the amp limit. You only get 150W at max rpm... and if you select the wrong gear, the load is 100W or even down to 50W... If you externally prevent pedals from turning, it shuts off.
 
VSkudarnov said:
the lower the rpm, the lower is the amp limit. You only get 150W at max rpm... and if you select the wrong gear, the load is 100W or even down to 50W... If you externally prevent pedals from turning, it shuts off.

Interesting. I assume this is all measured via the CA shunt. Just wondering why they drop the power at lower cadence, I assume it is to keep the waste heat in check at the lower speeds.

Got any more stats for us now that you are up and running with the Cycle Analyst? What is you wh/km? What sort of range? Is 150w the peak you see on the CA?

Also what do you think of the sound of the drive? From the videos I have seen it doesn't exactly sound quiet, but it is really hard to judge what it would sound like on the bike from a video off the net.

I would love to see dyno results on these type of systems. So we could work out what power actually gets to the road, and therefore what the efficiency really is, rather than just the economy on the road. I might just build one one day. Off to search the forum again....
 
Here are the stats:

1. 20km flat + 18km uphill

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Average watts: 100-150W (150W at high cadence of 80 rpms).
Range: did over 70km (40km flat + 18 uphil + 18 downhill) on 10ah. So my range shall be around 150km, but need to train my butt first to achieve that :)
 
Very interesting! :twisted:

I love the fact that on ES we have such a diverse group, I never would have dreamed to get this kind of first hand information about a Gruber Assist!

Thank you very much VSkudarnov for sharing! :D

Now all we need to do is have someone determine the best R/C motor to do a similar thing with to get something that puts out closer to 500W, would be a real challenge, but I bet if the frame tube became the "outer shell" of the in-runner powering the cranks, you could get pretty close, the real interesting thing is how they are able to make such a small diameter motor so efficient especially running at such low RPM's :)
 
Since my employer is relocating myself to Dubai (no biking there) - the subject bike is for sale!
Price: 3,000chf (50% of new price).
Condition: almost now, 5 cycles on the battery.

I will most likely sell it locally, but if anybody has seriously interest - may dissassemble and sell the Gruber kit alone + battery separately.

PM me.
 
VSkudarnov said:
Here are the stats:
...

Summary: 6.0wh/km at an avg of 15.8kmh [9.7wh/mi at 9.8mph]

Questions for you:
1) Did you pedal along? If you did, how much of the total needed power did you contribute? Best educated guess of course. 20%, 30%, 50%, etc...?
2) What was the average grade or degree of the 18km uphill portion?
 
Where to buy and how much in usd? Was thinking this would be a great purchase to get into ebikes. Sure it could be juiced up
 
Pm me some rc choices
 
SamTexas said:
VSkudarnov said:
Here are the stats:
...

Summary: 6.0wh/km at an avg of 15.8kmh [9.7wh/mi at 9.8mph]

Questions for you:
1) Did you pedal along? If you did, how much of the total needed power did you contribute? Best educated guess of course. 20%, 30%, 50%, etc...?
2) What was the average grade or degree of the 18km uphill portion?

1) I was pedalling lightly, delivering 50-75W. Gruber was adding 150W.
2) about 1000m+ elevation.
 
Thanks for the info. I don't have any hill where I live. On flat, it takes less than 50 watts to travel at 16kph (10mph). So if I were to contribute 50W, my hub motor consumption would 0.0 wh/km.
 
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