FUTR Beta with Lightning Rods Mid Drive

so… I took the Beta for a hill climb

modulation of power is so difficult when climbing - bike wants to wheelie continually! I did it as slowly as I could, just to keep the front wheel down - wanted to lift all the time!

[youtube]1dKuVUgcYaw[/youtube]

in contrast, my wife could use all the power of the BBSHD - it continues to impress.

[youtube]AprfI0Cax1s[/youtube]

so... I need to lean forward a bit more when climbing, to try to modulate the power delivery, and/or change gearing. Gearing is very low.
 
There are several motor driver sprockets available. 12t through 18t. You currently have a 12t which is the lowest. Maybe we should try raising the gearing.

Going slow is aggravating the tendency to wheelie while climbing. If you got some speed up before hitting the hill you’d have a lot less trouble.
 
LightningRods said:
There are several motor driver sprockets available. 12t through 18t. You currently have a 12t which is the lowest. Maybe we should try raising the gearing.
Click to expand...
Hi LR,

I think that would be good - I was wondering if I could change the front sprocket. At the moment, the bike tops out at around 24mph on the flat - so would aid top speed as well. Happy to change rear sprocket to something smaller as well.

Great motor, though!
 
I’ll work out some of the speed options for you. Changing the front motor sprocket to an 18t for instance will raise top speed to 36 mph without changing anything else.
 
LightningRods said:
I’ll work out some of the speed options for you. Changing the front motor sprocket to an 18t for instance will raise top speed to 36 mph without changing anything else.
Click to expand...
sounds good! that's all I need in terms of speed - and I guess it would quieten the chain? (not that that is a major concern)
 
Yes the smallest drivers are the noisiest. They also wear out the fastest. You’ll most likely love the 18t. We’ll need to get you a couple more links of 219 chain as well.

I rode my test mule bike around with the low gearing and liked it. I’m used to gas powered MX bikes so the power delivery didn’t bother me. Stephen in Sweden is changing his Beta over to an 8 speed cassette. He also thought the stock gearing was too low.
 
I just heard from Stephan in Sweden. He sent me this photo of his Beta at Gothenburg Harbor in Gothenburg, Sweden.

Karlsson_Beta.jpg


He finished switching over to an 8 speed rear cassette. Here are his comments:
"Tops out @ 60kph on rear 13T. Strong as a bull. Noise (from primary chain) is considerably lower."

Controller ASI BAC2000 , Battery 14S6P Sony VTC6 (18Ah) , SRAM EX1 groupset.
 
LightningRods said:
Going slow is aggravating the tendency to wheelie while climbing. If you got some speed up before hitting the hill you’d have a lot less trouble.
Click to expand...
agreed, but where you slow down/ tap off the power, and then pick up the speed again, the power hits very suddenly - that is where the bike jumps. Particularly off road uphill on a bumpy section, very difficult to modulate the power - the bike is a wheelie monster! You can see in the video at the top of the page where I am accelerating oh so gently at the start... the bike jumps at the 4 second mark.

LightningRods said:
I rode my test mule bike around with the low gearing and liked it. I’m used to gas powered MX bikes so the power delivery didn’t bother me.
Click to expand...

I used to ride a ktm 450 exc, and later a ktm 350 freeride - with a gas bike, I could use the clutch and rear brake to balance the power. This was the first off road test of the bike though, so am still getting used to it off road.

LightningRods said:
I just heard from Stephan in Sweden. He sent me this photo of his Beta at Gothenburg Harbor in Gothenburg, Sweden.

Karlsson_Beta.jpg


He finished switching over to an 8 speed rear cassette. Here are his comments:
"Tops out @ 60kph on rear 13T. Strong as a bull. Noise (from primary chain) is considerably lower."

Controller ASI BAC2000 , Battery 14S6P Sony VTC6 (18Ah) , SRAM EX1 groupset.
Click to expand...
the bike looks great - I would also like to know what front fender!

LR, if you could let me know gearing alternatives, that would be great - thanks
 
The Chinese throttles that almost everyone sells (including Grin, where I get mine) have big dead spots with poor modulation. Nothing, nothing, and then BAM!, the power comes on all at once. With a powerful motor like mine it can become a handful. People have upgraded to Domino throttles and reported a big improvement. Another tactic is to add an auxiliary switch to the CA that can govern power down to lower levels. Common is a 3 position set to 25%, 50% and full power. If you governed the power of my motor in half it would behave more like a Bafang HD.

Gearing at the motor sprocket can vary from 12t to 18t. Gearing at the driver chainwheel can vary from the custom 22t you have now up to the full range of 104 BCD chainrings, which is 32t up to 48t. Your single speed rear sprocket is presently a 48t. I checked my stock and the only other Shimano spline single speed I have on hand is a 16t. I think that would be too high for off road use. Once we figure the ideal single speed ratio I can have that tooth count cut. For now the quick and easy fix is a larger motor driver sprocket.
 
thanks LR, the 18T and extra chain sounds good. Please let me know (message / FB) how much.

Do you know if the domino throttle https://www.lmxbikes.com/en/spare-parts/54-domino-twist-throttle.html is plug and play with a CA?
 
219 driver sprockets including the 18t are $20. I’ll throw in the necessary extra 219 links at no charge. You will need a 219 chain tool if you don’t have one. You can get an inexpensive one here: https://cometkartsales.com/-219-Chain-Tool.html

The throttle plug on the CA is a 3 pin JST, which is what the Domino appears to have in the product shot. Between the better potentiometer throttle and 50% higher gearing your Beta will be much more controllable from a dead stop.
 
LightningRods said:
219 driver sprockets including the 18t are $20. I’ll throw in the necessary extra 219 links at no charge. You will need a 219 chain tool if you don’t have one. You can get an inexpensive one here: https://cometkartsales.com/-219-Chain-Tool.html

The throttle plug on the CA is a 3 pin JST, which is what the Domino appears to have in the product shot. Between the better potentiometer throttle and 50% higher gearing your Beta will be much more controllable from a dead stop.
Click to expand...
thanks Mike!
 
LightningRods said:
I'll ask Stephan about his front mud guard the next time I'm IMing with him.
Click to expand...

thanks! nothing fits the inverted fork that I could find
 
Here is a mock up of a single stage drive with the 12 tooth motor driver and then the 18 tooth motor driver installed. The 18t required two more links of 219 chain.

12t:
12tDriver.jpg


18t:
18tDriver.jpg


The chain tension on the 18t with two more chain links is better than the 12t. Every sprocket combination has a different ideal center to center distance between the sprockets. When that distance is fixed, as it is on this drive, the chain gets tighter as you add sprocket teeth until the chain won't reach and you have to add a link pair. Then the chain is too loose. Somewhere in between 12t and 18t you have to add two links. At that point the chain would be too loose for the tensioner to take up the slack.
 
so... reporting back on the change from 12 tooth to 18 tooth driver.

The bike is transformed, much easier to handle, and climbs like a very smooth goat! Top speed has also jumped to around 35mph, great for riding to the trails as well as on the trails. It's in its element on narrow single track...
 
PRW what are your thought on the middrive two months later? Does your Phasor hub bike exel in any way or do you just ride this now?
 
devo1223 said:
PRW what are your thought on the middrive two months later? Does your Phasor hub bike exel in any way or do you just ride this now?
Click to expand...
the middrive/Beta is great on tight trails, repeated steep hill climbs with tight corners and difficult lines - not only because of the middrive, but because the Beta is lighter and has a single crown fork as against the Phasor's triple crown.

I don't like riding the Beta where I am likely to see lots of bikers, walkers and horses - the motor seems to disturb them. They don't notice the Phasor, except to admire the looks of the bike.

The Phasor is great on flowing trails/ roads that are not too steep, and where there are crowds of people - the throttle is so well dialled in I can idle behind walkers, stop and balance on the bike until they move...

I still want to do a BBSHD with a Rohloff, on a Norco Atomik, for tight trails where there are crowds! There is no one ideal bike..
 
Thanks for your feedback. I was thinking of doing a BBHD with phaserunner as well. Have you though about a GT frame with the I-Drive? I was looking at the GT Verb, you can do a cable mod that tucks the motor up really high and their appears to be plenty of room in the triangle so you don't need to chop and box the frame. Sorry to digress, I'm going to do a single stage mid drive first......
 
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