Need an ISIS bottom bracket for a GNG mid drive

[robocam]

I've decided to go with a Cyclone crankset to replace the one that failed on my 2015 GNG mid drive, however, the 148mm ISIS bottom bracket that comes with it sticks out 10mm more on the left, and that bothers me. Has anyone found a good normal ISIS BB that works with the Cyclone and GNG?

I understand that the Cyclone used to come with this BB, so I was wondering if it might work, however, it is 128mm, so I don't know if the left crank will clear the mid drive.

http://www.taiwantrade.com.tw/EP/first/products-detail/en_US/545645/SCM_ISIS_Drive_BB_Set_%28Bike_Bottom_Bracket%29/

I was about to buy a Truvativ Giga Pipe until I read here that they're not ISIS.

I tried riding my bike with my left foot farther out, and it didn't really bother me, so if I have to use the asymmetrical 148mm BB that comes with the Cyclone, I should be ok, but another issue is that I have to use 3 spacers on the right crank between the crankset freewheel and the crank (in order to line up the GNG's jackshaft sprocket with the outer chainring on the Cyclone crankset). With that many spacers, I'm concerned the threads on the crank aren't engaging all of the threads on the freewheel (I think maybe 1 thread is visible on the freewheel, so I'm willing to give it a try).

Anyway, if someone is using the GNG and a Cyclone crankset with a different ISIS bottom bracket, I'd love to know what you're using, or even if you're using the bottom bracket that came with the Cyclone, I'd like to hear about your setup (like how many spacers you're using on the crank).

 

[k1kk0_1t4]

Hello, I'm changing the original gng 2015 square taper with a cyclone isis.

I'll CNC a support bearing because i don't trust the dicta freewheel at the power i'm going to use.
I'm also going to machine a custom spider and bashguard because i'm using the bike for hard offroad and i don't want to kill my chain on a log or something else.

I'm not worried about the problem with spacers and bb threads: the cyclone threaded cup is long enought to engage a sufficient number of threads in the bb even with 3 spacers.

I think that is the most worthy mod of the 2015 gng model because the new crank is really unusable as is it cause chain drops because is wobbly as hell.

Please post a photo of your chain line: that can be useful to others that are thinking about this upgrade.

 

[robocam]

Have you considered the Ultra HD freewheel that's coming out in a couple of months from Sickbikeparts? I'm thinking about using that unit once the Dicta freewheel wears out.

When will you be installing the Cyclone crankset? I'll try to post a picture once I install it. I'm waiting for some new steel Race Face chainring bolts and nuts.

http://www.raceface.com/components/parts/bolt-kits/bashguard-poly-fastener-kit/

On my bike, there's no way the triple chainrings would fit, so I took the inner chainrings off, and I'm only going to install the smaller chainring using the shorter Race Face bolts. The shorter bolts are necessary because the stock nuts were hitting the chainstay even with one of the inner chainrings removed. I also could not remove any of the spacers because the nuts do not fit through the 104 BCD holes on the outer chainring. I thought about drilling out the holes on the chainring, but I decided against it.

It would be great if someone had an idea on how to shift the jackshaft sprocket outwards. That way I could have the option to shift between the two front chainrings. I thought about installing a collar to move it out, but I worry that since so much torque is being transmitted through those threads, it probably needs all the thread engagement it can get, so I don't feel comfortable unthreading it to move it out.

I've also experienced a chain drop on my 2015 GNG as well during the very short period it worked (less than a few days). The chain got caught between the two chainrings, and it was very difficult to get it out. It may also have something to do with their using such a small BCD for the chainrings, resulting in their flexing more.

I fear I may have introduced a new problem by going from the stock 44T of the GNG to a 48T on the front. With a chain mounted, it is awfully close to the chainstay. And to think I even thought about mounting a 60T chainring up front. After some calculations, the largest chainring that wouldn't hit the jackshaft sprocket would be a 56T, but the design of my bike will not even allow that. Once I have it all mounted up, I'll report back.

Hello, I'm changing the original gng 2015 square taper with a cyclone isis.

I'll CNC a support bearing because i don't trust the dicta freewheel at the power i'm going to use.
I'm also going to machine a custom spider and bashguard because i'm using the bike for hard offroad and i don't want to kill my chain on a log or something else.

I'm not worried about the problem with spacers and bb threads: the cyclone threaded cup is long enought to engage a sufficient number of threads in the bb even with 3 spacers.

I think that is the most worthy mod of the 2015 gng model because the new crank is really unusable as is it cause chain drops because is wobbly as hell.

Please post a photo of your chain line: that can be useful to others that are thinking about this upgrade.

 

[k1kk0_1t4]

Yep i tought about the new ultra hd, but before spending 100usd for a freewheel i want to be sure is really bombproof.. so i'll wait some rewiews from "guinea pigs".

I'm actually waiting for the pedro's bb tool and new cups from cyclone because i ruined the first set of cups while mounting it .

I'll keep the standard ratios because i use the bike for offroad, but i need the custom spyder etc because my frame as a odd shaping in the bb area.

I'm sure the isis bb will eliminate the wobbling the stock gng freewheel has (and causes chaindrops), i'll post photoes too when ready because i think the quality of the standard part is really substandard and the kit has great potential.

 

[gman1971]

I did managed to put 2 chain rings on my 2015 GNG Gen2 geared build. It was a bit of a challenge but it works wonders for top end. When on motor I am always on the 42T chainring anyways and the chainring with an 11t pinion gives me ~32 mph top end on the stock controller. ~1100 watts on 12S LiPos.

I only use the 32T chainring when I use the bike as a regular bicycle...

The modification is completely reversible but I had to cut the old 3 chainring apart from the 2013 Diamondback Response (which has the same exact bolt pattern than the GNG Gen2 new crank freewheel and took their 42T big chainring.

G.

 

[gman1971]

And just like yours, my freewheel crankset failed today... leaving work, go to pedal to get it going and... nothing, I am pedaling in thin air. I've already ordered the cyclone 3 chainring set with the ISIS bottom bracket... anything will be better than the GNG setup... I wasn't happy because I modified the crankset to take three chainrings and now I have to do some reengineering to retrofit the cyclone with the GNG motor... At least I am stuck with the motor part, because the thing still runs fine while on electric; its just that if the motor fails or battery drains, I just can't pedal for squat...

G.