SZZS specific CEF50-main thread (initial builds and troubleshooting related only)

I wonder is one of us will be the first to build a CEF50 of if someone is Europe or elsewhere is riding one right now?
 
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mike_kelly said:
The only thing that gives me hope is that Bafang has been working with Forestal for a long while on their version of this engine. So we may have pretty debugged software by now.
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I'm hoping Forestal was field-testing the Bafang M820 "drive-unit" aka "motor"
firmware rather than an actual ICE aka "engine" ...if so, I've got the wrong M820!?😁

Sorry just poking fun on nomenclature...and a slip I made in a forum where one of mechanical engineers would have ripped me on.😜

Plus, get back on the Mandiran/Mandalorian callout!💪
 
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Kenk3589 said:
I don’t think we’re gonna be able to fit a coil shock with the seat post sitting so closely.
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Linda confirmed with her engineering team that it was a fit for my RS Ultimate MegNeg. I submitted caliper measurements and they gave me the thumbs up 👍

Chances are good if it's an accurate diagram and spring is same or less width. Posted below a few weeks ago
PXL_20230221_051936527.jpg


But it will be the very first item on my checklist to confirm as soon as it comes out of the box. 🍻

Screenshot_20230301-090127.png
 
Did we figure out if a chain guide was required and if there was a place to mount it? I guess testing would be required first to see if you need one in the first place.
 
Kenk3589 said:
I don’t think we’re gonna be able to fit a coil shock with the seat post sitting so closely.
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In my coil experience on Horst Link bikes, you can take the riders weight, times the Leverage ratio, to get very close to the needed spring rate. In reality only a percent of that weight is on the rear shock, and different seat tube angles and chainstay lengths alter this as well. Never-the-less, it's been shockingly close for me a few times.

So the LR at 30% sag is 3.23, 190# rider would require a 614# spring. So you have 3 problems: 1) that spring is really physically really heavy, 2) most spring rates top out at 650#, basically excluding riders that with their pack are > 200#s, 3) your spring rate just has to be a huge compromise, never being exactly what's needed. In fact, the springs aren't even to spec often varying wildly in rate.
 
Stephen B said:
I am looking at a used fork.

I read through everything but I can't tell how long does the Steer tube need to be?
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Depends...find your head tube height (HT) from the geo diagram, then measure your stem height. Next is stack height. Add another 2-5 mm for headset cap. Last add another 20- 40 mm for stem spacers as needed for preferred steering height.

I run mine about 30 +mm, but I also use 40-50 mm handlebar risers. The Enduro/trail slacker geo allows for higher steering height overall.

E-mtb headtubes tend to be a little longer than analogue bikes due to higher weight of E-mtb overall, so it might be more challenging to find a longer pre-cut steerer tube unless e-specfic (which Fox I believe is the only E-tuned fork to date).

But it all starts with your frame size HT measurement. The bigger the frame, the longer HT height.

Did I miss anything out there? If so feel free to jump in.🤛
 
You need to add about 10mm for the headset cap. Most stems will be more like 40-50mm. You need to add spacers according to how far you want to bend to reach the bars and as TC said how much rise you choose for your bars and any rise in the stem.
 
temon10 said:
usually bafang frame need 19cm up steertube length will safe.
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Agreed, it might be safer to get a little longer than 180 if you can. Any extra length can go above stem and then you can experiment with different sizes and then trim to preference.

I'm lazy once I get the build complete, any remaining extra I just leave and add spacers if less 5-8 mm, rather than trim a second time.
 
mike_kelly said:
There is no "usually" it totally depends on rider height and riding style. I need a full length steerer tube. Usual for me is 250mm.
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i said 19 up, so 19 is minimum for steertube length. And He just said used fork, so usually used fork of manual bike is 17 up. if u want longer just buy new one :ROFLMAO:
 
temon10 said:
i said 19 up, so 19 is minimum for steertube length. And He just said used fork, so usually used fork of manual bike is 17 up. if u want longer just buy new one :ROFLMAO:
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I think Mike was implying the longer the steerer tube the more options for best subjective fitment. But 200 mm + would be nice for used on that HT setup. 180 mm likely bare minimum. 🤙
 
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Wait for the battery for 15 days. If the frame is not painted, then you can send it. Painting the frame takes 20-25 days. To get the frames faster, you can go to China yourself and bring the frames home :-)
 
I believe i'll get my frame first/second week of april, with M820 and battery, since It's Europe maybe the shipping is a little bit faster?
Also ordered the frame as soon as it appeared in Alibaba, mid december.
 
temon10 said:
i said 19 up, so 19 is minimum for steertube length. And He just said used fork, so usually used fork of manual bike is 17 up. if u want longer just buy new one :ROFLMAO:
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Sorry I misread your post. Yes I was just indicating that buying a used fork that is too short would be a waste of money. Bike manufacturers pre-cut forks for the "average" rider but it is not right for everyone. Cheers
 
Stephen B said:
I am looking at used Fox x2 210 x 55 rear shock.
Will that fit?
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Linda's engineering team says it should. See above in recent thread.

But first thing I'll do is fit my MegNeg out of the box when frame arrives. My backup was going to be the Fox X2...so that should show you my confidence level.
 
I got a 210x55 at first but the note up in the thread is using a 27.5 wheel not a 29er...
 
mike_kelly said:
I got a 210x55 at first but the note up in the thread is using a 27.5 wheel not a 29er...
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210x55 Is a safe upgrade on rear stroke. Can go shorter crank arms too if worried about bottoming out. I find 155-160 mm is becoming more common to avoid pedal strikes. But some argue on lighter weight builds 165 mm may be optimal. lf u gotta pedal w/o power, they're still long enough for leverage.

I went 155 mm cranks on a 55 rear stroke on a 27.5er. But the 180 fork should give more motor clearance. 🤞

Nice thing is the CEF50 geo accommodates both Enduro and/or trail build. Hey, doesn't Transition do the same with the PNW (Enduro) v. their trail builds?😁

So should be several cool versions of CEF50 to fit your riding style.🤙
 
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