Still feeling the same ? Interesting !!perhaps not the best ad for selling the cheeb
I finally rode the bosch gen4 recently and I was blown away, im sure its more powerful than my levo and I love the EMTB mode.
no, after I posted that I was thinking that it was a bit misleading.Still feeling the same ? Interesting !!
Must be tricky for Spesh. They went brose because they could customise and they've done great things there. It's also given them individualism to an extent - and a quiet motor (not just when it's broken ! Better get in there before @Doomanic).
When you're buying a bike, would you buy a Levo is it was just another Bosch or ep8 bike ? OR would you just lump it in with the other choices ?
Maybe Mahle will churn something new and special out down the line and they'll use that , what though ? There's only so much you can do with current technology.
TBh, I just rode 2 bikes up a hill.I hope that both CHEEB and TREK were in a corresponding gear ratio from peddle stroke to rear wheel rotation given the differences in cassette, chainring and wheel/tyre size...
A dynamometer would help to measure what torque is delivered at the rear wheel.
I assume with Bafang the delivered motor torque to the human input torque ratio is realized (programmed) as a lineaire function (no punch) instead of a progressive one (punch). A throttle engine ?
Not that I would want it but what if the CHEEB had a throttle... more power ?
I conclude the M500 doesn't deliver 95nm . Or does the BOSCH deliver more ?
This is a great point. Someone shopping for a Bafang should have the means to know whether they're buying the newer version or not.Has anyone ever received the "new" reinforced M500 motor? Could he indicate the serial number of this new motor to be able to tell the difference with the old version?
The Cheeb looks like it will be great fun for the markets that can get it.Is no one else a little bit suspicious about the sudden demise of the Cheeb? Find a hill to prove the Bosch is more powerful, then sell the Cheeb so no other comparisons can be made. Looks like some pressure was applied??? I guess we’ll all find out when we get ours!
Wow, what a job !!One thing is clear: the Cheeb just loosing against a top spec Trek Rail is a very good result for the Cheeb. But the Cheeb has more power...
I tried to understand it by doing a simple calculation. I hope what I did is correct and please correct me where I am wrong.
What did I do ? Put all in a spreadsheet and calculate the force at the rear wheel.
I ignored any kind of loses, motor characteristics, pedal stroke, begin speed, tires, etc. I assumed the motors are as strong as claimed (Bosch 85 Nm and Bafang 95 Nm). To compare the results I set the force at the rear wheel of the Cheeb 2.0 as the reference (100%).
The calculations show:
- the difference between both is not so much, in numbers
- the Trek seems to benefit more from the added rider leg force
- by replacing the chainring of the Cheeb from 36T to 34T it could win, although it is a minimal win
- if you are willing to upgrade the cassette (plus derailleur and shifter combination) there is much more to gain for the Cheeb
- my Decoy 29 Pro (Shimano E8000 75 Nm) cannot win from the Cheeb
What if you change some numbers (yellow fields) ?
A Decoy 29 Pro with Shimano EP800 (85 Nm) and a 34T chainring and 10-52 cassette should be a match to the Trek (in numbers).
What if the Bafang is just a bit less strong as claimed (94-92 Nm) or the Bosch is a bit stronger (86-87 Nm) or both ? The Trek wins.
What if you go for the Bafang M600 with 120 Nm ? The Cheeb wins.
For a self build I will choose: 34T chainring and a 10-50 cassette.
So what would be the force delivered at the wheel ? The formula would be, with:
Fr = Rider leg force in kg
Lc = Crank length in meter
g = gravity earth 9.81 (kg to Newton)
Mt = Motor torque in Newtonmeter (Nm)
Tc = Teeth cassette (largest)
Tm = Teeth chainring motor
Fw = Force at wheel in Newton
Rw = Rear wheel radius
The total input torque is the sum from driver input and motor: (g * Fr * Lc + Mt).
What you put in in torque must come out: (g * Fr * Lc + Mt) / Tm == Fw * Rw / Tc
or (rewritten) the force at the rear wheel :
Fw = (g * Fr * Lc + Mt) * Tc / (Tm * Rw)
Cassette 10-52 (Rail 9.9) or 10-50 (Rail 5), both chainring 34T, crank lenght 0.165 mtr
wheelcircumstance Bontrager XR5 Team Issue 700c/29 x 2.60 = 2.36901 mtr, radius 0.3770 mtr
CHEEB (assuming these are the correct numbers):
SHIMANO M4100 cassette 11-46 , chainring 36T, crank length 0.170 mtr
wheelcircumstance 650b/27.5 x 2.40 inch = 2.21771 mtr radius 0.3528 mtr
Wheelcircumstance from: BikeCalc.com - How to calculate Bicycle Wheel Size
Spreadsheet (free): made with LibreOffice.
View attachment 60165
/about to retire with the £1M payment that Bosch sent me ?Is no one else a little bit suspicious about the sudden demise of the Cheeb? Find a hill to prove the Bosch is more powerful, then sell the Cheeb so no other comparisons can be made. Looks like some pressure was applied??? I guess we’ll all find out when we get ours!
Don't forget that Rob doesn't keep a fleet of 50 personal bikes (as far as we know).Is no one else a little bit suspicious about the sudden demise of the Cheeb?
The World's largest electric mountain bike community.