cycleops612
10 kW
brucemetras said:
"I just get my cadence (pedaling rate) close to the motor no load rpm? and shift normally?."
I am afraid i dont get your points.
could you elaborate pls?
Mid Drive with Internally Geared Hubs
- Thread starter bmurray7
- Start date
"I just get my cadence (pedaling rate) close to the motor no load rpm? and shift normally?."
I am afraid i dont get your points.
could you elaborate pls?
brucemetras
10 mW
- Joined
- Feb 2, 2012
- Messages
- 25
cycleops612 said:
I have my road bikes geared so my preferred cadence ( 80 to 100 rpm) and resultant mph (cruising at 23 to 25 mph) closely match that of the max assist rpm of the mid-drive at the selected assist level .. so as I approach my target cadence in a particular gear or assist level, I approach a speed where I am not getting much e-assist (based on amp reading, and general feel for power delivery) and at that point, I change gears as I would normally without electric assist.. so there is no obvious difference in shifting trauma to the drivetrain assisted or un-assisted.. well over 1000 miles on a 9 speed hollow pin SRAM chain and still within acceptable limits using a Park chain gauge.. so even though there is a gear sensor available, and I have used backpedal, and e-brake cutoff to stop the motor for clean shifting, by and large, I ride my bike normally, spin to near 'no motor assist' levels, and just upshift..
Chalo
100 TW
spinningmagnets said:
Minor quibble-- the ratio of the Sturmey Archer AW is 3:4, so the top gear is indeed 1.33 (or 4/3); however, the bottom gear is .75 (or 3/4).
Total range is 1.33/.75 or 178% overall.
cycleops612
10 kW
Much appreciate you sharing your experience. I look forward to trying it.
Chalo
100 TW
For what it's worth, the Sturmey Archer AW has a spotty reputation among sporting riders. The higher the loads fed through it, the more important it becomes too adjust it precisely. Incorrect adjustment or shifting under heavy load can cause slipping and rounding off of the shift dogs, which is a self-stoking cycle to failure.
The Shimano Nexus 3 would be my first choice-- not because of any mechanical superiority, but because its replacement parts supply chain is more robust. Using an internal gear hub with more than human power, I would plan for breakage and the steps that follow. I command only slightly more than human power myself, but I've broken a few gearhubs without the help of motor assist.
The Shimano Nexus 3 would be my first choice-- not because of any mechanical superiority, but because its replacement parts supply chain is more robust. Using an internal gear hub with more than human power, I would plan for breakage and the steps that follow. I command only slightly more than human power myself, but I've broken a few gearhubs without the help of motor assist.
LewTwo
1 MW
Back in the day, before most cars came with automatic transmissions, one was always supposed to lift their foot from the the accelerator (gas pedal) before engaging the clutch prior to shifting between gears. Doing otherwise sometime resulted in replacing the gears, synchronizers, bearing, countershafts, etc. I really do not see a lot of difference in that and backing off the throttle (or the pedals) when shifting a bicycle. Seems the most prudent course of action unless one keeps a spare transmission around (like I did in my misspent youth).
cycleops612
10 kW
Nonsense. How dare you say the emperor is naked.LewTwo said:
However, derailleurs are somewhat more delicate.
Philosophically, its kinda regrettable that folk are now so insulated from the mechanical processes that propel them.
A car is a comfy den that, incidentally, moves.
Thanks, Chalo...I appreciate that!
windtrader
1 kW
I bet plenty on a beer(ish) budget would line up for a 3-speed IGH capable of 3-6 kW. The SA AW and Nexus 3 speed units seem capable donors. So many tinkerers here but very few stories about mods to IGH to increase strength.
What's causing failure in high power applications? Seems like two primary causes. Shifting under load puts extra stress on parts. Failing parts is the second problem area. Can't fix stupid abuse, so scratch off the first cause.
What parts fail? The main shaft gear(K508), pawls(K512), planetary gears, pins, clutch(K505A)?
Who's interested in a modded IGH suited for high power geared hub??? Sign me up!
What's causing failure in high power applications? Seems like two primary causes. Shifting under load puts extra stress on parts. Failing parts is the second problem area. Can't fix stupid abuse, so scratch off the first cause.
What parts fail? The main shaft gear(K508), pawls(K512), planetary gears, pins, clutch(K505A)?
Who's interested in a modded IGH suited for high power geared hub??? Sign me up!
I don't remember what failed in the stuff AussieJester or 1000w posted; you'd have to look thru their posts for the take-apart pics and info.windtrader said:
I only remember it was teeth broken off at the roots from gear lash allowing shock loads, so if you can simply gently take up the lash first before applying power (like a cush drive would, among other methods) and not apply shock loads, it'd probably greatly reduce the failure chances.
cycleops612
10 kW
amberwolf said:I don't remember what failed in the stuff AussieJester or 1000w posted; you'd have to look thru their posts for the take-apart pics and info.windtrader said:
I only remember it was teeth broken off at the roots from gear lash allowing shock loads, so if you can simply gently take up the lash first before applying power (like a cush drive would, among other methods) and not apply shock loads, it'd probably greatly reduce the failure chances.
and/or a supplementary freewheeling front hub motor to smooth changes/starts/hills.
Joe T.
100 W
LewTwo said:
You mean the brain is connected to the foot? What a concept. :lol:
I can only imagine a shifting problem when you don't have full control of the power output in the first place. That is why I am not a fan of PAS. I rode a bike with an BBSHD1000 with PAS turned on. It was cool at first. As I actually road in the trails I found it quite annoying and abusive to the cogs when shifting.
My bike, which is throttle only, is much friendlier to the drive train as I too grew up shifting 4 speed big block muscle cars. I feel the N360 has a huge advantage in the single track Ebike world when it comes to quick shifting. All you have to do is release load on the drive long enough to twist the shifter in the direction desired and the shift is complete. PAS throws a wrench into this but a quick tap of the brake should stop the power output from what I read.
LewTwo
1 MW
In some cases there may be a faulty connectionJoe T. said:
Edit:
Or worse yet: erratic processing. A common problem with immature software.
(see my remark regards my own misspent youth)
Electro-Fox
10 W
- Joined
- Sep 26, 2013
- Messages
- 69
LewTwo said:
Yep...it was called double clutching.
Electro-Fox
10 W
- Joined
- Sep 26, 2013
- Messages
- 69
What about the Nivinci 380 Harmony? It allows you to keep a steady cadence that you choose and shifts for you. Seems perfect for mid drives, although it is as expensive as a Rohloff.
LewTwo
1 MW
Not exactly ... double clutching is when youElectro-Fox said:
0) disengage the clutch
1) shift from any gear into neutral
2) engage the clutch
3) spin the gear train ... a quick tap on the gas pedal
4) disengage the clutch
5) shift from neutral into any gear
6) engage the clutch
Double clutching was usually required only on transmissions without synchronizers.
There were also many four speed transmissions that were built with unsynchronized low (first) gears. One usually only needed to shift into first gear when stopped. Occasionally some activities (i.e. slalom and road racing or hauling moonshine) required double clutching to get into first from second or even third.
I had a 1964 Falcon that had a non-synchro first gear. The synchro's were often the first thing to wear out on the manual transmission (if you owned the car long enough for that to occur), and first gear was the one that wore out the fastest by far. I often down-shifted into first as I was slowing down, so that when I was at a stop, I could then take off easily without trying to jam the shifter into an obstinate first gear. Later I got a job as a truck driver, and my previous experience helped quite a bit.
As affordable as a 3-speed IGH is, I would prefer to have it last many years, rather than replace it often. So...I will go back to my habit of easing off the power to shift.
As affordable as a 3-speed IGH is, I would prefer to have it last many years, rather than replace it often. So...I will go back to my habit of easing off the power to shift.
cycleops612
10 kW
LewTwo said:
Well yes,but woe betide the uninitiated who needed first halfway up a hill with a bunch of mates on board.
cycleops612
10 kW
"Who's interested in a modded IGH suited for high power geared hub???"
A contradiction in terms?
Both in the one hub perhaps.
A contradiction in terms?
Both in the one hub perhaps.
Electro-Fox
10 W
- Joined
- Sep 26, 2013
- Messages
- 69
LewTwo said:
My bad....
LewTwo
1 MW
I just noticed that SRAM has ceased production of their G8 and G9 IGH hubs.
http://www.bike-eu.com/sales-trends/artikel/2015/2/sram-stops-g8-and-g9-internal-gear-hub-production-1019292
Some odf the reasoning is interesting:
Looking at that market situation, it quickly becomes clear that there are currently evident reasons for fitting city and e-bikes with Nexus-7 hubs.
http://www.bike-eu.com/sales-trends/artikel/2015/2/sram-stops-g8-and-g9-internal-gear-hub-production-1019292
Some odf the reasoning is interesting:
Looking at that market situation, it quickly becomes clear that there are currently evident reasons for fitting city and e-bikes with Nexus-7 hubs.
kdog
10 kW
Old thread but a goodie...anyone got any experience with a nexus inter8 with a middrive. A friend wants me to do a 350w bafang through it on a cargo bike ( often with two kids on board up hills). Im thinking it's not going to last very long so I might steer her towards a hub... But i think a middrive would suit her given the wide range of speeds and loads she'll have.
Any opinion on this combo?
Any opinion on this combo?
Chalo
100 TW
kdog said:
I haven't seen that hub used with a mid drive, but I've seen it used successfully in some very heavy load and high torque applications. As long as the total pedal + motor torque doesn't exceed the hub's rating, I think it would be fine with a 350W system. That's assuming she has enough sensitivity to avoid shifting at full power.
Recumbentrx
100 µW
- Joined
- Mar 7, 2019
- Messages
- 7
I am using the latest nuvinci igh (N380) with the newest. Erosion of the bafang bbshd 1000 watt motor and 48v 17ah battery. I have it in a rans dynamick crank forward. I also have a chain tensioner. I had it built up for me by Utah Trikes as they do this setup a lot. The key to using a 1000 w mid drive with this hub is in the gearing and the operation. They put a 22 tooth rear cog on the back and a 36 tooth lekkie bling ring on it. As long as I shift down to the easiest gear ratio and lower the assist to 3 or 4 when coming to a stop, starting off again doesn't put too. Ugh stress on the hub. I since swapped out the 36 tooth lekkie to a Luna. Cycles eclipse 42 tooth chainring as I was spinning out too soon. I will put the 36 tooth ring back on for mountain biking season though as it climbs walls. As long as you don't start off in a hard to pedal gear ratio (The little guy on the bike riding the flat line) with the assist set at 6 or above, you shouldn't have any problems destroying the in nerds of the hub. Like I said, it's all about the gearing and the rider. So far I havent had any problems. Yesterday I took my son out for a training ride (He races mountain bikes with the Morristown revolutions racing team). At the end he was wiped out so I hooked a tow strap to my rear rack and his handle bar to help him get up the steep 2 mile road climb to get home. I basically towed him up the climb for 15-20 minutes. The motor was running at full power (1500 watts) the entire time and all systems were perfect, including the nuvinci. I just made sure when we stopped at the light to switch the hub to its easiest gear and power down the motor to level 3 before starting off again
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