Mango

DIscuss anything relating to non-standard cycles and their equipment.
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squeaker
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Location: Sussex

Re: Mango

Post by squeaker »

I think you'd need to think carefully where the 2.5:1 jump with the HSD will occur. I use the MD on the WAW for the steeper hills: mostly I stay in the high range. If you'd only use the HSD to get the downhill overdrive, then that would probably be acceptable, but if you had to use it on the flat it could be annoying, although the SA hub would help you 'play tunes' and save a full 7 gear cassette shift when HSD activated.

Be interested to read how you get on :wink:
"42"
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Tigerbiten
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Joined: 29 Jun 2009, 6:49am

Re: Mango

Post by Tigerbiten »

Looks good ..... :D

An other vote to be careful about the HSD shift speed.
When you shift into overdrive the chain moves at 2.5x the normal speed which increases drag.
The main reason I run twin chainrings on my Rohloff-HSD setup is to shift my overdrive speed up from ~14 mph to ~20 mph while keeping my ultra low first gear.
This move my overdrive speed up from my flatland speed to the start of my downhill speed.
Plus it splits the 14-7 shift pattern to a 14-3-4-3 pattern with the 3 extra gears as an added bonus.

Luck ....... :D
UpWrong
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Re: Mango

Post by UpWrong »

I'd rather have a slick double FD upfront providing a second range of gears than a Schlumpf, and use the SA CS-RK3 most of the time. The FD can be operated by a bar-end located elsewhere from the SA controls.If you are concerned about the chain coming off at the front then a jump-stop and a triple with a chainguard as the outer ring could be used.

I was really impressed by the operation of the SA CS-RK3 on my Paseo. What put me off was the weight and the complication when removing the rear wheel. You won't have that problem when installed in the Mango.
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squeaker
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Location: Sussex

Re: Mango

Post by squeaker »

Another thing to consider is drivetrain noise. IME most derailleur systems are relatively quiet (except possibly when gear changing :roll: ) but hub gears of any sort can introduce additional ticks and whirrs (not to mention whines) which might not be intrusive on a conventional machine, but may be when radiated by the velomobile's body. Very much a subjective area, though.
"42"
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[XAP]Bob
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Re: Mango

Post by [XAP]Bob »

The front has been a little fiddly so far, with a little bit of a propensity not to shift particularly cleanly... I suspect the gaps and chainrings are a little oversized and the derailleur is therefore struggling a little bit - but don't really have any evidence for that, it might just not be well adjusted (I know it was put on just for the sale, the previous owner had e-assist up front).

I used the HSD on the raptobike, that worked pretty well feeding a 20" drive wheel, and I used the CS-RK3 on the ICE trike, again feeding a 20" drive wheel.
I never found the heel shift on the HSD an issue, either I'm dropping a massive ratio when at a standstill or I'm moving fast enough that it doesn't matter too much if I have a short interval in pedalling. The hardest shift is down when climbing, the pause matters at that point, but you drop enough gear inches fast enough that it's only a small loss of momentum.
The velo also loses momentum significantly slower than any other vehicle I've ridden - unsurprising, but still amazing to watch.

In terms of the chain speed, it would go fast, a 75 tooth chainring is pretty large, but the mango idler setup (and mine has an oversized tensioner setup which bypasses the tube altogether) seems quite well put together - the potential advantage of a high speed chain is relatively low tension, so theoretically lower defection losses, and the bearings are less laterally loaded - I've not done any theoretical or practical analysis of the competing effects of speed and tension (https://www.mdpi.com/2076-3417/10/21/7729/pdf seems like a place to start).

The alternative would be drop the front chainring sizes and keep a tall final ratio (along with the CS-RK3 I should still get a pretty decent range and some ability to drop gears at a standstill).

I've long thought that a rear hub with a simple "neutral" gear would be kind of useful for trikes in general, change a derailleur at a standstill ;) Could even put a dynamo in it for additional functionality :p
A shortcut has to be a challenge, otherwise it would just be the way. No situation is so dire that panic cannot make it worse.
There are two kinds of people in this world: those can extrapolate from incomplete data.
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[XAP]Bob
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Re: Mango

Post by [XAP]Bob »

Fettled the rear mech - rotated to give as much space as possible without touching the shell, one thing that might be causing issues is that the chain guide is potentially catching the tension side chain as I shift into the top couple of gears - probably not an issue unless I up, down, up within a hub rotation. I shall see what happens tomorrow (I have an early meeting).

Also made sure the mid hub is as high as possible in the dropouts.
A shortcut has to be a challenge, otherwise it would just be the way. No situation is so dire that panic cannot make it worse.
There are two kinds of people in this world: those can extrapolate from incomplete data.
Psamathe
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Re: Mango

Post by Psamathe »

I'm new to bents but my understanding of the Schlumpf is that the gear change is by pushing a rod/button on the pedal axel. Out today and thinking about the foot movement and seemed to me to to that you'd need to unclip. Maybe the arrangement is different but do you need to unclip to change gear on the Schlumpf?

(I don't have one and not thinking of changing so just an out of interest question having never seen one).

Ian
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[XAP]Bob
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Re: Mango

Post by [XAP]Bob »

I have enough float to do so without unclipping, and that's even with my short cranks which don't have the crank covers which mean you just have to hit the crank somewhere.

The button is on the BB axle, not a pedal axle, so you just tap it with your heel as your heel passes the BB.
A shortcut has to be a challenge, otherwise it would just be the way. No situation is so dire that panic cannot make it worse.
There are two kinds of people in this world: those can extrapolate from incomplete data.
Psamathe
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Re: Mango

Post by Psamathe »

[XAP]Bob wrote: 6 Sep 2021, 10:07pm I have enough float to do so without unclipping, and that's even with my short cranks which don't have the crank covers which mean you just have to hit the crank somewhere.
(Off-topic, sorry) what system do you use to give you that much float? I'm new to clipless and have standard SPD with Shimano PD-T8000 pedals and no float. I'd like more float but it's very early days getting used to it so still seeing how things go but on 2-wheels with toe-clips I'd be moving my feet around a fair bit.

Ian
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[XAP]Bob
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Re: Mango

Post by [XAP]Bob »

Just spd (MTB style) cleats and pedals.

Single release
A shortcut has to be a challenge, otherwise it would just be the way. No situation is so dire that panic cannot make it worse.
There are two kinds of people in this world: those can extrapolate from incomplete data.
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Tigerbiten
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Joined: 29 Jun 2009, 6:49am

Re: Mango

Post by Tigerbiten »

Another HSD user here.
Mine is fitted with 170mm cranks.
When I first got my HSD, I had great trouble hitting the axle button with the edge of my SPD sandals.
The spring plates fix to a pedal axle and cover the axle button.
This fixed the problem as I now just need to brush the crank with the edge of my sandals.

Luck ............ :D
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[XAP]Bob
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Re: Mango

Post by [XAP]Bob »

The plates are good, but when I transitioned to shorter cranks they obviously didn't fit any more, and I just got used to hitting the button.
I've not been wearing sandals for a long while though.

It's rather nice being able to carry shoes and walking poles easily in the Velo though. Just need to figure out hooking up the wheelchair next.
A shortcut has to be a challenge, otherwise it would just be the way. No situation is so dire that panic cannot make it worse.
There are two kinds of people in this world: those can extrapolate from incomplete data.
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[XAP]Bob
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Joined: 26 Sep 2008, 4:12pm

Re: Mango

Post by [XAP]Bob »

Hmm - going to need to think about gearing a bit more, particularly how to fit the HSD, since the BB shell is plastic (slight communication mixup between myself and Drymer). I might have to "recover" a BB from another frame and get it mounted on a plate by a local metalworker :?

Took the top off and started to fit my new lighting setup - I was a bit rushed and foolish though, there are a few things in my toolbox I should have used and didn't, which will make the next lighting upgrade (only did the rear) much more of a pain than it should be. Also left in a USB cable for reprogramming the micro controller :mrgreen:

Oh well - I'm getting quite good at taking the top off, and my garage workstand (old Ikea coffee table frame for the front wheels, fairly tall kitchen step for the rear) actually puts it at a really good height for working.

Rear lights, with indicators and brake lights, all installed - cabling for indicators, brakes and the horn are also all in place (just ordered a 6V battery to run the horn directly, since it just clicks when given 5V, the 6V battery charger is USB though, so I can route that to somewhere convenient to charge it from the "main" battery every so often.
A shortcut has to be a challenge, otherwise it would just be the way. No situation is so dire that panic cannot make it worse.
There are two kinds of people in this world: those can extrapolate from incomplete data.
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