bike without single point of failure
- Thread starter sjpt
- Start date
As an aside re the GAADI tube; do you use this simply as a get you home option or is it "bump" enough free to be a fit and forget solution.
My wifes bike with Gates with Nexus rear set up, makes these decidely appealing, even if just till I can rework the wheel back at home.
I use the Gaadi permanently in my Norco 700c rear wheel and my Boardman 700c tourer, it is good enough for a fit and forget solution until you get a flat. They don't prevent them but makes changing easier without removing the wheel.
My Boardman is used on rough tracks, N & S Downs on any off piste route.
Buy two fit one and carry a spare repair any puncture at leisure along the route or at home, SJS Cycles I paid £7.95 each +p&p.
My Boardman is used on rough tracks, N & S Downs on any off piste route.
Buy two fit one and carry a spare repair any puncture at leisure along the route or at home, SJS Cycles I paid £7.95 each +p&p.
Just had this pop up on my Facebook feed.
not sure how I feel about it!
not sure how I feel about it!
We'll know how good it is when they start using it in the Tour de France or MTB world championships.
If it turns out to be any good, it will doubtless be declared unsporting &/or illegal. The downside is probably the extra weight, both of the shaft and the hub gears required (if you need gears). Puts a crimp in rear suspension options too.
I can understand your scepticism, but it looks an interesting design and it might be quite efficient.
Of course, they have a way to go yet, it can't handle more than about 200W without breaking. But even if they have a drivetrain efficiency of say 97%, which can be enclosed and kept clean, I think it will have advantages over chain/derailleur systems, which when perfectly set up can have 99% efficiency, but soon get dirty and can drop to 90% efficiency.
The main thing will be cost, it has to be cheap, or be able to offer a significant advantage that outweighs the cost.
No shaft system with dual right angle drives will have that efficiency. Also weight will be a problem, especially if fully enclosed as well.
The most efficient transmission which maintains maximum efficiency with vanishingly little wear over at least two decades is the old pre war Sunbeam oilbath chaincase, either with single speed or hub gear.
But like this proposed system if fully enclosed, wheel removal can be bugbear.
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They have roller bearings as "teeth" on the right angles, so it's not like a normal set of bevel gears. It would be nice to see the data for it.
Single speed, large cogs chain drive at correct tension and in oilbath chain case would be fantastic for efficiency and longevity. However, even the best hub gears cause a significant drop in efficiency.
With modern materials like carbon fibre, I don't think the weight will be a massive issue. But as you say, unless properly engineered, wheel changing could be a pain.
Maybe the way to go is a single sided rear fork. It could be made to house the shaft.
What they do not say anything about is wear. All those little rollers will be vulnerable.
Personally. although a good try, I have many reservations about the basic design. The early idea (which is not new, remember DAF cars with continuously variable transmission?) obviously ran into problems, hence the two stage gear change, but will this get clogged up easily? Time will tell.
DAFs ran into problems because the rust protection was even worse than on UK cars of the time; the transmission was brilliant. We had two at different times with no transmission problems at all.
The transmission ran into problems when Volvo took it over and adapted it. DAFs 'forward to go forward, backwards to go backwards' replaced by 'forward to go backwards, backwards to go forward' for example.
This happened to me on my £100 second hand rear hub Oxygen Emate.
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Something that could have been a bit of a disaster on my Friday morning commute was saved by having a throttle.
Climbing a steep hill with still 4 miles to go the chain broke. I retrieved it from the road, and although I do carry a split link did not fancy finding it and doing the repair in the dark by the side of the road in the dark.
The throttle got me to work and shows how useful an un restricted throttle can be as an emergency get you home, or in my case to work devise if you get a problem that means you cannot peddle.
Anyway the chain was back on for the ride home and to work the next day. "
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Something that could have been a bit of a disaster on my Friday morning commute was saved by having a throttle.
Climbing a steep hill with still 4 miles to go the chain broke. I retrieved it from the road, and although I do carry a split link did not fancy finding it and doing the repair in the dark by the side of the road in the dark.
The throttle got me to work and shows how useful an un restricted throttle can be as an emergency get you home, or in my case to work devise if you get a problem that means you cannot peddle.
Anyway the chain was back on for the ride home and to work the next day. "
Oddly enough other car firms use the reverse logic too. My Nissan latest Leaf is gear puck back to go forward, puck forwards to engage reverse.
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On a lot of those old motorbikes, there's a hollow piece that retains the brake, chain and sprocket on the swinging arm. There's a spacer on the other side. You pull out the axle, remove the spacer, shift the wheel to the left to disengage a spline for the sprocket, then the wheel drops down and is removed rearward. The whole thing only takes a few seconds. This is how they were able to use fully enclosed chains.
Here you can see the two-stage axle under the rest of the stuff. The system could easily be adapted for bicycles.
Agreed, but Sunbeam and others with oilbath and dry full chaincases never bothered on bicycles for a couple of reasons. One was the hub gears ruling that out. The other was the steel frames that meant frame expanders allowed tube and tyre changes by only removing the left hand wheel nut.
Alloy frames and rims have their benefits but also some very real disadvantages.
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Yes. Actually the reason that Volvo changed it was to make it fit this 'standard' for automatic transmission gear levers. Most people don't notice how odd this standard setup is, unless they've driven a DAF.
Another problem with the DAF was that the mid-point was neutral, and there wasn't a locked/park position for parking on a hill. This was illegal in some countries; especially US (I think) where many people are in the habit of never using a handbrake or it's foot operated equivalent.
On the Leaf the gear change puck always returns to the middle after an action is selected. So it's forward for Reverse, back for Forward, to the right for Park or held to the right for a few seconds for Neutral. Took me a little while to get used to. It's all electrical actions for each, no mechanical linkage, and on my model even the "handbrake" is an electrical switch which lets itself off when the accelerator is depressed.
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Have you any idea why the link failed?
I note that this was not a case of an actual chain 'breaking' merely the connector becoming undone, and as the bike was second hand, you have no idea if the connector had not been fitted correctly in the first place.
I totally agree about the full throttle and would not have a bike without one.
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