Basic tadpole trike question - brakes

DIscuss anything relating to non-standard cycles and their equipment.
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[XAP]Bob
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Re: Basic tadpole trike question - brakes

Postby [XAP]Bob » 22 Jul 2020, 3:10pm

Whilst it was beyond the wit of legislators, tadpole trikes did exist before then I think...

I can't recall what the legislation actually says, but I think it talks about both brakes on a single wheel, or axle....
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tatanab
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Re: Basic tadpole trike question - brakes

Postby tatanab » 22 Jul 2020, 3:18pm

Tigerbiten wrote:The 1983 regs state:- Both fronts off one lever and the back off another one.
That is not my reading of 1983 paragraph 9(2) https://www.legislation.gov.uk/uksi/198 ... 176_en.pdf
It says that in tadpole configuration the minimum is two independent REAR brakes. If you have ever ridden a trike with just that you will agree that it is lethal. Sensibly manufacturers add front brakes, independent or coupled does not matter but they still require a rear brake which is why a minimal brake is often used as a parking brake or bobby dodger. This is logical if you consider the same legislation about delta. If you were to fit a brake or more to the rear you would still require a front one.

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[XAP]Bob
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Re: Basic tadpole trike question - brakes

Postby [XAP]Bob » 22 Jul 2020, 3:50pm

Also of course depends on what you consider the seat height to be....

Personally I don’t consider the “back” of the chair to be part of the “seat”.
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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squeaker
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Re: Basic tadpole trike question - brakes

Postby squeaker » 22 Jul 2020, 3:53pm

tatanab wrote:
Tigerbiten wrote:The 1983 regs state:- Both fronts off one lever and the back off another one.
That is not my reading of 1983 paragraph 9(2) https://www.legislation.gov.uk/uksi/198 ... 176_en.pdf
It says that in tadpole configuration the minimum is two independent REAR brakes. If you have ever ridden a trike with just that you will agree that it is lethal. Sensibly manufacturers add front brakes, independent or coupled does not matter but they still require a rear brake which is why a minimal brake is often used as a parking brake or bobby dodger. This is logical if you consider the same legislation about delta. If you were to fit a brake or more to the rear you would still require a front one.

But 7(1)(b) excludes trikes with a saddle height below 635mm ;) A bit like car barrier poles: 'bent trikes slide beneath them :roll:
"42"

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[XAP]Bob
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Re: Basic tadpole trike question - brakes

Postby [XAP]Bob » 22 Jul 2020, 4:07pm

Summary:

Para 6:
- Excluding EAPC (1983) cycles shall confirm to 7/8

Para 7:
- At least one braking system
- Bike or trike with saddle height > 635mm and any quad....
- If fixed wheel then a brake on the front wheel, or at least two front wheels
- Else two systems, one operating on the front wheel or at least two front wheels, the other on the rear, or at least two rear.
- Saddle height is defined as the highest point of "the part of the seating area of the saddle" when it's as high as it goes and the tyres are inflated.

The "at least 2" is in the case where there is more than one wheel at that end.

Para 8:
- 7 doesn't apply to bikes older than 1984 under various conditions.

Para 9:
- Nothing applies to bikes where the cranks are directly (ungeared, unchained) connected to a hub
- Doesn't apply to temporary imports (i.e. tourists)

- Non cargo trike. Two independent systems on the front wheel if it has two back wheels and vice versa.


Opinion:
It is this last item that is most perplexing... Even on an upright trike there is little to no chance of a single rear wheel providing any significant braking capability.
However for a bent I would argue that the seating area of our "saddle" is most certainly below 635mm (which is higher than a standard chair (~50cm max)), even if the backrest is higher.
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.

belgiangoth
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Re: Basic tadpole trike question - brakes

Postby belgiangoth » 22 Jul 2020, 6:57pm

Great, I can remove the back brake from my SPM!
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Jdsk
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Re: Basic tadpole trike question - brakes

Postby Jdsk » 22 Jul 2020, 7:12pm

Windcheetah 100 has two front hub brakes operated by a single lever and a rear paddle brake on the tyre for parking.

Jonathan

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pjclinch
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Re: Basic tadpole trike question - brakes

Postby pjclinch » 23 Jul 2020, 8:26am

If you have a chance to try a Kettwiesel delta, with a brake each side and the seat pretty much over the back axle, you can actually do very effective "handbrake turns" which can be great fun (though may be a little alarming when you find out about it empirically!)

Pete.
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[XAP]Bob
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Re: Basic tadpole trike question - brakes

Postby [XAP]Bob » 23 Jul 2020, 9:54am

pjclinch wrote:If you have a chance to try a Kettwiesel delta, with a brake each side and the seat pretty much over the back axle, you can actually do very effective "handbrake turns" which can be great fun (though may be a little alarming when you find out about it empirically!)

Pete.



I'd have expected the single front wheel to grip up as you started braking, and keep you pointed the right way.

It is the one trike configuration where rear brakes make a lot of sense though.
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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Re: Basic tadpole trike question - brakes

Postby Marc » 23 Jul 2020, 10:00am

belgiangoth wrote:My understanding is that with tadpole trikes the rear brake (if any) is purely a parking brake and the front brakes are where it's at.

Mostly, yes. You can use the rear brake on a tadpole trike, but combining front brakes and rear brake is usually a bad idea. The rear wheel gets awfully "light" when braking hard at the front and the rear can easily wash-out when you apply the rear brake as well. That usually results in a "rubber side up" situation.

My trikes (and velomobile) all have a rear disk brake for parking, because its very practical.