Bicycle restrictor

General cycling advice ( NOT technical ! )
Vorpal
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Re: Bicycle restrictor

Postby Vorpal » 28 Apr 2016, 1:06pm

Bicycle restrictor? I prefer to refer to them as #&#*%!!. And my opinion is well laid out in these previous threads about them...

viewtopic.php?f=6&t=92505
viewtopic.php?f=6&t=93982
viewtopic.php?f=7&t=92263
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MartinC
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Re: Bicycle restrictor

Postby MartinC » 28 Apr 2016, 2:14pm

pwa, apologies if I've overstated what you were suggesting. I read your account of their installation as an invitation to believe that they work. If all that you are saying is that they are a placebo then we agree. Helping to get them installed if you think they don't work and know they discourage legitimate users just to prove that you're listening to residents seems a bit cynical.

pwa
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Re: Bicycle restrictor

Postby pwa » 29 Apr 2016, 7:33am

MartinC wrote:pwa, apologies if I've overstated what you were suggesting. I read your account of their installation as an invitation to believe that they work. If all that you are saying is that they are a placebo then we agree. Helping to get them installed if you think they don't work and know they discourage legitimate users just to prove that you're listening to residents seems a bit cynical.


You still only half understand what I said. Firstly, I said that they do not work in all circumstances and should not be used everywhere as a default measure. Where they do work, it is as a deterrent, not as a complete bar to motorcycles. In the example I gave, they worked in that way. The narrow alleys used by a few motorcyclists, terrorising non-motorised users of those paths, had A Frames installed and the motorcyclists stopped using those paths and stuck to the roads instead. The paths became unattractive to the motorcyclists. Not completely impassable, just unattractive. A nearby area of scrubland saw an increase in motorcycle use. The A Frames installed were put in very carefully, ensuring that the gaps were at least as wide as the design specs, and they were (and still are) used by people using mobility scooters. Of course they are an inconvenience for everyone, just like speed bumps in the road, and it would be better if they were not needed. But sometimes they are needed, and sometimes they do a good job.

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RickH
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Re: Bicycle restrictor

Postby RickH » 30 Apr 2016, 11:52am

I think more recent installations (at least round here) use a better design that reduces the inconvenience for legitimate users (& reduces the risk of catching a bar end/ drop bar on the side for cyclists).

Image
(that's my MTB with the 53cm wide bars)

I think the comparison with speed bumps is a reasonable one - well designed bumps regulate those who need it but don't cause significant problems for other users. Badly done in both cases... :?

Rick.

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gaz
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Re: Bicycle restrictor

Postby gaz » 30 Apr 2016, 12:21pm

That's a K frame, like the example I posted earlier although with much more generous clearances.

On some K-frames the gap is adjustable. They are set narrow at first until the motorcycle problem has been eliminated or lessened substantially, then they are widened out. If the problem returns they can be squeezed in again.
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Mattyfez
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Re: Bicycle restrictor

Postby Mattyfez » 30 Apr 2016, 1:06pm

Wide bars are nice though, I Rode my friends ancient mtb the other day and the bars were unnervingly short!

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Re: Bicycle restrictor

Postby Bmblbzzz » 2 May 2016, 3:13pm

Why is it called a K-frame? I'm struggling to see a letter K shape in there. Confused here!

As for that particular example, it does look problem-free but I'd note that 53cm is very narrow compared to many MTB bars.

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Re: Bicycle restrictor

Postby pwa » 2 May 2016, 5:53pm

Bmblbzzz wrote:Why is it called a K-frame? I'm struggling to see a letter K shape in there. Confused here!

As for that particular example, it does look problem-free but I'd note that 53cm is very narrow compared to many MTB bars.


On a purely technical point, I found that when cutting down a straight (ish) MTB bar I was limited by how close I could put my brake levers. With three levers (including an extra one for a rear disc brake on a three brake tandem) and a Rohloff twist-grip I could get the bar to 54cm (including the bar ends) which feels about right on a bike ridden on roads and smoothish tracks. Trying to cram everything into a smaller space would have had things crowding each other and cables getting in the way of fingers. With the bars uncut, at 60cm+, my hands felt ridiculously far apart, as if I were a goal keeper about to face a penalty kick.

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gaz
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Re: Bicycle restrictor

Postby gaz » 2 May 2016, 6:03pm

Bmblbzzz wrote:Why is it called a K-frame? I'm struggling to see a letter K shape in there. Confused here!


http://www.kbarriers.co.uk/
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Re: Bicycle restrictor

Postby Bmblbzzz » 2 May 2016, 7:20pm

I'm still not seeing a letter K! :?: Never mind. I am seeing "* Double, side-by-side design, pushchairs and larger wheelchairs and mobility scooters may need extra access space provided by our K Barrier range of products, please ask for details." on the A barriers page.

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Re: Bicycle restrictor

Postby pwa » 3 May 2016, 7:40am

Bmblbzzz wrote:I'm still not seeing a letter K! :?: Never mind. I am seeing "* Double, side-by-side design, pushchairs and larger wheelchairs and mobility scooters may need extra access space provided by our K Barrier range of products, please ask for details." on the A barriers page.


I'm not sure what that barrier is meant to stop. It is so wide. Anything it does stop would surely be too wide to travel safely down a path anyway.

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Re: Bicycle restrictor

Postby Vorpal » 3 May 2016, 9:11am

pwa wrote:
Bmblbzzz wrote:I'm still not seeing a letter K! :?: Never mind. I am seeing "* Double, side-by-side design, pushchairs and larger wheelchairs and mobility scooters may need extra access space provided by our K Barrier range of products, please ask for details." on the A barriers page.


I'm not sure what that barrier is meant to stop. It is so wide. Anything it does stop would surely be too wide to travel safely down a path anyway.

Like a triple wide baby buggy?
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pwa
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Re: Bicycle restrictor

Postby pwa » 3 May 2016, 9:21am

It depends on the width of the path, but there has to be a limit to the width of what can go down a path without incurring danger to the user and other people on the path. With the barrier in the picture, much wider and you might as well let cars in. I'm curious about the thinking behind it.

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Re: Bicycle restrictor

Postby Bmblbzzz » 3 May 2016, 10:41am

pwa wrote:It depends on the width of the path, but there has to be a limit to the width of what can go down a path without incurring danger to the user and other people on the path. With the barrier in the picture, much wider and you might as well let cars in. I'm curious about the thinking behind it.

Which particular barrier are you talking about? The photos of the "Standard K barrier" http://www.kbarriers.co.uk/barrier-type/ show a woman on a mobility scooter just passing through it and a man on a mountain bike having to lift his front wheel and turn his bars to fit through.

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Re: Bicycle restrictor

Postby pwa » 3 May 2016, 11:10am

Bmblbzzz wrote:
pwa wrote:It depends on the width of the path, but there has to be a limit to the width of what can go down a path without incurring danger to the user and other people on the path. With the barrier in the picture, much wider and you might as well let cars in. I'm curious about the thinking behind it.

Which particular barrier are you talking about? The photos of the "Standard K barrier" http://www.kbarriers.co.uk/barrier-type/ show a woman on a mobility scooter just passing through it and a man on a mountain bike having to lift his front wheel and turn his bars to fit through.


RickH's photo with the MTB leaning against the inside of the barrier. The gap is so wide that the largest motorcycle could get through without so much as a wiggle, which leaves me wondering what it was meant to stop. I can't see what it achieves that could not be more elegantly achieved with a car-stopping pair of posts acting as a gateway.