I went for a little trip to London today - and while I was there I had a go on a couple of the "Boris Bikes".
Of course, it was raining :-)
All the time I was there.
But, hey, it would be rude not to try a couple of bikes while I was there!
Quick comments:
- I tried two different bikes - on both the front brake was rather weak, but the rear was more powerful than expected (and it was better for stopping than the front!).
- The3-speed gears are rather low, but that low first is needed for getting back up "Broad Walk" (there is a little hill in the park when one is heading from the South to the North).
- Seats are tipped a little too far forwards for my tastes, but the seat angle didn't seem to be adjustable.
- The seat posts have a quick release lock with numbers prominently marked on the seat post - so if you know, for example, that you are a "number 4", then just set the seatpost to that height - quick and easy. Even better, often you can just choose a bike already set to "your" height - just walk down the row and look at the seatpost numbers, and take the one that suits - even quicker and easier!
These London bikes seemed to be OK for maintenance - for example there
was almost no slack in the brake levers before they started to bite, BUT
the front brake, which was perhaps a shimano roller brake, looked rather
small in diameter and rather narrow (the design leads me to think it was
either a "roller" brake or a band brake).
Either that, or some part of the brake mechanism wasn't set up properly
If those two "hire bike" front brakes are typical of what other folks have used in the past, perhaps that is why some of them so vehemently argue that "drum" brakes are ineffective - they simply have never used a decent drum brake, like a 90mm Sturmey Archer, for example.
The physics is basically that a bigger drum and a wider shoe provides better braking power - end of. A small, narrow, set-up, even when correctly adjusted, isn't going to match up to a "proper" drum brake (which I have used in the past, and was very happy with the performance - a 20kg bike plus a 20 kg load plus a 100kg rider is quite a reasonable test for a bike's brakes when going down a decent hill!).
As an aside, the zenith of drum brake design was probably the multiple-leading shoe designs used on early 1960's racing motorcycles, so there is no fundamental reason why a properly designed drum brake should not be quite powerful, if a little heavy.
Only cost me 2 pounds (a bit more than 3 dollars), and that was for the one-day "system" registration - the actual cost of the bikes was free (as I kept each of them for less than 30 minutes).
Overall, they are rideable enough, especially once you get used to their foibles :-)
Either that, or some part of the brake mechanism wasn't set up properly
If those two "hire bike" front brakes are typical of what other folks have used in the past, perhaps that is why some of them so vehemently argue that "drum" brakes are ineffective - they simply have never used a decent drum brake, like a 90mm Sturmey Archer, for example.
The physics is basically that a bigger drum and a wider shoe provides better braking power - end of. A small, narrow, set-up, even when correctly adjusted, isn't going to match up to a "proper" drum brake (which I have used in the past, and was very happy with the performance - a 20kg bike plus a 20 kg load plus a 100kg rider is quite a reasonable test for a bike's brakes when going down a decent hill!).
As an aside, the zenith of drum brake design was probably the multiple-leading shoe designs used on early 1960's racing motorcycles, so there is no fundamental reason why a properly designed drum brake should not be quite powerful, if a little heavy.
Only cost me 2 pounds (a bit more than 3 dollars), and that was for the one-day "system" registration - the actual cost of the bikes was free (as I kept each of them for less than 30 minutes).
Overall, they are rideable enough, especially once you get used to their foibles :-)
No comments:
Post a Comment