Author Topic: One brake or two?  (Read 11188 times)

Re: One brake or two?
« Reply #25 on: 05 January, 2016, 12:06:43 pm »
I don't like the muck and rim wear from a caliper brake.

There won't be any - it's only there in case the front brake fails.

I've had a brake cable snap, so my bikes have a rear brake. I need to remember to pull the lever every few months as the cable can seize.
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Torslanda

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Re: One brake or two?
« Reply #26 on: 05 January, 2016, 01:34:29 pm »
How about 135mm rear with track ends and use the A2Z disc adapter?

It partially mounts on the axle so will always be concentric with the hub.

VELOMANCER

Well that's the more blunt way of putting it but as usual he's dead right.

Re: One brake or two?
« Reply #27 on: 05 January, 2016, 01:40:59 pm »
The frame designer has come back to me with a rocker dropout, a bit like these: http://www.spanner.org.uk/wp-content/uploads/2014/06/Screen-Shot-2014-06-01-at-07.51.50.jpg :thumbsup:

That’s not bad. Assuming those are aluminium, there can’t be much of a weight penalty. Neatly remove the gear hanger and that could end up very tidy.

Chris N

Re: One brake or two?
« Reply #28 on: 05 January, 2016, 03:00:28 pm »
There won't be any - it's only there in case the front brake fails.

I've had a brake cable snap, so my bikes have a rear brake. I need to remember to pull the lever every few months as the cable can seize.

If I've got the brake, I'll use it - and I've never snapped a brake cable.

How about 135mm rear with track ends and use the A2Z disc adapter?

It partially mounts on the axle so will always be concentric with the hub.

Ok for an OTP frame, but I'd like something neater for a custom frame.  The rockers shown above are much nicer, but pricey.

That’s not bad. Assuming those are aluminium, there can’t be much of a weight penalty. Neatly remove the gear hanger and that could end up very tidy.

I think the plates are aluminium.  Just need to find out if they do a SS specific RH plate. :thumbsup:

Re: One brake or two?
« Reply #29 on: 05 January, 2016, 08:28:22 pm »
That looks workable.  I went for rim brakes only because I wanted a double-sided hub.

Re: One brake or two?
« Reply #30 on: 05 January, 2016, 09:08:13 pm »
I'm in the two brake camp ( Hilly up here in Cumbria ! )  - also I believe the bike always steers better when NOT applying the front brake on the rare occassions when I maybe carrying a little too much speed into corners.

Pedaldog.

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Re: One brake or two?
« Reply #31 on: 06 January, 2016, 09:49:28 pm »
It's only a Little Law, this two brakes thing, isn't it?

is a fixed wheel legally classed as a brake, if it is I apologise.
You touch my Coffee and I'll slap you so hard, even Google won't be able to find you!

Re: One brake or two?
« Reply #32 on: 06 January, 2016, 10:45:22 pm »
It's only a Little Law, this two brakes thing, isn't it?

is a fixed wheel legally classed as a brake, if it is I apologise.

Yes it is, so it's legal to ride fixed on the road with just a front brake. (I'm in the two brakes camp, though!)

Re: One brake or two?
« Reply #33 on: 06 January, 2016, 11:40:13 pm »
Yes, this whole discussion is being conducted on the basis that people realise that "two brakes" means not counting the fixed wheel, which of course is a brake in legal terms.

Pedaldog.

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Re: One brake or two?
« Reply #34 on: 07 January, 2016, 12:59:16 am »
Thanks, I was uncertain of the legal situation. I would be a "Two brakes regardless" on a fixed gear but the single speedhas a freewheel so I have no choice on that score.
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Re: One brake or two?
« Reply #35 on: 17 January, 2016, 08:35:16 pm »
Old Fixie: double fixed hub, two brakes, front canti, but at the rear a fairly useless Weinmann sidepull - I did hang onto it pretty hard a few times, but to probably only psychological effect, on the Dorset Coast, Elenith, though...TT'd on it with front brake only.

New Fixie: single fixed hub, two disc brakes. No problem with the rear brake and wheel position. [Genesis Day-One 853: track ends with screw adjusters, brake on the seatstay.]

But which set-up is best...hmmm?

Nelson Longflap

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Re: One brake or two?
« Reply #36 on: 17 January, 2016, 09:21:26 pm »
Doesn't the gearing make a difference? If the gear is low enough ( <65" say) there's less need for a back brake because (a) you never really go that fast anyway (even, or especially, downhill) and (b) leg braking is easier the lower the gear.

Contrary to expectations, I'm quite enjoying a 64" gear on winter roads. The low gear definitely enhances control.
The worst thing you can do for your health is NOT ride a bike

Re: One brake or two?
« Reply #37 on: 17 January, 2016, 10:06:34 pm »
Doesn't the gearing make a difference? If the gear is low enough ( <65" say) there's less need for a back brake because (a) you never really go that fast anyway (even, or especially, downhill) and (b) leg braking is easier the lower the gear.

Contrary to expectations, I'm quite enjoying a 64" gear on winter roads. The low gear definitely enhances control.

At over 35mph on 43x18 with a heavily laden bike, I do appreciate two brakes.

Nelson Longflap

  • Riding a bike is meant to be easy ...
Re: One brake or two?
« Reply #38 on: 18 January, 2016, 10:29:00 am »
At over 35mph on 43x18 with a heavily laden bike, I do appreciate two brakes.
I agree completely Ian. Momentum defeats leg strength quite quickly.

My special case is an unladen track bike ridden carefully on potentially dodgy surfaces where I don't go near 35mph and leg braking works very well in these conditions.

If you have the choice, two brakes plus fixed cog is wise, but recognising the limitations, a lightweight bike with front brake only is OK. It helps if the front brake is a good one (good = nicely modulated in this case).

Your 43x18 is pretty much identical to my 48x20 so I do know how spinny 35mph feels on that gear, and leg braking could easily turn into leg breaking! A back brake definitely helps at that cadence!  :thumbsup:
The worst thing you can do for your health is NOT ride a bike

Re: One brake or two?
« Reply #39 on: 18 January, 2016, 10:37:51 am »
Doesn't the gearing make a difference? If the gear is low enough ( <65" say) there's less need for a back brake because (a) you never really go that fast anyway (even, or especially, downhill)

I found it difficult to keep speed on long downhill slopes. Spinning at high revs while applying back pressure is really tiring, especially when you have to keep it up for a couple of miles (thinks of descent from holme moss to glossop).

(b) leg braking is easier the lower the gear.
Not in my experience. Much easier with higher gears. More strength needed yes, but less skill.
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Chris N

Re: One brake or two?
« Reply #40 on: 18 January, 2016, 10:42:27 am »
Doesn't the gearing make a difference?

A little, but in my case I'll most likely be using 43/17 and not carrying much luggage whether I've got a rear brake or not.

Nelson Longflap

  • Riding a bike is meant to be easy ...
Re: One brake or two?
« Reply #41 on: 18 January, 2016, 11:06:42 am »
I found it difficult to keep speed on long downhill slopes. Spinning at high revs while applying back pressure is really tiring, especially when you have to keep it up for a couple of miles (thinks of descent from holme moss to glossop).
Agreed. Long downhills are hard work on fixed, and the back brake helps considerably.
(b) leg braking is easier the lower the gear.
Not in my experience. Much easier with higher gears. More strength needed yes, but less skill.
Now that's interesting. We gear lower to enable more torque , especially helpful when pedalling forwards uphill, but surely the same applies when leg braking ... more torque means easier braking and finer control. So my experience is the opposite of yours - there must surely be a scientific answer here ...
The worst thing you can do for your health is NOT ride a bike

LittleWheelsandBig

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Re: One brake or two?
« Reply #42 on: 18 January, 2016, 11:14:06 am »
It is hard to leg-brake at higher revs.
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Nelson Longflap

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Re: One brake or two?
« Reply #43 on: 18 January, 2016, 02:34:19 pm »
It is hard to leg-brake at higher revs.
Is that because, for a given gear ratio, higher revs brings more momentum which is just harder to scrub off with the fairly weak force of leg braking? Or are there other factors? (Like stupidly high revs need so much concentration leg braking is a distraction we can't handle?)

You seem to be implying that at a given speed, lower gear ==> higher cadence ==> harder to brake. I'm genuinely not sure if that's right. Looks like a practical trial is called for (unless somebody here knows a mathemagical answer).

Here's a challenge for next time we meet: you roll along at 85rpm on a 52x15 (92") =  38kph, and see how long it takes you to come to a stop by leg braking.
I'll ride at 100rpm on 42x22  (51") = 25 kph and stop similarly. Even though your legs are stronger than mine I bet I would still win easily even though I start at a higher cadence.  ;D

I suspect momentum is the dominant factor, but for me anyway, there comes a point where high cadence impedes leg braking because I can't do both at once. 
The worst thing you can do for your health is NOT ride a bike

Re: One brake or two?
« Reply #44 on: 18 January, 2016, 02:50:27 pm »

You seem to be implying that at a given speed, lower gear ==> higher cadence ==> harder to brake. I'm genuinely not sure if that's right.
For a given speed, a lower gear MUST produce a higher cadence.

If we are just braking/slowing down, then we don't want to lock up the rear wheel. A lower cadence means you aren't having to do things as fast. It is much easier to leg brake at, say, 80rpm than 120rpm.
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Nelson Longflap

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Re: One brake or two?
« Reply #45 on: 18 January, 2016, 03:38:02 pm »
A lower cadence means you aren't having to do things as fast. It is much easier to leg brake at, say, 80rpm than 120rpm.
Other things being equal (same rider, same speed, same bike, ...) I'm really not sure any more. I ride my Genesis on 42x16 (70") and, atm, my playtime Orbit track on 48x20 (64"). 28kph is 83rpm on the Genesis and 91rpm on the Orbit. I'll see which is easiest to stop, although perhaps the gear ratios are too close to tell (they do feel different though).

Your example of 80 v 120 rpm would require a substantial gear difference and I'm not sure I can imagine it. 80 rpm on 52x15 (92") is 36kph and 120 rpm on 52x22 (63") is also 36kph.  Like you I'd rather be on the bigger gear because it's more comfortable, but which one stops faster I can't tell without trying. I suspect the low gear would be initially slower to decelerate while the rider gets the control to apply proper back force, but the increased tourque would allow greater deceleration as the cadence drops. However 120 rpm isn't that uncomfortable, so my bet is the low gear would stop marginally quicker, but it really is a guess.

And back on topic I run two brakes on the Genesis, and find it worthwhile on long descents and long rides, but front brake only on the Orbit, and don't really feel the need for a back brake on Hampshire hills (it does have a very nice feeling front brake though).
The worst thing you can do for your health is NOT ride a bike

Re: One brake or two?
« Reply #46 on: 18 January, 2016, 03:44:30 pm »
I suspect the low gear would be initially slower to decelerate while the rider gets the control to apply proper back force, but the increased tourque would allow greater deceleration as the cadence drops.
Not really - most cyclists are strong enough to lock up their rear wheel even when riding, say, a 90" gear.

I used to ride on double-fixed. 64" on one side, 79" on the other.  Leg braking was much easier with the 79" gear.
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Nelson Longflap

  • Riding a bike is meant to be easy ...
Re: One brake or two?
« Reply #47 on: 18 January, 2016, 05:05:04 pm »
Not really - most cyclists are strong enough to lock up their rear wheel even when riding, say, a 90" gear.

I used to ride on double-fixed. 64" on one side, 79" on the other.  Leg braking was much easier with the 79" gear.
Does your use of the word 'even' mean that skidding is easier on a low gear than on a high one? I think it is ... I used to TT on a fixed gear in the mid 80s (with one brake) but didn't/couldn't induce a skid by leg braking. However on low gears I can skid, which is why I suggest the braking force using a low gear is greater (being closer to the skid threshold).

If by 'easier' you mean 'more comfortable' or 'easier to do' then I agree, but I don't agree it means 'more effective'. Is the difference measurable? Maybe, but it might need a bit of careful experimentation.

However much of the argument between us is moot as like most others I'm a leg-retarder rather than a leg-braker really. Having said that I can ride for days sometimes without ever touching the rim brakes ... which is another reason to love riding fixed, especially in winter. A bit of anticipation coupled with leg retardation is good enough for slowing and stopping in most situations outside town and steep hills.

I'd like to ride 79" again because the bike seems to run more smoothly and I would rarely approach my cadence threshold, but I'd be walking up too many hills nowadays ...
The worst thing you can do for your health is NOT ride a bike

Chris N

Re: One brake or two?
« Reply #48 on: 28 January, 2016, 03:40:03 pm »
Two brakes it is.  Deposit paid, detailed drawings to follow.  Initial sketch below:

PaulF

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Re: One brake or two?
« Reply #49 on: 28 January, 2016, 04:01:18 pm »
It is hard to leg-brake at higher revs.
Is that because, for a given gear ratio, higher revs brings more momentum which is just harder to scrub off with the fairly weak force of leg braking? Or are there other factors? (Like stupidly high revs need so much concentration leg braking is a distraction we can't handle?)

You seem to be implying that at a given speed, lower gear ==> higher cadence ==> harder to brake. I'm genuinely not sure if that's right. Looks like a practical trial is called for (unless somebody here knows a mathemagical answer).

Here's a challenge for next time we meet: you roll along at 85rpm on a 52x15 (92") =  38kph, and see how long it takes you to come to a stop by leg braking.
I'll ride at 100rpm on 42x22  (51") = 25 kph and stop similarly. Even though your legs are stronger than mine I bet I would still win easily even though I start at a higher cadence.  ;D

I suspect momentum is the dominant factor, but for me anyway, there comes a point where high cadence impedes leg braking because I can't do both at once. 

Unless I'm missing something then you'll always stop faster from 25kph than 38kph because for the same weight of rider you'll have half the kinetic energy. Assuming riders of equal weight