Brakes. Specifically, rear brakes.

[DCBassman]

Some statements re efficacy on various bikes I've had, and brakes used on them:
Trek 800 Sport - V - good.
Revell mixte- dual pivot - very poor.
Trek Navigator 200 - V - poor.
Merida Big 9 40 - hyd. disc - very good
Marin Pine Mountain - cantis - poor.
Scott Expert - dual pivot - outstanding.

Comparing between all bar the Scott, this is probably doing all of them a disservice to some degree. Why? Because the rear brake on the Scott is so damned good. It had OEM Tektros originally, then BR5500 105s. Different wheelsets too. The back easily gives 70% as much retardation as the front. All the other bikes are pretty hopeless by comparison. Ok, the Merida's discs were pretty reasonable, but still not as good.

This may just be an odd quirk of this bike with me on it, but otherwise, why is the Scott so good at stopping? Its overall stopping performance is better than all these others, not just the rear.

Puzzled. In a good way! Anyone got any insight?
Edit: the Scott is the lightest of all these, but not by much over, say, the Revell or the Marin.

 

[Alex321]

Is your weight further back on the Scott?

I find that road grip is by far the biggest factor in rear wheel braking, I have easily (possibly too easily at times) been able to lock the rear wheel at pretty well any speed.

But both my current main bike and my hybrid have hydraulic disc brakes.

If it is the ability to slow the wheel that is the issue, rather than road grip, then I would suspect something to do with cable routing making it a harder pull than the front brakes, and the Scott just has better routing (or better lubricated outer sheath).

 

[figbat]

Braking effectiveness is down to myriad variables:

• Lever length
• Lever pivot location
• Cable run/friction
• Cable outer rigidity
• Hydraulic multiplier factor
• Hydraulic fluid condition
• Hydraulic hose condition
• Caliper friction
• Caliper pivot configuration
• Caliper/mounting flex
• Caliper piston condition
• Brake pad/shoe surface area
• Brake pad/shoe material
• Wheel/disc friction surface type and condition
• Frame geometry/weight distribution
• Tyre grip
• And probably other stuff

The only bike I have that ever had noticeably reduced braking effort was an old shopper type with Weinmann calipers and chrome/steel wheel rims. Replacing the flexy levers with some MTB 2-finger ones, the front caliper with a dual-pivot one and - most importantly - the steel wheel rims with aluminium ones made such a difference that I feared for the integrity of the fork and headset!

Amongst my disc brake fleet, the one cable-operated one requires more of a squeeze but will still pull up sharply. The rim brakes on my road bike are surprisingly good and always surprise me at first.

 

[Cycleops]

Rear brakes are always less effective than front, especially with rim types.

 

[Ajax Bay]

Rear brakes are always less effective than front, especially with rim types.

Why "especially with rim" brakes?

The back easily gives 70% as much retardation as the front.

BS. How measured?
Rear brakes are for slowing, not stopping. Skid/slide the rear wheel momentarily: no problem. Lose traction on the front wheel: no stability.
Alex has offered 'road grip' and figgy has given a list longer than your braking distance in the wet on steel rims, to which I'd add 'rim material'.

 

[Alex321]

Rear brakes are always less effective than front, especially with rim types.

AFAIK, the main reason rear brakes are less effective than the front is the unweighting effect causing less grip between the rear tyre and the road (and conversely the front wheel getting the added weighting).

Why would rim brakes be any more affected by those than disc brakes?

 

[Cycleops]

Or maybe the cable run is longer
? Don't know but that's always the way I've found it and perhaps why the front is located in the left in some countries, the right being the stronger hand?
Hydraulic systems would not be so affected.

 

[Ajax Bay]

the right being the stronger hand?

Sinister. Very sinister!

 

[Jameshow]

AFAIK, the main reason rear brakes are less effective than the front is the unweighting effect causing less grip between the rear tyre and the road (and conversely the front wheel getting the added weighting).

Why would rim brakes be any more affected by those than disc brakes?

That's why when going downhill esp a steep down hill, you should move your body back to the rear of the saddle to keep weight over the back wheel.

 

[Cycleops]

That's why when going downhill esp a steep down hill, you should move your body back to the rear of the saddle to keep weight over the back wheel.

I always slide forward and drag my feet on the ground.

 

[figbat]

That's why when going downhill esp a steep down hill, you should move your body back to the rear of the saddle to keep weight over the back wheel.

And also to keep your CofG well behind the front wheel contact point.

 

[Cycleops]

That's why when going downhill esp a steep down hill, you should move your body back to the rear of the saddle to keep weight over the back wheel.

And also to keep your CofG well behind the front wheel contact point.

Nine of these things are going to make any difference if your brakes are cr@p in the first place.

 

[C R]

Nine of these things are going to make any difference if your brakes are cr@p in the first place.

What if there are ten of these?

 

[All uphill]

Sinister. Very sinister!

Not for those of us who have dexterity!

 

[Nigelnightmare]

Rear brake on the Linear LWB recumbent is far more powerful than the front and is the main brake.
So the rear 'always' being less effective is an incorrect statement!
In general though most of the stopping power comes from the front brake.