Cycling and bicycle discussion forums. 
   Click here to join our community Log in to access your Control Panel  


Go Back   > >

General Cycling Discussion Have a cycling related question or comment that doesn't fit in one of the other specialty forums? Drop on in and post in here! When possible, please select the forum above that most fits your post!

User Tag List

Reply
 
Thread Tools Search this Thread
Old 11-27-13, 12:26 PM   #1
Darth Lefty 
Disco Infiltrator
Thread Starter
 
Darth Lefty's Avatar
 
Join Date: May 2013
Location: Orangevale CA
Bikes: '76 Paramount, 02 Hardrock, '98 C'Dale XR800, '04 Burley Samba, '15 Priority Classic
Posts: 5,541
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 60 Post(s)
Why same brakes front and rear?

From another thread...

Quote:
Originally Posted by Cyclebum View Post
Disc on rear, rim up front. Best of both.
This got me thinking more generally. Why do bikes always seem to have the same brake front and rear? Not just same style but same size, too, and same lever with same pull. Only with disk brakes do you see rear disks that are a little smaller. But on nearly any other wheeled vehicle I can think of, the front brake is several times larger than the rear, and has a caliper to match. Cars often have vented disks in the front that are a couple sizes larger than non-vented in the rear. On both the motorcycles I've owned, the two front disks were about a foot across and the rear was a saucer-sized afterthought, basically only useful in slippery conditions and starting off uphill. If you were an engineer looking to save ounces from one component to strengthen another, why would you put, essentially, two front brakes on the bike?
Darth Lefty is offline   Reply With Quote
Old 11-27-13, 01:07 PM   #2
A10K
Senior Member
 
Join Date: Jun 2011
Location: Austin, Texas
Bikes: Unidentifiable CX-based franken-commuter
Posts: 172
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Ummm... there's a lot of meat for discussion here. I'll get the ball rolling:
1. Bikes are lighter than cars. Apples to oranges. Bikes can endo, cars can't. Bigger front brake? Go nuts!
2. Same brake front+rear means same installation tools, same pads, same lever ergonomics, same adjustment skillset, and half price for keeping spares on hand. Keep it simple.
Not to say there aren't reasons to get mismatched brake styles (mostly related to inclement weather riding), but any well-adjusted set of brakes can stop a bike at the speeds one usually finds oneself riding.
A10K is offline   Reply With Quote
Old 11-27-13, 01:18 PM   #3
knobster
.
 
Join Date: May 2006
Location: Hillsboro, Oregon
Bikes: Specialized Roubaix Comp, Soma ES
Posts: 3,979
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
I have seen bikes with a disk brake on the front and rim brakes on the back. Most of your braking is done with the front so it makes sense to have the best brake up where it'll do the most good. I wouldn't want a disc on the back as the back is more prone to skidding so less capable braking on the rear makes sense.

A motorcycle is the same situation. When you brake, inertia is going to put much more of the weight towards the front of the bike. Having a lot of braking capability on the front is going to provide much more stopping power than on the rear where the weight is much less during braking.
__________________
Demented internet tail wagging imbicile.
knobster is offline   Reply With Quote
Old 11-27-13, 01:51 PM   #4
fietsbob 
coprolite
 
fietsbob's Avatar
 
Join Date: Jun 2010
Location: NW,Oregon Coast
Bikes: 7
Posts: 18,773
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 209 Post(s)
Number one it's a choice.. Manufacturers by now all being concentrated in ROC,
follow the contract , and the parts manager for the importer company makes those choices.

More silly Blanket GENERALIZATIONS, but it wes no doubt to stir controversy
an discussions amongst people who have nothing to do with the design or economic decisions
of a bike manufacturing corporations , but

I'll play. in a Contrarian Curmudgeon role (as usual)

not all do.. nobody does anything all the time, the same
without being a single purpose Machine, assembly line serf,
Or under threat of sacking from your Job..


2 Examples..

Trek had one with a shimano Roller brake on the rear hub, disc brake on the front ..

Sun Spider, a fat bike, has a coaster brake kick back 2 speed, with the fork
& front hub set-up to take a disc brake, (just not included to keep the Selling price down)

[my old SAAB had disc on the front, drums on the rear.

(drum is a simpler mechanisim to use combined, as a parking brake.
hold a Hot disc, stationary, as a parking brake can cause it to warp )



even side pulls , Campag uses a double pivot front, single pivot rear in their top range,

[Both dual pivot on the lower range component sets.. whole different economics there ..

Last edited by fietsbob; 12-19-13 at 02:13 PM.
fietsbob is offline   Reply With Quote
Old 11-27-13, 01:56 PM   #5
RPK79
Senior Member
 
RPK79's Avatar
 
Join Date: May 2013
Location: SE MN
Bikes: Fuji Roubaix Pro & Fuji Track Classic
Posts: 7,860
Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 203 Post(s)
Why not same brake for front and rear?
RPK79 is online now   Reply With Quote
Old 11-27-13, 02:05 PM   #6
fietsbob 
coprolite
 
fietsbob's Avatar
 
Join Date: Jun 2010
Location: NW,Oregon Coast
Bikes: 7
Posts: 18,773
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 209 Post(s)
Quote:
Why not same brake for front and rear?
Your money your choice, you own a bike manufacturing company you can do
WTF you want.


what is the purpose of the Bike? that influences what it's design-criteria are..

Last edited by fietsbob; 11-28-13 at 01:10 PM.
fietsbob is offline   Reply With Quote
Old 11-27-13, 02:26 PM   #7
Drew Eckhardt
Senior Member
 
Drew Eckhardt's Avatar
 
Join Date: Apr 2010
Location: Sunnyvale, CA USA
Bikes:
Posts: 5,018
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 13 Post(s)
Quote:
Originally Posted by Darth Lefty View Post
From another thread...

This got me thinking more generally. Why do bikes always seem to have the same brake front and rear?
Because fewer types of parts to make means higher profits, and assembling brakes which differ only in center bolt length, nut length, and pad holder mounting direction means fewer parts than two totally different brakes.

Quote:
If you were an engineer looking to save ounces from one component to strengthen another, why would you put, essentially, two front brakes on the bike?
In response to Shimano's lightened DuraAce calipers for the 2001 model year Campagnolo introduced a "differential" brake option with dual pivot front and single pivot rear saving 40g a pair (380->340g a pair for Chorus, 348->308g for Record which is identical except some of the hardware is titanium where it's steel for Chorus).

The rear single-pivot unit is on the left and front dual-pivot right.



In the unlikely event that you're a racer, competitive, built for climbing (two pounds per inch suggests the right morphology which is 140 pounds at 5'10"), and racing to an up-hill finish in the mountains the 0.05% speed increase means a 2 second advantage for each hour you spend off the front (assuming a 140 pound rider atop a bike approaching the 15 pound UCI minimum). The difference is less for heavier rider + bike combinations.

The single pivot option offers a bit more tire clearance and the 2001-2006 Chorus/Record hidden hardware single pivot rear looks great, although outside a very narrow range of competitive situations the only substantial benefit is marketing.

Supposedly the rear is easier to modulate because the lever travels farther although I haven't found that to be significant. It does take a harder squeeze to lock up.

Dual pivot front and rear are also offered at the same component levels, with some people preferring that option for the lower lever effort in back.
Attached Images
File Type: jpg record-brakes.jpg (97.0 KB, 24 views)

Last edited by Drew Eckhardt; 11-27-13 at 10:35 PM.
Drew Eckhardt is offline   Reply With Quote
Old 11-27-13, 02:56 PM   #8
no1mad
Thunder Whisperer
 
no1mad's Avatar
 
Join Date: Apr 2008
Location: NE OK
Bikes: '06 Kona Smoke
Posts: 8,660
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 47 Post(s)
Quote:
Originally Posted by RPK79 View Post
Why not same brake for front and rear?
Quote:
Originally Posted by A10K View Post
Ummm... there's a lot of meat for discussion here. I'll get the ball rolling:
1. Bikes are lighter than cars. Apples to oranges. Bikes can endo, cars can't. Bigger front brake? Go nuts!
2. Same brake front+rear means same installation tools, same pads, same lever ergonomics, same adjustment skillset, and half price for keeping spares on hand. Keep it simple.
Not to say there aren't reasons to get mismatched brake styles (mostly related to inclement weather riding), but any well-adjusted set of brakes can stop a bike at the speeds one usually finds oneself riding.
And if a bike comes stock with a mixed brake system set up, it is because it was spec'd that way (for whatever reason).

Note: It is easier to convert to a front disc from a rim brake than it is the rear. Just swap out the fork for one that is disc capable and you are golden. The rear would require finding someone to weld the tabs on.
__________________
Community guidelines
no1mad is offline   Reply With Quote
Old 11-27-13, 02:56 PM   #9
fietsbob 
coprolite
 
fietsbob's Avatar
 
Join Date: Jun 2010
Location: NW,Oregon Coast
Bikes: 7
Posts: 18,773
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 209 Post(s)
Back in the day Universal brand, (?)Italian, the reach of the rear Brake
was much Longer than the front. frame bridges and fork crowns were placed as such.

Last edited by fietsbob; 11-27-13 at 02:59 PM.
fietsbob is offline   Reply With Quote
Old 11-27-13, 03:48 PM   #10
wahoonc
Senior Member
 
wahoonc's Avatar
 
Join Date: Jan 2005
Location: On the road-USA
Bikes: Giant Excursion, Raleigh Sports, Raleigh R.S.W. Compact, Motobecane? and about 20 more! OMG
Posts: 16,687
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Cost

Aaron
__________________
Webshots is bailing out, if you find any of my posts with corrupt picture files and want to see them corrected please let me know. :(

ISO: A late 1980's Giant Iguana MTB frameset (or complete bike) 23" Red with yellow graphics.

"Cycling should be a way of life, not a hobby.
RIDE, YOU FOOL, RIDE!"
_Nicodemus

"Steel: nearly a thousand years of metallurgical development
Aluminum: barely a hundred
Which one would you rather have under your butt at 30mph?"
_krazygluon
wahoonc is offline   Reply With Quote
Old 11-27-13, 04:08 PM   #11
wphamilton
rugged individualist
 
wphamilton's Avatar
 
Join Date: Apr 2011
Location: Alpharetta, GA
Bikes: Nashbar Road
Posts: 9,634
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 85 Post(s)
It seems to me like OP raises a good point. One of the objections to disc brakes on road bikes is that it's necessary to beef up the rear triangle and front fork due to the higher torsional stress. Which means some sacrifice in ride quality. Just one disc means you'd only have to do half of that and could keep your super-carbon responsive vibration-damping front fork for example.
wphamilton is offline   Reply With Quote
Old 11-27-13, 07:02 PM   #12
Darth Lefty 
Disco Infiltrator
Thread Starter
 
Darth Lefty's Avatar
 
Join Date: May 2013
Location: Orangevale CA
Bikes: '76 Paramount, 02 Hardrock, '98 C'Dale XR800, '04 Burley Samba, '15 Priority Classic
Posts: 5,541
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 60 Post(s)
Quote:
Originally Posted by knobster View Post
Most of your braking is done with the front so it makes sense to have the best brake up where it'll do the most good. I wouldn't want a disc on the back as the back is more prone to skidding so less capable braking on the rear makes sense.
That's funny because the guy I quoted in the first post had exactly the opposite idea. And that makes more sense to me, if you were going to do it. The bad conditions where the disk brake supposedly works better are also the conditions where you would use the rear brake more. "Modulation" is something you do with your hand, in response to the brake feedback; you'd get used to it, whatever it is. And the rim brake has advantages at the front, as follows:

Quote:
Originally Posted by wphamilton View Post
One of the objections to disc brakes on road bikes is that it's necessary to beef up the rear triangle and front fork due to the higher torsional stress.
The front wheel, too. My math says that the front hub under braking would get the same or more torque as a rider standing on the pedals in mountain bike granny gear, so it probably ought to be built as strong as the rear wheel. I'm not so sure about the rear triangle.

I'm not really buying the different front-to-rear argument either, there are plenty of larger or wider or heavier-duty rear parts that could be used at the front. Axles, bearings, same number of spokes.
Darth Lefty is offline   Reply With Quote
Old 11-27-13, 07:22 PM   #13
BlazingPedals
Senior Member
 
BlazingPedals's Avatar
 
Join Date: Dec 2004
Location: Middle of da Mitten
Bikes: Trek 7500, RANS V-Rex, Optima Baron, Velokraft NoCom, M-5 Carbon Highracer, homebuilt recumbent
Posts: 8,795
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 27 Post(s)
Disc brake front, dual-pivot rear.

BlazingPedals is offline   Reply With Quote
Old 11-27-13, 07:47 PM   #14
bkaapcke
Senior Member
 
Join Date: Jul 2005
Bikes:
Posts: 3,222
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 4 Post(s)
Because. bk
bkaapcke is offline   Reply With Quote
Old 11-27-13, 09:28 PM   #15
Murray Missile 
Bike hoarder.
 
Murray Missile's Avatar
 
Join Date: Jun 2013
Location: 700 Ft. above sea level.
Bikes: Too many according to my wife.
Posts: 1,171
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 3 Post(s)
Quote:
Originally Posted by no1mad View Post
Note: It is easier to convert to a front disc from a rim brake than it is the rear. Just swap out the fork for one that is disc capable and you are golden. The rear would require finding someone to weld the tabs on.
I have seen bolt on rear disc brake adapters, don't know how well they work and they're kind of ugly but they are available.
__________________
Analog man in a digital world.
Murray Missile is offline   Reply With Quote
Old 11-28-13, 01:42 AM   #16
ThermionicScott 
Gratuitous glib and snark
 
ThermionicScott's Avatar
 
Join Date: Aug 2011
Location: CID
Bikes: 1991 Bianchi Eros, 1964 Armstrong, 1988 Diamondback Ascent, 1988 Bianchi Premio, 1987 Bianchi Sport SX, 1980s Raleigh mixte (hers)
Posts: 13,169
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 50 Post(s)
Quote:
Originally Posted by Drew Eckhardt View Post
In response to Shimano's lightened DuraAce calipers for the 2001 model year Campagnolo introduced a "differential" brake option with dual pivot front and single pivot rear saving 40g a pair (380->340g a pair for Chorus, 348->308g for Record which is identical except some of the hardware is titanium where it's steel for Chorus).

The rear single-pivot unit is on the left and front dual-pivot right.



The single pivot option offers a bit more tire clearance and the 2001-2006 Chorus/Record hidden hardware single pivot rear looks great, although outside a very narrow range of competitive situations the only substantial benefit is marketing.

Supposedly the rear is easier to modulate because the lever travels farther although I haven't found that to be significant. It does take a harder squeeze to lock up.
I really dig how they made the SP and DP look so similar. At least in principle, a DP in the rear seems like overkill to me.
__________________
Quote:
Originally Posted by chandltp View Post
There's no such thing as too far.. just lack of time
RUSA #7498

Last edited by ThermionicScott; 11-28-13 at 01:42 AM. Reason: whoops, wrong smiley
ThermionicScott is offline   Reply With Quote
Old 11-28-13, 08:27 AM   #17
JanMM
rebmeM roineS
 
JanMM's Avatar
 
Join Date: Jan 2006
Location: In Central IN
Bikes: RANS V3, RANS V-Rex, RANS Screamer
Posts: 13,281
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 9 Post(s)
V-brake front with mechanical disc brake rear.

__________________
RANS V3 - Ti, RANS V-Rex - cromo, RANS Screamer - cromo
JanMM is offline   Reply With Quote
Old 11-28-13, 09:29 AM   #18
cyccommute 
Mad bike riding scientist
 
cyccommute's Avatar
 
Join Date: Nov 2004
Location: Denver, CO
Bikes: Some silver ones, a black one, a red one, an orange one and a couple of titanium ones
Posts: 17,803
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 72 Post(s)
Quote:
Originally Posted by Darth Lefty View Post
That's funny because the guy I quoted in the first post had exactly the opposite idea. And that makes more sense to me, if you were going to do it. The bad conditions where the disk brake supposedly works better are also the conditions where you would use the rear brake more.
The guy you were talking about knows nothing about brakes, braking and how braking works on a bicycle. He's got lots and lots of company. Thankfully, there are people who know a lot about bicycles and bicycle brakes. One is David Gordan Wilson who wrote "Bicycling Science" which is about a nerdy a bicycle book as you'll find but worth reading if you want to know the physics of why we do what we do on a bike. The book is a bit dated...it was published in 1974...but, thankfully, the physics hasn't changed since then.

Let's start with the idea that most of your braking is done on the front brake. Knobster is right, it is. When you brake on a bike, the weight of the bike and, more importantly, the rider, gets transfer forward over the front wheel. Even on a bike that brakes with only the rear wheel, this transfer is evident. If you've ever ridden a coaster brake equipped bike, you will soon find that the bike can be skidded to your heart's delight. That skid is the rear wheel wanting to lose on contact with the ground as the weight of the rider is pushed forward over the front axle. You can't endo a coaster brake bike because you lose all what little braking power you have when the rear wheel leaves the ground but you can certainly skid it very well. You can do the same with a bike that have brakes front and rear by simply using the rear brake. If you throw in a little hip check, you can slid the bike to a fantastic sideways stop.

When you have brakes on both wheels, you are in a different situation. Since you can continue to brake after the rear wheel lifts, it is possible to endo. In fact the point of maximum deceleration comes at the point just before the bike pitches the rider over the handlebars, i.e. an nose wheelie. This is the point of maximum possible deceleration and is a mathematical oddity. Practically, you don't really want to find yourself in that situation every time you come to a stop for the simple reason that if you do a nose wheelie, you are riding a poorly designed unicycle.

You should still have the larger more powerful brake in the front of the vehicle (any vehicle) because that's where most of the braking occurs even if you aren't doing a nose wheelie. In a regular braking situation, i.e. with the rider seated on the saddle in a "normal" position, you can develop about 0.5g of deceleration ('g' is the deceleration due to gravity). 0.4g or about 80% of the power comes from the front brake. The rear brake provides 0.1g or 20% of the braking power. If you remain in that position, and start to lift the rear wheel, the amount that comes from the rear decreases and the amount that comes from the front increase. At the maximum possible deceleration point, the rider is about the spin around the center of gravity right above the axle and smash into the ground. Not a good place to be.

You can get more deceleration out of your bike than 0.5g, however. If you shift your weight rearward and down, you can double it while also decreasing the change of going over the bars. The amount of the shift of the center of gravity is tiny. A movement of your body back about 4" and down about 2" is all that's needed. It's a practice that every mountain biker learns on their first day of riding. If you actually want to do a nose wheelie (or a cool skidding stop), shift your weight forward and the amount of deceleration you can attain before being thrown over the bars goes down.

The reason you use less front in bad conditions is because the front wheel could slide on slick pavement. A rear wheel sliding is easily dealt with and you can usually recover from that. If the front wheel slides, you lose all control of that wheel and probably can't keep from crashing.

Braking on a bike is complicated. Most people don't know anything about it although they may do it all the time. Usually, they find out what they don't know only at the point where they need to know it. The guy you are referencing is one of those people.
__________________
Stuart Black
New! Pokin' around the Poconos A cold ride around Lake Erie
New! Dinosaurs in Colorado A mountain bike guide to the Purgatory Canyon dinosaur trackway
Solo Without Pie. The search for pie in the Midwest.
Picking the Scablands. Washington and Oregon, 2005. Pie and spiders on the Columbia River!
Days of Wineless Roads. Bed and Breakfasting along the KATY
Twisting Down the Alley. Misadventures in tornado alley.
An Good Ol' Fashion Appalachian Butt Whoopin'.
cyccommute is offline   Reply With Quote
Old 11-28-13, 09:40 AM   #19
cyccommute 
Mad bike riding scientist
 
cyccommute's Avatar
 
Join Date: Nov 2004
Location: Denver, CO
Bikes: Some silver ones, a black one, a red one, an orange one and a couple of titanium ones
Posts: 17,803
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 72 Post(s)
Quote:
Originally Posted by JanMM View Post
V-brake front with mechanical disc brake rear.

Sorry but your bike is set up completely wrong and a good example of wrong thinking on brakes. A long wheel base vehicle with a low center of gravity like yours will never be able to endo. You could actually lock the front wheel and slide it before you would be pitched over the bars. If you did lock the front wheel, your bike is less likely to crash as well (low center of gravity and small wheel). Your bike is more like a car in the physics of braking than a bicycle. All vehicles transfer weight to the front wheel. From bicycles to 80,000lb 18 wheelers.

Your bike you could actually brake up to the point where the front tire can no longer adhere to the road without pitching you over the bars. If you were to put the hub mounted disc on the front, you would see a vast improvement in your braking ability, especially with that huge rotor and metal pads.
__________________
Stuart Black
New! Pokin' around the Poconos A cold ride around Lake Erie
New! Dinosaurs in Colorado A mountain bike guide to the Purgatory Canyon dinosaur trackway
Solo Without Pie. The search for pie in the Midwest.
Picking the Scablands. Washington and Oregon, 2005. Pie and spiders on the Columbia River!
Days of Wineless Roads. Bed and Breakfasting along the KATY
Twisting Down the Alley. Misadventures in tornado alley.
An Good Ol' Fashion Appalachian Butt Whoopin'.
cyccommute is offline   Reply With Quote
Old 11-28-13, 10:07 AM   #20
Darth Lefty 
Disco Infiltrator
Thread Starter
 
Darth Lefty's Avatar
 
Join Date: May 2013
Location: Orangevale CA
Bikes: '76 Paramount, 02 Hardrock, '98 C'Dale XR800, '04 Burley Samba, '15 Priority Classic
Posts: 5,541
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 60 Post(s)
Quote:
Originally Posted by cyccommute View Post
Braking on a bike is complicated. Most people don't know anything about it although they may do it all the time. Usually, they find out what they don't know only at the point where they need to know it. The guy you are referencing is one of those people.
I've read your post through and I don't actually find where you say why you think he's wrong (that he'd like a rim brake on the front and disk on the rear). But you did insult him twice for it. So why? I really didn't want this thread to turn into another go-round on braking technique or how many gees anyone can pull - because that got dumb last time. It suffices for this discussion that the front brake is probably the most powerful thing on the bike but the rear doesn't need to be. It probably needs to be 1/4 as powerful. And if we agree they don't need to be the same, then which style would you like on which end, and why?
Darth Lefty is offline   Reply With Quote
Old 11-28-13, 10:23 AM   #21
Spider
Hill Climber
 
Spider's Avatar
 
Join Date: Jun 2004
Bikes:
Posts: 106
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by cyccommute View Post
You should still have the larger more powerful brake in the front of the vehicle (any vehicle) because that's where most of the braking occurs...
Yes, this is why my motorcycle, like most others, was spec'd with more powerful front brakes. It used a disc braking system with two large disc rotors up front (one on each side of the wheel) and only one small disc rotor in back.
Spider is offline   Reply With Quote
Old 11-28-13, 11:43 AM   #22
cyccommute 
Mad bike riding scientist
 
cyccommute's Avatar
 
Join Date: Nov 2004
Location: Denver, CO
Bikes: Some silver ones, a black one, a red one, an orange one and a couple of titanium ones
Posts: 17,803
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 72 Post(s)
Quote:
Originally Posted by Darth Lefty View Post
I've read your post through and I don't actually find where you say why you think he's wrong (that he'd like a rim brake on the front and disk on the rear). But you did insult him twice for it. So why? I really didn't want this thread to turn into another go-round on braking technique or how many gees anyone can pull - because that got dumb last time. It suffices for this discussion that the front brake is probably the most powerful thing on the bike but the rear doesn't need to be. It probably needs to be 1/4 as powerful. And if we agree they don't need to be the same, then which style would you like on which end, and why?
First, I didn't insult him. I made a statement that he didn't know what he what he was talking about. Big difference. I said he was ignorant, not that he was an ignorant...well look up Dan Aykroyd and Jane Curtin.

The reason that he is wrong about putting the more powerful brake on the rear is because the rear doesn't provide that much braking power. Granted, the difference between the hub mounted disc and the rim (disc) is small but the hub mounted disc is a little easier to lock up the wheel, especially in slick conditions. If you have a brake that is very touchy, you don't what it to be on the wheel that is easier to skid. A brake that is easier to modulate...hub mounted discs really aren't...is the one that you should put on the wheel that might cause you problem.

Look at JanMM's bike. I'll bet you that he can skid the rear tire in just about any condition. While that may seem like a good thing, a skidding tire does nothing to stop you. A skid can be viewed as a failure of the brakes. You aren't stopping, you are just sliding. Swap the brakes on his bike and I'd suspect that he could squeeze the brakes as much as possible and never skid the rear. He'd stop more quickly without the drama.
__________________
Stuart Black
New! Pokin' around the Poconos A cold ride around Lake Erie
New! Dinosaurs in Colorado A mountain bike guide to the Purgatory Canyon dinosaur trackway
Solo Without Pie. The search for pie in the Midwest.
Picking the Scablands. Washington and Oregon, 2005. Pie and spiders on the Columbia River!
Days of Wineless Roads. Bed and Breakfasting along the KATY
Twisting Down the Alley. Misadventures in tornado alley.
An Good Ol' Fashion Appalachian Butt Whoopin'.
cyccommute is offline   Reply With Quote
Old 11-28-13, 11:49 AM   #23
Looigi
Senior Member
 
Looigi's Avatar
 
Join Date: Dec 2010
Bikes:
Posts: 8,942
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by cyccommute View Post
Sorry but your bike is set up completely wrong and a good example of wrong thinking on brakes. A long wheel base vehicle with a low center of gravity like yours will never be able to endo. You could actually lock the front wheel and slide it before you would be pitched over the bars. If you did lock the front wheel, your bike is less likely to crash as well (low center of gravity and small wheel). Your bike is more like a car in the physics of braking than a bicycle. All vehicles transfer weight to the front wheel. From bicycles to 80,000lb 18 wheelers.

Your bike you could actually brake up to the point where the front tire can no longer adhere to the road without pitching you over the bars. If you were to put the hub mounted disc on the front, you would see a vast improvement in your braking ability, especially with that huge rotor and metal pads.
There's one further consideration you might comment on: It wasn't uncommon for tandems to add a disc in the rear as a drag brake, to manage speed and heat dissipation on long descents (over twice the weight and significantly less aero drag on a tandem), saving the front brake for slowing for corners and stopping as needed. Newer tandems might have discs front and rear.
Looigi is offline   Reply With Quote
Old 11-28-13, 01:15 PM   #24
fietsbob 
coprolite
 
fietsbob's Avatar
 
Join Date: Jun 2010
Location: NW,Oregon Coast
Bikes: 7
Posts: 18,773
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 209 Post(s)
Quote:
At least in principle, a DP in the rear seems like overkill to me.

At least in a gram conscious carry nothing road Racer , or roadie Wannabe bike.

then again .. cost.. make a single piece used twice per bike will be a savings/profit center.
fietsbob is offline   Reply With Quote
Old 11-28-13, 01:50 PM   #25
JanMM
rebmeM roineS
 
JanMM's Avatar
 
Join Date: Jan 2006
Location: In Central IN
Bikes: RANS V3, RANS V-Rex, RANS Screamer
Posts: 13,281
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 9 Post(s)
Quote:
Originally Posted by cyccommute View Post
Sorry but your bike is set up completely wrong and a good example of wrong thinking on brakes. A long wheel base vehicle with a low center of gravity like yours will never be able to endo. You could actually lock the front wheel and slide it before you would be pitched over the bars. If you did lock the front wheel, your bike is less likely to crash as well (low center of gravity and small wheel). Your bike is more like a car in the physics of braking than a bicycle. All vehicles transfer weight to the front wheel. From bicycles to 80,000lb 18 wheelers.

Your bike you could actually brake up to the point where the front tire can no longer adhere to the road without pitching you over the bars. If you were to put the hub mounted disc on the front, you would see a vast improvement in your braking ability, especially with that huge rotor and metal pads.
Just working with the hand that I was dealt - it came with F/R V-brakes as the primary and the rear disc as the 'auxiliary'. Seeing as we don't do loaded touring in the mountains and only ride steep but short hills in Southern Indiana, a robust BB7 as an 'auxiliary' brake seemed not needed and a waste of a great brake. So, simply removed the rear V-brake and hooked up the disc as the primary rear. No disc tabs on the fork - not interested in a front disc at this point. Still have the option of putting the rear v-brake back on and using it as an extra brake - to bleed some speed - if we ever need it.
The bike stops great and yes, this tandem is not a candidate for an endo.
F/R V-brakes would be completely fine for this bike except that folks sometimes ride these down long mountain grades and sometimes that is done fully loaded for touring. An Arai drag brake used to be the standard for those uses but they are no longer available. RANS has opted to throw on a BB7, instead.
__________________
RANS V3 - Ti, RANS V-Rex - cromo, RANS Screamer - cromo
JanMM is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -6. The time now is 09:40 AM.