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Old 07-17-17, 08:21 AM   #1
slebo3213
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Rim Brakes on a BF NWT?

Anyone ever tried to fit standard rim brakes on a Bike Friday NWT? The frame looks to be drilled for brakes, although the reach on the rear seems like it might need some kind of extension.
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Old 07-17-17, 08:41 AM   #2
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It comes with V-brakes I would guess which have much better leverage and stopping power. Caliper brakes when they end up with long arms from the frame to the rim do not work very well. Callipers work well with very tight clearance on 700c road bikes and really short arms and the tiny contact patch of the tire (very limited traction). They have never worked even reasonably well on BMX bikes which have much better traction and long distance between the rim and the mounting hole in the frame.
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Old 07-17-17, 09:25 AM   #3
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Yeah, I would have to ask why anyone would want to fit calipers.
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Old 07-17-17, 10:21 AM   #4
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Thanks
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Old 07-24-17, 03:23 AM   #5
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Perhaps you want to fit caliper brakes so you can fit drop bars on your NWT..I fitted mini V brakes to my NWT so I could use drop bars .But they will only work with tyres 20 x 1.50 inches..Any bigger and the cable will be touching the tyre..
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Old 07-24-17, 04:52 AM   #6
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I have a question why people use fit caplisers I think there is no need of this it just a burden on bike
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Old 07-24-17, 10:37 AM   #7
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....tiny contact patch of the tire (very limited traction). They have never worked even reasonably well on BMX bikes which have much better traction...
Huh?

On a soft/loose surface, sure.

But I've never experienced, or heard about 700 C road bikes having poor traction on firm, grippy surfaces.
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Old 07-24-17, 03:03 PM   #8
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Huh?

On a soft/loose surface, sure.

But I've never experienced, or heard about 700 C road bikes having poor traction on firm, grippy surfaces.
700x25c have some grip on pavement but not nearly what you get from a wide low pressure---30-40 psi tire. The contact patch is directly related to PSI. Higher psi equals smaller contact patch. with 110 psi the contact patch is so small any irregularity, sand, grease, water will allow the tire to slip.

If you have not experienced a 700x25 tire slide on pavement you are lucky. Firm grippy surfaces need very little irregularity to cause a high pressure tire to lose traction at fairly high speed.
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Old 07-24-17, 04:32 PM   #9
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I got some new cheap cantis for my 90`s Scott MTB. Tectro I think. Great brakes, regular brakepads easy to adjust. They are w i d e so maybe not the best if you fold and pack the bikes often but plenty clerance for fat tyres. Same as drum brakes, they are not rubish just becouse they are not "new".

And since brakes is discussed: Did anybody try out these:

or something like this: http://www.ebay.com/itm/V-brake-exte...c8fHcuKAIS-sSA

bumped into them by accident. several sellers and similar products for the second one. Found only one for the first one.

Last edited by badmother; 07-25-17 at 04:52 AM.
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Old 07-25-17, 05:18 AM   #10
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700x25c have some grip on pavement but not nearly what you get from a wide low pressure---30-40 psi tire. The contact patch is directly related to PSI. Higher psi equals smaller contact patch.
But available friction is higly dependent on pressure between tire and road. The smaller the contact patch, the higher the pressure between tire and road becomes.

A wider tire has a bigger contact patch, but lower tire/road pressure. On a firm road surface (and regular friction mechanics) - no net gain.

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... any irregularity, sand, grease, water will allow the tire to slip.
Then it's not what I consider as a "firm surface", and outside the scope of my original statement.

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If you have not experienced a 700x25 tire slide on pavement you are lucky.
Clean and dry pavement - no. Not unless I intentionally lock the rear wheel up.
On sandy patches, manhole covers, lane markers, wet leaves etc - sure.
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Old 07-26-17, 05:45 PM   #11
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But available friction is higly dependent on pressure between tire and road. The smaller the contact patch, the higher the pressure between tire and road becomes.

A wider tire has a bigger contact patch, but lower tire/road pressure. On a firm road surface (and regular friction mechanics) - no net gain.



Then it's not what I consider as a "firm surface", and outside the scope of my original statement.


Clean and dry pavement - no. Not unless I intentionally lock the rear wheel up.
On sandy patches, manhole covers, lane markers, wet leaves etc - sure.
So I guess you are saying that a skinny tired bike with caliper brakes on clean dry pavement can stop in as short a distance as a fat tire bike with large contact patch disc brakes?

I am certain the more forward position of high end road bikes makes me feel more susceptible to launching over the front. But with the same riding positions you are saying small contact patch will create the same friction.

I don't know the answers to the traction equation---

I have always thought wider tires with lower tire pressure (and larger footprints) could stop faster. I have no physics to back this up----only feelings from my riding no data or physical equations to back up the feeling.

The other factor I have rarely seen is clean dry pavement throughout my ride.---Hence my fondness for fatter tires----grin

What I have tried to say is I have no knowledge of the physics behind friction mechanics...

Last edited by Rick Imby; 07-26-17 at 05:52 PM.
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Old 07-27-17, 12:54 AM   #12
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So I guess you are saying that a skinny tired bike with caliper brakes on clean dry pavement can stop in as short a distance as a fat tire bike with large contact patch disc brakes?
Overall stopping distance depends on a chain of things. It's friction between tire and ground, brake power, brake modulation, rider CoG, wheel base, rider skill...
But yeah, on clean, firm pavement, the bigger contact patch is not a guaranteed advantage.
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I am certain the more forward position of high end road bikes makes me feel more susceptible to launching over the front....
I can't argue with what you feel. That's a personal experience.

Whether your concern is valid or not, I can't tell straight off.
You'd have to compare rider CoG WRT contact patch position.

I think that a properly positioned (off the saddle, body back and low) road bike rider would have less risk of OTB than a casually positioned Fat Bike rider.

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But with the same riding positions you are saying small contact patch will create the same friction.
Pretty much. If all other things remain the same, the pressure is proportional to the area. 1/3 of the area gives 3x the pressure. And that pressure over the contact patch is the main driver of how much available friction there is.

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I don't know the answers to the traction equation---...I have no knowledge of the physics behind friction mechanics...
Friction quickly becomes complicated. There's static friction, sliding friction...
Then you add a tire that deforms and squirms. After awhile you get into the sticky, high-performance car and motorcycle tires.
But for bicycles, fairly basic assumptions will get you there.

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I have always thought wider tires with lower tire pressure (and larger footprints) could stop faster....
There is a saying:"logic is a way of going wrong with confidence".

But really, if the wider tire is ALSO knobbly, it doesn't take much to notice that you're losing out.
Particularly high/tall knobs quickly starts to wiggle and squirm when cornering or braking, reducing your control of the bike.

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The other factor I have rarely seen is clean dry pavement throughout my ride.---Hence my fondness for fatter tires----grin
Plenty of reasons to avoid the skinniest tires, even if riding on good roads.
Just ar there are good reasons to avoid wide, knobbly tires on roads.
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Old 07-31-17, 03:13 AM   #13
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And since brakes is discussed: Did anybody try out these:DIY Bicycle Bike Brake Modified Refit holder Support Base V Brake to Disc Brake | eBay
I've considered buying those. Not to use as-is, but to use as prefab mounts to weld to frames and forks. Save me some hacksawing and filing.

I rather doubt their overall usefulness. Disc brake calipers don't have much sideways adjustability. And that design has the caliper's position dependent on dropout thickness.
And I suspect that can vary enough to cause trouble for the design.
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No.
That design too has me wondering. Moving the brake boss like that, there'll be a decent amount of force pushing the adapters apart. What's keeping the adapters aligned?
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Old 07-31-17, 06:20 AM   #14
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^ the pin on the back.
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Old 07-31-17, 06:59 AM   #15
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^ lol
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Old 07-31-17, 08:34 AM   #16
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Anyone ever tried to fit standard rim brakes on a Bike Friday NWT? The frame looks to be drilled for brakes, although the reach on the rear seems like it might need some kind of extension.
they use V brakes, if not using disc brakes, maybe if you use a 451 rim wheel set,

In a 406 wheel frame and fork, then you may be able to use a side pull caliper.. good luck..


my 2 Bike Fridays are V and Disc Brake.





....
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Old 07-31-17, 08:41 AM   #17
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I've considered buying those. Not to use as-is, but to use as prefab mounts to weld to frames and forks. Save me some hacksawing and filing.

I rather doubt their overall usefulness. Disc brake calipers don't have much sideways adjustability. And that design has the caliper's position dependent on dropout thickness.
And I suspect that can vary enough to cause trouble for the design.


No.
That design too has me wondering. Moving the brake boss like that, there'll be a decent amount of force pushing the adapters apart. What's keeping the adapters aligned?
Sounds like a good idea to use the disk mounts for weld on projects. Would have been nice if there was an easy solution for frames that need a good brake solution but I am not sure this is the solution. Adjustment is one thing but I`d like to know if they stay in position under heavy braking or if they twist

The other ones: What keeps them in position may be that small thingy sticking out at the back in picture four pluss I would guess they are made so that tightening the screw that conects them to the frame would keep them in place instead of letting them rotate like a V brake would do.
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