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41 votes
Accepted

Pros and cons of single-sided forks (Cannondale Lefty)?

The single-legged fork must truly withstand heavier bending forces than conventional forks, simply due to physics and asymmetricity. But because of its different construction, the fork is actually ...
  • 2,094
34 votes
Accepted

Why did curved forks disappear?

The main reason is the materials used. Basically, on all bikes with bent forks the bent forks are made of steel. Steel has been mostly replaced by carbon and aluminium. While steel is heavier, it is ...
  • 1,600
31 votes

Why is the steering so twitchy? Steel 90's MTB fork

Short answer - your fork is stuffed. Stop riding it. Longer answer - Here's your bike with the main lines drawn on top And compare that with this approximate equivalent Peugeot bike. Spot the ...
  • 103k
30 votes

Bike unstable (difficult to ride without hands on bars) after changing fork after collision

Bicycle dynamics A bicycle may only be ridden because of the peculiar steering geometry. The centre of the contact patch of the tyre is behind the point where the steering axis intersects with the ...
  • 9,181
18 votes

Fork bent on a flat pack bike - what to do?

Your bike (27.5 Orkan 21 spd. MB) sells for less than US$150 and is shipped flat packed. This puts it firmly in what we call BSO or bicycle shaped object territory. At US$150, it’s hard to find a ...
  • 28.6k
18 votes
Accepted

Should amateurs install their own headsets?

The headset is a straightforward unit. Two cups are pushed into the frame with an interference fit and the crown race is smacked onto the top of the fork in a similar way. In the past, when I have had ...
  • 11.4k
17 votes
Accepted

What is this spring between the fork and the frame?

The purpose of such a steering damper is to stop the front wheel from turning when using a (two-leg) kickstand or while pushing the bike. Not much use otherwise.
  • 2,552
17 votes
Accepted

How does fork offset affect bike handling?

Offset primarily affects your mechanical trail - that is, the distance between the imaginary straight line going through your head tube down to the ground, and your tire’s contact patch. Normally, the ...
  • 11.8k
17 votes

Can I safely drill a hole from the crown into the steerer in my carbon fork?

When carbon manufacturers and fabricators put holes in things, they're thinking about: Whether disrupting the continuity of the carbon layers in that way will leave it strong enough. Whether there ...
16 votes

Is front-suspension a false-economy for cheaper bikes?

Benefits of suspension forks (city/gravel road use): Remove chatter from bumpy roads Take the jar out of major bumps Better traction Drawbacks of suspension forks: Entire bike is heavier, leading ...
15 votes

Can my fork support disc brakes?

In order to fit a disc brake, you need a compatible fork and a compatible wheel, plus a compatible brake lever. Your fork does have a disc brake mounting already designed in, it is an International ...
  • 12.1k
14 votes

Why did curved forks disappear?

Frames and forks were made of tubes that are brazed into lugs. Lugs are cast standard parts. Frames are sized by using tubes of the correct length. The respecive production processes makes lugs stiff ...
  • 9,181
13 votes
Accepted

Are curved aluminum forks safe?

It depends on how the fork is engineered for safety. While its plausible that the curved shape does add to some shock absorption, that is determined by the width and construction of the fork tubing. ...
  • 45.6k
13 votes
Accepted

Why do bikes have carbon forks?

There are an intersection of a number of reasons: Public Perception - Carbon as that "wow" factor. Colloquial it is associated with "space age" technologies. Therefore it must be better! The ...
  • 30k
13 votes
Accepted

What are the benefits of *rigid* lefty fork?

One obvious advantage for most lefty bikes is You’re able to change the tire and tube without taking the wheel off the bike. So wheel adjustments and repair can be made without interfering with the ...
  • 28.6k
13 votes

What to do with a bent but not broken aluminum seat stay

Aluminum alloy is weakened by being bent. The seat-stay is bowed in so that loads will tend to bend the stay more. The stay probably will not fail suddenly, but it will develop a crack where it's bent ...
13 votes
Accepted

What to do with a bent but not broken aluminum seat stay

Safe - probably yes. Good idea - no. As Argenti Apparatus stated, the bike should not fail without some warning, but it probably will fail sooner or later. As people noted in the comments - the ...
12 votes

Upside-down Fork vs Traditional Fork

The unsprung weight thing is a myth for the most part. Cast aluminum and magnesium lowers are extremely light, for example, old marzocchi 66 ones were only 3/4 of a pound, total weight. It's not as ...
  • 121
12 votes

Why did curved forks disappear?

A big part of the change from curved to straight forks is the engineering requirements for disc brakes. Curved forks provide structural flexibility, in that forces applied to the tire become ...
  • 1,464
11 votes
Accepted

Why do modern mountain bike forks no longer use boots on fork stanchions?

As technology goes, seal and wiper advance to the point that boots on fork stanchions becomes obsolete, for both economical and practical reasons. The seal has advanced to the point that air ...
  • 3,461
11 votes
Accepted

Crack in fork or just paint

On the surface it doesn't look good, but I wonder if there is a reinforcement wrap for the brake posts, with an unfinished edge). There are some informal ways to try and confirm whether the structural ...
  • 30k
11 votes
Accepted

On fitting 700C rims to a dynamo hub rated for up to 20"

Generator hubs for small wheels will output less and produce less drag at a given speed when built to a 700, because they'll be operating at fewer RPMs than expected. AFAIK all the non-sondelux ...
11 votes
Accepted

Does this carbon fork have a crack in it that would make you replace it?

What is visible in the photo is a paint scratch. Letting the bike simply fall over will not structurally damage carbon fiber composite. People seem to think CFC is fragile but it’s really quite robust....
10 votes

Crack in fork or just paint

I'm sorry to say that looks like a crack rather than a scratch. Bike looks quite new (I notice the dual pivot calipers), but I believe Trek's lifetime warranty covers CF frames and forks beyond 5 ...
10 votes

Is it possible to convert a suspension fork to rigid by drilling it?

DO NOT DRILL HOLES IN YOUR FORKS That would weaken them substantially and run the risk of them breaking under stress (e.g., when you hit a pothole). A broken fork will probably put you in the ...
10 votes
Accepted

Why do coil suspension forks have coils placed inside the stanchions, when the rear shocks place it exernally?

Attributes of telescopic forks: A fork is a structural part that takes all of the front wheel’s loads. Its stiffness is greatly linked to its stanchion diameter. (Second moment of area vs stiffness ...
  • 11.8k
10 votes

Where is the Air Valve on a swiss made ark hollow reverse fork?

Remove the top panel on the left side of the fork to expose the valve.
9 votes

Pros and cons of single-sided forks (Cannondale Lefty)?

My experience with Lefty goes back to 2000 when I purchased my Cannondale Super V. One thing I've liked about it how easy it is to 'turn off'. There's a small dial at the top that disengages the ...
  • 191
9 votes
Accepted

holes on the inside of metal fork blades, what are they

On steel forks the tiny holes at the bottom end of the fork-blade are vent holes for the brazing process. The brazing produces fumes the fumes and the heat expands the air in the blade which makes ...
  • 8,175
9 votes
Accepted

Scratches on fork stanchions

It really depends how deep the scratch is. If it's deep enough, then a new CSU (crown-steerer unit) is the only sure-fire fix. However, here are some steps I've taken in the past, which have given ...
  • 3,231

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