39
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 stiffer than most 2-legged.
Pros
The top is attached like a dual crown downhill fork, which is much stiffer than a single-crown.
The wheel axle is one-piece with ...
31
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 differences and compare with my list below...
Headtube angle is steeper on your bike - closer to vertical
Negative trail -
A line drawn straight down from your ...
30
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 ground. The distance between these points is called trail. In order to visualise it you may have a look at this figure from the bicycle dynamics article on ...
18
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 repair that isn’t going to cost half as much that the bike is worth. You might have the best success going to a bike coop and finding a used fork for $10-20 (or ...
17
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.
16
Bouncyness* may not be the appropriate term for the behavior you need from your suspension.
Suspension has two main functions: Shock Absorbing and Dampening. Shock absorbing is what the fork does by compressing, allowing the wheel to travel upwards. In this process, kinetic energy from the shock is used to compress either a coil spring or an air spring. ...
16
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 to a less agile bike. A bike with suspension (all else being equal) will hit more holes and hit them harder. It will also climb like a pig and accelerate ...
16
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 contact patch is behind the steering axis, hence the nomenclature “trail”.
Image from Wikipedia
Increasing the fork offset will bring the contact patch ...
15
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 Standard (I.S.) mount. Most mtb brakes now are Post Mount fittings so are fitted using a simple adapter. You can see the differences here or search around images....
13
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. You could design a fork which was reliable and curved in aluminum or carbon or whatever, but the engineering wouldn't be the same as a steel fork. Whether the ...
13
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 if you keep riding it.
It's probably OK to ride on temporarily, even if the stay does fail the other stay will support the wheel.
You say the bike is a Cube ...
13
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 geometry seems to have been changed - the wheel seems to be pointing slightly to right, the drop-out seems out of plane etc. The hub axle might be bent, also the ...
12
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 if the stanchions, dropouts, lower-internals and anything other parts are weightless on an inverted fork, then you have to compare the weight difference with ...
12
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 truth is that the performance of carbon depends heavily on manufacturing techniques used (e.g., materials and layup). See point 3 for an example.
Weight - Carbon ...
12
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 disk brake rotor. This is especially useful on rear wheels as you also don’t have to take off the chain.
In the case of these rental bikes, I suspect that the ...
11
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 suspension fork was possible and economical, leaving alone keeping dirt and grimes off the suspension.
So the answer is Technical obsolescence
Edit: And as @...
11
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 carbon has been damaged.
'Carbon usually has a very crisp sound to it [when tapped] and when it’s damaged the tone changes completely,' says John Hansell of ...
11
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 Schmidts still have output suitable for halogen, including XS-M. You should double check when you order the hub. If so it will pair fine with LED in a larger wheel.
11
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.
The fact that you had a collision is much more worrying. How hard? At what angle?
Hard, head-on collisions can certainly damage the frame or fork. The ...
10
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 years anyway.
10
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 emergency room, and potentially the morgue if you're unlucky with vehicles nearby.
Hopefully, other answers will address how to fix your forks; worst case is ...
9
how does a higher fork contribute to higher stress in the frame?
By creating a longer lever, and stretching the end of that lever to a greater angle, it transmits more force to the bottom of the head tube (the part of the frame where the steer tube passes through). This can cause damage to the head tube itself or where it joins both the down tube and top ...
9
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 that these holes are needed to evacuate both. On steel frames you may find similar holes in the seat-stays and in the chain-stays where they are usually close to ...
9
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 me some success:
Sand the scratch down to remove the burrs. You can use super-fine wet & dry paper for this; something like 2000 grit should do the job ...
9
Not fixable. (Or more specifically, not for anything like the cost of just replacing it even if it is theoretically fixable, which with broken magnesium/aluminum parts like this is a black hole of a metallurgy/welding/machining/heat-treating/fatigue/etc question.)
There are two layers to this question - physical compatibility with the frame and parts and ...
9
They're for full fenders. Many disc road and fitness/urban/hybrid bikes now have them here in order to completely avoid strut interference with the brake. To install the fenders neatly I've been mounting the fender, then mounting the struts sticking off into space in the general direction they'll run in from the mount, then bending one with a non-marring ...
9
You can do it with files. The chrome does make the surface harder but it's not a big deal. This is usually seen when the fork was originally slotted to take a 5/16" axle. I'm not a Raleigh historian but I'd be a little surprised were that the case on a Grand Prix. It's also possible that it's a fork that fits a 9mm front axle very tightly, and you're ...
9
You can easilly find the manual just by googling the visible words from your photo "Marzocchi Bomber 2001", for example https://www.manualslib.com/manual/1728712/Marzocchi-Bomber-2001.html Adjustments are on page 10 and in detail from page 24. A schematic picture is on page 14.
There are air and coil variants.
What you can adjust in the air ones is the ...
9
The grey part is a wedge and has a split in it. You could use a metal pick to pry it out at the split. If you deform it in your attempt, file or sand off any burrs before you reuse it.
If you hit the top of the fork too hard it's possible to knock it out of round, even with a rubber mallet.
The problem you have encountered is quite common and can be ...
8
Proviso - my advise presumes you are not looking at forking out $2K or more for a bike, and probably significantly less. At a high price point I might suggest suspension. I also presume the gravel section is well maintained with average (pea - grape) size gravel (Where I ride, we sometime use logging roads, the "gravel" is stones about 2"-3" across.), and ...
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