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Questions and answers about sports

Does headtube angle affect which fork you can use?

5 min read

Does fork offset change headtube angle?

Fork offset — also known as rake — is the distance between the axle and a straight line through the head head tube. Offsetting the fork more (increasing offset) pushes the axle further in front of the head angle. Reducing the offset — which is what many bike designers are doing today — pulls the axle closer.

How important is head tube angle?

The steeper the head tube angle, the better handling you’ll achieve, but with less stability at speed. Most trail bikes have settled on a minute range of somewhere between 65 and 67 degrees. Downhill bikes will have angles anywhere from 62 to 64.

What difference does the head tube angle make?

So, the slacker the head angle, the less the bike steers for a given steering angle at the handlebar. With a 63-degree head angle, turning the bars by 10 degrees will steer the contact patch by 8.9 degrees about the vertical axis; with a 70-degree head angle, the contact patch will steer by 9.4 degrees.

How does head tube angle affect handling?

In simple terms, head tube angle dictates how much effort is required to turn the front wheel. As head angle increases, the front wheel becomes easier to turn. It is also possible to make a sharper turn, and thus, the manoeuvrability of the bike generally increases with the angle of the head tube.

Can I use a 29er fork on a 26 bike?

Yes, BUT. Many (most?) 29er forks have more rake/off-set than most 26er forks, to make steering more sensitive.

What is the difference between 44mm and 51mm offset?

44mm vs 51mm Offset



Mechanical trail has a similar difference. 44mm offset has 108.7mm while the 51mm offset comes in at 101.7mm. This means that the 44mm offset will have a bit more stable platform. If we wanted to design the same amount of trail into the 51mm offset fork we would need to decrease the headtube angle.

Does 1 degree head angle make a difference?

TBH 1 degree dont make a difference. It feels the same, unless you change your stem and handlebar and then your bike will feel a bit more of a difference.

Is a 68 degree head angle slack?

For example, older bikes may have had an effective seat tube angle anywhere from 68 (very slack), to 74 (steep). Newer bikes may range anywhere from 72 degrees to 77 degrees and possibly even steeper.

What is an aggressive MTB?

Hardcore or Aggressive Hardtail is the name given to any Mountain Bike that has no rear suspension, and has a geometry profile that is Long, Low and Slack!

What is headtube angle for MTB?

Generally on a mountain bike, it will be anywhere from 62 degrees (slack) to 73 degrees (steep). Cross country bikes have steeper head angles, whilst downhill bikes have slacker head angles.

What does a steeper seat tube angle do?

Seat tube angle is the angle of the seat tube relative to the horizontal plane, measured from behind the seat tube (e.g. a perfectly-upright seat tube would be 90º and would decrease in angle as the tube tilts backward). A “steep” angle moves the saddle forward while a “slack” angle moves it backward.

What does a steeper seat tube angle mean?

A steeper seat angle puts you in a more centered position for climbing, and it’s easier to shift your weight forward and backward as needed, compared to feeling like you’re going to loop out any time you start climbing.

Is it OK to use 29er fork on a 27.5 bike?

Basically it will slightly mess with the geometry of your bike a bit but that’s about it. I’m assuming you’ll be keeping the 27.5″ wheel on there. If so it won’t be an inch increase. I currently am using a 29″ fork with a 27.5″ wheel on my bike and it works perfectly fine for me.

Can I run 27.5 wheels on a 29er fork?

You can run a 27.5 Plus fork and then swap between 29 and 27+ wheels no problem. Most 29er forks will not fit a 27.5+ tire, not because of the diameter, but because of the width.

Can I use 27.5 fork on 29er frame?

27.5 fork usually will not fit a 29 wheel.

How much difference does fork offset make?

Increasing fork offset reduces trail. Larger wheels increase trail. With a larger wheel (e.g., a 29” wheel) the axle is higher off the ground compared to a smaller wheel. If you draw a line through the steering axis to the ground, it intersects the ground farther forward of the axle, increasing trail.

Does fork offset change wheelbase?

A common one is the thought that a reduced offset fork will pull your front wheel towards you, significantly reducing the wheelbase length. In actuality, the change is negligible. In the case of a 29’er with a 65 degree head angle, going from a 51mm to a 44mm offset fork will reduce your wheelbase length by 5.78mm.

Does fork offset really matter?

While a slack headtube increases stability, along with longer reach, you start to lose that front end feel and thus, losing traction. By reducing the forks offset, you are bringing the wheel back under the mass of the body, helping keep that traction, while still having a longer wheelbase and slack head tube angle.

What does a shorter offset fork do?

In simplest terms, a shorter fork offset increases the trail measurement of the fork. It does so by way of increasing the distance between the tire’s traction patch on the ground and the point where the steering axis line intersects the ground.

Can I put 27.5 wheels on a 29 fork?

Most 29er forks will not fit a 27.5+ tire, not because of the diameter, but because of the width.

What does 44mm offset mean?

Again, it’s all personal preference. Here’s the skinny: 51mm offset reduces “trail” and adds turning agility, while 44mm offset adds “trail” and adds straight-line stability, especially at high speeds.