Head tube angle change ?

How much would my head tube angle change when going from an 80mm to a 130mm
fork.

When new, my bike was bought with an 80mm fork - 70 degree angle.

What effect will it have on the steering.

I know there are variables like amount of sag but "on average"

How can I check the angle?

-
DTW .../\.../\.../\...

I've spent most of my money on mountain biking and windsurfing.
The rest, I've just wasted.

"D T W .../\..." wrote in message
news:Jw3wd.221$4u4.214@trndny01...
How much would my head tube angle change when going from an 80mm to a
130mm
fork.

When new, my bike was bought with an 80mm fork - 70 degree angle.

What effect will it have on the steering.

I know there are variables like amount of sag but "on average"

How can I check the angle?

-
DTW .../\.../\.../\...

I've spent most of my money on mountain biking and windsurfing.
The rest, I've just wasted.

About 2 degrees.

How can I check the angle?

Use a plumb line and trig. Take the length from a certain spot on the
headtube to about 10 or 15mm behind the axle. Then let the line hang.
Measure that length when it's at the same height as the axle.

arccos(hang/head) = angle

Tada!

For a less scientific response, you're looking at about 2 degrees slacker.

Your bike will be slightly less maneuverable, and it will have a tendency to
flop over more. You'll also likely be more comfortable on the downhills,
and your climbs will tend to wheelie more instead of staying planted.
--
Phil, Squid-in-Training

Phil, Squid-in-Training wrote:
How can I check the angle?

Use a plumb line and trig. Take the length from a certain spot on the
headtube to about 10 or 15mm behind the axle. Then let the line hang.
Measure that length when it's at the same height as the axle.

arccos(hang/head) = angle

Tada!

For a less scientific response, you're looking at about 2 degrees
slacker.

Your bike will be slightly less maneuverable, and it will have a
tendency to flop over more. You'll also likely be more comfortable
on the downhills, and your climbs will tend to wheelie more instead
of staying planted.

It will want to wander off the trail on climbs too. If you get a fork with
adjustable travel like the Fox TALAS you'll have the best of both.

Mike

Michael Dart wrote:
Phil, Squid-in-Training wrote:
How can I check the angle?

Use a plumb line and trig. Take the length from a certain spot on
the headtube to about 10 or 15mm behind the axle. Then let the line
hang. Measure that length when it's at the same height as the axle.

arccos(hang/head) = angle

Tada!

For a less scientific response, you're looking at about 2 degrees
slacker.

Your bike will be slightly less maneuverable, and it will have a
tendency to flop over more. You'll also likely be more comfortable
on the downhills, and your climbs will tend to wheelie more instead
of staying planted.

It will want to wander off the trail on climbs too. If you get a
fork with adjustable travel like the Fox TALAS you'll have the best
of both.

That's the one thing that gets me when I'm riding a 5" fork with 16"
chainstays...
--
Phil, Squid-in-Training