Go Back  Bike Forums > Bike Forums > Cyclocross and Gravelbiking (Recreational)
Reload this Page >

How much does Headtube angle matter?

Notices
Cyclocross and Gravelbiking (Recreational) This has to be the most physically intense sport ever invented. It's high speed bicycle racing on a short off road course or riding the off pavement rides on gravel like : "Unbound Gravel". We also have a dedicated Racing forum for the Cyclocross Hard Core Racers.

How much does Headtube angle matter?

Old 08-31-17, 06:32 PM
  #1  
Senior Member
Thread Starter
 
DarKris's Avatar
 
Join Date: Dec 2015
Location: Buffalo, NY
Posts: 619

Bikes: Kona Kahuna DL Drop Bar - Sensah SRX Pro 1x11 (2012 Frame), Giant Toughroad GX 1 - Shimano Road Hydro + SLX 1x10 (2018), Diamondback Sync'r - SRAM NX 1x12 (2020)

Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 160 Post(s)
Liked 97 Times in 54 Posts
How much does Headtube angle matter?

So my current Gravel Bike has a 70.5 degree head-angle paired with a fork that has a 45mm rake. I don't know the trail, but from my experience it's on the higher end due to it requiring more input to turn.

A bike that I had been considering (Giant TCX) in L has a 72.5 degree head-angle but with a 50mm fork rake. I haven't had a chance to test the TCX extensively to see how it feels so I don't know how it would handle compared to my current bike.

So my question is how much would a 2 degree change in head-angle matter? Could different stems + raising stem height alter the handling to replicate a bike with a slacker head-angle? I know the other parts of bike geometry affect handling as well but I'm specifically curious about head-angle.

(Geo chart of my bike vs. Giant TCX - Mine is LG)

12e880ed6eb613ebcd6d3093e76b2444 (2).jpg


Last edited by DarKris; 08-31-17 at 06:36 PM.
DarKris is offline  
Old 08-31-17, 07:14 PM
  #2  
Senior Member
 
Spoonrobot's Avatar
 
Join Date: Jul 2006
Posts: 3,096
Mentioned: 63 Post(s)
Tagged: 0 Thread(s)
Quoted: 1237 Post(s)
Liked 192 Times in 120 Posts
So my question is how much would a 2 degree change in head-angle matter? Could different stems + raising stem height alter the handling to replicate a bike with a slacker head-angle? I know the other parts of bike geometry affect handling as well but I'm specifically curious about head-angle.
Yes, fork rake is important too. Not really, the front end handling is pretty set by mechanical trail and pneumatic trail. There's a little wiggle room by using larger tires but not really enough to mimic a 20mm+ trail difference. What does make a mid-trail bike handle like a high trail bike is a front rack with a moderate load.

Stem lengths change the speed of the bar arc but it's not the same feeling as trail, it's different and more disconcerting. Like if you used a 40mm stem your perception of the steering would be that it was very fast and very touchy and hard to settle down - this is not like a low-trail bike where the bike turns by steering and has more active steering. Same with a longer stem and a mid/high-trail bike - bar arc is slow but not the same as how a high-trail bike turns by leaning and less by steering.

Here's a trail calculator, you only need head angle, tire size and fork rake to calculate.

Bicycle Trail Calculator | yojimg.net

Looks like using a nominal 700x35 tire your current bike is high trail at 76mm and the bike you are considering is more mid-trail at 58mm.
Spoonrobot is offline  
Old 08-31-17, 09:00 PM
  #3  
Senior Member
Thread Starter
 
DarKris's Avatar
 
Join Date: Dec 2015
Location: Buffalo, NY
Posts: 619

Bikes: Kona Kahuna DL Drop Bar - Sensah SRX Pro 1x11 (2012 Frame), Giant Toughroad GX 1 - Shimano Road Hydro + SLX 1x10 (2018), Diamondback Sync'r - SRAM NX 1x12 (2020)

Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 160 Post(s)
Liked 97 Times in 54 Posts
Originally Posted by Spoonrobot
Yes, fork rake is important too. Not really, the front end handling is pretty set by mechanical trail and pneumatic trail.
So then I guess my question is will the lower HT angle make it feel like I'm more forward on the bike, and to a lesser concern will the lower trail make the bike less stable? My current bike has me in a more upright position with my positioning being further back. I ride my bike like a street MTB so my positioning is a hybrid between road and MTB, and I want to maintain that sort of position.
DarKris is offline  
Old 08-31-17, 09:16 PM
  #4  
Senior Member
 
Spoonrobot's Avatar
 
Join Date: Jul 2006
Posts: 3,096
Mentioned: 63 Post(s)
Tagged: 0 Thread(s)
Quoted: 1237 Post(s)
Liked 192 Times in 120 Posts
I take it you mean the higher headtube angle?

Anyway, put the geometry for the two bikes in here: Stack and reach calculator

The Giant has less reach and a higher stack so it would probably be better suited to a upright position. The difference in trail isn't really going to affect stability, it might be a positive change as wheel flop will be significantly less at mid-trail. High-trail gets more stable at higher speed and less stable at lower speeds, so if you're riding like a street MTB I think the mid-trail Giant may be better.

What don't you like about your current bike that you are trying to solve with a new bike?
Spoonrobot is offline  
Old 08-31-17, 09:50 PM
  #5  
Senior Member
Thread Starter
 
DarKris's Avatar
 
Join Date: Dec 2015
Location: Buffalo, NY
Posts: 619

Bikes: Kona Kahuna DL Drop Bar - Sensah SRX Pro 1x11 (2012 Frame), Giant Toughroad GX 1 - Shimano Road Hydro + SLX 1x10 (2018), Diamondback Sync'r - SRAM NX 1x12 (2020)

Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 160 Post(s)
Liked 97 Times in 54 Posts
Originally Posted by Spoonrobot
What don't you like about your current bike that you are trying to solve with a new bike?
My current bike I built up for cheap so the parts so it's basically my knock around bike. I wanted the TCX specifically because of the massive tire clearence for a CX bike. I'd run it with 650b WTB "Road Plus" tires (not officially on WTB's site but know it'll fit) and since I run flat pedals the higher BB means more clearance considering I am running 650b wheels. It'll basically be my "Do-it all-within-reason" bike that I can potentially race CX/Gravel as well. Plus I just reeeeeally like that bike.
DarKris is offline  
Old 09-06-17, 01:24 PM
  #6  
Senior Member
 
chas58's Avatar
 
Join Date: Jul 2010
Location: Michigan
Posts: 4,863

Bikes: too many of all kinds

Mentioned: 35 Post(s)
Tagged: 0 Thread(s)
Quoted: 1147 Post(s)
Liked 415 Times in 335 Posts
That is a huge difference in head tube angle. No, the head tube angle is not going to make the bike feel different in a straight line (although reach would). All things being equal, the 72 is going to be a lot more responsive, while the 70 is going to track straighter and hold its line better. Depends what you are after. If I want an agile bike, I choose the 72, if I want a bike that I want to track straight going downhill with changes in terrain, I go for the 70...
chas58 is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
cormacf
Long Distance Competition/Ultracycling, Randonneuring and Endurance Cycling
21
03-12-19 05:13 PM
tkm
Framebuilders
19
05-17-16 04:52 AM
ftwelder
Framebuilders
20
12-15-12 03:41 PM
Juggler2
Bicycle Mechanics
7
09-25-12 03:06 AM
rangerdavid
Road Cycling
14
11-10-10 05:39 PM

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service -

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.