Changing Head Angle
#1
Senior Member
Thread Starter
Changing Head Angle
Just rode a new frame and have found that I pushed the envelope too far with the head tube angle. Thinking about how to change the head angle I came up with removing the down tube, bending the head tube/top tube to get to the desired head angle (needs to move about 3 degrees) to steepen the angle. Any thoughts or is it replacement of the top tube/head tube/down tube and rebuild the front triangle?
#2
Full Member
Join Date: Dec 2009
Posts: 495
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 49 Post(s)
Likes: 0
Liked 13 Times
in
12 Posts
Just rode a new frame and have found that I pushed the envelope too far with the head tube angle. Thinking about how to change the head angle I came up with removing the down tube, bending the head tube/top tube to get to the desired head angle (needs to move about 3 degrees) to steepen the angle. Any thoughts or is it replacement of the top tube/head tube/down tube and rebuild the front triangle?
How is it joined?
#3
Senior Member
Join Date: Feb 2012
Location: Rochester, NY
Posts: 18,084
Bikes: Stewart S&S coupled sport tourer, Stewart Sunday light, Stewart Commuting, Stewart Touring, Co Motion Tandem, Stewart 3-Spd, Stewart Track, Fuji Finest, Mongoose Tomac ATB, GT Bravado ATB, JCP Folder, Stewart 650B ATB
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 4205 Post(s)
Liked 3,863 Times
in
2,311 Posts
3 degrees of bending? That's a lot IMO. Better to remove the HT and see if the existing TT and DT can be remitered for the new head angle. Andy
__________________
AndrewRStewart
AndrewRStewart
#4
Senior Member
Join Date: Dec 2019
Posts: 956
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 321 Post(s)
Liked 263 Times
in
212 Posts
Just rode a new frame and have found that I pushed the envelope too far with the head tube angle. Thinking about how to change the head angle I came up with removing the down tube, bending the head tube/top tube to get to the desired head angle (needs to move about 3 degrees) to steepen the angle. Any thoughts or is it replacement of the top tube/head tube/down tube and rebuild the front triangle?
#6
Senior Member
Thread Starter
Here is what happened. I designed the frame around a 60mm fork rake, then changed my mind on the fork as I wanted the bike to look more modern, but the frame was already built by that time. Decided to install a 45mm rake fork and try it anyway. It is ridable, but rides like a chopper, lots of rise and fall with the front end, and it is a handful in high winds. The frame is lugged and figured redoing the whole front end of the bike would be best, but figured if there was a short cut, someone here will know.
#7
Senior Member
Join Date: Jan 2013
Location: South Jersey
Posts: 2,266
Mentioned: 18 Post(s)
Tagged: 0 Thread(s)
Quoted: 714 Post(s)
Liked 800 Times
in
475 Posts
What is the purpose of the bike? Road, gravel, touring? My bikes vary in trail from about 60mm on the road bike to 75mm on the gravel bike and 90mm on the MTB. The longer trail bikes are not so easy to ride with no hands, but winds don't seem to be a problem. The only time I have problems with cross winds is with a deep section front wheel.
It just seems like a radical approach to re-build the front triangle, when riding the bike a few more times might allow you to become accustomed to the way it rides.
It just seems like a radical approach to re-build the front triangle, when riding the bike a few more times might allow you to become accustomed to the way it rides.
#8
Senior Member
Join Date: Jan 2005
Location: Baltimore, MD
Posts: 5,373
Mentioned: 15 Post(s)
Tagged: 0 Thread(s)
Quoted: 2482 Post(s)
Liked 2,955 Times
in
1,678 Posts
That's a sensible suggestion. I bent the (steel) fork on a 1986 Cannondale in 1990, left it unused for 20 years with a vague plan of replacing the fork, and then started commuting on it. Took a few rides to get used to the handling, but I've since ridden it for a good proportion of my annual mileage.
#10
Randomhead
Join Date: Aug 2008
Location: Happy Valley, Pennsylvania
Posts: 24,398
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 4 Post(s)
Liked 3,697 Times
in
2,518 Posts
have you put your proposed numbers into a trail/flop calculator? 45mm rake fork is going to need a steep hta to get it to reasonable flop. What is the current HTA and proposed HTA?
Seems like it's time for a new frame, chalk this one up to experience. But if you really want to do this, replace the TT/HT/DT.
Seems like it's time for a new frame, chalk this one up to experience. But if you really want to do this, replace the TT/HT/DT.
#11
Senior Member
Thread Starter
I find my trail preference is between 71-73 mm. I have considered a straight blade fork with 60mm taken but need to draw it to get an idea of how it will look. As it is, I will give the thing another ride and see how it goes.
#12
Team Beer
Join Date: Apr 2004
Location: Sacramento CA
Posts: 6,339
Bikes: Too Many
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 114 Post(s)
Liked 159 Times
in
104 Posts
A 7 degree fork crown with a 390-400 ac would get you really close to 60 mm.
__________________
I'm not one for fawning over bicycles, but I do believe that our bikes communicate with us, and what this bike is saying is, "You're an idiot." BikeSnobNYC
I'm not one for fawning over bicycles, but I do believe that our bikes communicate with us, and what this bike is saying is, "You're an idiot." BikeSnobNYC
#14
I am potato.
Join Date: Jun 2015
Location: Pacific Northwest
Posts: 3,116
Bikes: Only precision built, custom high performance elitist machines of the highest caliber. 🍆
Mentioned: 29 Post(s)
Tagged: 0 Thread(s)
Quoted: 1789 Post(s)
Liked 1,629 Times
in
933 Posts
Rodriguez had someone contract build them bunches of 55mm rake forks (1&⅛) for their disc braked bikes. You might give them a call. Maybe they have one on the shelf.
Rodbikes.com
55mm is not 60mm, but it'd get you closer than you are. They are aluminum, smooth, disc. Nothing retro or lugged about 'em.
They also do custom to whatever your specs are.
Mine is 55mm rake for a 26 inch (559) wheel for a 69 degree head tube angle. ~55 to 62mm of trail depending on tire.
Rodbikes.com
55mm is not 60mm, but it'd get you closer than you are. They are aluminum, smooth, disc. Nothing retro or lugged about 'em.
They also do custom to whatever your specs are.
Mine is 55mm rake for a 26 inch (559) wheel for a 69 degree head tube angle. ~55 to 62mm of trail depending on tire.
Last edited by base2; 05-06-20 at 10:05 PM.
#15
Senior Member
Thread Starter
I believe I will try to save the head tube as it is special to me. Last of the 531 tubes my brother gave me, and replace the lugs and TT/DT. Winter project.
Likes For TiHabanero:
#16
Senior Member
Thread Starter
dsaul, I have been riding the bike with the inappropriate fork and am becoming accustomed to the low speed weirdness. I will say once I am up around 17+ mph, the thing settles down and is very comfortable to ride. Does not like to deviate from a straight line so a little extra effort on the bars is required for cornering. Oddly, this does not bother me at all. Only the low speed instability is bothersome, but I bet that can be overcome in time.
The OS down tube seems to make a difference in the responsiveness to heavy input such as climbing and sprinting. At 40mph on a downhill the bike was very stable, but as mentioned before, it did not like to deviate from a straight line without some heavy handedness. Again, I can deal with that. Thinking that using the wrong fork is livable. Thanks, dsaul!
The OS down tube seems to make a difference in the responsiveness to heavy input such as climbing and sprinting. At 40mph on a downhill the bike was very stable, but as mentioned before, it did not like to deviate from a straight line without some heavy handedness. Again, I can deal with that. Thinking that using the wrong fork is livable. Thanks, dsaul!
Likes For TiHabanero: