Go Back  Bike Forums > Bike Forums > Bicycle Mechanics
Reload this Page >

"funny" steering feel only on serious downhill (road)

Bicycle Mechanics Broken bottom bracket? Tacoed wheel? If you're having problems with your bicycle, or just need help fixing a flat, drop in here for the latest on bicycle mechanics & bicycle maintenance.

"funny" steering feel only on serious downhill (road)

Old 07-15-13, 11:22 PM
  #1  
khan
rider
Thread Starter
 
Join Date: Dec 2005
Location: st.louis
Posts: 138
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
"funny" steering feel only on serious downhill (road)

So, it started happening a while ago but, when going downhill at a pretty good grade and longish distance, it feels like my bike is not tracking straight. I've checked the rigidity of all the suspect parts (bars, stem, headset, frame, wheels, seat post, bottom bracket) and everything seems solid and tight. I don't have trouble shifting (thinking alignment of the frame). The wheelset is about fourteen years old but, solid as a rock and I had them repacked recently along with new cones in the front. I'm at a loss. People riding behind me don't notice anything but, they're also descending and are more focused on what they're doing. Short of pulling everything apart and inspecting piece by piece throughout the bike, I have no idea what to look at. Any suggestions would be very appreciated. Feel free ask questions for clarification.
Thanks!
khan is offline  
Old 07-16-13, 03:09 AM
  #2  
Frum
Senior Member
 
Join Date: Nov 2012
Posts: 66
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Slightly bent fork or the front wheel is seated in the frame to one side (not perpendicular to the ground.) It won't be easy to see in either case--if you try riding handless and get tracked off to one side you'll know it's one of these.

Think on it for a minute and you should be able to discern the principals that govern the direction of the pull and the irregularity in the fork.
Frum is offline  
Old 07-16-13, 04:57 AM
  #3  
Kimmo
bike whisperer
 
Kimmo's Avatar
 
Join Date: Dec 2009
Location: Melbourne, Oz
Posts: 7,829

Bikes: https://weightweenies.starbike.com/forum/viewtopic.php?f=10&t=152015&p=1404231

Mentioned: 8 Post(s)
Tagged: 0 Thread(s)
Quoted: 335 Post(s)
Likes: 0
Liked 1 Time in 1 Post
AFAIK a DIY approach to checking fork alignment is a tough one. Best bet might be having it checked on a jig.

But as far as the frame goes, there's the string test for a start... and eye up the head tube against the seat tube (can be a bit hard these days with flared head tubes, but usually the diameter is the same at each end).

Check your wheels for dish by flipping them in the frame, but not before sitting the bike upside down, releasing the QRs and rotating the spindles to ensure they're straight.
Kimmo is offline  
Old 07-16-13, 05:21 AM
  #4  
cny-bikeman 
Mechanic/Tourist
 
Join Date: Apr 2007
Location: Syracuse, NY
Posts: 7,508

Bikes: 2008 Novara Randonee - love it. Previous bikes:Motobecane Mirage, 1972 Moto Grand Jubilee (my fave), Jackson Rake 16, 1983 C'dale ST500.

Mentioned: 10 Post(s)
Tagged: 0 Thread(s)
Quoted: 474 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Actually once you have confirmed that the rear triangle is centered using the "string test," and wheels are dished and true, with both wheels sitting in the middle of the stays/blades, it's not hard to visually check fork alignment. Turn the bike upside down - best done on a rotating stand, otherwise use a friend to assist. Sight over the top of the front wheel toward the back of the bike, noting whether it is tilted in relation to the rear. Then sight along both sides to see if one side of the rear wheel shows more than the other, making sure of course that you hold the wheel straight. Finally sight along the side of the front wheel again toward the top and seat tubes, again checking to see if the appearance is different from side to side.
__________________
There's no such thing as a routine repair.

Don't tell me what "should" be - either it is, it isn't, or do something about it.

If you think I'm being blunt take it as a compliment - if I thought you were too weak to handle the truth or a strong opinion I would not bother.

Please respect others by taking the time to post clearly so we can answer quickly. All lowercase and multiple typos makes for a hard read. Thanks!

Last edited by cny-bikeman; 07-16-13 at 08:46 PM.
cny-bikeman is offline  
Old 07-16-13, 06:49 AM
  #5  
JohnDThompson 
Old fart
 
JohnDThompson's Avatar
 
Join Date: Nov 2004
Location: Appleton WI
Posts: 20,339

Bikes: Several, mostly not name brands.

Mentioned: 106 Post(s)
Tagged: 0 Thread(s)
Quoted: 1660 Post(s)
Liked 34 Times in 21 Posts
Park used to make a gauge for checking fork alignment (the "FT-4"):



Perhaps your LBS or co-op has one?
JohnDThompson is offline  
Old 07-16-13, 07:13 AM
  #6  
DaveSSS
Senior Member
 
Join Date: Sep 2008
Location: Loveland, CO
Posts: 5,211

Bikes: Look KG461, Colnago C-RS

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 69 Post(s)
Likes: 0
Liked 2 Times in 2 Posts
Be sure that your headset is not adjusted too tightly. If the fork isn't free enough to self-center itself, then it might track funny. You should also notice the problem after a fast turn, when the bike wants to keep turning and not return to a straight-ahead position.

It's also possible to cut cable housings to the wrong length and create a situation where a housing tries to push or pull on the bars.

Last edited by DaveSSS; 07-16-13 at 08:55 AM.
DaveSSS is offline  
Old 07-16-13, 07:21 AM
  #7  
rydabent
Senior Member
 
Join Date: Apr 2010
Location: Lincoln Ne
Posts: 7,516

Bikes: RANS Stratus TerraTrike Tour II

Mentioned: 19 Post(s)
Tagged: 0 Thread(s)
Quoted: 1312 Post(s)
Liked 11 Times in 10 Posts
There is a good and cheap method to check rear frame alignment. Take a piece of string and tie to one side of the rear dropout. Loop the string around the headset and tie to the other side of the the rear dropout in the same place. Pull the string tight. The measure the distance to the string from each side of the seat tube. If that measurement is equal, as others say it may be a fork problem.

BTW I would always check this frame alignment on any used bike that I might buy.
rydabent is offline  
Old 07-16-13, 08:54 AM
  #8  
FBinNY 
Senior Member
 
Join Date: Apr 2009
Location: New Rochelle, NY
Posts: 36,049

Bikes: too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter

Mentioned: 121 Post(s)
Tagged: 1 Thread(s)
Quoted: 4339 Post(s)
Likes: 0
Liked 1 Time in 1 Post
No one asked or mentioned, but does the bike have a suspension fork? If so, sometimes the fork compresses unevenly, causing the wheel to deflect to either side.
__________________
FB
Chain-L site

An ounce of diagnosis is worth a pound of cure.

“Never argue with an idiot. He will only bring you down to his level and beat you with experience.”, George Carlin

“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN

WARNING, I'm from New York. Thin skinned people should maintain safe distance.
FBinNY is offline  
Old 07-16-13, 10:12 PM
  #9  
khan
rider
Thread Starter
 
Join Date: Dec 2005
Location: st.louis
Posts: 138
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Thanks for all of the great suggestions for things to look at. I will start going through these to see if anything shows up.

Btw, it's not a suspension fork. Ti road frame w/ carbon fork and steerer.

Again, thanks everyone for the ideas.
khan is offline  
Old 07-16-13, 10:21 PM
  #10  
Kimmo
bike whisperer
 
Kimmo's Avatar
 
Join Date: Dec 2009
Location: Melbourne, Oz
Posts: 7,829

Bikes: https://weightweenies.starbike.com/forum/viewtopic.php?f=10&t=152015&p=1404231

Mentioned: 8 Post(s)
Tagged: 0 Thread(s)
Quoted: 335 Post(s)
Likes: 0
Liked 1 Time in 1 Post
Originally Posted by DaveSSS View Post
Be sure that your headset is not adjusted too tightly.
Yeah, that's another possibility; I collected a bike to ride back to the workshop last week that had super-spooky handling... I was thinking something must be seriously wrong so I stopped and checked it out.

To my surprise it was just the result of the most badly indexed headset I've come across. Upon disassembly one of the cartridges felt a bit damaged, but lacking an immediate replacement was reused; thankfully it was quite passable after being properly reassembled.

Obviously some total goose had assumed the top cap was for fastening rather than adjustment...
Kimmo is offline  
Old 07-16-13, 11:06 PM
  #11  
FBinNY 
Senior Member
 
Join Date: Apr 2009
Location: New Rochelle, NY
Posts: 36,049

Bikes: too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter

Mentioned: 121 Post(s)
Tagged: 1 Thread(s)
Quoted: 4339 Post(s)
Likes: 0
Liked 1 Time in 1 Post
I haven't commented, and the others have covered some bases,

BUT

What, exactly do you mean by "it feels like my bike is not tracking straight"?

Is it pulling to one side? If so is it always to the same side? Do you have high speed shimmy? Are you overcompensating when steering? or what EXACTLY?.

Diagnosing a problem accurately (especially blind) requires a good description of what the problem is. Absent that folks are just throwing shist against the wall to see what sticks.
__________________
FB
Chain-L site

An ounce of diagnosis is worth a pound of cure.

“Never argue with an idiot. He will only bring you down to his level and beat you with experience.”, George Carlin

“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN

WARNING, I'm from New York. Thin skinned people should maintain safe distance.
FBinNY is offline  

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


Thread Tools
Search this Thread

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

Copyright © 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.