Cycling and bicycle discussion forums. 
   Click here to join our community Log in to access your Control Panel  


Go Back   > >

Classic & Vintage This forum is to discuss the many aspects of classic and vintage bicycles, including musclebikes, lightweights, middleweights, hi-wheelers, bone-shakers, safety bikes and much more.

User Tag List

Reply
 
Thread Tools Search this Thread
Old 11-14-11, 10:39 PM   #1
Puget Pounder
Wookie Jesus inspires me.
Thread Starter
 
Puget Pounder's Avatar
 
Join Date: Mar 2011
Location: Seattle, WA
Bikes:
Posts: 2,225
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Filing down steer tube under the fork crown?

32c paselas graze the bottom of my fork's steer tube under the crown on my Nishiki Road Compe. Do you think I could file it down a few mm to gain extra clearance?

What an odd bike... With the 27" wheels on there, the bike has ample clearance in the rear, but almost none in the front. I converted to 700c and there is no room for fenders even with 28c for the front. What a strange construction... Anyways I've since decided that it's going to get 32 paselas and be my beater/commuter.

Has anyone had light tire grazing on the steer tube and safely filed it down a bit before?

Last edited by Puget Pounder; 11-14-11 at 10:50 PM.
Puget Pounder is offline   Reply With Quote
Old 11-14-11, 10:41 PM   #2
Michael Angelo 
Senior Member
 
Michael Angelo's Avatar
 
Join Date: May 2010
Location: Hurricane Alley , Florida
Bikes: Treks (USA), Schwinn Paramount, Schwinn letour,Raleigh Team Professional, Gazelle GoldLine Racing, 2 Super Mondias, Carlton Professional.
Posts: 3,805
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 26 Post(s)
I would not file down the Fork. Seems like it would weaken it.
Michael Angelo is offline   Reply With Quote
Old 11-14-11, 11:03 PM   #3
Puget Pounder
Wookie Jesus inspires me.
Thread Starter
 
Puget Pounder's Avatar
 
Join Date: Mar 2011
Location: Seattle, WA
Bikes:
Posts: 2,225
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
I'm thinking more of the steer tube protrusion at the bottom. I don't see anything structural about it, but I guess I am here for your opinions
Puget Pounder is offline   Reply With Quote
Old 11-14-11, 11:06 PM   #4
illwafer
)) <> ((
 
illwafer's Avatar
 
Join Date: Mar 2008
Location: San Diego, CA
Bikes:
Posts: 2,406
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 6 Post(s)
a picture would help, but i would probably recommend a different bike or 650B.
illwafer is offline   Reply With Quote
Old 11-14-11, 11:11 PM   #5
Puget Pounder
Wookie Jesus inspires me.
Thread Starter
 
Puget Pounder's Avatar
 
Join Date: Mar 2011
Location: Seattle, WA
Bikes:
Posts: 2,225
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by illwafer View Post
a picture would help, but i would probably recommend a different bike or 650B.
I wouldn't be able to get one until this weekend as it's in storage. I am not attached to this bike really, but it's what I have on hand and it's already half way built up. Has it's fair share of scratches so I don't have to worry about scuffing. I already plan on doing a 650B on another bike, but that's coming down the line
Puget Pounder is offline   Reply With Quote
Old 11-14-11, 11:13 PM   #6
3speed
Senior Member
 
Join Date: Aug 2009
Location: Madison, WI
Bikes:
Posts: 2,689
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
I'm no fork structural integrity genius(though I doubt most anyone else here is either. ), but I'd think that if it were just a small area in the middle and just a tiny bit filed off, it should be fine. The crown shouldn't be so fragile that such a small alteration, at what I would think to be the strongest point, is going to cause it to collapse under you. I do know the weakest part of the crown is typically the section between the steer tube and where the blades go into the crown, so I wouldn't go filing out far enough to reach that area at all.
3speed is offline   Reply With Quote
Old 11-14-11, 11:15 PM   #7
Captain Blight
Senior Member
 
Captain Blight's Avatar
 
Join Date: Oct 2009
Location: Minneapolis
Bikes: -1973 Motobecane Mirage -197? Velosolex L'Etoile -'71 Raleigh Super Course
Posts: 2,473
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
If it's protruding, it's not doing a darn thing but adding weight and getting in the way. Grind away happily.

I've seen pictures of very tight track frames with the underside of the crowns filed for tire clearance. If you have to get into the crown a bit, it shouldn't make so much of a difference.
Captain Blight is offline   Reply With Quote
Old 11-15-11, 03:09 AM   #8
GrayJay
Senior Member
 
GrayJay's Avatar
 
Join Date: Sep 2009
Location: EagleRiver AK
Bikes:
Posts: 1,230
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
If it is a unicrown, should be fine so long as you dont grind/file into the welds attaching the blades to the steer tube. If it is a lugged crown, you dont want to attack the actual crown but it should be OK if the steer tube protrudes a bit to file it flush with the lug.

Another idea- fill the top of the fork-end dropout slots a bit with JB-weld so that the axle is located 1-2mm further down on the fork. 30mm tires would also gain you clearance for very little difference in ride/feel.
GrayJay is offline   Reply With Quote
Old 11-15-11, 07:30 AM   #9
miamijim
Senior Member
 
miamijim's Avatar
 
Join Date: Aug 2003
Location: Tampa, Florida
Bikes:
Posts: 13,409
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 77 Post(s)
I use to do it all the time with something like an 8" half round file. Due to the curvature of the wheel you only need to do the front edge of the crown/steerer and you dont need to file off much.
miamijim is offline   Reply With Quote
Old 11-15-11, 07:51 AM   #10
Henry III 
is just a real cool dude
 
Henry III's Avatar
 
Join Date: Aug 2010
Location: The Thumb, MI
Bikes:
Posts: 3,102
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 10 Post(s)
I don't think it would be an issue. I've seen it done before and the folks are still alive. Does the caliper clear the tire though? I think your caliper would have more of an clearance issue of the tire is grazing the crown? Plus if the steerer tube is being touched by the tire and not the crown it's just excess tubing not serving any additional strength to the fork. I had very tight clearances on my frame/fork when I built it. My caliper needs to have tension on it or just left open it touch the tire. Nothing bigger then a 650-23 tire will fit it. Yes I made it that way when building it. That's weird why you'd lose clearance when using a 700c wheel over a 27"? Any pictures at all?
Henry III is offline   Reply With Quote
Old 11-15-11, 08:09 AM   #11
Grand Bois
Senior Member
 
Grand Bois's Avatar
 
Join Date: Mar 2005
Location: Pinole, CA, USA
Bikes:
Posts: 16,834
Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 138 Post(s)
I used a half round file to keep a 27X1 1/4" tire from rubbing this fork, but I ended up switching to 700c wheels. It's still a close fit with 28s. It has no structural effect. That's ridiculous. The brake clears only because it's a factory slotted MAFAC Competition.

Grand Bois is online now   Reply With Quote
Old 11-15-11, 08:20 AM   #12
T-Mar
Senior Member
 
Join Date: Nov 2004
Bikes:
Posts: 12,475
Mentioned: 64 Post(s)
Tagged: 1 Thread(s)
Quoted: 376 Post(s)
Quote:
Originally Posted by Puget Pounder View Post
...What an odd bike... With the 27" wheels on there, the bike has ample clearance in the rear, but almost none in the front. I converted to 700c and there is no room for fenders even with 28c for the front. What a strange construction...
It is not usual to have more clearance on the rear and it is done on purpose to install longer reach brakes. In a braking situation, most of the braking is achieved via the front brake as the load on the rear wheel lessens. This results in a tendency for the rear wheel to lock up and skid. A skid requires a longer distance to stop the bicycle, not to mention the affect on steering. By utilizing a longer reach rear brake, the pressure at the pads is reduced and the rear tire is less likely to skid. Basically, a longer reach rear brake optimizes braking performance for most cyclists.

The Road Compe was a tubular tired competition bicycle and was intended for 700 x 25C tires, so I'm not surprised you're running into these issues. Personally, if the opening in the dropouts has sufficient vertical allowance, I'd opt for filling in the top of the dropouts, as previously suggested.
T-Mar is offline   Reply With Quote
Old 11-15-11, 09:39 AM   #13
Puget Pounder
Wookie Jesus inspires me.
Thread Starter
 
Puget Pounder's Avatar
 
Join Date: Mar 2011
Location: Seattle, WA
Bikes:
Posts: 2,225
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by Henry III View Post
I don't think it would be an issue. I've seen it done before and the folks are still alive. Does the caliper clear the tire though? I think your caliper would have more of an clearance issue of the tire is grazing the crown? Plus if the steerer tube is being touched by the tire and not the crown it's just excess tubing not serving any additional strength to the fork. I had very tight clearances on my frame/fork when I built it. My caliper needs to have tension on it or just left open it touch the tire. Nothing bigger then a 650-23 tire will fit it. Yes I made it that way when building it. That's weird why you'd lose clearance when using a 700c wheel over a 27"? Any pictures at all?
Sorry, the only reason I lose clearance is because I was using 27" wheels with narrower tires before. I should have made that clear. I thought that going to 700c and popping on some fatter tires would more or less put me at the same spot. The tire grazes the steerer, but there is sufficient room to clear the calipers.
Puget Pounder is offline   Reply With Quote
Old 11-15-11, 11:11 AM   #14
mudboy
Senior Member
 
mudboy's Avatar
 
Join Date: Sep 2008
Location: Collegeville, PA
Bikes: Ruckelshaus Randonneur, Specialized Allez (early 90's, steel), Ruckelshaus Path Bomber currently being built
Posts: 1,354
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Apart from the paint or chrome you'll lose, it won't be a problem. I sculpt the underside of my fork crowns whenever I build a frame.
mudboy is offline   Reply With Quote
Old 11-15-11, 11:58 AM   #15
shelbyfv
Senior Member
 
Join Date: Jun 2007
Bikes:
Posts: 2,955
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 179 Post(s)
Interesting thread. I have the same problem with a Bridgestone RB2 and Pasela 28s. The steerer tube extends below the crown maybe 1/4 inch. I filed it a little, but now I think I will take it down all the way to the crown. Who knows, maybe I can then fit 32s!
shelbyfv is offline   Reply With Quote
Old 11-15-11, 12:01 PM   #16
Puget Pounder
Wookie Jesus inspires me.
Thread Starter
 
Puget Pounder's Avatar
 
Join Date: Mar 2011
Location: Seattle, WA
Bikes:
Posts: 2,225
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by T-Mar View Post
It is not usual to have more clearance on the rear and it is done on purpose to install longer reach brakes. In a braking situation, most of the braking is achieved via the front brake as the load on the rear wheel lessens. This results in a tendency for the rear wheel to lock up and skid. A skid requires a longer distance to stop the bicycle, not to mention the affect on steering. By utilizing a longer reach rear brake, the pressure at the pads is reduced and the rear tire is less likely to skid. Basically, a longer reach rear brake optimizes braking performance for most cyclists.

The Road Compe was a tubular tired competition bicycle and was intended for 700 x 25C tires, so I'm not surprised you're running into these issues. Personally, if the opening in the dropouts has sufficient vertical allowance, I'd opt for filling in the top of the dropouts, as previously suggested.
Wow. Thank you for this! I thought everyone at Kawamura was just a little drunk on sake
Puget Pounder is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

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



All times are GMT -6. The time now is 03:53 PM.