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

Another bent frame issue... Can it be true via HTS-1 or similar tool?

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.

Another bent frame issue... Can it be true via HTS-1 or similar tool?

Old 09-07-12, 02:49 PM
  #1  
Branimir
Merckx wannabe
Thread Starter
 
Branimir's Avatar
 
Join Date: May 2007
Location: Zagreb, Croatia
Posts: 254

Bikes: Rampon EL/OS 5700 groupset

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Another bent frame issue... Can it be true via HTS-1 or similar tool?

So, here's what happened:




You can see the top and down tube got a "belly".

Is it possible to straighten it out via HTS-1 similar method - I've searched the forums and saw salvaged Peugoet and some others...

Thanks.
Branimir is offline  
Old 09-07-12, 04:01 PM
  #2  
cny-bikeman 
Mechanic/Tourist
 
Join Date: Apr 2007
Location: Syracuse, NY
Posts: 7,510

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: 477 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
You might want to just leave it, unless the fork interferes badly with the pedals or if the handling is squirrely. but there's no guarantee the fork is not bent - to one side or one blade back more than the other. It's possible to do it with that tool if you know someone who has it, but THIS TOOL IS NOT FOR USE ON FRAMES WITH AIR-HARDENED STEEL TUBING, e.g. Reynolds 753, 853; True Temper OX, etc.
__________________
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!
cny-bikeman is offline  
Old 09-07-12, 04:02 PM
  #3  
Branimir
Merckx wannabe
Thread Starter
 
Branimir's Avatar
 
Join Date: May 2007
Location: Zagreb, Croatia
Posts: 254

Bikes: Rampon EL/OS 5700 groupset

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
The fork is bent, but I could go with replacing the fork... Though I find it hard to part with the frame...
Branimir is offline  
Old 09-07-12, 09:01 PM
  #4  
Andrew R Stewart 
Senior Member
 
Andrew R Stewart's Avatar
 
Join Date: Feb 2012
Location: Rochester, NY
Posts: 11,654

Bikes: Stewart S&S coupled sport tourer, Stewart Sunday light, Stewart Commuting, Stewart Touring, Co Motion Tandem, Stewart 3-Spd, Stewart Track, Fuji Finest, Raleigh Pro, Trek Cycle Cross, Mongoose tomac ATB, GT Bravado ATB, JCP Folder

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1730 Post(s)
Liked 45 Times in 32 Posts
Branimir- People do a lot of things to old and bent bikes for a lot of reasons. Not all are what might be considered "best choices". Don't base your decission of what you see on line. You should take your bike to someone who has experience with this kind of damage. They will be able to discern the whole picture and give you a better understanding to what should be done.

You're photos show some bending of the frame and fork in a rearwards direction. But not whether there's a side/twisting component. Is the fork's steerer bent or just the blades? Do you know the original head angle or front center? It's not hard to bend the frame/fork into a new place but hard to know if this new place is where it was before the incident.

The best repair would be to replace the TT, DT and HT with a new fork. This way all could be tied into a compatible design, geometry wise. And no residual stresses or weakenesses would remain. But still no insurance of perfectly duplicating the geometry. And the cost would be high.

All your solutions have their judgements to be happy with, good luck. Andy.
Andrew R Stewart is offline  
Old 09-07-12, 09:35 PM
  #5  
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: 4342 Post(s)
Likes: 0
Liked 1 Time in 1 Post
Originally Posted by cny-bikeman View Post
You might want to just leave it, unless the fork interferes badly with the pedals or if the handling is squirrely.
+1, leave it alone, it's only slightly bent and will probably ride fine with a new fork. A skilled mechanic might be able to improve it, but you're better off leaving bad enough alone.

This was very common back in the day, and bikes like this could be ridden for years in this condition, but it's a permanent weak spot, and eventually the tubing will fatigue there. The bright side is that these frames are very polite and take a long time to finally let go, and will give you fair notice with visible crack formation starting at the ripple, and slowly over hours, days or even weeks propagating around the tube before it finally lets go.
__________________
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 09-08-12, 01:44 AM
  #6  
Branimir
Merckx wannabe
Thread Starter
 
Branimir's Avatar
 
Join Date: May 2007
Location: Zagreb, Croatia
Posts: 254

Bikes: Rampon EL/OS 5700 groupset

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Okay thanks for your comments. I cannot notice if bent made notable changes to the geometry, maybe a couple of mm's.

I'll probably leave it as is, use it for commuting, and avoid any serious stress to the bicycle, rather than to try to straighten it up.

Cheers,

B.
Branimir is offline  
Old 09-12-12, 01:57 PM
  #7  
Branimir
Merckx wannabe
Thread Starter
 
Branimir's Avatar
 
Join Date: May 2007
Location: Zagreb, Croatia
Posts: 254

Bikes: Rampon EL/OS 5700 groupset

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Sorry for bumping this topic up, but it seems I've found a person that repairs steel bicycles, actually changes tubes, still trying to contact him and appoint for repair, since he's in Slovenia, but luckily, only 80km away from here...

A question for builders/experts:

In this case the top and downtube are damaged, so that means they should be replaced - is it possible to alter the size of the frame while doing this, while keeping the geometry? Actually what I mean - for the repair expert who's replacing the tubes - to also take out the seat tube and shorten all three of them to keep the geometry, just to reduce size. Top tube is now something like 55.5cm, seat tube C-T is 56, and I was wondering, if he's pulling out top and down tube, why now seat tube and then make it 2cm shorter on those measures also (top tube and C-T), the bike would fit me a bitt better

Is this doable/common practice/etc?

Thanks!

Last edited by Branimir; 09-12-12 at 02:02 PM.
Branimir is offline  
Old 09-12-12, 02:05 PM
  #8  
cny-bikeman 
Mechanic/Tourist
 
Join Date: Apr 2007
Location: Syracuse, NY
Posts: 7,510

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: 477 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Originally Posted by Branimir View Post
I'll probably leave it as is, use it for commuting, and avoid any serious stress to the bicycle, rather than to try to straighten it up.
Smart move

Originally Posted by Branimir View Post
...I've found a person that repairs steel bicycles, actually changes tubes... luckily, only 80km away from here...In this case the top and downtube are damaged, so that means they should be replaced - is it possible to also take out the seat tube and shorten all three of them to keep the geometry, just to reduce size. Is this doable/common practice/etc?

Thanks!
Not so smart move...

The tubes are only slightly bent - they have very little chance of failing, are unlikely to affect you significantly.

Anything is doable. but to travel 80 km to have the main triangle on a low-end bike rebuilt (after which it will need painting as well) does not make sense. You would likely spend more on that process than by throwing out the bike and starting over, and you STILL don't know if the fork is bent to the side.

Common practice would be to buy a bike that fits you that is not damaged.
__________________
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; 09-12-12 at 02:12 PM.
cny-bikeman is offline  
Old 09-12-12, 02:11 PM
  #9  
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: 4342 Post(s)
Likes: 0
Liked 1 Time in 1 Post
Originally Posted by Branimir View Post
Sorry for bumping this topic up, but it seems I've found a person that repairs steel bicycles, actually changes tubes, still trying to contact him and appoint for repair, since he's in Slovenia, but luckily, only 80km away from here...

A question for builders/experts:

In this case the top and downtube are damaged, so that means they should be replaced - is it possible to alter the size of the frame while doing this, while keeping the geometry? Actually what I mean - for the repair expert who's replacing the tubes - to also take out the seat tube and shorten all three of them to keep the geometry, just to reduce size. Top tube is now something like 55.5cm, seat tube C-T is 56, and I was wondering, if he's pulling out top and down tube, why now seat tube and then make it 2cm shorter on those measures also (top tube and C-T), the bike would fit me a bitt better

Is this doable/common practice/etc?

Thanks!
Anything is possible, but you're passing the point where a new frame, custom built would be less expensive and simpler. Shortening the seat tube means lowering the seat lug. That means cutting and shortening the 2 seat stays, and angling them a bit lower, so possibly both seatstay/dropout joints would need rework.

Now the only thing left untouched is the bottom bracket/seat tube joint both ends of the two chainstays.

When you figure the extra labor of taking a joint apart, which os often harder than brazing was, you're looking at a big bill.

I'd either leave this alone and ride it as is, or do the minimum necessary. Otherwise talk to the builder in Slovenia about starting fresh, based on this bike as modified for you.
__________________
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 09-12-12, 02:14 PM
  #10  
Branimir
Merckx wannabe
Thread Starter
 
Branimir's Avatar
 
Join Date: May 2007
Location: Zagreb, Croatia
Posts: 254

Bikes: Rampon EL/OS 5700 groupset

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Uh, silly me, I forgot about the seat stays! Yes, makes sense, it's too much hassle, though - a new frame, would be a much wiser idea... certainly not money waisting...

Btw the fork IS bent, don't know if it's fixable, or should I search for a new one...

And I lost an ebay auction on an Columbus SLX frame, that went for 159 euros on italian ebay with 20euro shipping to here... I stopped at 152... oh well...
Branimir is offline  
Old 09-12-12, 02:29 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: 4342 Post(s)
Likes: 0
Liked 1 Time in 1 Post
Steel forks can be straightened, but it depends on the location and severity of the bend. I think it might make sense to visit the guy in Slovenia, and bring the frame for a consult, plur to talk about other options.

As for your lost shot on ebay, there's be others.
__________________
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 09-13-12, 11:26 AM
  #12  
miamijim
Senior Member
 
miamijim's Avatar
 
Join Date: Aug 2003
Location: Tampa, Florida
Posts: 13,923
Mentioned: 37 Post(s)
Tagged: 0 Thread(s)
Quoted: 323 Post(s)
Likes: 0
Liked 4 Times in 4 Posts
I had a frameset with similar visible damage awhile back and the head tube angle measured with 'spec'. I dont know what the original angle was so I looked up what it might be by comparing various geometry table and what I measured was close enough not to bother tinkering with. Steel is unique in that it springs back a touch after an impact which expains why you'll see damage without a compromise in head tube angle.

Another way to check is to measure the wheelbase and chain stay lengths. A typical road race wheel base may bee 1005mm with chainstays of 400mm which means the distance from the BB center to fork ends would be 605mm.

go through a bunch of old frame geometry charts and calculate average dimensions of what similar frame sizes to your have and measure yours in comparison.
miamijim is offline  
Old 09-13-12, 01:30 PM
  #13  
Andrew R Stewart 
Senior Member
 
Andrew R Stewart's Avatar
 
Join Date: Feb 2012
Location: Rochester, NY
Posts: 11,654

Bikes: Stewart S&S coupled sport tourer, Stewart Sunday light, Stewart Commuting, Stewart Touring, Co Motion Tandem, Stewart 3-Spd, Stewart Track, Fuji Finest, Raleigh Pro, Trek Cycle Cross, Mongoose tomac ATB, GT Bravado ATB, JCP Folder

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1730 Post(s)
Liked 45 Times in 32 Posts
Not sure about trusting the charts for any one bike. I know of many small but real differences from claimed specs to the actual ones. Also if a tube has a ripple in it after an impact then the length on that part of the tube has changed. Unless you're saying that the tube stretched so the ripple could exist and the angle not change. Not likely, espically with the ripple on the underside of a tube is in the compression zone. I don't know of a typical head end impact that has a force acting on the frame which after compressing the fork rearwards then pulls it back out past the original point (remember springback). So my take is that if there's a ripple there's an angle change.

Now how much and how important (to the bike's handling0 is an angle change is a different story.

Lastly be careful how you measure a bike's geometry. It's easy to confuse center points, centerlines and whether the measurement is based on the two dimensional or the three dimensional. The below comment about wheelbase-chainstay=front center doesn't mention BB drop as an example. Andy.


Originally Posted by miamijim View Post
I had a frameset with similar visible damage awhile back and the head tube angle measured with 'spec'. I dont know what the original angle was so I looked up what it might be by comparing various geometry table and what I measured was close enough not to bother tinkering with. Steel is unique in that it springs back a touch after an impact which expains why you'll see damage without a compromise in head tube angle.

Another way to check is to measure the wheelbase and chain stay lengths. A typical road race wheel base may bee 1005mm with chainstays of 400mm which means the distance from the BB center to fork ends would be 605mm.

go through a bunch of old frame geometry charts and calculate average dimensions of what similar frame sizes to your have and measure yours in comparison.
Andrew R Stewart is offline  
Old 09-22-12, 07:32 PM
  #14  
gomango 
Senior Member
 
Join Date: Jul 2006
Location: STP
Posts: 14,888
Mentioned: 63 Post(s)
Tagged: 0 Thread(s)
Quoted: 666 Post(s)
Liked 9 Times in 6 Posts
Save your pennies and get a real Zullo.

I've owned four of these now and still have one.

Incredible riders. imho

Lookers too!

Here's one I found after a few minutes of searching.

NOS!



Here's the link to the frame. Little high on the price, but shoot him an email.

Make an offer. Shipping can't be that bad from Hamburg.

ww.ebay.it/itm/ZULLO-Rennrad-Rahmen-aus-Oria-KK-Stahl-54-cm-NEU-NOS-Stahlrahmen-/200820594993?pt=Sport_Radsport_Fahrradteile&hash=item2ec1d71931

BTW The frame you lost was nice for sentimental reasons, but it was only a Zullo fork anyway.

Frame was unidentified right?

Same seller had this one.

Certainly set my tail wagging!

__________________


Bikes and stuff

https://www.flickr.com/photos/36270004@N06/

Last edited by gomango; 09-22-12 at 07:37 PM.
gomango is offline  
Old 10-03-12, 08:29 AM
  #15  
Branimir
Merckx wannabe
Thread Starter
 
Branimir's Avatar
 
Join Date: May 2007
Location: Zagreb, Croatia
Posts: 254

Bikes: Rampon EL/OS 5700 groupset

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Sorry for bumping this topic back to life, but!

Local experienced repair guy/cycling champ straightened the frame, and since the fork was not repairable - he gave me a Colnago fork! Well not gave, but sold. Total repair+fork=53$



Wooohoo!
Branimir is offline  
Old 10-03-12, 12:26 PM
  #16  
miamijim
Senior Member
 
miamijim's Avatar
 
Join Date: Aug 2003
Location: Tampa, Florida
Posts: 13,923
Mentioned: 37 Post(s)
Tagged: 0 Thread(s)
Quoted: 323 Post(s)
Likes: 0
Liked 4 Times in 4 Posts
Originally Posted by Andrew R Stewart View Post
Not sure about trusting the charts for any one bike. I know of many small but real differences from claimed specs to the actual ones. Also if a tube has a ripple in it after an impact then the length on that part of the tube has changed. Unless you're saying that the tube stretched so the ripple could exist and the angle not change. Not likely, espically with the ripple on the underside of a tube is in the compression zone. I don't know of a typical head end impact that has a force acting on the frame which after compressing the fork rearwards then pulls it back out past the original point (remember springback). So my take is that if there's a ripple there's an angle change.

Now how much and how important (to the bike's handling0 is an angle change is a different story.
I'm not sure how many frames you've straightened but I have a few 2-300 under my belt. Very simply the answer is yes, a ripple can still exist once a frame is straightened to its original angles.

The frameset I referenced to was within +/- 1/2 degree of the catalog spec without it being straightened. I'm sure that was within the original early 90's tolerance range.

Last edited by miamijim; 10-03-12 at 12:34 PM.
miamijim is offline  
Old 10-03-12, 12:33 PM
  #17  
fietsbob 
coprolite
 
fietsbob's Avatar
 
Join Date: Jun 2010
Location: NW,Oregon Coast
Posts: 41,928

Bikes: 8

Mentioned: 188 Post(s)
Tagged: 0 Thread(s)
Quoted: 6833 Post(s)
Likes: 0
Liked 213 Times in 178 Posts
Lugged frames do allow for frame builders to replace bent tubes
with straight new tubes.
fietsbob is offline  
Old 10-03-12, 04:31 PM
  #18  
Andrew R Stewart 
Senior Member
 
Andrew R Stewart's Avatar
 
Join Date: Feb 2012
Location: Rochester, NY
Posts: 11,654

Bikes: Stewart S&S coupled sport tourer, Stewart Sunday light, Stewart Commuting, Stewart Touring, Co Motion Tandem, Stewart 3-Spd, Stewart Track, Fuji Finest, Raleigh Pro, Trek Cycle Cross, Mongoose tomac ATB, GT Bravado ATB, JCP Folder

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1730 Post(s)
Liked 45 Times in 32 Posts
Originally Posted by miamijim View Post
I'm not sure how many frames you've straightened but I have a few 2-300 under my belt. Very simply the answer is yes, a ripple can still exist once a frame is straightened to its original angles.

The frameset I referenced to was within +/- 1/2 degree of the catalog spec without it being straightened. I'm sure that was within the original early 90's tolerance range.
Of course there will still be a ripple remaining after rebending the frame. The area that distorted (the ripple) has work hardened. It will not bend as quickly as another area near by that hasn't been as cold worked. I never said that the ripple would need to go away for a frame repair. I was trying to say that the tube has changed it's length in a way that won't be restored by simple rebending. Aligning won't remove the missalignment, just add another to try to compensate for the first. Now the more skillful the repair person the less the extra stress that's added and the closer to a workable new geometry that results. I do agree that there is a workable range of head angle tolerance for a given fork geometry (to have a handling goal achieved).

One of my concerns with "lay people" doing this kind of repair is that they don't fully understand the factors involved and when "good enough" is achieved. Sometimes bending over and over again adding insult to injury. These same people often will neglect to monitor the frame/fork over the future. While steel is a wonderfully resilient material it will fail over time and if not looked for, the failure will happen when one doesn't expect it.

BYW I do know what I speak of. I've been doing this stuff since the mid 1970s. Learned from a number of very experienced guys along the way as well as my frame building work. I haven't bothered to count the repair jobs and have learned that more often then not they're not worth doing. But there are always the exception and these I consider. Andy.
Andrew R Stewart is offline  
Old 10-03-12, 04:36 PM
  #19  
Branimir
Merckx wannabe
Thread Starter
 
Branimir's Avatar
 
Join Date: May 2007
Location: Zagreb, Croatia
Posts: 254

Bikes: Rampon EL/OS 5700 groupset

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
On the topic, the top tube does not show signs of a ripple, though on the downtube, there is an evidence of ripple, but on a different place than before. I don't know how exactly did the repair guy did it, but the geometry is now correct. Well, at least, I trust him, his experience and skills.
Branimir is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
bicyclebill1
Recumbent
1
08-02-12 08:43 PM
seanharan
Singlespeed & Fixed Gear
6
08-27-11 01:41 AM
gremlin76
General Cycling Discussion
0
04-26-10 08:42 PM
Poppaspoke
Foo
10
03-05-07 01:55 PM
ranger5oh
General Cycling Discussion
3
07-15-06 09:27 AM

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.