Lengthening A Steerer Tube
06-20-20, 03:09 PM
#51
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06-20-20, 03:16 PM
#52
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Amazing you were not hurt.
This should probably be a sticky.
John
This should probably be a sticky.
John
06-20-20, 05:44 PM
#53
Banned
well I assume Now you bought a new fork.. maybe a steel one..
alternatives in retrospect (Horse ran out of the barn long ago)
use a carbon composite dowel & since it looks externally flared at the bottom
add more thickness around the joint by wrapping, adding a couple layers of carbon cloth soaked in more epoxy..
will be heavier negating some of what you bought a carbon fork for...
...
alternatives in retrospect (Horse ran out of the barn long ago)
use a carbon composite dowel & since it looks externally flared at the bottom
add more thickness around the joint by wrapping, adding a couple layers of carbon cloth soaked in more epoxy..
will be heavier negating some of what you bought a carbon fork for...
...
Last edited by fietsbob; 06-20-20 at 07:47 PM.
06-20-20, 05:56 PM
#54
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Kudos and thanks for the update, some would not have been so forthcoming. Glad you weren't hurt but also happy this idea has been put to rest. 
06-20-20, 06:55 PM
#55
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Nuts!
This entire discussion seems nuts to me. How could anybody recommend that anyone ride a bike with this kind of kludge? It could work, but the consequences of it not working would be disastrous. The preload on the headset bearing is actually pulling the seam of the spliced steerer tube apart - pin it at least? Or a long bolt or threaded rod running all the way through the fork crown to a nut and washer?
I don't know, this is the kind of repair you might have to do to limp home, like stuffing grass in your tire after a blow out, not something you do when you are home.
I don't know, this is the kind of repair you might have to do to limp home, like stuffing grass in your tire after a blow out, not something you do when you are home.
06-20-20, 07:50 PM
#56
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This entire discussion seems nuts to me. How could anybody recommend that anyone ride a bike with this kind of kludge? It could work, but the consequences of it not working would be disastrous. The preload on the headset bearing is actually pulling the seam of the spliced steerer tube apart - pin it at least? Or a long bolt or threaded rod running all the way through the fork crown to a nut and washer?
I don't know, this is the kind of repair you might have to do to limp home, like stuffing grass in your tire after a blow out, not something you do when you are home.
I don't know, this is the kind of repair you might have to do to limp home, like stuffing grass in your tire after a blow out, not something you do when you are home.
06-20-20, 11:52 PM
#57
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06-21-20, 02:44 AM
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Actually, bamboo might have been an interesting choice of material.
John
John
06-21-20, 08:43 AM
#60
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I still think you had options.
However, you say the eBay fork didn't fit? I've seen just about every standard represented there, tapered, straight, 1", 1.125", it's all there in pretty common rakes. Usually right around $100.
Be weary of the ones that have a built in crown race, I had endless problems with that style.
I still think using aluminum and set pins would have worked.
However, you say the eBay fork didn't fit? I've seen just about every standard represented there, tapered, straight, 1", 1.125", it's all there in pretty common rakes. Usually right around $100.
Be weary of the ones that have a built in crown race, I had endless problems with that style.
I still think using aluminum and set pins would have worked.
06-21-20, 09:41 AM
#61
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Thread Starter
Wow holy ****, you ok bro?
I was just scrolling through looking for the reply section and I saw your post.
The fracture was expected, the fork endures a lot of shock on the road from pot-holes, curbs, etc...
Glad you walked away from that, you might want to add a reference to your first post about the accident for future readers.
Kret
I was just scrolling through looking for the reply section and I saw your post.
The fracture was expected, the fork endures a lot of shock on the road from pot-holes, curbs, etc...
Glad you walked away from that, you might want to add a reference to your first post about the accident for future readers.
Kret
I have taken your suggestion and edited my reply with a reference to my original post.
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06-21-20, 09:51 AM
#62
Banned
I extended the fork om my Koga Trekking bike's fork, but, it's steerer tube was steel.. I used a stem raiser. It had a stem on it already, ..
(& 3 CM thick spacers)
so the stem was relocated on top of the added stem raiser part. , and I lengthened the brake lines..
..
You said in # 1 post " I now had the desired length of steerer tube, and one I could count on not to fail.)
that statement, since it did fail, I'd say needs amending? no?
..
(& 3 CM thick spacers)
so the stem was relocated on top of the added stem raiser part. , and I lengthened the brake lines..
..
You said in # 1 post " I now had the desired length of steerer tube, and one I could count on not to fail.)
that statement, since it did fail, I'd say needs amending? no?
..
Last edited by fietsbob; 06-21-20 at 09:57 AM.
06-21-20, 09:53 AM
#63
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Almost to the top of the Darwin list....
06-21-20, 12:08 PM
#64
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Thanks for posting the results. I think we all learned an important lesson here: Use Oak next time.
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06-22-20, 07:17 AM
#66
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I still think you had options.
However, you say the eBay fork didn't fit? I've seen just about every standard represented there, tapered, straight, 1", 1.125", it's all there in pretty common rakes. Usually right around $100.
Be weary of the ones that have a built in crown race, I had endless problems with that style.
I still think using aluminum and set pins would have worked.
However, you say the eBay fork didn't fit? I've seen just about every standard represented there, tapered, straight, 1", 1.125", it's all there in pretty common rakes. Usually right around $100.
Be weary of the ones that have a built in crown race, I had endless problems with that style.
I still think using aluminum and set pins would have worked.
06-22-20, 07:53 AM
#67
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IMPRESSIVE! If you would have used Epay dowl……. Nah! Impervious to humidity and one of the hardest, longest lasting hardwoods. Heavy because of the density.
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06-22-20, 09:27 AM
#68
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There was a morality play here.
OP: "I screwed up and I'm going to try a really off-beat, questionable repair approach in a critical, safety-related part of a vehicle that I ride at significant velocity"
Crowd": "Don't do it! It's dangerous! It will break and you'll get hurt!"
OP: "Well I tried it. It broke and and I got hurt."
Bikes are mechanically pretty simple. But they do need to be strong and relatively stiff. To do that super alloys (titanium, maraging stainless steels) are often used. Aerospace-strength materials like CF are also often used. It seems that there are a lot of people (the OP is not the only one) who lack understanding and respect for the several hundred years of material science that got us to 953 or CF.
The fork cutoff was so short it was almost cutting into the flared section of the fork. The OP bought a dowel. The dowels at Lowes are gonna be pine or poplar - not the strongest or stiffest of woods. Even if you had very strong wood (hickory, ash, white oak, rock maple, yellow birch, none of which are probably available as dowels at Home Depot), to make anything that would work you'd have to have a a taper in the piece of wood to avoid it wiggling around in that tapered section. And it might not be able to fit into the fork from the bottom. But even if you had a tapered wood piece, the wood would be of smaller (less strong, less stiff) diameter than the original CF. The cut in the CF makes a stress riser. The break was in a high-stress area of the fork (midway between the bearings would have a maximum bending moment). For this reason I don't think any insert approach could work. If the insert did hold together, the ends of the CF fork tubes would fray and break. There's just so many things wrong with the approach. There is no way at all to make that cut fork work. Given how short it was cut (what was the objective here? Wow that's short!) the fork was, is, and always will be toast.
Knowledge of which you have acquired, if painfully. Buy a new fork. Go over the youtube videos on measurement and size. Measure twice. Cut once. Assemble. Good luck and good riding!
OP: "I screwed up and I'm going to try a really off-beat, questionable repair approach in a critical, safety-related part of a vehicle that I ride at significant velocity"
Crowd": "Don't do it! It's dangerous! It will break and you'll get hurt!"
OP: "Well I tried it. It broke and and I got hurt."
Bikes are mechanically pretty simple. But they do need to be strong and relatively stiff. To do that super alloys (titanium, maraging stainless steels) are often used. Aerospace-strength materials like CF are also often used. It seems that there are a lot of people (the OP is not the only one) who lack understanding and respect for the several hundred years of material science that got us to 953 or CF.
The fork cutoff was so short it was almost cutting into the flared section of the fork. The OP bought a dowel. The dowels at Lowes are gonna be pine or poplar - not the strongest or stiffest of woods. Even if you had very strong wood (hickory, ash, white oak, rock maple, yellow birch, none of which are probably available as dowels at Home Depot), to make anything that would work you'd have to have a a taper in the piece of wood to avoid it wiggling around in that tapered section. And it might not be able to fit into the fork from the bottom. But even if you had a tapered wood piece, the wood would be of smaller (less strong, less stiff) diameter than the original CF. The cut in the CF makes a stress riser. The break was in a high-stress area of the fork (midway between the bearings would have a maximum bending moment). For this reason I don't think any insert approach could work. If the insert did hold together, the ends of the CF fork tubes would fray and break. There's just so many things wrong with the approach. There is no way at all to make that cut fork work. Given how short it was cut (what was the objective here? Wow that's short!) the fork was, is, and always will be toast.
Knowledge of which you have acquired, if painfully. Buy a new fork. Go over the youtube videos on measurement and size. Measure twice. Cut once. Assemble. Good luck and good riding!
06-22-20, 12:00 PM
#69
Banned
FWIW Dragon plate is a source of carbon fiber materials https://dragonplate.com/..
