Questions tagged [framebuilding]

Building the frame of a bicycle, starting with just a pile of tubes.

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19 votes
4 answers
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Why did curved forks disappear?

Forks on historical bikes are often curved forward in a smooth curve, sometimes called a "French bend". This is sometimes claimed to add a small amount of compliance and comfort. It ...
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2 votes
2 answers
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What are these parts of the frame called?

Intro I am drafting a question about a frame problem, but I'm struggling with terminology. It seems "appropriate for stack-exchange" to start by asking about the terminology first. Main ...
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1 vote
2 answers
321 views

Do recumbent bicycles cause knee pain?

I've been thinking about the way the body is positioned on a recumbent bicycle and it seems like knee pain might result. Even if you use a low gearing I think the force direction will always be in a ...
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2 votes
2 answers
164 views

Are worse QC'ed carbon frames chosen for pairing with lower tier components? Does it matter?

I am wondering if in carbon (or any other material, for that matter) manufacturers explicitly choose the better crafted frames to pair with higher tier components. By better crafted I mean of all ...
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  • 387
2 votes
2 answers
212 views

What are the advantages of having a road bicycle frame with lower tyre clearance?

Say, I won't ever put tyres above 28mm and the frame allows upto 30mm vs a frame that has an allowance of upto 35mm. So, what are the advantages with a frame with lower tyre clearance or the ...
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0 votes
1 answer
103 views

How to adjust when i am 5'5 foot tall and having a 42 cm roadbike frame?

Im planning to buy a roadbike frameset in my local store but they say that the size of the frame is 42cm and i am 5'5 should i buy that frame?
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9 votes
2 answers
798 views

Standard forces on a bike frame

Let's say I was going to design a bike frame for a specific size of individual. I'd start with some basic frame geometries, then I assume I'd calculate the necessary member sizes, stiffnesses, etc. by ...
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2 votes
1 answer
388 views

Why are bicycle tubing diameters often metric approximations of imperial measurements?

This is related to my previous question about seatposts and handlebars, but I’d like to generalize the question this time. The majority of bicycle tubes are metric equivalents of imperial sizes. The ...
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6 votes
7 answers
712 views

Spring frame in place of shocks?

Could a bike frame be springy like an athletes prosthetic spring leg instead of rigid? The frame would look like a bow, of a bow and arrow, open end ending at the tires. What problems may arise that I ...
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0 votes
0 answers
204 views

Identify bike maker from frame number (DAXXXX)

I have a vintage lopro bike and would like to identify the frame maker, the serial stamped on bottom bracket starts with "DA" and is then 4 numeric digits, I was told it may have been used ...
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-2 votes
1 answer
94 views

Santa Cruz but idk which model and year, please!

Hey can someone please tell me the model and year of this Santa Cruz frame I just bought... thanks!
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3 votes
1 answer
111 views

my first frame jig - a customized one - which addons and features to add?

i am currently workin on the Bicycle-Frame-Building-Jig that is designed by tanner W at Instructables https://www.instructables.com/id/Bicycle-Frame-Building-Jig/ which bottom bracket assemblies ...
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  • 143
10 votes
1 answer
3k views

How does brazing and welding not ruin the heat treat on steel tubes?

How does brazing and welding not ruin the heat treat on steel tubes? With such high temperatures, wouldn't the heat treat be ruined? Edit: Specifically in this video ...
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  • 379
2 votes
1 answer
273 views

Dent on aluminium frame?

I have a Cube Stereo 120 2018. When I was driving today a car hit me. I'm fine but the bike has a dent in it made by the car door. Can it be fixed? Can I still ride it, and go MTB? Can I make a sort ...
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1 vote
3 answers
2k views

How can I connect two pieces of square aluminum tubing together to make a bike trailer using n55 docs?

Me and a friend are trying to build a trailer using principles found here ... http://www.n55.dk/MANUALS/SPACEFRAMEVEHICLES/DIY.pdf They are using 25 mm aluminum square tubing with a 2mm thickness ...
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  • 151
2 votes
0 answers
85 views

Any shared workspace in the DC Metro area where I can build/weld bike frames?

Anyone in the DC metro area know of a community workspace that I could join to learn to build bike frames? I'm not looking for any equipment or lessons, just a space where I can work. I've been ...
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3 votes
2 answers
281 views

How is chainstay length defined for frames with horizontal dropouts?

Just reading our own definition of Chainstay Length in the terminology index. It is written currently as the distance between the centre of the chainring and the centre of the rear cog. This is ...
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-5 votes
1 answer
257 views

How to get or build Superman Swimming bicycle? [closed]

Human body front area depending on pose in case it will be possible to ride in horizontal position drag must be way smaller as front area will be at least 5x smaller. Pardo face down HPV design. ...
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  • 276
11 votes
1 answer
3k views

How to attach cable mounting points to a bicycle frame?

I have a frame-building project that is near completion: An old 90ies steel MTB frame was cut, and converted into a frame for a cargo bike. In my enthusiasm, I have overlooked one detail: The ...
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5 votes
4 answers
2k views

Is it possible to rebuild a a steel bike frame (to make it lighter) by welding aluminum tubes

I have an old (80's I guess) road bike, it is heavy, I'd like to make lighter. is it posible to cut and replace the tubes on the frame by welding aluminum ones?
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3 votes
2 answers
241 views

Why aren't vertical dropouts truly vertical?

Making some custom rear dropouts (vertical) for a project (nonstandard bike, they must be custom) and as I look to dropout examples, I notice that "vertical" dropouts never seem to have the slots ...
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1 vote
1 answer
216 views

Is there a non-proprietary standard for oval seat-tube/post?

I see Pinarello Dogma and Gan S frames have a proprietary seatpost/seattube combination, which don't have a circular section. An advantage of that design in my opinion is that it's impossible to have ...
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3 votes
1 answer
448 views

How to evaluate different alloy types used for bicycle frames?

Only certain alloys are used for bicycle frames besides other materials like carbon fibres (at least for the mass market). I often stumble over aluminium alloy 6061 and 7005 (and I think I saw 8004 ...
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5 votes
2 answers
559 views

tall bike build

Hi everyone just a silly question. I have built a tall bike which is a wee project at the moment. I live in a hilly area in Scotland and having gone down a hill at 25 mpg (40 km/h) on the beast. I ...
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12 votes
2 answers
2k views

Feasibility of bike frame design by a layperson

I'm sure for many bike builders, their ultimate dream bike starts with a frame that they designed themselves. And herein lies the problem: it seems that modern means of frame production (e.g., ...
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1 vote
1 answer
477 views

Chain contact on rear triangle

Hi can anyone help with some advice. I have built up a 2007 specialized big hit 2 and fitted it with a 32t narrow wide chain ring as that is what I've been used to riding. It rides great it handles ...
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  • 113
7 votes
2 answers
4k views

Why almost every custom framebuilder builds steel bikes, but not many work with aluminum?

I know it's easier and cheaper to work with steel, but is it THAT MUCH easier and cheaper?
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2 votes
1 answer
452 views

Crankset fitting issues

May sound like a dumb question bit here goes. Is it possible to run a 68/83 hollowtech crankset on a frame designed for 68/73? I can see the crankset fitting without issue as the crank axle is the ...
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  • 113
7 votes
2 answers
3k views

Can I fit a modern internally geared hub on an old bike ?

I have an old Hercules frame that I have no use for but don't want to get rid of - I am in need of a new "town" bike for running around on, however I need something practical with a nice gear range... ...
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2 votes
2 answers
260 views

Seat stay width issues

Hi I currently ride a decent spec 2003 mongoose full suspension but I find that the seat stay is slightly too narrow to run my maxxis high roller 2 2.3 tyre without it rubbing on the frame. In theory ...
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4 votes
1 answer
6k views

What are the differences between Columbus Tubings?

I'm just wondering why there are seven kinds of tube sets by Columbus (or Reynolds). There's XCr, Spirit, Life, Zona, Max, SL, and Cromor. I recently had a frame made using the Cromor tubeset; mainly ...
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  • 787
2 votes
1 answer
431 views

Fork trail vs chainstay length in steering

Is fork trail or chainstay length is a bigger determinant in the overall steering of the bike? Consider an arbitrary frame that I think is steers too slowly. I'm going to rebuild it because I want a ...
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6 votes
2 answers
1k views

Lugged carbon frame repair

In broad terms, I'm wondering if it is possible to repair a high quality lugged carbon frame, say a Colnago C60, that has been cracked in the top and/or down-tube. Normally once a carbon frame has a ...
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  • 5,326
0 votes
2 answers
990 views

What are the advantages of having a aluminium frame? [duplicate]

are there any advantages that an aluminium body brings to the tables over carbon frames?
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1 vote
1 answer
153 views

DIY Bamboo bike? [duplicate]

I am wondering whether or not I can build my own bike. I was thinking of buying some steel lugs or maybe carbon ones or whatever off the internet, and a steerer tube too, and was hoping I could ...
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  • 573
5 votes
1 answer
444 views

How is a frame designed for an easy step-thru?

My question is very specific towards bikes which have a curved top-tube. How is it decided that a particular height of the top tube above the ground for a set of people in a certain height range is ...
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8 votes
2 answers
638 views

3D printing frames?

Are there any technical limitations that make 3D printing frames impractical? And, if it is just a matter of time before our technology is able to overcome any limitations (like manufacturing ...
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  • 5,326
2 votes
1 answer
2k views

Can a bike frame be retrofitted with internal cable routing without Disassembly?

Would I be able to have a local framebuilder retrofit an existing steel mountain bike frame to install internally routed cable guides on the top tube without disassembling the frame? I would probably ...
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4 votes
4 answers
33k views

How to repaint a Carbon bike frame?

I have recently purchased a Specialized Roubaix SL4 Elite Disc carbon frame bicycle - But I am not particularly happy with the colour. It is charcoal and white. I like to have a brighter colour. Is ...
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6 votes
1 answer
9k views

Just found a vintage Sears & Roebuck 'Ted Williams' Free Spirit 3 wheeler. Can I modernize it?

It's been in my girlfriends back yard for years and I'm under the impression that it's a pretty uncommon bike because I can't find any information on it. Her stepfather spray painted a camo pattern on ...
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4 votes
4 answers
1k views

What are the advantages of a custom frame for a touring bike?

I'm building a new bike for touring while traveling, so I want a break-apart frame with S&S couplers, like the Salsa Vaya Travel, or another steel touring frame retro fit with couplers. I want a ...
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3 votes
1 answer
2k views

building a cargo trike (bakfiets): steel thickness

I'd like to build a "bakfiets"; a cargo-trike with the box in front. I've found several resources, but none of them talk about the framebuilding material. What is are my material options; steel? what ...
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  • 33
1 vote
2 answers
3k views

top tube angle on steel and carbon road bikes

You generally see the top tube on steel bikes being parallel to the ground, whereas on a lot of carbon bikes it's angled. Why is that? (my observations are obviously limited, but it seems like a ...
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  • 89
7 votes
3 answers
17k views

MIG Welds vs Brazing for simple bike hacks

Given that frames are generally brazed, not welded and given that MIG welding will work on simple bike hacks what are the downsides of MIG welding these hacks? For example, I would like to make a ...
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  • 293
13 votes
4 answers
19k views

Why offset the rear rim to the hub and not the hub in the frame?

I'm currently reading The Bicycle Wheel by Jobst Brandt, and I'm reading all of the issues with offsetting the rear rim toward the drive side of the hub... Asymmetry in a rear wheel built for a ...
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  • 3,833
4 votes
1 answer
5k views

What would be the "definitive" formula to calculate chainstay length from sprocket size, chainring size and number of chain links?

Before I started to write this answer, I thoroughly read this question, its answers and comments: How do I calculate the diameter of a chainring from the number of teeth? So, my question tries to ...
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  • 18.6k
4 votes
5 answers
1k views

Where can I buy lugs for a classic roadster frame geometry?

The title says it all. I want to build my own frame and need lugs that will fit the roadster (e.g. Raleigh Tourist) geometry.
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  • 143
3 votes
3 answers
1k views

Bottom bracket for framebuilding

This question has got me hugely excited about building a bamboo bike. I've found some instructions and tips here and here. I plan to find/buy an old bike to use as a donor. I think I'll use the head ...
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12 votes
3 answers
36k views

How do I calculate the diameter of a chainring from the number of teeth?

Simply knowing the number of teeth on a chainring can we determine an accurate diameter?
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  • 599
5 votes
1 answer
796 views

What tools are required to begin building a frame?

What tools are required to begin building a frame? Are there DIY substitutes for any of them? Are there things that aren't requirements, but simplify the process enough to be worth the cost? Aside ...
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