bicycle geometry database
 

okay so tell me if this is a stupid idea or not. I was thinking of starting an online bicycle geometry database in which people can add frame geometry of their production bicycles and it could be searched. It would be a wiki of sorts. Since many manufacturers do not give out full specs on their bicycles this could fill the gap. This could also show bicycle geometry of older bicycles as well. The site will include instructions on how to make the measurements. The website will also be able to switch between in and cm measurements.

Sorry, most manufacturers do give full specs on their websites.

I think one aspect of geometry that is really important that most companies totally ingnore is allowable tire clearances (w/ and w/o fenders). That gets asked a lot on bikeforums.

You would need to use a real database type setup, wiki is crap for databases.

not really (see above) and its nice to have it all avaible on one pages, especially for cross-comapny comparisons.

I believe this would be a good idea. Some manufacturers will only list the specs of the newer model years on their sites, finding geometry for older models can be a challenge. (Giant is one Manufacturer that comes to mind.) This could be a good resource when buying a used bike off of Ebay or Criag's list.

One other thought would be to include parts information about the bike (brakes, seats, seatposts, Front/Rear Derailleurs, Wheels, etc.) for each particular model year.

Oh yeah, and list braze-ons, bosses, eyelets, etc. The important stuff.

It would be cool to go beyond that site and have the specs for as many sizes as possible. Ken's page is great for seeing which models have which tendencies (sorting by chainstay length is particularly telling, as it puts race bikes at one end and touring bikes at the other), but it's not as good for shopping around for frames that would fit a person's particular size.

Go over to slowtwitch and read their tech articles on fitting and frame design. Without stack and reach measurements, don't see value in this project.

I think this site is exactly what the OP was asking for. It will have more sizes if more people contribute measurements. This project was designed and is maintained by David Mann.

If he wants more sizes, he'll have to change the wording on the page -- it's still asking for around 56-58 cm as the manufacturer's published "size".

But, picture this, though -- input a range for the effective top tube length, a range for the chainstay, and a range for seat tube angle, and it'll spit out the frames & models that fit within those parameters.

I think that's the goal that the OP is looking for.

I meant that it would be a wiki in the sense that it could be added to by anyone. An open database.
you pretty much hit the nail on the head.
your such a killjoy.

That is pretty important and would be a good addition. Maybe someone could just take the bike geometry project and make a searchable database as a spinoff that includes more information.

Ok, good...

What would make it really useful would be loads of data from older frames, especially those that are no longer published on manufacturers' websites. That would take a lot of the guesswork out of choosing whether to buy a particular used bike.

I was thinking of the domain bicycleprofile.com. How does this sound to you guys? Who can code a database? I would also like the ability to add pictures of the bicycles. I would like the database to include as many diamond frame bicycles as possible.

Why not ask Pinnah, the owner of the Bicycle Geometry Project, about doing this as an extension to his, or at least permitting his Excel file to be used as a data core and starting point? He's on BikeForums. His list of frames is Excel, but I think it could be ported to SQL, then expanded into what the OP and some of the rest here might like to see.

BTW, Ken on the Project site only contributed some of his frame data and the frame measuring essay. I think he's planning an update using digital levels.

Road Fan

With this kind of detail the frame characterization becomes close to what a custom framebuilder might need. Could there be some software over at the Framebuilder Forum that is useful as a hosting environment?

<-- doesn't know jack squat about coding, database creation, web page creation, Wiki-type searching, etc. Just thinking like an end user; in other words, it should be easy enough for a doofus like me. :D

Did you read any of those articles? Without stack and reach it doesn't help much, there are simply too many variables when all that matters are:

1. height of saddle above bb
2. horizontal offset of saddle to bb
3. reach to handlebars
4. vertical offset to handlebars

You can have all sorts of variety of seat tube angles, top tube lengths,
etc and yet have all 4 of those the same.

Right, but then again, using a ridiculously long or short stem, or a whole lot of saddle setback, or both, changes the characteristics of the bike so that it no longer behaves as the manufacturer intended.

There are two things you care about with a frame -- fit and handling. Since your body only touches the bike in three spots -- hands, feet and seat -- fit is entirely determined by the shape of the triangle between saddle, handlebars, and bottom bracket. So you're kind of right.

But handling is determined by everything else. That's why bikes come in so many shapes and sizes.

What I would like to see is a database where I put in the dimensions I want and it gives me examples. Even better would be one where I tell it my fit dimensions and my desired handling and it gives me suggestions.

Okay now say a person has a completely original Raleigh with all original parts. If all the components are original they could also be included in the bicycles profile such as crank length, brake type, deraillers etc. What do you guys think of that? Would it be of any value? Should we just stick with frames? I think it would be great to include as much info as possible on every bike model. The extra info cant hurt can it?

This may help, If you have not already seen it

http://www.bikepedia.com/QuickBike/Default.aspx

Pretty cool; it's got everything but geometries, but that's a huge resource.

I agree, it needs geometries and pictures. It could also use bicycles before 1993.

Hiyo, I think you're right for the full breadth of utility that Toto has in mind, a very full set of frame numbers is needed. But that poses a problem, of whether that info is available, or does it have to be measured? What should the site owner do with partial data submissions?

I would say design the site to handle the full breadth, including the items you asked for, but accept all the inputs you get, regardless of completeness. Hope that they'll become "finished" somehow later on.

Road Fan