Building a 12 pound fixed speed bike. Possible?
 

Pardon my intrusion into your illustrious forum! I am contemplating to add a fixed bike to my stable and I think a light one I can ride fast would do the trick.

I like to build bikes and thought a 12 pound fixed speed bike would be a nice project. I already have a 17 pound CAAD12 so I want this one to be extra light.

I figure 4 pounds for the frameset, 4 pounds for the wheelset and tires and 4 pounds for the saddle,post,bars, stem etc is doable.

But when I look at the bikes on offer (i.e. Kilo TT) they are all close to 20 pounds which seems odd as my CAAD only cost $1300 and has a full 5800 groupset on it. That groupset weights 5.5 pounds and if you subtract the crank and chain it would weight 3.5 pounds.

So is a 12 pound fixed speed bike doable and is it desirable (i.e. does having weight add something). I'm riding this on the road/MUPs not on a track.

Doable, yes. It’s just a matter of $. However, for your needs, it is really not necessary. Weight matters only when climbing hills and accelerating. Far more important is wind resistance, which is a function of body position, not bike weight.

True about climbing and accelerating but in my neck of the woods there are lots of twisty roads so your constantly slowing down to turn and then accelerating up to top speed.

I'm a bit puzzled by the lack of light-weight track parts. In the road bike world my CAAD12 frameset weights 1500 grams (frame and forks) and cost brand spanking new $650. But a lot of the ALU track framesets are upwards of 2000grams and cost more! Also, the lack of lightweight clincher track wheels is puzzling. I see lots of 1900 gram wheelsets by Campy and Mavic but not only 1500 gram ones.

Am I missing something or is weight not seen as that important in the track world?

Generally speaking, strength and stiffness are more important than weight in track racing. Also, the emphasis is more on aerodynamics for timed events such as the pursuit.

As far as lightweight track wheels, they are readily available at affordable prices from companies like Wabi. I own a 15 lb Wabi Lightning fixed gear, which has an aluminum frame and mostly aluminum parts, although it is a small 650c wheeled version that is lighter than a larger bike would be.

7.47lbs


https://i.imgur.com/XIw4Udo.jpg

Whats the spec on that??

Like I said, it’s just a matter of $$$. I’d sure hate to trash those Veloflex tubies on a MUP.

hey.
here is a video of a dude who built a 5.1kg fixed gear. He goes through all the specs, and talks about the race he rode it in.

I recon you can make 12lb fixie that's actually nice to ride for under $1500 with clinchers, bullhorns, and a front brake.

the link is in my post - click the 7.47lbs

cheapest route would be finding a used carbon road bike on craigslist, stripping off the drivetrain and building some light-ish wheels (all city sheriff SL and 300g kinlin rims?).

should be able to do 15lbs for maybe $1k? helluva lot cheaper than building a 15lb road bike.

I'm seriously contemplating using this rear hub and replacing the stock bolts with Ti ones on my next set of cross wheels.

Getting down to 15 lbs is not too difficult, but 12 lbs will probably at least double the cost.

Bingo. There are no hills on the track. Some riders in international competition actually have to add weight to their bikes to meet UCI regulations because track bikes just wind up being lightweight due to having far fewer parts.

But why. If I can get a 1500g CAAD 12 frameset for $650 can't I get a 1500g fixie frameset for as cheap?

I can buy 1500g campy Zondos for my road bike for $400

So that's 3000g for the main parts of the bike.
For tires/tubes add 500g
Cog/chain/crankset 1000g
Seat post and saddle 500g
Handle bars 350g

So that's 5.35 kilograms which is about 12 pounds?

Pedals, stem, front brake...? It all adds up. Do the cranks include a bottom bracket ? I suggest you make a detailed list of every single part that you need to build a complete bike. Even little stuff like bar tape and toe clips/straps weighs something.

https://www.unicycle.uk.com/media/ca.../hoppley20.jpg
http://www.ucd.ie/juggling/images/props/clown_bike.jpg

Totally possible. It was done 45 years ago with a steel frame. You can look it up. Eddy Merckx's hour record bike. (Road use on that bike, however, was not recommended.)

You have the advantage now of carbon fiber for the frame, bars and stem, crankset and wheels, allowing you to get to same weights at far less (very expensive) labor.

Ben

UCI-sanctioned races have a minimum bicycle weight of 6.8kg. And on the track, weight isn't very significant since there are no sustained climbs; you lose speed going "uphill" when you move toward the outside of the track, but this is usually a short-term thing and you gain most of your speed back when you roll back toward the inside.

But the speeds are high and aerodynamics are important, so high-end track bikes tend to burn lots of weight on aerodynamic shaping.

Very doable. Consider that there are full-featured production road bikes that weigh less than that. And no, there's no magical performance issue that crops up from a bike being "too light"; super-lightweight bikes feel great to ride, and to carry, and whatnot.

The question is just how much you're willing to spend to get the weight down.

Alibaba has sub 1500 gram Chinese carbon track frames for between $400 and $600 all day long.

LOL. That little red bike probably is made of high-ten steel and weights an easy 25 to 30 lbs. My 5 year old has a high ten bike that weighs more than the adult size bikes I have lol.

Dave

I bet some custom frame builder would love to build a super light version of that little red bike and someone who does cranks as well could probably make something pretty neat with like a splined WI fixed cog mounted to it. Plus with the tons of lightweight parts out there you could really have some fun.

Reminds me of THIS BIKE

I can only find Pinterest links to the picture, but no details anywhere of anyone doing something like it. But it looks proper fun!!

That is a cool bike I actually wouldn't mind one of those with maybe a Rohloff for a sweet whackadoo touring thing.

Haha just this week there was a dude riding one of those down a major road w/o designated bike lanes during rush hour. It was a hilarious sight. I made sure to give him additional space.