Is 32 pounds ok for a fixed gear bike?
 

Hello I am new to this forum and I wanted to ask if I should replace the frame and fork of my fixed gear with a fairly light high quality steel or aluminium frame set. I used to own a fixed gear bike almost twice as light as the one i currently own I was amazed at how with little effort i can go very fast and with the current bike i struggle to go at a fast speed.

That's pretty heavy. A decent steel or aluminum frame could very easily and fairly inexpensively be built into a bike weighing in the low 20s. Up the budget by a couple hundred dollars more, and you can get under 20 pounds without too much difficulty. I'm not really a fixie aficionado, but here's an example of a well executed fixie for not much money - and just eyeballing it, I'd be surprised if it was much above 20 pounds:

MASI Speciale Fixed with reversible hub

32 pounds !?!?!?!
Solid steel tubes ?
:wtf:

Not that unbelievable. I've seen fixies/SS built on old Schwinn frames from the 1980s. The 1980 Schwinn Varsity weighed 37 pounds and the Continental weighed 35. With the weight savings from changing the drive train to single speed, I can see a bike of this vintage still weighing in over 30#. Some of the old cruisers were even heavier.

Yes

My current fixed gear is 18.6 lbs. So to me, no, 32 lbs is not OK, for any bike. I could still go a bit lighter but it is coming close to being as light as it will be.

My FG weighs in the upper 20's and that's when it isn't carrying a load.

Methinks there are other factors slowing down the OPs bike that he isn't aware of or sharing.

I agree with ThermionicScott in that there are a lot of factors, in addition to weight, that affect a bike's performance. It really wouldn't pay to get a lighter frameset if the components were low-end or badly worn, the tires were heavy with a lot of rolling resistance, or issues of fit, maintenance and adjustment hadn't been addressed first.

On flat ground a lighter bike will accelerate more easily but once at speed, bike weight becomes much less of an issue in a steady state.

The OP also needs to address for what purpose he wants the bike. If you live in a relatively flat area and are looking for a comfortable commuter, cruiser, grocery-getter, then a 32# fixie/SS would be just fine. If you plan on doing a lot of climbing or want a quick and agile bike for dodging city traffic or winning Strava segments, then the answer is "no".

Of course a 32 pound fixed gear bike is OK, but it may not be what you want.

Before going whole hog and replacing the frame and fork, I would suggest looking for low hanging fruit on that bike. Part of that 32 pounds may be big heavy tires and those will slow you down in addition to adding weight. Maybe you have a heavy comfort saddle. Look at how your position is set up because that makes a big difference in speed.

The single speed I ride is just over 40# with the rear rack and goodies I carry, along with two water bottles. It's a Dawes with the 4130 tubing....

To the OP, when you're climbing slow up a big hill, speed for a fixed power output is inversely proportional to mass and the grade of the hill. The difference between a 30lb bike and a 20lb bike is 10 lbs, so 6% of total weight if you weigh a slight 150 lbs.


You'll go 6% slower up a big hill. If that's ok is up to you. Oh, and no, you don't get it back coming down (a little, but not much).


Now, when you're cruising on flats, you ride at the speed where your power output is equal to resistive power loss. Air resistance and rolling resistance are the main two. Air resistance has nothing to do with weight, and weight has a miniscule impact on rolling resistance, even more miniscule once you optimize tire pressure for your weight.


In other words, on flats, it makes no difference to top cruising speed.


Of course accelerating is more difficult, again, by about 6%.


I tend to agree, it's not the weight. Bearings, maybe? Brakes dragging? Legs?

... oh and yes, rotational weight matters extra, but only for acceleration, still not for flat cruising and for hills it only matters the same as any other weight. In fact on small hills and bumps rotational weight actually helps you carry more speed over them (cancelled by small dips though I'm afraid.. like a toy friction car with a fly wheel, rotational weight likes to keep you moving the same speed). So 6% still on hills, maybe a bit more than 6% effect in acceleration.

Post a photo of your bike and we might be able to point out some of the heavier components.

32lbs sounds heavy, but little things can add up quickly.

Does not bother me it's Your choice, Your Bike .. Add a Heavy Lock to Keep it Yours..

My Rohloff trekking bike is 45 pounds but it has 13 more speeds than a Fixie.

and brakes mudguards racks and a lot more..


I go pretty fast downhill, but then I apply my Brakes to keep my speed reasonable . :rolleyes:

I have removed the wheels and the weight difference was not that big, the tubing especially on the rear end is all solid steel till the mid section of the frame I am thinking of purchasing a aluminium Aventon frameset and later a pair of lightweight wheels replacing the 40/50mm deep v rims i currently use.

Aventon isn't a bad frame at all. It would be drastically lighter. You could probably buy their $400 Cordoba complete bike and shed 10-11lbs right off the bat.

Why, in 2016, would anyone willingly ride a 32 pound bike?

Well I was stupid enough to buy a 30+ pound $300 bike when i could have bought a high quality bike for less

Maybe because they don't race, or pretend to.
Maybe because they want lights, fenders, racks, durability.

I'm a bit surprised to hear that. A lot of the inexpensive single speed/fixed gear bikes have deep cross section rims that are really heavy. Have you compared the weight of the wheel(s) with higher quality ones? The difference should be quite noticeable, plus you feel the effects of lighter wheels more than swapping to a lighter frame.

My workhorse fix gear is around 28 pounds with the U-lock on which is almost always. (Also fenders, LowRider, frame pump and tool bag.) It is not the bike my 20 pound good fix gear is, but iti s still a good ride. If I swap wheels, the riders get a lot closer. Good bike has Revolution gauge spoke, the workhorse Competiton, good - Open Pro in front, workhorse - Mavic Sport, good - Vittoria Open Paves or equiv., workhorse Pasela 28c.

Ben

As I said above, only in acceleration. You feel neither on top speed and you only feel it equally compared to frame weight on hills, not more. This factor maybe tends to get overstated slightly.