balindamood

How much does this matter, and what is generally a reasonable weight for an un-laden bike??

Bacciagalupe

Weight is not as important as people think; training and aerodynamics are far more important.

Weight only slows you down in two situations: accelerating and climbing. You won't be accelerating enough during a typical LD ride for 5 or 10 extra pounds on the bike to make a difference; even in a Cat 5 or Cat 4 criterium, it's arguable if 5 pounds would actually slow you down.

As for climbing: Let's take a 150 pound rider, generating 160 watts, climbing a 2-mile, 4% grade. On a 17 pound bike, it'll take you 13 minutes and 15 seconds (9.1mph); on a 27 pound bike, 13 minutes and 45 seconds (8.7 mph). The heavier bike will also descend a hair faster -- about 8 seconds, going down the same grade; thus the total gap is more like 20-25 seconds. Maybe you will find that significant, maybe you won't; but I doubt it's as profound an effect as you expect.

One thing to note is that a lighter bike will often handle, or just feel, snappier than a heavier bike. Part of this is due to the weight, part is also due to design considerations. Lighter bikes are usually made to suit the tastes of the "alpha" set; so the geometry, frame materials and tube designs are selected to emphasize stiffness and responsiveness. Meanwhile, "sport touring" or "randonneuring" bikes are made more for comfort and stability. This may fool you into thinking the bike is slower, but it's mostly perception and expectations.

Most bikes these days wind up in the "reasonable" range, which to me is anywhere from 17 to 25 pounds. In some instances, things that will add weight can be highly advantageous. In the long run you may benefit more from strong wheels, tough tires, a compliant frame, stable handling and extra gear than you would from selecting lighter options.

Longfemur

Makes no difference unless you're in a race to get to the end of it. You will just go a bit slower for the same effort, since you will be using different gears, and you may want to ride the bike setup more laid back for comfort. The kind of weight differences we're usually talking about are not that significant compared to your weight and the weight of your stuff. Pay a lot of money to lose a couple of pounds on the bike, or pay nothing to carry less, or to lose the couple of pounds on your body if it's that important to you.

Touring bikes, real ones, tend to give you a different riding experience anyway. They don't require the cyclist to be pumping out a lot of speed and power at all times. It seems more natural, comfortable and very stable to be riding at a slower pace.

CliftonGK1

My brevet bike is a tank.

62cm Surly Cross Check with full fenders, SON hub, front rack and bag, Brooks saddle. If it's heavy, I've probably got it on my bike. Just checked it on my bathroom scale, and it's 33 pounds without water, and the front bag is empty.

noteon 

I have some ten-pound barbells if you want them.

balindamood

Thanks for the input. I just got done putting together the summer turing bike. I never really thought much about weight as I could loose 10 pounds if it mattered that much. The bike seemed to be OK, 27 lbs with racks, but without water and gear. However, it occured to me I did not know what I should be shooting for. Saving 10 grams here, 100 grams there, though they might add up, did not seem to apply well.

bmike

a 20 lb difference in a rider putting out 125 watts over a 400km course with 3% avg grade could result in about 2.57 hours saved. (200 pound total bike + rider vs. 180 pound total bike + rider)

same weight @ same power over @ 600k = 3.85 hours

the lower the average power output, the greater percentage change one could expect, as low power + high weight = slower times.

the 400k above @ 100 watts = 3.35
the 600k above @ 100 watts = 5 hours saved

but note at 200 watts average the numbers look like this:

the 400k above @ 200 watts = 1.41 hours saved
the 600k above @ 100 watts = 2.12 hours saved


(source for the data is by playing with analytic cycling)

so yes, on a short ride weight won't make much difference, but for a long ride, with someone who can't put out much average power (or who has a power output declines as the course gets longer...) weight plays a much greater role than you allude to. you'd have to check the descents for any sort of benefit to carrying more weight up hill just so you could go down faster - but it seems like a waste.

i'm not suggesting that all rando's run out and get zero gravity bikes and gear - obviously there is a blend between durability and comfort over the long haul versus having the lightest everything... becuase if you're on the side of the road fixing things - you're speed is zero, even slower than a heavy bike that works!

and yes, training, fit, and nutrition play huge roles into overall speed - but for a non racer, non 'competitive' rando - every little bit adds up. knock 5-10 pounds off the rider, 5-10 pounds off the gear that you carry, and build a bike up with sensible components that weight reasonable amounts for the level of $$ you spend and the level of risk on the road - and it all adds up.

valygrl

I think loaded touring and long distance / randonneuring have really different answers to this question. Compared to the weight of all the other junk I'm carrying on a long tour, 5-10 pounds of bike makes little difference, but on a day ride the 15 pound difference between my roadie and my tour bike is very noticeable.

Your 27 pounds with racks is better than my 33 pounds with racks & fenders for my tour bike.

Bacciagalupe

If my calculations are correct, a 3% grade over a 248 mile course involves 39,000 feet of climbing. That's more than the Furnace Creek 408, or nearly twice the elevation of the allegedly "world's toughest double century," the Alta Alpina 8 Pass Challenge. Kind of ambitious, aren't we?

At a 1% grade (around 13,000 feet of climbing), it's 45 minute difference. With a 0% grade, it's a 10 minute loss.

So while I do agree that lighter is better for a course that involves massive amounts of climbing (and perhaps didn't emphasise that enough), it seems like you have to look at a somewhat extreme scenario in order for weight to be a big factor....

bmike

i think Jan Heine did a great job of this (better than me) in BQ Vol 5 #1.
over the course of a PBP a 5kg difference in weight could turn anywhere from a 0:46 hour difference from someone putting out 250 average watts to a 2:45 hour difference for someone putting out 70 watts.

the point of the average grade is to exaggerate the differences. while a 3% grade over those distances certainly adds up to much much climbing, the Boston 600k had 22,000 feet on it, and most of it was far steeper than 3%, coming in several long climbs (from 2 miles+ to 6 miles+) and sharp rollers, so your speed suffers even more on these stretches. Add in the time to recover (while a time trialist or racer might put out the same power on a climb and a descent...most rando's i know don't put out the same power on the descents - but sit up, eat, breathe, rest, adjust cue sheets, etc. - ). if our courses were designed on perfect and 'average' gradients we could put our heads down at one end and put out the same power for the duration and arrive on a pretty tight schedule - but sharp rollers and stiff climbs sap a higher % of speed of low powered riders than high powered riders, and weight works against the lower powered rider at a far higher percentage overall than the guy putting out a steady state of 200 watts.

again, it all adds up. small changes in numerous areas could affect the overall performance of rider, and these small changes have larger payoffs as the courses get longer...

rumrunn6

One of my bikes must be 40 lbs, but you mknoiw what? it's a comfortable ride. I'm thinking about doing a century with it. It's also a quiet well-tuned ride and that has something to do with a bike's performance I think.

Longfemur

My relatively light sport touring bike provides a snappier ride than my mid-80's full-load touring bike which weighs more, but like I said in a previous post, it's a different kind of ride... and so the extra weight isn't really a factor when I'm riding it. I don't ride it the same way, and I never feel like competing with anyone or with a speedometer, nor do I expect to be drag racing with it. I just enjoy the slower-paced ride, and with the racks, full fenders, generator, etc. on that bike, the bozos who make a fetish out of passing or "dropping" every bike they encounter aren't interested in me anyway. So, it all depends on what your goals are, your personality, etc. I mean, look, nobody is going to deliberately go out and buy an excessively heavy bike, but there's no need to worry too much about a good bike's weight either.

MBinMTL

I'm in the process of building a bike to go on 200k + rides. It will weigh about 19 lbs naked and cost me $2500 USD when I'm done. Just for kicks I used my excel file parts template to 'build' a money is no object equivalent (I like to dream about winning the lotto). It cost $9000 more and only weighed 2.3 lbs less.

northboundtrain

When riding with a group, the difference between getting dropped on a climb and just barely being able to dangle on the back might be 5-10 watts or a couple of pounds. If you're dropped you slow down much more . . .

The Smokester

Climbing slowly up a hill of slope s with speed v and mass m, the amount of power required from the rider is is P0 = s*m*g*v0. Climbing up the same slope with mass m+dm going at speed v1 the power output will be P1 = s*(m+dm)*g*v1. Given that the rider outputs the same amount of power in each case then P0 = P1 so that V1/V0 = m/(m+dm).

For me, my rando bike and stuff weighs about 30lb, I weigh about 170 lb. Rando total = 200 lb.
Touring bike is 32 lb, touring stuff is 30 lb, I still weight 170 lb. Touring total = 232 lb.
Road bike is 18 plus water and small amount of stuff is 25 lb. Roadie total for me is 195 lb.

Relative velocities up the hill are roadie:rando:touring = 1:0.98:0.84. Just the touring bike with small load it's roadie:tourNoLoad = 1:0.93.

Based on this, for a ten-mile uphill at 10 mph, the roadie will take 60 minutes; The Rando will take 61 minutes; The fully loaded tourer will take 71 minutes; and the lightly loaded tourer will take 64 minutes.

valygrl

The Spokester, that's an interesting analysis. It helps put some numbers on something that I've also had a feeling about - which is that for a smaller person, the difference in bike weight makes a bigger difference.

rumrunn6

HOWEVER!!!!!!!!!! If my 13 commute is not uphill but rather a mix of ups and downs and even planes, then a bike that weighs 10 lbs more doesn't affect my overall time by much at all!

Barrettscv 

Just passing this on...

My steel framed Soma Double Cross comes in @ ~22.5 lbs without added gear, bags, water...



It weights in at ~26.0 with two bags, food, mini-tool, 1 folding tire & 2 tubes, camera, lock, spare gloves & socks, poncho...



The only problem is that the motor is 215 lbs

reversegear

A little off topic, but what kind of frame bag is that on the Soma?

Barrettscv 

It's a cheap $4.99 Nashbar pump bag: https://www.nashbar.com/bikes/Product...2_167578_-1___

and it's ideal to use.

The Smokester

Yes. If one weighs only 100 lb then, under these circumstances, a 10 lb weigh difference translates into a 10% speed or time difference.

One can also couch this in terms of power-to-weight ratio: P0/m. Lighter people tend to have higher P0/m and the result is that they can climb proportionately more quickly.

The Smokester

Yes. This is true if you are riding solo. In fact, I have been tracking my time for a couple of years on a 40 mile return trip with 1700' of climbing which I do regularly on all three bikes...To my surprise, the average times for each of the three bikes are indistingushable within the variance. Thus, by observation, there are often a lot of random variables effecting average speed over a return course which will mask a few percent systematic speed reduction on the uphills.

Riding in a group is a different matter, though. As has been mentioned previously in this thread, the heavier bikes will struggle due to both slower acceleration and slowness on the hills and, being systematically and constantly left behind (except on downhills which don't weigh much in the average) will eventually miss the draft afforded by riding with a group.

njkayaker

When climbing. Just to be clear, it's the difference of the total weight (bike+gear+you).

The difference is going to be much smaller when "cruising" at a constant speed.

Longfemur

No matter what the weight, any decent road bike will do fine for long distance, because no matter what anyone says, long distance, as most people understand the term, means riding for endurance, not as a non-stop time trial... and endurance means pacing yourself so you last, not so you can drop anybody. A few pounds of weight is going to mean zilch, but a solid bike will, and so might having tires that resist having to make you spend time fixing flats, etc. And sticking with the long distance endurance ride context, so what if some guy on a stupid light bike gets up a hill a little faster than you do? It will only matter for that hill, not for the whole long distance ride.

Weight is actually going to matter even less for shorter daily rides, so, I would say that weight doesn't matter all round. Your riding position, your fitness, your own weight, the weight of your gear if any, etc. are all going to matter a lot more than the weight of your frame. Look at the late Ian Hibbell's accomplishments and then come back and tell us that weight matters for this kind of cycling. It's hard to imagine that any cyclist over the age of 12 wouldn't understand that.

wanderingone

one perspective that's been left out of this is simply the enjoyment of riding a really light bike : ) it's fun to be on a bike that always feels ready to accelerate and responds to every input from the rider. it doesn't have to impact your total time or total energy in the long run, if it's more fun then it's more fun right?