I counted the teeth on the smallest sprocket to make sure, and there are 14 as I thought, and the crank says 50 on it. So according to the Sheldon Brown site, that puts me at 22.9 mph at 80 rpm. Going to 13t would make it 24.7 mph at 80 rpm. So an improvement of 1.8 mph. I didn't realize 100 rpm was the goal to shoot for - thanks Lar! The crank is a Sugino ATP btw. I kind of like it and would prefer a 13t freewheel anyway. My goal is to go long distances at high speeds with as little effort as possible, sort of trying to shrink this huge city. Being able to cruise at 25 mph would mitigate the problem of people trying to pass me while in a 25 mph hour zone as well.

Rare were the ones Alex Moulton got made for his Bikes , now with the cassette wheels that is unnessisary.

eliminating the atmosphere will take care of wind resistance..

I can almost guarantee you that without a hefty tailwind you are not going to push a 50/13 at 80 rpm. You can't go faster just by havingn a higher gear, neither can you get in better shape by pushing a high gear at low revs, for reasons related to both your body and the mechanics of a bicycle. Racing cyclist go at high rev's for a reason. Even among elite cyclists there are very few who can push high gears successfully.

100 rev's is great, but if you're going at 80 now getting up to 90rpm will be a big help. That is what will get you to your goal, and eventually to the point where you actually need that 13 tooth cog.

I can't find Sugino ATP, just Sugino AT, GP, and VP.

here's the AT...
http://velobase.com/ViewComponent.as...c-23fb9e204511


52T is a fairly big chainring for a 110mm BCD. here's a classic one that would probably look perfect
http://www.ebay.com/itm/SPECIALIZED-...item43b80b28d6

there's others on ebay for $25-30ish.

Hey thanks. I went and bought that one. One reason being that my outer chainring seems to be worn/wobbly anyway, so this will help narrow down the problem, between a loose bottom bracket and the chainring. It was an AT btw.
One last question: Is there a standard way of measuring one's RPMs?

if you have a bicycle speedo with a clock, or something, count pedal strokes (I find it easier to count BOTH strokes, not just one side) for a full minute, and divide by two if you counted both strokes. or time how long 100 strokes take, and divide 100/2/seconds * 60

a fancier bike computer has a second pickup you put on the crank so it can measure your cadence for you in addition to your speed etc etc.

btw, a cadence of 100/minute is what a racer might maintain. most amateur cyclists who are just out having fun would be doing well to maintain 60-80

Get a pro contract. Your sponsors will buy you a very nice 15 pound 11 cog bike with 12-25, 11-23, and whatever other combinations you care to use.

Inability to do that means you're not "maxing out" your 52x14 which is about 31 MPH at cruising intensities you can sustain for an hour (100-105 RPM feels good for a threshold effort) and 42 MPH sprinting (140 RPM is OK in short high intensity bursts) . 50x14 is still a 30/40 MPH combination.

Eddy "The Cannibal" Merckx dominated the spring classics with a 52x13 big gear. For example after summiting the Tour Malet first on stage 17 of the 1969 Tour de France he decided to break away. He didn't let the 130km to the finish line discourage him. He won the stage. He won the polka dot jersey for climbers. He won the green jersey for sprinters. He won the yellow jersey for the overall victory.

I'm guessing that you're not in Eddy's league and can make do with a big gear a notch or notch and a half smaller. Pedal faster on flatter ground. On sustained grades steeper than about 3% get more aero (your speed may even be better than pedaling).

I've ridden a big gear no harder than 50x13 (half a cog bigger than 52x14) since entering the 8 cog era when I realized 50-40-30 x 13-21 meant I could have a low like 42x28 in the mountains west of Boulder, CO and plains gearing for rides east like a 13-19 corncob without changing cogs or wheels which would mean some agreement from my riding group before we rode to our meeting spot. That worked awesome.

I've been playing with 50-39-30 x 14-15-16-17-18-19-20-21-22-23. The 14 is enough to pedal down slopes up to about 3% in spite of being halfway between 52x14 and 52x15.

pssst? the OP has a 50T big ring not a 52T (although he ordered one).

Even so, a person ought to be able to keep pedalling that 94" up into the mid-30s and cruise in the 20s.

50x14 is still a 30 MPH cruising gear, 40 MPH sprinting gear, or 24+ MPH at an all-day endurance pace.My get a pro contract or pedal faster argument stands.

Rather than messing around with freewheels, the first thing I'd do is change the hub for any old Shimano cassette one.

...Except Uniglide

One does not narrow down a wobbly chainring by buying a new one. The spider (what the chainwheel is attached to) can be the source of wobble, and the bb is easily tested by pushing the crank arms from side to side.

I would disagree somewhat with the latter point. Casual cyclists who ride a few miles at a time may rev low, but many riders who go out for fun rides of 5 miles or more tend to pedal at 80 or above. Those who actually do "go long distances at high speeds with as little effort as possible" will predictably be at 90-100 rpm. Racers will be in the 100 - 110 range most often.

As long as we've gotten on this tangent I may as well talk about some of the why for high revs.

Mechanics/physics plays a part. Pedaling forces are off-center to the plane of the bike's direction. That means that there is a both a levered force to each side and torsional movement. If one pushes harder at low revs more of one's effort goes into rhythmically stressing parts, which is dissipated as heat. In addition, due to the off-center pedaling forces, the bike will to some degree lean to one side and then the other and actually deviate from a straight line. Both effects waste energy.

Physiology plays an additional part. When you pedal with higher force and lower rev's the muscles more easily build up lactic acid due to higher stress and less efficient transport of oxygen in and waste out, so they become less efficient. Yet it does not increase strength as in weight training. In weight training you are pushing directly against the ground or against a fixed object such as the back and seat of a machine, whereas the bike, as noted above, absorbs or transferring your effort. It is mostly with high speed that one increases fitness at high gears and (slightly) lower revs, with the sole exception of out-of-the saddle climbing.

When spinning the blood flows more efficiently, and because one can go faster it's easier to get the heart into better shape due to the aerobic effect. Oddly enough, once one has done so for a bit the muscles and heart and muscles become more efficient, and the cyclist who spins expends fewer calories than a masher to go the same speed.

Not really. Both of the bikes I bought for me and my son in the mid '80's came with 110 mm bcd SR or Suguino cranks and 52T big rings.

As a narrow dropout frame, I'd convert it to a single speed , [resell, or keep] a pretty cheap project,

buy a single speed freewheel, take dish out of the rear wheel, on the truing stand,
remove RD shorten the chain and call it good.

and go down and buy a new bike that has the go fast features the lad wants..

Again, this is not a math problem but a power/efficiency problem. Going from 22.9mph to 24.7mph (an 8% increase in speed) will require 16% more effort just to overcome wind resistance. That is true no matter what gear you are able to push at that speed, and whether you have a tailwind or headwind. If you want to go that much faster you either need to have 16% greater strength and endurance or you need to be more efficient in how you use what you have. Actually at that speed for any distance you will most likely need both. Few cyclists can maintain 25mph for long, let alone "cruise" at that speed.

Guys I get it. I don't know that much about bikes and I'm not training for the olympics. I also didn't realize how important RPMs are in cycling when I started this thread ... I've learned a lot. My copy of Zinn and the Art of Road Bike Maintenance (4th ed just released) is on its way and I hope to learn a lot more.

About the chainring upgrade, I already took it to the LBS to have the problem diagnosed. He snugged up the bottom bracket and called it good. Then I noticed the same side-to-side wander of the chainring. So he either didn't tighten the bottom bracket tight enough, the spider is bad, or the chainring needs to be replaced, from my understanding. Once I get it fixed I'll let you know.

Something close to the ground and shaped like the Weinermobile, that you lay on your back , inside of .
will be the better path.

Great, nothing more important than being open to learning. FYI - I was posting not only for you but for others who may think that higher gears are the solution to higher speed. Nobody tells you this stuff when you start riding or when you buy a bike.

If the cranks do not have sideplay and the chainwheel still wobbles it's not the BB. If the two chainwheels wobble at the same point then it's the spider, if only one wobbles its that chainwheel. It's really just a process of logic and elimination.

If the chainwheel wobbles only when riding make sure they check the fixed cup for tightness. It can be loose enough to shift under pedaling pressure but yet not be noticed on the stand. With your bike not moving try standing hard on one pedal and then turn the cranks so the other pedal is down and do the same. If the fixed cup is loose you will feel a shift/clunk.

Nope. You need to apply 25% more effort overcoming wind resistance.

While aerodynamic drag only increases with the square of velocity, you're covering proportionally more distance in the same time so power requirements to offset drag go up with the cube of velocity.

Well, technically we are both correct. I was speaking of effort at any one point. Of course in an equal amount of time you are correct. But for a fixed distance course I believe I am correct. The point is the same either way - it's a lot harder to go a little faster at that speed.

So as promised, an update. The 52t chainring came in and I installed it Monday. Did not have to raise the front derailleur. Did my 10.x mile route and noticed a huge difference in how tough it is to pedal the top gear. Also there was an increase in speed. I was going fast enough for my out-of-true wheels to finally affect the ride quality.

Anyway I'm loving the new chainring but it didn't eliminate the wobble. I guess that leaves the spider and chainwheel but I won't be able to dig into it any further until I invest in the tools, but thanks a lot for the help guys!

The placebo effect is strong.

Replacing a 50 ring with a 52 ring is a 4% change in gearing which got you a big gear halfway between 50x14 and 50x13.

Well my highly scientific cell phone-recorded laptimes will prove you wrong. I went from 34 minutes to 33 today.

Going faster always feels good, but 1/2 mph (3%) is not a scientifically significant difference, given the variables of wind, tire inflation, wind resistance differences (clothing) and yes, placebo effect and the desire to "prove" oneself right. You have not surpassed the laws of physics. You must expend more energy in order to go faster, and there is nothing in a larger chainwheeel that helps you do that, in fact it is more likely the opposite.