What Back and Front Tooth Ratio is Fastest???
04-02-19, 09:11 AM
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If you put a Ferrari transmission into a Yugo or something similar do you think it would go 150 MPH? Of course not because it doesn't have enough power. Bicycles are the same.
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04-02-19, 09:20 AM
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That works for me, but you have to have the ability to apply an awful lot of torque before that is efficient. I suspect the answer for best starting gear combo is going to vary a lot with the rider's capabilities and strengths.
04-02-19, 09:22 AM
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One day on my usual route, I thought I had a pretty good pace going when I got passed by a little chick spinning an incredible cadence.
As I struggled to keep up, I was curious what her cadence really was, so I downshifted until I matched it.
She was spinning 120rpm, and was still doing that as she cruised away from me!
As I struggled to keep up, I was curious what her cadence really was, so I downshifted until I matched it.
She was spinning 120rpm, and was still doing that as she cruised away from me!
04-02-19, 09:25 AM
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04-02-19, 09:29 AM
#30
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OP, set your 2 bikes against a wall , step back 5 paces.. wait & watch ,
1st one that moves on its own, must be the fastest ..
1st one that moves on its own, must be the fastest ..
04-02-19, 09:30 AM
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One day on my usual route, I thought I had a pretty good pace going when I got passed by a little chick spinning an incredible cadence.
As I struggled to keep up, I was curious what her cadence really was, so I downshifted until I matched it.
She was spinning 120rpm, and was still doing that as she cruised away from me!
As I struggled to keep up, I was curious what her cadence really was, so I downshifted until I matched it.
She was spinning 120rpm, and was still doing that as she cruised away from me!
I'm guessing she wasn't running 52x13, though!
I can't even relate to riding like that.
04-02-19, 10:38 AM
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04-02-19, 11:10 AM
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Tandem with a good stoker and 54/11 gearing is the closest i’ve come to 40mph on the flats.
04-02-19, 02:45 PM
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My wheels with 622mm rims and 28mm tires on are about 27". I run my 32s kinda soft, so they're about 27" effective when I'm on the bike
04-02-19, 02:53 PM
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What's a good back:front tooth ratio and gear stepping system from standstill to top speed on road bikes?
I have seen that some riders are taking road bikes up to 40+ mph. I'm just looking for the 30+ mph range on the road, and I'm not looking for expensive produce or parts. I don't care how old or what it looks like to be honest as long as it stays together, handles, and gets to top speed rapidly.
Some back:front gear ratios are better than others, right? I'm messing with two bikes right now which are just older road bikes that have mountain and cruiser features. They're just fun and project bikes. I noted on the second one I bought yesterday that it was going much faster with very minimal effort compared to what the first one could do without much more effort. The first one is 21spd and the second, faster one is 18spd, however I don't believe the number of sprocks but the number of teeth matters.
I have seen that some riders are taking road bikes up to 40+ mph. I'm just looking for the 30+ mph range on the road, and I'm not looking for expensive produce or parts. I don't care how old or what it looks like to be honest as long as it stays together, handles, and gets to top speed rapidly.
Some back:front gear ratios are better than others, right? I'm messing with two bikes right now which are just older road bikes that have mountain and cruiser features. They're just fun and project bikes. I noted on the second one I bought yesterday that it was going much faster with very minimal effort compared to what the first one could do without much more effort. The first one is 21spd and the second, faster one is 18spd, however I don't believe the number of sprocks but the number of teeth matters.
04-02-19, 02:56 PM
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Yes, but if you are riding normal 700c tires, 27" is plenty accurate enough (unless you are a junior and the race official does a rollout. There it matters. The bike is either legal or it is not.) I use the old 27" for all my 700c tires. But very large tires are slower, so I knock my gearing down, usually a tooth. Very fast (and usually small) tires, I might go up a tooth. It all works out. 27 is a number that allows me to calculate gear ratios in my head. Long rides give me plenty of time to do that.
04-02-19, 03:09 PM
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FWIW, I will do drag race intervals during crit season where I'll alternate big (53x16) and small ring sprints (38x15) and try to go 0-30 as quickly as possible. On the big ring, the challenge is at the start to get on top of the gear as quickly as possible. On the small ring, the challenge is at the end to keep my feet moving and the gear engaged before spinning out.
04-02-19, 03:53 PM
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My suggestion is to look up how gear ratios are calculated for bikes... there are a few different terms, but a common one is "gear inches," which is the number of inches that you move for one complete revolution of the pedals. Also think about "cadence" which is revolutions per minute of your pedals. There are online calculators that will work these things out for you, along with things like the speed that you can ride for a particular gear combination at a particular cadence.
This is practically pure math, which scares some people, but is not really all that difficult. There's no absolute answer because each rider has their own preferred cadence and top speed. For instance for myself, 30+ mph is unattainable due to wind resistance and my own strength, so I have no use for gearing that can reach that speed.
This is practically pure math, which scares some people, but is not really all that difficult. There's no absolute answer because each rider has their own preferred cadence and top speed. For instance for myself, 30+ mph is unattainable due to wind resistance and my own strength, so I have no use for gearing that can reach that speed.
I'm in shape.
How about wheel size in the ratio of gears? Does that make a difference? And thin tires probably put on a little more speed and acceleration than the average mtb width, eh.
04-02-19, 04:01 PM
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Okay, but what about the human power involved. To take this to an extreme example, say the tires were four feet across in dia. Yeap, the gearing is the same, however turning the wheel for the person is not. I wonder anybody with experience with the higher diameter wheels has any antidotes to explain.
04-02-19, 04:02 PM
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If you're running sewups, Dugast has 18mm tires.
There used to be 18mm clinchers all over the place, and I think someone still makes 'em, can't think of who, though.
04-02-19, 05:14 PM
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So 2x or 2.5 minute miles is okay with acceleration that is comparable to cars at take off at the stop lights/signs. The main thing is to keep up the pace with traffic on the long mains. I have been riding the ole mountain bikes mostly for style preferences. That's just what I always rode. Whatever. LOL But in this case I need a bike that can pace it with traffic who's going about 35-45 mph.
04-02-19, 05:18 PM
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"Gear Inches" is a useful and widely-accepted measure of mechanical advantage when cycling, but it is not the number of inches travelled during one crank revolution. GI is usually calculated as (crank teeth#/sprocket teeth#)*27", 27" being the nominal diameter of a standard bicycle wheel, so, for example, a 52-13 gear would develop a "108" gear". However, wheel circumference, rather than diameter, determines the wheel rollout, or the distance travelled by one wheel revolution, and circumference is 3.14x greater than diameter. The actual distance travelled (in inches) is 3.14-fold greater than the calculated gear inches. Therefore, in the 108 gear inches example above, the bicycle would travel ~339" (108" x 3.14) with one crank revolution.
Everything matters. Tire width is one of those "all other things being equal" things. Rolling resistance of the tires depends on their width, but also on pressure, tire construction, tread pattern, and possibly the surface that you're riding on. But if you go down the "build me the fastest possible bike" rabbit hole, I won't be following you there, because I'm satisfied with riding at a more sedate speed based on my own abilities.
04-02-19, 05:20 PM
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What's a good thin tire compromise for the above situation: fast and occasional road jags? It only takes one the wrong way one time, and it's a dented rim and probably a rim pinched tube, eh.
04-02-19, 05:27 PM
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Okay, but these streets are always smooth, and I'll run it up on the side walk to cut a corner, shave an inche, etc. The sidewalks have wanks and jags, so... This kind of stuff was the reason I like the mtb set ups.
What's a good thin tire compromise for the above situation: fast and occasional road jags? It only takes one the wrong way one time, and it's a dented rim and probably a rim pinched tube, eh.
What's a good thin tire compromise for the above situation: fast and occasional road jags? It only takes one the wrong way one time, and it's a dented rim and probably a rim pinched tube, eh.
04-02-19, 05:32 PM
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No, I'm just trying to understand some basic science, and then get a formula that I can take to the used market or new for parts and rides now and then.
So I researched the bike seats last night and the angle of body lean and speed increase. I took from Bike Forum people the "what's-what" on gear ratios, wheel dia and width, crank/BB/shell specs, and I have my post clamp bike stand in the mail almost to the house this minute. Hehe.
Just the basics, eh.
04-02-19, 08:21 PM
#46
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I'm starting urban courier. I have just a few multi mile long flat roads and lots of little left and right turn streets in between that are flat too. That's what I'm working with.
So 2x or 2.5 minute miles is okay with acceleration that is comparable to cars at take off at the stop lights/signs. The main thing is to keep up the pace with traffic on the long mains. I have been riding the ole mountain bikes mostly for style preferences. That's just what I always rode. Whatever. LOL But in this case I need a bike that can pace it with traffic who's going about 35-45 mph.
So 2x or 2.5 minute miles is okay with acceleration that is comparable to cars at take off at the stop lights/signs. The main thing is to keep up the pace with traffic on the long mains. I have been riding the ole mountain bikes mostly for style preferences. That's just what I always rode. Whatever. LOL But in this case I need a bike that can pace it with traffic who's going about 35-45 mph.
-Tim-
04-02-19, 08:33 PM
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2’/mi = 30mph. 2.5’/mi = 24mph
04-02-19, 10:16 PM
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04-02-19, 10:17 PM
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04-03-19, 04:12 AM
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I suggest some sort of JATO device.
35-45 mph running speed is completely unrealistic. If you can do that, quit your day job. Anything but bicycling is a waste of talent.
35-45 mph running speed is completely unrealistic. If you can do that, quit your day job. Anything but bicycling is a waste of talent.