Fixed gearing ratio options
08-22-18 | 06:15 AM
#26
Senior Member
Joined: Sep 2017
Posts: 1,581
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From: Center of Central CA
"Yes, there is an argument that two larger cogs will be smoother than the same ratio achieved through two smaller cogs. On the other hand, the two smaller ones will be lighter."
08-22-18 | 06:23 AM
#27
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Joined: Aug 2018
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Realistically, the tiny difference in weight is unlikely to be more than could be saved by the rider losing a bit of weight, or only half filling the water bottle for short rides, or rationalising your keyring so you only carry the keys you need. Before you worry about how the size of your sprocket affects friction losses, is the chain clean and well oiled and are the tyres at the right pressure?
08-22-18 | 07:49 AM
#28
Thread Starter
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Joined: Aug 2018
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I ride 49/17 on 700c x 23mm tyres and find it versatile. I live in a flattish area but I have got up the biggest local hills on this ratio. I ride with brakes so I don't have to rely on back pressure to control speed on the descents.
To remove the lock ring, ideally you need a C spanner of the right size. In practice, it is usually possible to tap it round with an old screw driver and a mallet. If you do that too often, it'll cause damage, but if it's only now and again it's OK.
I have always been able to remove the sprocket by putting a sudden hard shock through the pedal. Just keep the bike on the ground and apply all your weight suddenly to the pedal in the obvious direction.
All these tools are reasonably cheap, readily available, and easy to use. Why pay a LBS to do the job, when you could spend the same money on a tool and do the job yourself this time and every time after?
A change of 1 tooth on the sprocket will always make a bigger percentage difference than a change of 1 tooth on the chain ring. For example, 1/17 difference is bigger than 1/48 difference.
You can increase the gear ratio by putting on a bigger chainring but you will need more chain. You can increase the gear ratio by putting on a smaller sprocket. For 1 tooth difference, you may not even need to shorten the chain. Yes, there is an argument that two larger cogs will be smoother than the same ratio achieved through two smaller cogs. On the other hand, the two smaller ones will be lighter. As there are no hills in NYC, weight is not really an issue for you.
Chain rings come in different thicknesses and I think this depends on whether they are designed for a 1x, 2x or 3x set up. The differences are slight, but I had one once that never sat right on my single speed.
Chain sets come in 4 or 5 arm varieties, but there are also different "BCD". That stands for "bolt circle diameter". The 4 or 5 bolts are evenly spaced around a circle. You need a chainring that is drilled with the same BCD as the chainset. The two common BCDs are 130mm and 110mm.
To remove the lock ring, ideally you need a C spanner of the right size. In practice, it is usually possible to tap it round with an old screw driver and a mallet. If you do that too often, it'll cause damage, but if it's only now and again it's OK.
I have always been able to remove the sprocket by putting a sudden hard shock through the pedal. Just keep the bike on the ground and apply all your weight suddenly to the pedal in the obvious direction.
All these tools are reasonably cheap, readily available, and easy to use. Why pay a LBS to do the job, when you could spend the same money on a tool and do the job yourself this time and every time after?
A change of 1 tooth on the sprocket will always make a bigger percentage difference than a change of 1 tooth on the chain ring. For example, 1/17 difference is bigger than 1/48 difference.
You can increase the gear ratio by putting on a bigger chainring but you will need more chain. You can increase the gear ratio by putting on a smaller sprocket. For 1 tooth difference, you may not even need to shorten the chain. Yes, there is an argument that two larger cogs will be smoother than the same ratio achieved through two smaller cogs. On the other hand, the two smaller ones will be lighter. As there are no hills in NYC, weight is not really an issue for you.
Chain rings come in different thicknesses and I think this depends on whether they are designed for a 1x, 2x or 3x set up. The differences are slight, but I had one once that never sat right on my single speed.
Chain sets come in 4 or 5 arm varieties, but there are also different "BCD". That stands for "bolt circle diameter". The 4 or 5 bolts are evenly spaced around a circle. You need a chainring that is drilled with the same BCD as the chainset. The two common BCDs are 130mm and 110mm.
thanks for the info but here’s the update, I was able to get NOS 17t cog on eBay and I went to my local bike shop and they put it on for free, so I bought a tube of grease to do some very basic stuff, plus I’ve been using Vaseline in a pinch for new pedals and seat adjustments lol. All squeaks are gone. Love the new ratio, I feel as if I maintain the same cadence and just go faster, either it’s a mental thing or my body type I just don’t spin well for long durations 70-90 is my happy zone without focusing on it and for my purpose I get a better workout in less time. Very zippy ratio, still can slow down well using my legs and brake with the front, I’m ecstatic. Strava has been blowing up with records lol
08-22-18 | 07:58 AM
#29
Full Member
Joined: Aug 2018
Posts: 305
Likes: 119
thanks for the info but here’s the update, I was able to get NOS 17t cog on eBay and I went to my local bike shop and they put it on for free, so I bought a tube of grease to do some very basic stuff, plus I’ve been using Vaseline in a pinch for new pedals and seat adjustments lol. All squeaks are gone. Love the new ratio, I feel as if I maintain the same cadence and just go faster, either it’s a mental thing or my body type I just don’t spin well for long durations 70-90 is my happy zone without focusing on it and for my purpose I get a better workout in less time. Very zippy ratio, still can slow down well using my legs and brake with the front, I’m ecstatic. Strava has been blowing up with records lol
On the fixed gear, I don't have those choices, and strangely I just power through. At aged 55 and 20 Pounds overweight, I'm not breaking any records except my own, but the fixed is definitely faster over many local rides of around an hour or so.
To make the comparison fairer, I must confess that the 2 x 10 is a gravel bike: heavier, slightly rougher tyres, less aerodynamic.
08-22-18 | 06:09 PM
#30
Super-duper Genius
Joined: Aug 2016
Posts: 1,759
Likes: 1,054
From: Muskrat Springs, Utah
