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Discussion Starter · #1 ·
This week I began the 2021 upgrade of my 2011 Trek Rig to a single speed gravel and urban toy.

If you did not see the previous thread where I was trying to decide what to do; my son in law has been borrowing this old Trek Rig of mine for the last year while they were here. They have gone back overseas, with my first grandchild who is only 4 months old :( so I have it back and was deciding what to do with it.

I am not a big fan of drop bars being as tall as I am, my back just can't take that position.

However, I have been running the Surly Moloko bar on my Ogre backpacking build and I really like it a lot. Especially the upper hood/horns where I spend a ton of my time. Just a very comfortable place.

So when I was thinking about this I ran across the Surly Corner bar, a drop bar alternative.

I wanted to do a number of other upgrades to this bike but keep it all very simple. So I ordered up the bar from the only place in the US I could find one (Eado Bike down in Houston - Eado Bike Co - Home ). Now being a big guy I was initially looking at the widest bar they offered. It comes in a Drop Bar Equivalent Width: 46cm, 50cm, or 54cm. But the 54mm bars have not been available as yet. However, when looking at the measurements between the "hoods" the 46cm bar measured 18 inches. My Moloko measured at 14 inches. So I really did not want an even wider grip between the hoods as the 14 inch of the Moloko fits me well. So I went ahead and ordered the 46cm bar.

It came today and I mounted it up. I also put on a new 46 tooth Renner front chain ring and a new chain, since I had no idea when I last replaced the chain. I got all that installed and tried it out. Overall it feels pretty good. I will have to get used to using the drops, but in general while the brakes are mounted to be used from the drops, I found that I could actually use them either there on on the hoods.

I think I got lucky with the Bontrager SSR 110mm stem. It seems just about right. This bike came from the days of short bars and long stems. I have a 90 in the parts bin if I feel this one is too long.

Here are a few first shots. I welcome your comments and suggestions on this build.

The next big step will be to replace the current tires with a 29x2.2 tubeless tire (Maverick rims are tubeless ready amazingly) - probably either a Maxxis Crossroads II or a Teravail Rutland or Sparwood.

Bicycle Tire Bicycles--Equipment and supplies Wheel Bicycle wheel rim


Bicycle Bicycles--Equipment and supplies Wheel Tire Crankset


Bicycle Tire Wheel Bicycle wheel rim Bicycles--Equipment and supplies
 

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Discussion Starter · #5 ·
Actually, the gearing thing is where I feel the most inadequate. I need a tutorial on the math behind figuring out what would be best. I know it is a calculation of the tire diameter, cog and chainring, but knowing what to target and how to best get there is where I fall down.

I think that my current set up give me about a 3.8 to 1 ratio. I read that it should be closer to 3.0 to 1 for a fairly flat riding area. But I see setups with much larger front chainrings.

Anyhow who can help me with this, give it up.
 

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Discussion Starter · #9 ·
That's really flat, just run a gear that you feel is comfortable and can keep a good pace for the trails or roads that you ride.
After breaking the new chain I just got, I went to my local shop and talked to the guy who helped me build my Ogre. He suggested swapping the 18 rear cog for a 16 as I feel like I am running out of gear more than anything, even on the flat areas. So we ordered up a new chain and cog.
 

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Actually, the gearing thing is where I feel the most inadequate. I need a tutorial on the math behind figuring out what would be best. I know it is a calculation of the tire diameter, cog and chainring, but knowing what to target and how to best get there is where I fall down.

I think that my current set up give me about a 3.8 to 1 ratio. I read that it should be closer to 3.0 to 1 for a fairly flat riding area. But I see setups with much larger front chainrings.

Anyhow who can help me with this, give it up.
Gear ratio is only the dependent on the size of the chainring and sprocket, but how hard it is to pedal depends on tyre size as well (and crank length, but only by a tiny bit so we'll ignore it). Are you familiar with gear-inches? Essentially it's the equivalent gear ratio as a wheel/tyre of a given diameter on a penny-farthing. Multiply the number in inches by pi (3.14) to get the distance travelled for one rotation of the crank.

So a penny-farthing with a 72" diameter tyre (pretty typical size) has a gear of 72". A gear ratio of 3.8:1 on a bike with a 29.2" tyre like yours has a a gear of 111", which is pretty big (my gravel bike's top gear is 106", most road bikes top out at about 120-130" and a 36/11 top gear on a 29er is only 96"). A ratio of 3:1 gives you 87.6". In the singlespeed boom of the early 2000s there was a great website called 63xc.com, based on a typical gear of 63" for off-road SSing. For this you'd need roughly a 38/17 or 36/16. Obviously if you want to do a bit of speed on gravel rather than singletrack you'll want a bigger gear (maybe 70-75", 36/14ish which is 2.57:1), especially being somewhere flat.
 

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Discussion Starter · #11 ·
Gear ratio is only the dependent on the size of the chainring and sprocket, but how hard it is to pedal depends on tyre size as well (and crank length, but only by a tiny bit so we'll ignore it). Are you familiar with gear-inches? Essentially it's the equivalent gear ratio as a wheel/tyre of a given diameter on a penny-farthing. Multiply the number in inches by pi (3.14) to get the distance travelled for one rotation of the crank.

So a penny-farthing with a 72" diameter tyre (pretty typical size) has a gear of 72". A gear ratio of 3.8:1 on a bike with a 29.2" tyre like yours has a a gear of 111", which is pretty big (my gravel bike's top gear is 106", most road bikes top out at about 120-130" and a 36/11 top gear on a 29er is only 96"). A ratio of 3:1 gives you 87.6". In the singlespeed boom of the early 2000s there was a great website called 63xc.com, based on a typical gear of 63" for off-road SSing. For this you'd need roughly a 38/17 or 36/16. Obviously if you want to do a bit of speed on gravel rather than singletrack you'll want a bigger gear (maybe 70-75", 36/14ish which is 2.57:1), especially being somewhere flat.
Thank you, that is really helpful detail that I will use.
 

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Gear ratio is only the dependent on the size of the chainring and sprocket, but how hard it is to pedal depends on tyre size as well (and crank length, but only by a tiny bit so we'll ignore it). Are you familiar with gear-inches? Essentially it's the equivalent gear ratio as a wheel/tyre of a given diameter on a penny-farthing. Multiply the number in inches by pi (3.14) to get the distance travelled for one rotation of the crank.

So a penny-farthing with a 72" diameter tyre (pretty typical size) has a gear of 72". A gear ratio of 3.8:1 on a bike with a 29.2" tyre like yours has a a gear of 111", which is pretty big (my gravel bike's top gear is 106", most road bikes top out at about 120-130" and a 36/11 top gear on a 29er is only 96"). A ratio of 3:1 gives you 87.6". In the singlespeed boom of the early 2000s there was a great website called 63xc.com, based on a typical gear of 63" for off-road SSing. For this you'd need roughly a 38/17 or 36/16. Obviously if you want to do a bit of speed on gravel rather than singletrack you'll want a bigger gear (maybe 70-75", 36/14ish which is 2.57:1), especially being somewhere flat.
Thank you, that is really helpful detail that I will use.
I've found http://www.gear-calculator.com/ to be useful - enter your gear/tire/wheel specs and can display results in ratio, gear inches, etc.
 

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just wait til the study and stuff is nerfed by the real world. You'll get into the SS and ride some miles over time and soon enough, you are looking for more top end. You discover, you get out of the hole expediently, and get into a spin to discover the end of the gear you have, it's all on the table... You JONES for more!!
 

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Discussion Starter · #15 ·
Thought I would drop a pic of the bars completed. Well partially. The bar wrap I got once I went over the horns was not long enough to cover the ends of the bars. So I used some push on grips I had handy. I will try it like this for a while to see if I like it over just a full wrap.

I hope to have a job soon so I can get a new set of tires on order.

Bicycle Tire Wheel Bicycles--Equipment and supplies Crankset
 

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Discussion Starter · #16 ·
Thought I would provide an updated pic. Here are the changes I have made so far;
  • Surley Corner Bar
  • Maverick wheel tubeless setup
  • Teravail Sparwood 29x2.2 tubeless tires
  • Wolftooth 16 tooth rear cog (teamed up with the Renner 34)
  • New 9 speed chain cut down

Next steps;
  • Rebuild or replace front Rock Shock?
  • Brake tune

I put 10 miles on it today after the previous chain break. It is a really fun bike to ride, but it whipped my butt. I am going to have to ramp up my game to ride it regularly, but the 34/16 setup feels pretty good as I am not running out of gear too quickly and it is easy enough to ride up the moderate hills here.

Oh, and I named it the OG Rig (for Original Gangsta/Grandpa/Gravel Rig)

Bicycle Tire Bicycle wheel Bicycles--Equipment and supplies Land vehicle
 
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