Removing secondary crankshaft cog from Trek 5200

davelloyd

New Member
I am considering removing the rarely used large secondary crankshaft cog from my Trek 5200 bike to reduce its overall weight. I could also theoretically remove the front derailleur as well, further lightening the bike.

In essence, I would be converting the drive train from 2x10 to 1x10.

Is this process fairly straight forward and/or feasible? Do I simply remove the screws pictured below and pull off the cog? Any other tips to ensure I don't destroy this bike?

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Sharky

Guru
Location
Kent
Fairly straight forward. Removing the chainrings is simple, but you will need to get new bolts just for a single ring. The existing ones will be too long and you wont be able to tighten them.

Need to think about gear ratios. Keeping the outer (50t) might give too high a gear for climbing.

I did the same and bought a 40t narrow/wide chain ring, which was a good compromise. Then you will need to shorten the chain by a couple of links to stop it catching the cassette.

Finally, decide which gives you the best chain line for the most used sprockets. I kept mine on the inner position.

Remove the front mech and should work a treat.

Good luck
 

Globalti

Legendary Member
Yes exactly. I once knew a mountain biker who removed his granny ring (when everybody had triples) and everybody thought he'd done it just to prove a point as it probably only weighed 25 grammes.

You'd lose far more weight by opening your bowels before a ride or not carrying as much water. I once weighed myself before and after a shortish ride on a hot day and I had sweated out almost 500 grammes.
 

Sharky

Guru
Location
Kent
Seems like a lot of effort to remove a few grams.
In my case, it wasnt for weight saving. With my old 50-34 chain rings, I always seemed to be using gears in the middle. So bordering on little/little or big/big combinations and commuting in the dark made it a hassle. Switching to a 1x10 system just simplifies gear changs. Just one lever and one click to go up or down.
 

Globalti

Legendary Member
In my case, it wasnt for weight saving. With my old 50-34 chain rings, I always seemed to be using gears in the middle. So bordering on little/little or big/big combinations and commuting in the dark made it a hassle. Switching to a 1x10 system just simplifies gear changs. Just one lever and one click to go up or down.
Just yesterday morning I stopped for a chat with a cyclist on a new touring bike with a 1x system. She admitted that the big gap between ratios is irritating and we both agreed that for touring you still can't beat a narrow-range cassette with a triple chainring setup, giving the fewest possible overlaps between ratios but small steps and a nice wide overall range.

I'm baffled by the idea that a double chainring is a hassle in the dark. Surely you know which chainring you are using?
 

Sharky

Guru
Location
Kent
Just yesterday morning I stopped for a chat with a cyclist on a new touring bike with a 1x system. She admitted that the big gap between ratios is irritating and we both agreed that for touring you still can't beat a narrow-range cassette with a triple chainring setup, giving the fewest possible overlaps between ratios but small steps and a nice wide overall range.

I'm baffled by the idea that a double chainring is a hassle in the dark. Surely you know which chainring you are using?
Kent's quite hilly, always going up and down. I used to find roads getting steeper and on the big ring, changing down, then realising I would be running out of sprockets, so would have to change down on the front and change up on the rear.

In the dark, you can tell which front ring you are on, but sometimes when it is pitch black, can't see the rear sprockets clearly and you run out of sprockets before you realised.

My commuting days and riding in the dark are over now, but still appreciate the one touch click up and down that a 1x system gives.

Re big gaps, I am still using a close ratio cassette, with the bulk of the sprockets just 1 tooth difference. Something like a 13-26 cassette.
 
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davelloyd

New Member
Thanks chaps for your kind replies. To clarify, I live in a fairly flat area. When I mean flat, I mean the steepest hill to climb (and descend for that matter) is my 15 ft long driveway. I like to ride with fairly high cadence hence, I rarely ever use the large cog, day or night. I figure I could drop at lease 300+ grams by removing both the cog and derailleur.
 

boydj

Guru
Location
Paisley
It's a lot of trouble for a weight loss that you'll never notice and give you a bike that you won't be able to go exploring on in case you hit some big hills.
 
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