# No need for chain tensioner?



## bank5 (May 7, 2008)

I'm considering dropping my chain tensioner as I can just barely get my chain on the chainring. It's a bit loser than I'd prefer, but not dealing with a tensioner, reducing weight and friction would be nice.

I have a KMC chain which is quite stiff laterally and may try a narrow wide chainring if I have any chain drops. Any other recommendations to prevent chain drops?


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## Radioinactive (Aug 2, 2011)

i dont know how much it could help but a narrow-wride cog like an Absolute black might help keep it on.

a Ghost ring will do ya good to if you can get it nice and flush


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## chazpat (Sep 23, 2006)

It depends on the tension without the tensioner, unless you have the magic gear, it will probably be too loose. But you can try it with a ghost ring as Radio suggested. My converted Dakota uses the magic gear, but from what I've read, that's pretty lucky.


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## Velobike (Jun 23, 2007)

You can have the chain just about hanging in the dirt so long as you have the following:

Single speed chain (ie little or no lateral flex)
Single speed chainring and rear cog
Reasonably laterally stiff chainstay
Straight chainline.

Anything intended for a derailleur is designed to unship the chain. 

Quite a lot of of bikes that were intended for derailleur use have chainstays that flex laterally - that's a design feature, not a flaw. 

It's why a lot of older road bikes were ridden with a fixed wheel instead of singlespeed - the flex would cause the rims to rub on the brake blocks on steep climbs so the brakes would have to be backed right off to stop that. Fixed wheel riders could do without a back brake. 

If you had the dohickey to instantly slacken the cable for wheel removal, you could flick that open on climbs, but the problem was remembering it on the declines.


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## bank5 (May 7, 2008)

I took it back out tonight with the tensioner in my pack and did my typical ride with a ton of trail chatter. I never dropped the chain so it seems pretty solid. I've never heard of a magic gear (or ghost ring), but think I stumbled upon one. Assuming it continues to work without issues, it'll be a great reason for me to stay in shape and not have to switch back to 20T


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## Velobike (Jun 23, 2007)

A point about Magic Ratio. On an mtb that gets ridden in the dirt the wear in the front ring will soon produce some slack.

I find that using a steel chainring (eg Surly) keeps the tension for longer because it wears slower.


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## Jack Burns (Nov 18, 2005)

Once upon a time I made a single speed out of a Schwinn Homegrown for my wife, her first SS, and put a spring tensioner on it to make it work. It worked well for her.

But I was very delighted with riding my SS that didn't need one and felt bad for her and her bike. So when it came time to put a new chainring I found a cheap single ring crank...it was great quality though...that had a 33t chainring on it. The bike had either a 32 or 34 on it before. I can't remember now.

Anyway when I assembled the bike with a new chain I decided to give the magic gear thing a try and it was incredibly excellent.

She rode it for 3 or four years like that until she demanded an SS with disc brakes.

Then we sold the Homegrown to a good home for a pittance. Pity, it was a classic. But we value simplicity. Too many bikes are too many bikes.

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## Jack Burns (Nov 18, 2005)

Just want to add that half-link chains increase the potential for magic gear on many frames.

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## mack_turtle (Jan 6, 2009)

Half-link chains stretch like mad crazy. I would use a single half-link in a regular chain and replace it once ina while but BMX riders learned long ago that a chain of all half-links (the shadow conspiracy, KHE, KMC, DK, etc) will have you adjusting your chain tension after every ride, which is useless on a bike without a tensioning feature.


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## Jack Burns (Nov 18, 2005)

mack_turtle said:


> Half-link chains stretch like mad crazy. I would use a single half-link in a regular chain and replace it once ina while but BMX riders learned long ago that a chain of all half-links (the shadow conspiracy, KHE, KMC, DK, etc) will have you adjusting your chain tension after every ride, which is useless on a bike without a tensioning feature.


Really?!

Wow. Well I will keep an eye on one of my bikes that I ride once or twice a week that is a rigid dingle with a chrome half link chain.

This dingle bike is switched from high to low on most rides due to the fact that I ride it on the road to the dirt. Hence there is always some slight adjustment going on. The tension adjustment takes about 20 seconds or so.

I have not had any experience with half link chains before this one, of which I have been using for a couple of years.

One thing for sure is the chain seems to weigh twice as much as the SRAM PC1! But it looks awesome.

I am not doubting you. Buy I haven't noticed unusual stretch. I will measure my chain and see if it grows much.

This might be a great insight to me. I didn't BMX and came to MTB in the late 80s from biking skiing and motorcycling.

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## mack_turtle (Jan 6, 2009)

Just Google "half-link stretch." Everyone thinks they are a good idea until they use one.


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## Jack Burns (Nov 18, 2005)

mack_turtle said:


> Just Google "half-link stretch." Everyone thinks they are a good idea until they use one.


Yo, I just browsed the topic and there's a lot of smoke, so there must be fire.

Half link chains are heavy and wear faster is the consensus. It appears to be true.

You know, it seems like my chain rings are wearing faster than they should as well, with the half link chain.

Well I am not going to throw out my beautiful chrome half link chain just yet.

And when I do change it, I will clean it up and make a belt out of it. It looks that good.

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## socal_jack (Dec 30, 2008)

I ran a full length Gussett Slink half-link for over 4 years on my GT PEACE 9r, pretty much zero stretch and there was almost no adjustment range on those backend track forks, that chain was crazy strong replaced it with another. Finally broke but that was a combination of excessive chaining/cog/chain wear all at once. Chain gave due notice of the wear with weird creaking noises so I didn't get caught by surprise. Ran it to bring in the CS 1/4".


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## Jack Burns (Nov 18, 2005)

I just came back from a ride on my half link chain and it was smooth and quiet.

I can't remember what brand it was.

No pics really, but here's a pic from last week of my dingle thing.









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## butryon (Aug 12, 2005)

I have ran all types of stuff but I love it when I can get the magic gear to work! in fact, when I set a bike up I have multiple chains around in hopes of one of them allowing me the perfect length. Other than the magic gear I would use a Paul melvin tensioner. The classic surly is pretty good but the Paul is real solid, IMO.


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## Jack Burns (Nov 18, 2005)

Took out the SS with the half link chain this eve. Really pedaled hard to clean some steep trails. It worked fine.

Later I switched the dingle gear ratio to high for the pavement ride home. This entailed retensoining the chain.

If there is excess stretch happening I can't tell because adjusting the tension is one thing I do on every ride.

But I did notice that I need to try fixed gear SS again, as I have a cog mounted on the flip side of the hub where a rotor would go. Oh boy, another whacky feature of the bike.

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## Jack Burns (Nov 18, 2005)

Here is a photo of a rear hub with a fixed cog mounted by six bolts to the disc rotor position (wrapped by the half-link chain)on the drive side, and the freewheeling side of the hub, on the non-drive side with two cogs positioned by spacers which are mounted on the cassette carrier.

This arrangement actually functions excellently. I was doubtful upon conception and assembly. Many rides on the three possible configurations prove it works. It's a pleasure to ride.

Now as for chain stretch on the 1/2 link chain, I have no evidence, because every time I change the gear ratio or flip the wheel to ride fixed, I always perform very slight tension adjustments to the chain tug bolts.

Happily over the years I have ridden this frame, the chain tug bolts are easy to turn with my fingers; I don't turn them with an Allen key. As with anything minorly technical yet frequently done, like squeezing toothpaste twice a day, pumping gas, forming a chord, this process is now perfunctory.

As I look at the tugs now, I do see that they are nearly maxxed out, and I think they've been the same since I put the chain on.

It runs very good, smooth and quiet. The only thing I might do is flip the chainrings this summer if I find time.

I try only to climb in the fixed gear on non tech climbs where ratchet pedaling is not required or expected. It does feel different. There is a cool pull through effect at the dead spot of the crank. That's a way to describe it, but that's not what is really happening.

Anyway, this is an unusual configuration possible with an old 135mm rim brake set-up. For me, a fun bike to ride.









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## Jack Burns (Nov 18, 2005)

Here's the right view for fixed. I posted the freewheel position in the post above accidentally.









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