Stopping tensioner from hitting spokes?

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ballinchestr

ballinchestr

Member
Mar 6, 2014
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Central MA
My drive chain tensioner swiveled into the rear wheel, clipping three spokes and bent the rim out of shape when I went over a bump. I got the wheel replaced, but how can I stop that from happening again? I don't want to make changing the rear sprocket over to a new wheel a regular thing.
 
Chaz

Chaz

Well-Known Member
Jun 3, 2012
1,004
72
48
Vancouver, British Columbia
Ouch. If you have the stock tensioner you can pound the channel with a hammer to flatten it out a bit to give you a better grip. make sure the chainstay and channel are clean, free of grease or oil. And you can put some jbweld in the channel to give you more of a gripping surface.
 
crassius

crassius

Well-Known Member
Sep 30, 2012
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check that tensioner is tight - if frame is small there, you can saw off a couple pieces of old handle bar split into "C" sections to use as shells under the tensioner clamp to give it more bite

note that no matter how tight the tensioner is mounted, a chain too tight will pull it loose - be sure to adjust chain tension at the tightest part of the chain run as you turn the wheel thru a full turn
 
L

Legwon

Member
Mar 2, 2013
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Van bc Canada
you can get aftermarket tensioner as xseler mentioned.. theres a couple different models out there....

what i did, after going thru what you are ....
i cut up some old tubes.. cleaned off the white chalk(will make it slip) and placed it under the tensioner... hasnt moved in over 5 yrs :D
 
S

Slogger

Member
Sep 8, 2014
544
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nohio
I got better bolts and roughed up the chain stay for a few inches and sprayed it with plasti-dip. After the tensioner was fitted and ready to mount, it got hosed with plasti-dip, too. When those bolts are loose I still have trouble moving it. It's pretty stable.
Where there's a will, theres a way.
 
Trey

Trey

$50 Cruiser
Jan 17, 2013
1,432
5
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Where cattle outnumber people 3 to 1.
Ballinchestr- I'm surprised no-one has mentioned that you can simply remove the tensioner, adjust your drive chain length, and you will never have that problem again.
I never use the kit tensioner under any circumstances, it is not needed, and it is not safe. Aftermarket ones can be awesome, or not, and occasionally a tensioner is needed for certain builds.
Not everyone agrees with me, so use the search bar up top to read more opinions.
Good luck!

Trey
 
Trey

Trey

$50 Cruiser
Jan 17, 2013
1,432
5
0
Where cattle outnumber people 3 to 1.
Was just reminded that the 'arch' tensioner from custom motored bicycles, or at least that design, is a pretty good option.
Bridging the seat and chain stays seems to be the safest option for mounting a tensioner.

Trey
 
3

350

New Member
Jun 19, 2015
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Riverside, Ca
Ballinchestr,
Tray is right I am new to this and have been doing my homework NO tensioner is needed don`t be afraid to cut your chain if you are off a link you can get half links to make better adjustments.

350
 
Davezilla

Davezilla

New Member
Mar 15, 2014
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San Antonio Texas
My opinion on tensioner is to try your best to avoid using them... sometimes there's no other option, but with half links available it definitely makes it a lot more possible to go tensionerless. I've used the factory tensioner successfully on my mountain bike but most likely because my lower frame tube was more oval shaped than round on that bike and it stayed put just by making sure it was nice and tight, then I didn't loosen it or try to move it after it was lined up and tightened down.

my newest build I will be going tensionerless since it worked out really well using a half link, and if the chain stretches I can most likely cut one more link out and just use the regular master link. There are higher quality chains that are pre stretched but these can get quite pricy. If I do end up needing to run a tensioner I would go with one like turbobuick sells or go with one like that arch type that bolts or welds to both the top and bottom tube on the rear triangle, then use a modified roller blade wheel instead of the failure prone white plastic one that comes in the kits.
 
maniac57

maniac57

Old, Fat, and still faster than you
Oct 8, 2011
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I simply tack weld the bracket to the frame to prevent movement.
Any muffler shop can do this for you cheap if you don't have access to a welder.
Cheapest fix.
BEST fix is to set it up to run WITHOUT a tensioner.
 
ballinchestr

ballinchestr

Member
Mar 6, 2014
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Central MA
I have a welder, but it's a 90watt flux core mig, so I'm not sure how well it'll work on the bike's aluminum frame. I found a bit of JB weld though, which I can usually trust to keep things where they need to be.

I would like to go tensionerless, but I've run into a problem. I thought I had #415 chain, so I ordered a #415 half link, and it came in the mail today, but it doesn't fit. I needed to bend the outer part of it for it to fit my chain (see picture), which worked, but when I tried to put it on, the master link's pin was too big to fit into the half link. I didn't think i should force it, because that's not how a masterlink works. Also the half link generally looks thinner.

Now I don't know what size chain I have, because it has different measurements than every other size. The pin diameter is 5/32", and the only chains that fit that are #420 and #425. However, between the inner plates is 3/16", while #420 and #425 are 1/4" and 5/16. I really don't know what size it is, because everything on the chart (http://www.azusaeng.com/chain/mcyclchn.html) has different sizes. If anyone knows this chain, the dimensions are below.

Pitch: 1/2"
Between inner plates: 3/16"
Pin diameter: 5/32"
Roller diameter: ~~10/32 or ~.3125 ( I don't have calipers )

picture: http://i.imgur.com/J7yWL2d.jpg
 
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crassius

crassius

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Sep 30, 2012
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USA
I use 415h 1/2 links that fit the chain, but they are a bit too thick for a standard master link - I have to grind the roller end of the link a bit thinner to make the master pins go all the way thru. Sounds like the opposite of your problem. Never found any with an exact fit for all kit chains. If you get the "H" version of the 1/2 link, it will take fitting by hand, but works OK once you get it on.
 
ballinchestr

ballinchestr

Member
Mar 6, 2014
60
0
6
Central MA
Neither of those charts have a size that matches what I have. The closest size is #40/425, but mine has 3/16" between inner plates, instead of 5/16".

Apparently, the half link I bought was actually 415H, not 415... Kind of stumped now.
 
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Trey

Trey

$50 Cruiser
Jan 17, 2013
1,432
5
0
Where cattle outnumber people 3 to 1.
Are you rich? Can I help you spend some of it? LOL
Seriously, replacing the entire drive chain is an option. There are many good arguments for doing so.
I normally build knowing that I won't use a tensioner, and make small adjustments during mounting that avoid having to replace the kit chain- but it still is only what it is.
If memory serves, the agreed upon 'best' replacement is #41 industrial chain. It should be easy enough to get adjustment links for that.

[Ladies and gentlemen, please correct me if I am wrong on that chain.]

If you want to use what you've got, like crassius said, hand-fitting may be your best option. Consider the stresses when working with chain and alignments, and you'll probably be ok.

BTW 'Stumped' is about half of what this hobby is about ;)
 
ballinchestr

ballinchestr

Member
Mar 6, 2014
60
0
6
Central MA
Looks like I'm gonna end up getting some #420 half links, they seem to be the closest fit. Like crassius said, I'm probably just gonna grind the roller end enough for the masterlink to fit. Other than that, I think it looks pretty good.
 
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