Single speed conversion - which chain?

[Percy]

Just had a look at them PP - they look good. Might give it a go. Cheaper than a sprung one too, which is a bonus!

The nightmare continues...

I am now the proud owner of one of these, on padallingpasty's recommendation:

http://www.chainreactioncycles.com/Models.aspx?ModelID=17724

And it looks good and much sturdier than the sprung tensioner I was using before. On attempting to fit, it became clear that the position of the drop out and the derallieur hanger hole didn't allow for it to push the chain up, as is the preferred method - but it does fit pushing it down, which is fine.

The problem I have with it is chain line - the tensioner only sits on one line, not allowing for lateral movement. The roller is quite wide but with the chain line I have, it's in the wrong place - the chain 'grabs' the plastic edge of the roller as the chain runs over it. I've tried fitting a washer to bring it back out a bit but this wasn't enough and it put the quick release skewer at a funny angle. I've also tried changing my chain line, as of course you would, but to move it to fit with the tensioner would render it completely out of line - it started skipping on the front chainring.

If I'm looking at adjusting the lateral line of this tensioner, is my only option now to physically bend it to the position I need it in? I'm happy to do that but reluctant to start on it if there's a more obvious solution I've not recognised yet.

 

[Percy]

The nightmare continues...

I am now the proud owner of one of these, on padallingpasty's recommendation:

http://www.chainreac...x?ModelID=17724

And it looks good and much sturdier than the sprung tensioner I was using before. On attempting to fit, it became clear that the position of the drop out and the derallieur hanger hole didn't allow for it to push the chain up, as is the preferred method - but it does fit pushing it down, which is fine.

The problem I have with it is chain line - the tensioner only sits on one line, not allowing for lateral movement. The roller is quite wide but with the chain line I have, it's in the wrong place - the chain 'grabs' the plastic edge of the roller as the chain runs over it. I've tried fitting a washer to bring it back out a bit but this wasn't enough and it put the quick release skewer at a funny angle. I've also tried changing my chain line, as of course you would, but to move it to fit with the tensioner would render it completely out of line - it started skipping on the front chainring.

If I'm looking at adjusting the lateral line of this tensioner, is my only option now to physically bend it to the position I need it in? I'm happy to do that but reluctant to start on it if there's a more obvious solution I've not recognised yet.

Anyone had any experience with chain line problems with a Gusset chain tensioner...before I stick it in the vice this afternoon..?

 

[pedallingpasty]

Percy, didn't spot your post yesterday. But hopefully you are not sat there with 2 bits of tensioner in your hand. If it is cast ali, it may not like being bent around.
I have no experience with that type of tensioner myself, as mentioned i have managed to get mine running now without the tensioner. But with your gear ratio it looks like the best way to go to get the chain wrap.
Looking at your picture, your wheels look very similar to my old ebay clunker. Its not very clear, but is your rear wheel a screw on type hub fitted with a freewheel cog?
Also your crank looks like a track type.
If it is, this may be why your tensioner doesn't seem to fit.
If its a screw on hub, your chainline is going to be nearer the centerline of the bike than a normal mtb ( more like a road bike). But your dropout width is still the normal mtb width of about 135 mm, so when you fit your tensioner to your dropout it looks as though its too far out from the chainline.
My own mtb is fitted with the normal freehub with splines with a chain ring fitted to the mid position on mtb cranks, so the chainline maybe further out then yours by using spacers on the rear cog. So i expect i wouldn't have any problems with the tensioner you have.
I am guessing a bit from the picture, so above could be a load of b*ll*cks.
Not sure of any fixes, is it posible to fit it on the inside of your dropout?
Hope it goes ok, apologies for no solutions at the moment.

 

[Percy]

Percy, didn't spot your post yesterday. But hopefully you are not sat there with 2 bits of tensioner in your hand. If it is cast ali, it may not like being bent around.
I have no experience with that type of tensioner myself, as mentioned i have managed to get mine running now without the tensioner. But with your gear ratio it looks like the best way to go to get the chain wrap.
Looking at your picture, your wheels look very similar to my old ebay clunker. Its not very clear, but is your rear wheel a screw on type hub fitted with a freewheel cog?
Also your crank looks like a track type.
If it is, this may be why your tensioner doesn't seem to fit.
If its a screw on hub, your chainline is going to be nearer the centerline of the bike than a normal mtb ( more like a road bike). But your dropout width is still the normal mtb width of about 135 mm, so when you fit your tensioner to your dropout it looks as though its too far out from the chainline.
My own mtb is fitted with the normal freehub with splines with a chain ring fitted to the mid position on mtb cranks, so the chainline maybe further out then yours by using spacers on the rear cog. So i expect i wouldn't have any problems with the tensioner you have.
I am guessing a bit from the picture, so above could be a load of b*ll*cks.
Not sure of any fixes, is it posible to fit it on the inside of your dropout?
Hope it goes ok, apologies for no solutions at the moment.

Thanks for the reply PP.

All components are as per a standard MTB conversion - so cassette hub with cog/spacers fitted and the crank is a Shimano replacement three ring MTB crank with the smaller two chain rings taken off. So in theory, it's a standard conversion that the tensioner is supposedly made for. Never that simple though is it!

Been away this weekend but will have another proper look at it when I get in from work today. It is strange - it's almost there, maybe half a centimetre out, but then I guess that's all it needs.

May post another pic or two later if I don't manage to find a solution.

p.s. Oh and no, tensioner isn't in two bits yet! I haven't tried bending it yet - will use that as a last resort and proceed with caution when/if I do!

 

[Percy]

A few pics in the hope that one of you might spot whatever it is that I am evidently missing. The thing that is really confusing me (i.e. seriously annoying me now!) is that the chain runs along the tensioner fine when pedalling backwards - as shown in pic 1 (incidentally, you may notice the pics are with the bike upside down, looking at the drivechain from the back).

Pedal forwards, however, and the chain runs over to the extreme left of the tension wheel (pic 2) and causes juddering on the plastic side of the wheel.

Pic 3 is attached in the hope it might help in some other way - chain line? I'm using the same chain line as was originall set up by the shopp who converted it originally, and I ran it fine like that for over a year.

SOmething I have just noticed in sorting these pictures out is that the derailleur hanger looks like it might be slightly bent - pushing the tensioner offline, towards the wheel. Can you see that? Maybe that's the problem!

I'm also not entirely convinced by the chainline, despite what I say about the LBS above. In current set up the front chainring teeth 'grab' at one side of the chain - suggesting that (and looking like) the chian runs across them with a bias to one side. But to move the chain to attempt to correct this would be to push it further towards the frame and, seemingly, completely out of line.

I dunno - the hanger bend does look like it mightn't be doing a whole lot of good..!