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PostPosted: Fri Feb 10, 2012 8:15 pm 
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cyfa2809 wrote:
If your running a 68mm shell you may have to get a 73mm bb and spacers to compensate and possibly a slightly lnger axle.


I hadn't thought about this? I saw a thread on here today through a search that had a Cotic owner welding extra width onto the BB. I guess this was what it was for now...

Would I have to compensate the Chainline to the middle of the block at the back? Hence the spacing on the 68mm shell.


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PostPosted: Fri Feb 10, 2012 8:21 pm 
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This is the link I found.
http://www.retrobike.co.uk/forum/viewto ... ight=cotic

& The Cotic is a 73mm Shell, so my hoard of SQ Tapers won't fit...So, 73 BB or Modern Chainset...Just I really like the RF Turbines...


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PostPosted: Fri Feb 10, 2012 8:48 pm 
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The only issue I have with 1x9/10 set ups with chain devices all the one I have seen have chain rub against the guide in extreme gears. This included an On-one 456 1x9 with a e:13 guide tensioner. The roller created a bit more resistance as well. Fine for downhill hilling but for trail riding it would annoy me. 2x10 would works quite well. SS works very well so long as it not hilly like the peaks/cannock/wales e.t.c

I just don't like tensioners/guides, makes a bike look messy. I agree using an unramped chainring is a good idea but I use a ramped chainrings on both single speeds without guides and never had a chain trying to escape. Also I ran one single speed as 2x9 (when I fitted a bash guard) and then 1x9 (when I bent the granny ring) and then as single speed when the cogs wore out. No guides and I never had a chain trying to escape. I just don't believe the need for them.


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PostPosted: Fri Feb 10, 2012 9:06 pm 
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I guess to begin with I'll have to ascertain the rear chainline & then calculate the necessary front. This would decide on a Mod to the frame as in the Link post above or see what I can do with Spacers.

Would also be an option to decide on a chainguide or not?...With SS isn't the tension keeping the chain on, whereas with geared it would free the chain more liable to drop off the front?


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PostPosted: Fri Feb 10, 2012 9:28 pm 
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'E type' BB's do accomodate for an e type front mech which is where the chain device would sit. You can also get seat tube mounted devices.
Not sure how your chain line would be, you MAY be able to get away with the same length axle. Some devices are flexible/can be bent though. I think i can space mine out or in and what not (blackspire ns1 and ds1).


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PostPosted: Sat Feb 11, 2012 10:30 am 
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Well since I ran 2x9 and 1 x9 on my Orange for a while before it became single speed I never had the chain coming in the trail riding I did.

I can understand the logic of these devices but I think it worth seeing if you need one first ortherwise you maybe buying a solution in search of a problem.

Also you would be surprised at how any people and shops think you need a chain guide to keep the chain on a single speed!


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PostPosted: Sat Feb 11, 2012 10:43 am 
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i see what you a saying re the chain guides but it really is a matter of riding style and terrain. as i say my fr bike has a full device as it is used on trails with drops, tables and other assorted jumps. the device also has a skid plate so i dont need a bash guard. as you say you do get a bit of rubbing on the extremes, but the blood is usally pumping so hard in my ears i cant hear it. the xc bike has a bb mounted roller just to add a bit of tension, probably dont need it but seems to sharpen up the shifting bit. also looks bad ass in my opinion.


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PostPosted: Sat Feb 11, 2012 8:32 pm 
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That's the thing -riding style. I was persuaded once that I needed a guide and tensioner for my Orange SS. Bought them used them then removed them and found I did not need it given my riding style.

What you do sounds like you might need a guide. I am too much of a chicken to try big drops, table tops and free riding in general. I am XC rider and I cannot change that.


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PostPosted: Sun Feb 12, 2012 2:10 am 
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I'm thinking along the lines of Trail/XC...but 1x9 is maybe a fad idea? Anyhow, keen to give it a bash & see. I've seen the JumpStop chain device that may help along with getting the chain length right.


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PostPosted: Sun Feb 12, 2012 10:58 am 
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3x9 Is a fad idea haha.


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