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converting a mid-80's cannondale ten speed to single speed


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#1 ExtremeSupreme

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Posted 11 October 2009 - 02:41 AM

So i just came into this mid 80s cannondale ten speed and the rear derailer screws into the frame just behing the rear wheel. the part of the frame broke and am having a hard time finding an aluminum fab shop to weld it back. even a full weld and then i would drill and tap the new hole.


so im wondering if i can just convert it to a single speed and drop all that. Is it possible?

thanks
FM

#2 dreaded

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Posted 11 October 2009 - 02:49 AM

make it a two speed...

keep the cassette in the back, get a shop to remove enough links off a chain to fit around whichever sprocket you want in the back..

front derailleur works right, viola, two speed..

#3 isma

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Posted 11 October 2009 - 02:55 AM

No, single speed! The rear derailleur is what effectively allows a variable length chain. Find a friend who's into bicycles and they'll have a chain tool.

#4 ExtremeSupreme

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Posted 11 October 2009 - 03:14 AM

so it is possible to turn it into a single speed, then.


Im not sure that the chain would be able to be shortened to just one sprocket in the rear and the shift to either in the front. there is just too big a differance between the front sprockets. I think it would be one or the other.

#5 mikewof

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Posted 11 October 2009 - 03:47 AM

so it is possible to turn it into a single speed, then.


Im not sure that the chain would be able to be shortened to just one sprocket in the rear and the shift to either in the front. there is just too big a differance between the front sprockets. I think it would be one or the other.


A chain tool is just a few bucks, and they're pretty easy to use.

You can take the Norge method and just turn it into a fixed gear bike. There are few things in life more satisfying than a fixed-gear bike. And once you fix, there are only two kinds of riders ...

Converting to a fixed gear bike

#6 mikewof

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Posted 11 October 2009 - 03:51 AM

No, single speed! The rear derailleur is what effectively allows a variable length chain. Find a friend who's into bicycles and they'll have a chain tool.


I think that's not going to be a problem for him, I think his derailleur hanger snapped off. He needs to pull the cluster on the back and either go for a single-speed ratchet or single-speed fix.

The derailleur hanger is the Achilles Heel of modern bike design. I remember one manufacturer used to make one with a replaceable hanger.

#7 judge

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Posted 11 October 2009 - 10:44 AM

It will be an expensive fix and will need somebody who knows which way is up, but if you want to keep some ratios what about a Shimano Nexus or a Sram internal gear hub set up? From 3 to 9 speeds and not too heavy really unless you're in competition. Or even a Rholhoff[?] if money is no object.

#8 Derek Grebe

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Posted 11 October 2009 - 10:58 AM

make it a two speed...

keep the cassette in the back, get a shop to remove enough links off a chain to fit around whichever sprocket you want in the back..

front derailleur works right, viola, two speed..



still need a rear derailleur thingy for the front one to work to take up the slack.....

#9 mad

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Posted 11 October 2009 - 11:10 AM

Nearly all good bikes come with replaceable mech hangers. Its these that save your frame


No, single speed! The rear derailleur is what effectively allows a variable length chain. Find a friend who's into bicycles and they'll have a chain tool.


I think that's not going to be a problem for him, I think his derailleur hanger snapped off. He needs to pull the cluster on the back and either go for a single-speed ratchet or single-speed fix.

The derailleur hanger is the Achilles Heel of modern bike design. I remember one manufacturer used to make one with a replaceable hanger.



#10 punter

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Posted 11 October 2009 - 12:33 PM

So i just came into this mid 80s cannondale ten speed and the rear derailer screws into the frame just behing the rear wheel. the part of the frame broke and am having a hard time finding an aluminum fab shop to weld it back. even a full weld and then i would drill and tap the new hole.


so im wondering if i can just convert it to a single speed and drop all that. Is it possible?

thanks
FM


If you can get someone to weld the derailer bit on, then you can get one of these, http://www.jensonusa...Singleator.aspx

I have one on my single speed and works a treat. Also means it holds chain up when you change wheels.

Also if it is just the derailer that is broken, then some attachable derailers may fit and be welded on.

#11 punter

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Posted 11 October 2009 - 12:42 PM

But also saw this method of converting which ignores the derailer hanger,

http://sheldonbrown....inglespeed.html

Picture in the section called cassette hub.

#12 Great Red Shark

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Posted 11 October 2009 - 05:37 PM

I remember one manufacturer used to make one with a replaceable hanger.


Yeah, funny -that was CANNONDALE ! Really, - back when they first introduced thier all- aluminium frames they incorporated a separate drop-out back there that could be changed out - perhaps your is just prior to that ? My 1985 mountain bike from them sure had it.

Another way that Cannondale sold past the objection that the frame would be more difficult to repair was to offer frame REPLACEMENT at about the cost of a good weld-repair - do you have a good Cannondale dealer nearby ? perhaps ask them if the offer is still valid, and if so strip the frame & send it off to them - they'll either do the fix correctly or if they determine it's boned sell you a replacement - but with a 20+ year-old frame that may be expecting a bit much.

#13 Damp Freddie

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Posted 11 October 2009 - 07:56 PM

make it a two speed...

keep the cassette in the back, get a shop to remove enough links off a chain to fit around whichever sprocket you want in the back..

front derailleur works right, viola, two speed..



still need a rear derailleur thingy for the front one to work to take up the slack.....



let him set it on 42 ( small ring, front) to 17 and just shorten the chain so it doesn't flap.

BUT I would try to get a small bit of aluminium, drill it and get a thread cut and epoxy it on. Maybe one of the canondale replacement hangers, all ready to go, cust cut and shut it!! (first saw one on a carbon frame)

The derailleur doesn't take all that much force so it should work. Buy some glass filler (bead type) to make the epoxy a bit thicker. If it doesn't work you can just chisel or burn it off.

#14 mikewof

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Posted 11 October 2009 - 08:25 PM

Anyone one this thread ride a fixed-gear bike?

Losing his derailleur hanger is the best thing that could have happened, because the cheapest solution is fix-gear it, and then he's left with the purest expression of the bicycle art. (Leave the brakes on for a while though, until you get the hang of bouncing back.)

Fixes really condition you, there is just no comparison, the body never stops riding the legs never stop working. And the whole idea goes away of keeping your revs constant with the gears, it forces a wide range of efficiencies. I love 'em.

#15 ExtremeSupreme

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Posted 12 October 2009 - 01:08 AM

thanks for all the info

I found sheldonbrowns website and found some stuff there but the best and cheapest is from the ehow.com page.
Hopefully the cassette can come apart and then use the spacers and small ring to straighten up the chain.

thanks again

FM

#16 mikewof

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Posted 12 October 2009 - 01:29 AM

thanks for all the info

I found sheldonbrowns website and found some stuff there but the best and cheapest is from the ehow.com page.
Hopefully the cassette can come apart and then use the spacers and small ring to straighten up the chain.

thanks again

FM


I wouldn't hold out on your cassette coming apart, unless you have the high-end stuff. You'll be able to take the front sprockets apart and just use the big one though. You'll need a cluster remover for the back to get it off because of the freewheel (About $5), assuming it doesn't come apart just toss it into your parts box, put a new rear sprocket on, use your chain tool to shorten your chain. Between the chain tool, cluster remover, spacers and a cheapish back sprocket you'll only be out $30 or so.

By the way, if you have the high-end Dura Ace hardware, it might be worth enough to buy yourself a new bike. Some vintage bike guys go nuts for that stuff.

#17 dogsridewith

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Posted 13 October 2009 - 12:46 AM

you can't epoxy the broken part back on and you can't just shorten chain to have a one speed. With earlier bikes having "horizontal" dropouts, you could get the axle position adjustment required for single speed. Yours has "vertical" dropouts.

You can weld on a dropout. You can screw on a new dropout if it has a replaceable dropout. You can get a Wheelsmith dropout replacer that is held under the rear axle. You can get an eccentric bottom bracket (crank axle bearings), or an eccentric rear hub, and convert to single speed. (With eccentrics options, you can use a special link that replaces a link pair...at least with single-speed/BMX chain.)

#18 MoeAlfa

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Posted 13 October 2009 - 12:56 AM

thanks for all the info

I found sheldonbrowns website and found some stuff there but the best and cheapest is from the ehow.com page.
Hopefully the cassette can come apart and then use the spacers and small ring to straighten up the chain.

thanks again

FM

Just make sure the chain line is good, or it'll derail at exactly the wrong time and lock up your rear wheel and/or destroy the chain ring, or wreak other havoc. You will also have to tighten the shit out of the quick release to keep the axle from working forward on the cog side, unless you have truly vertical dropouts. You may be able to get chain tugs that will fit and keep this from happening. I rode just such a beast for years before all the conversion stuff was available.

Instead of the existing cluster, you may be able to screw on a single speed freewheel of fixed cog and play with the spacing up front. I know I've seen parts that do this.

#19 Akaron

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Posted 13 October 2009 - 01:05 AM

Anyone one this thread ride a fixed-gear bike?

Losing his derailleur hanger is the best thing that could have happened, because the cheapest solution is fix-gear it, and then he's left with the purest expression of the bicycle art. (Leave the brakes on for a while though, until you get the hang of bouncing back.)

Fixes really condition you, there is just no comparison, the body never stops riding the legs never stop working. And the whole idea goes away of keeping your revs constant with the gears, it forces a wide range of efficiencies. I love 'em.


Yeah, it's great (if you're a hipster) until your knee ligaments shit a brick. If you don't believe me, talk to your local sports-med expert. Gears where invented for a reason, and i'll keep mine, thanks.

#20 MoeAlfa

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Posted 13 October 2009 - 01:16 AM

Anyone one this thread ride a fixed-gear bike?

Losing his derailleur hanger is the best thing that could have happened, because the cheapest solution is fix-gear it, and then he's left with the purest expression of the bicycle art. (Leave the brakes on for a while though, until you get the hang of bouncing back.)

Fixes really condition you, there is just no comparison, the body never stops riding the legs never stop working. And the whole idea goes away of keeping your revs constant with the gears, it forces a wide range of efficiencies. I love 'em.


Yeah, it's great (if you're a hipster) until your knee ligaments shit a brick. If you don't believe me, talk to your local sports-med expert. Gears where invented for a reason, and i'll keep mine, thanks.

Don't confuse single speed and fixed gears and anyone who injures a knee cycling is either using pre-1980s cleats or doing something equally strange. I have both fixed and free on a flip-flop hub and use the fix occasionally on weekends, but commute about 75 fairly hilly miles a week on the free side (42/18) and my 53 year-old knees love it.

#21 razorback

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Posted 13 October 2009 - 01:35 AM

Anyone one this thread ride a fixed-gear bike?

Losing his derailleur hanger is the best thing that could have happened, because the cheapest solution is fix-gear it, and then he's left with the purest expression of the bicycle art. (Leave the brakes on for a while though, until you get the hang of bouncing back.)

Fixes really condition you, there is just no comparison, the body never stops riding the legs never stop working. And the whole idea goes away of keeping your revs constant with the gears, it forces a wide range of efficiencies. I love 'em.


Yeah, it's great (if you're a hipster) until your knee ligaments shit a brick. If you don't believe me, talk to your local sports-med expert. Gears where invented for a reason, and i'll keep mine, thanks.

Don't confuse single speed and fixed gears and anyone who injures a knee cycling is either using pre-1980s cleats or doing something equally strange. I have both fixed and free on a flip-flop hub and use the fix occasionally on weekends, but commute about 75 fairly hilly miles a week on the free side (42/18) and my 53 year-old knees love it.

Yeah, I was going to point out that fixed and SS are not one and the same. I ride a SS 29er MTB and love it, but respectfully pass on the fixie on any surface.

#22 Akaron

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Posted 13 October 2009 - 01:53 AM

Anyone one this thread ride a fixed-gear bike?

Losing his derailleur hanger is the best thing that could have happened, because the cheapest solution is fix-gear it, and then he's left with the purest expression of the bicycle art. (Leave the brakes on for a while though, until you get the hang of bouncing back.)

Fixes really condition you, there is just no comparison, the body never stops riding the legs never stop working. And the whole idea goes away of keeping your revs constant with the gears, it forces a wide range of efficiencies. I love 'em.


Yeah, it's great (if you're a hipster) until your knee ligaments shit a brick. If you don't believe me, talk to your local sports-med expert. Gears where invented for a reason, and i'll keep mine, thanks.

Don't confuse single speed and fixed gears and anyone who injures a knee cycling is either using pre-1980s cleats or doing something equally strange. I have both fixed and free on a flip-flop hub and use the fix occasionally on weekends, but commute about 75 fairly hilly miles a week on the free side (42/18) and my 53 year-old knees love it.

Yeah, I was going to point out that fixed and SS are not one and the same. I ride a SS 29er MTB and love it, but respectfully pass on the fixie on any surface.


I know, I was refering to mike's question about fixies.

I've injured both my knees cycling, both PRIOR to owning a bike with cleats. The first was from a bike (single speed) that did not fit properly, and riding too much, after which I was told on no uncertain terms I was to ride nothing without gears. The second was a bizarre accident, that I can not fully comprehend. Somehow I managed to jam my leg between the handlebar and the pedal (the bike should have a 110mm stem, but it's got a 20mm) whilst unsuccessfully riding down a set of stairs in a parking garage. Yeah, I know, riding in parking garages is both stupid and illegal, but it was fun.

#23 mikewof

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Posted 13 October 2009 - 03:06 AM

Anyone one this thread ride a fixed-gear bike?

Losing his derailleur hanger is the best thing that could have happened, because the cheapest solution is fix-gear it, and then he's left with the purest expression of the bicycle art. (Leave the brakes on for a while though, until you get the hang of bouncing back.)

Fixes really condition you, there is just no comparison, the body never stops riding the legs never stop working. And the whole idea goes away of keeping your revs constant with the gears, it forces a wide range of efficiencies. I love 'em.


Yeah, it's great (if you're a hipster) until your knee ligaments shit a brick. If you don't believe me, talk to your local sports-med expert. Gears where invented for a reason, and i'll keep mine, thanks.


As a "hipster" thing that's fairly new. Back in the day we rode fixes because they were less likely to get stolen, they were cheaper and could be converted from otherwise trashed bikes, they could be used on the track and they were faster for the shorter runs.

I've never taken one on a century, but for street riding, they're excellent. Another reason they're good; they're easier to manage with a lot of stop & go riding.

#24 Damp Freddie

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Posted 13 October 2009 - 09:31 PM

you can't epoxy the broken part back on and you can't just shorten chain to have a one speed. With earlier bikes having "horizontal" dropouts, you could get the axle position adjustment required for single speed. Yours has "vertical" dropouts.

You can weld on a dropout. You can screw on a new dropout if it has a replaceable dropout. You can get a Wheelsmith dropout replacer that is held under the rear axle. You can get an eccentric bottom bracket (crank axle bearings), or an eccentric rear hub, and convert to single speed. (With eccentrics options, you can use a special link that replaces a link pair...at least with single-speed/BMX chain.)



Seen both jobs done- epoxy for a hanger, which is near the drop out but on an aluminium cannondale there would be enough surface area to glue one on., maybe best a splint over the joint. Beacuse deraileurs are so adjustable, it does not need to be micron perfect! Just very straight in the two main axis and adjusted for a good distance from top jockey wheel to lowest sproket ( eg 21 or 24 tooth biggie) . There is little load on the derailleur if you set it up right.

Putting the chain on one of the middle sprockets, say 17 on a 24-12 set, forgetting the derailleur is a bad way compromise admitedly, you will struggle to get it perfect without chain slap. I have seen a guy on a mountain bike limping home with this having used a little breaker on a multitool to affect the job after an involuntary derailleur-ectomy!

You can, however it being an old frame, rebuild with a cheap fixed hub, because the axle width is narrow, is not like a modern 8 speed frame/axle set up. You will probably need some spacers/washers to get it really in line with your small ring on the chain set though.

- there was actually a two sided hub available, with a free wheel single on one side to get you used to no gears, and a fixed gear on the other side. Some road racers used them in the winter or to try out track riding with the 'wrong' forward facing horizontal-ish drop outs and I presume verticle. Proper track bikes had 'reverse' horizontal ie wheel was a back loader :P not to use it in the biblical sense that is....making it impossible to pull out it out with leg muscles ( :) ) it gets worse....inuendos, italian suppositories that is.




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