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PostPosted: Sun Mar 18, 2018 1:56 am 
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Joined: Tue Jul 07, 2015 10:52 am
Posts: 258
Location: Colchester, Essex
I wanted to recreate a bike I rode in the 70's for nostalgic reason and to have something to experiment with. The bike, late 50's Holdsworth Monsoon, came with 5sp Cyclo gears and at the time I rebuilt it as 10sp very much in a 70's style. For this bike I also wanted more than the std. 5 speeds.

Having looked at the Sheldon Brown web site it was clear that a modern cassette spacing could fit more gears into the reach of the Cyclo RD. I found some old 105 uni glide hubs that fit the rear spacing then swapped the free hub for a hyper glide one to fit a 10sp cassette. In theory the 24mm movement should cover 7 10sp cogs, in reality it does't quite so having to modify the barrel of the RD I took it to 8sp by drilling it out further to give 32mm moment. The narrow chain needed fits the jockey wheels ok, but tends to slip off the lower plane jockey wheel and jam on the cage. This was fixed by getting the chain line in the middle of the cassette and swapping the plain jockey wheel for a toothed one.

Once setup correctly a front rod derailleur was added to give 16 speeds. Once I got used to the friction shiftier again it changes really nicely, even with the closer gear spacing. I did try a trigger indexer, but the coil spring is too strong when fully compressed and a step too far. So a traditional Campag down tube level does the job very well. Done just over a couple of hundred miles on it now and so far all is going well.

May not be to everyone's liking, but it can be done.

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PostPosted: Sun Mar 18, 2018 8:48 am 
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Joined: Thu May 20, 2010 9:03 am
Posts: 2047
Location: Bodmin,Cornwall.
Are you some kind of trouble maker a rebel maybe, people will get very upset at what you've done.
I think it's great and have always wondered about doing similar.


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PostPosted: Sun Mar 18, 2018 10:12 am 
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Joined: Tue Jul 07, 2015 10:52 am
Posts: 258
Location: Colchester, Essex
Yes, I did think twice about posting, but it is RETRO bike. Initially I didn't know about the rod FD , I'd seen lever ones, but didn't fancy them. So it was a way to increase the gears. Pushing the limit of tooth capacity, but seems to work.


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PostPosted: Mon Mar 19, 2018 7:28 am 
r.B.o.T.M. & P.o.T.M. Winner
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Joined: Sun Jul 11, 2010 1:41 pm
Posts: 2670
Location: Plymouth, UK
Must be very small movements/increments on the front lever for the rear mech to move.


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PostPosted: Mon Mar 19, 2018 8:40 am 
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Joined: Tue Jul 07, 2015 10:52 am
Posts: 258
Location: Colchester, Essex
Yes, I guess so. 5sp is around 5mm spacing and the 10sp is 3.95mm so that the difference, but I think because the narrow chain is sitting snug on the jockey wheels that helps with the precision. Because I have extended the reach a bit you need nearly a full 180 Deg movement at the leaver.

I have to say so far it changes really nicely, just as well as my other bikes. I think where it does show up is if you are a bit out with the lever movement. it's either nicely in gear or jumping badly, there is no clattering of the chain on teeth when you are slightly off. Mind you that could also be the effect of the teeth profile on modern cassettes. It is very satisfying when it just drops into gear quietly.


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