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Post by cusqueno on Jun 23, 2014 11:00:44 GMT
I know Stella has a block with skip tooth cogs and as I recall one or two other people have them as well. Question is: are they at all different in their shifting behaviour to ordinary cogs? I am refurbing one of my Aerospace bikes and have fitted a 14 - 17(=34) skip tooth block.
I am using a short cage Crane and Lambert/Viscount 'porthole' chain wheels (52-42). So the total teeth to be shifted is 30 (although Sutherland gives the total capacity of the Crane as 28 teeth). 34 teeth is the largest on any of my bikes. Any problems, tips?
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Post by Stella on Jun 23, 2014 11:39:41 GMT
Hey, John.
You'll find that they ride easier. If I remember correctly, I've got the same gear ratio on my blue one and I'm running it with a long cage derailleur, which I'd advise you to do, too. Never tried the short cage, but could imagine that shifting on the largest ring may be a problem as it's basically 34 teeth, whereas the Crane short cage will only cope, as you already stated, with up to 28 teeth.
In general I really like riding the skiptooth freewheels, hence my rally bike will have one and I've got another one which I'll probably put on the Lambert. You'll love it.
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Post by cusqueno on Jun 23, 2014 12:32:42 GMT
As I understand it, the total capacity is the difference between the largest and smallest chain wheels added to the difference between the largest and smallest cogs. So, in my case, it will be (52-42) + (34-14) = 10+20 = 30 ; which is still more than 28 but only by 2. I have hopes that it will work, but perhaps I should look out for a Crane GS. They're nice derailleurs as well.
Edit - I now see that Sutherland also says that the maximum cog size is 28, as well as the maximum capacity - so Stella is right. Sorry!
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Post by Stella on Jun 23, 2014 12:52:04 GMT
Sorry. :-(
My understanding is that the front chain rings don't matter. It's the distance the jokey wheels on the rear mech have to travel to push the chain onto the largest cog that is the problem. The cage's just not long enough. Try it out, nothing wrong with that, then swap for a long cage if it doesn't work. I prefer long cage derailleurs anyway. Pretty little beast, they are. :-)
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Post by velocipete on Jun 23, 2014 14:36:39 GMT
You may find that the cage fouls the block teeth while trying to get onto the largest cog.
You may be able to overcome this by use of the mechs b screw.If not,it's mech change time!
I think I've got a spare Tourney gs which I'll be bringing this week end.
Cheers,
Pete.
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Post by sprockit on Jun 23, 2014 20:32:50 GMT
I'm no expert, but once enquired about lowering the gearing on my 5-speed Sport and was told that, to allow the necessary clearance, I'd need a long cage derailleur and maybe a different hanger.
The LBS owner was very interested in the bike because he'd once visited the Viscount factory at Potters Bar, and knew they'd gone out of business a long time ago.
Regards,
Sprockit
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Post by cusqueno on Jul 5, 2014 9:19:12 GMT
I've just got this Crane GS from the US. Quite cheap as it needs a good clean. Strangely, the cage appears to have the date code TN - you might be able to see this on the second picture. I can't account for this as 1976 was year A, and Cranes were made,IIRC, from about 1972 to 1978. Impatient to fix up my bike but domestic chores are likely to intrude. flic.kr/p/ocUA5Zflic.kr/p/ocUzZPEdited because I found the cable clamp - it was loose in the package. |
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Jem
Viscount
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Posts: 3,391 
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Post by Jem on Jul 5, 2014 9:49:52 GMT
I can't really see enough detail in that picture John, but if I had to make a rational stab at it, I'd have a go at one of these two options below 1) Mistake 2) The 'T' is in fact an 'I' with uneven pressure exerted on the punch? Not very likely though. Mystery?  ? |
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Post by Stella on Jul 5, 2014 10:28:12 GMT
I remember this one. If you clean it up and give it a polish it should come up nicely. This will work a treat. Just a quick note: I noticed on my Viscountess, that I need to pull the shifter down quite a bit until it shifts up. Down is not so much a problem. Something I haven't encountered with the blue bike.
In general, this skiptooth freewheel seems a little different in performance. Its ratio is: 14,17,22,14,17
Have to look at the blue Sport to see if it's the same. If so I'll need to investigate why the shifting feels different. Both have long cage derailleurs.
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Post by cusqueno on Jul 13, 2014 19:55:34 GMT
Yesterday fitted the Crane GS to my Sport/Pro now with a skip tooth block and bar end shifters. Looks promising but bike not yet rideable so more adjustment will probably be needed before it all works properly. Sent from my iPhone using Tapatall Attachments:
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Post by Stella on Jul 16, 2014 7:31:13 GMT
Drooling here.
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