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Re: Shifting with downtube shifters

Posted: Thu Aug 16, 2012 8:55 pm
by Grog
Now to really confuse the situation....
Any comments on downtube shifters vs headstem shifters?

Re: Shifting with downtube shifters

Posted: Thu Aug 16, 2012 9:18 pm
by bychosis
I have my bell on my stem, and I reckon its more difficult to reach than the downtube shifters, especially when on the drops.

Maybe I should put the bell on the down tube?

I seem to be getting the hang of shifting too. I don't shift anywhere near as often as on the MTB where the trigger is at your fingertips, but it's not hard. I've found it is easier to overshift a little then move back than it is to 'creep up' on the next gear.

Re: Shifting with downtube shifters

Posted: Thu Aug 16, 2012 10:14 pm
by rkelsen
Grog wrote:Now to really confuse the situation....
Any comments on downtube shifters vs headstem shifters?
Headstem shifters were usually installed on the low end "racers" of the 70s and 80s. Their best use is to indicate which bikes you should leave on the hard rubbish pile.

Re: Shifting with downtube shifters

Posted: Thu Aug 16, 2012 10:56 pm
by bigfriendlyvegan
rkelsen wrote:
Grog wrote:Now to really confuse the situation....
Any comments on downtube shifters vs headstem shifters?
Headstem shifters were usually installed on the low end "racers" of the 70s and 80s. Their best use is to indicate which bikes you should leave on the hard rubbish pile.
+1 - and suicide levers. They're junk tags.

Re: Shifting with downtube shifters

Posted: Fri Aug 17, 2012 8:38 am
by WyvernRH
Big_Red wrote:I'd have thought that indexing on DT shifters would be limiting as you are constrained to only using a freewheel or cassette with the sprockets a particular distance from each other. I'm considering getting a new wheelset for my old Paconi, which will result in a replacement of the suntour 6sp freewheel with a shimano 9 speed (casette) and relish the fact that it'll be just a swap of the wheels to achieve as the trimming between the gears is all manual.
Well, Yes/No on that one. The limitation you mention is a limitation on all indexed gear systems not just downtube levers. Also, providing you stick to one brand you can generally use any number of sprockets up to at least 8 speed as the spacing stays the same. Assuming you are not trying to mix an 8spd block with a lever that only has 5 indexes of course :) . But if you have a 8spd indexed Shimano lever it will work with 5->8 speed Shimano spaced sprockets, Shimano spacing is virtually industry standard these days since SunTour and Campag gave up using their own spacing on sprockets.
You can run into problems with non-index systems as well when upgrading. Sometimes an older 5-speed lever just doesn't have the cable wrap needed to pull a particular type of rear derailleur across the 9 sprockets. Early Campag (and copies thereof like Gian Robert) are a good example of this.
Still, I have to agree that friction does give you the most versatility across the whole range of sprocket spacings and actuation ratios in rear derailleurs that various manufacturers have used over the last few decades.
Cheers
Richard

Re: Shifting with downtube shifters

Posted: Fri Aug 17, 2012 9:36 am
by rkelsen
You can also turn off the indexing on many of the Shimano downtube shifters.

Incidentally, I ran an A400 7 speed d/t shifter with an 8 speed cassette for a while. After the 6th click (at about 90 degrees) it goes into friction mode and you can keep turning it for another 90 degrees. The spacing of the cassettes is the same, and the 8th "click" into low gear was actually against the derailleur limit screw.

I still have it, but it has been supplanted by a Centaur Ergopower brifter.

Re: Shifting with downtube shifters

Posted: Fri Aug 17, 2012 12:42 pm
by WyvernRH
rkelsen wrote:Incidentally, I ran an A400 7 speed d/t shifter with an 8 speed cassette for a while. After the 6th click (at about 90 degrees) it goes into friction mode and you can keep turning it for another 90 degrees. The spacing of the cassettes is the same, and the 8th "click" into low gear was actually against the derailleur limit screw.
That's interesting to know. Thanks for the info!
Cheers
Richard

Re: Shifting with downtube shifters

Posted: Fri Aug 17, 2012 12:43 pm
by frailer5
rkelsen wrote:You can also turn off the indexing on many of the Shimano downtube shifters.
Interesting. I missed some of the transition stuff back then. More familiar with really old stuff, like me. :lol: What's the go with these, when I finally get the pedals in an get on the road? Don't have a pic right now on the RHS shift lever, but pretty sure it has a half-round flip-out tension ring as well. What are the adjustment procedures on them; with that slotted cap?

Image


OK, this one shows it...

Image

Re: Shifting with downtube shifters

Posted: Fri Aug 17, 2012 1:35 pm
by rkelsen
frailer5 wrote:
rkelsen wrote:You can also turn off the indexing on many of the Shimano downtube shifters.
Interesting. I missed some of the transition stuff back then. More familiar with really old stuff, like me. :lol: What's the go with these, when I finally get the pedals in an get on the road? Don't have a pic right now on the RHS shift lever, but pretty sure it has a half-round flip-out tension ring as well.
The LH downtube shifter in your photo isn't indexed. Most of them weren't. Some may have been, but I've never seen an indexed LH d/t shifter.

The ring on the RH one isn't for tension. It's a 'switch' that allows you choose between indexing or friction.

Re: Shifting with downtube shifters

Posted: Fri Aug 17, 2012 1:45 pm
by koen
All early indexing allowed a switch to friction except maybe some really cheapo shifters. I ran/raced with these right into the 2000s and usually with more gears than the clicks as someone mentioned. It is easy to get 7speed indexing off 6 speed shifters using the rear mech limit as the last "click". The middle few spacers need to be 6 speed width though. Some late eighties Suntour rear mechs I couldn't get to cover 8 or 9 speeds ...not enough movement in the mech.

Re: Shifting with downtube shifters

Posted: Fri Aug 17, 2012 3:35 pm
by frailer5
koen wrote:All early indexing allowed a switch to friction except maybe some really cheapo shifters. I ran/raced with these right into the 2000s and usually with more gears than the clicks as someone mentioned. It is easy to get 7speed indexing off 6 speed shifters using the rear mech limit as the last "click". The middle few spacers need to be 6 speed width though. Some late eighties Suntour rear mechs I couldn't get to cover 8 or 9 speeds ...not enough movement in the mech.
.... while you're there.... :D That refers to spacers in the shifter spindle mech? :|

Re: Shifting with downtube shifters

Posted: Fri Aug 17, 2012 5:52 pm
by munga
cassette spacers:

Image

Re: Shifting with downtube shifters

Posted: Fri Aug 17, 2012 6:43 pm
by verbs and nouns
Semi-related, I raced 'cross with 7 speed friction bar end shifters last weekend. No problems at all, and it being friction meant I could dump it into the smallest sprocket in the fast parts, then yank it back up for the muddy sections.

Re: Shifting with downtube shifters

Posted: Fri Aug 17, 2012 7:47 pm
by munga
so it was two-speed with five transitioning ramps :P

Re: Shifting with downtube shifters

Posted: Fri Aug 17, 2012 9:16 pm
by Mulger bill
munga wrote:so it was two-speed with five transitioning ramps :P
:lol: :lol:

Re: Shifting with downtube shifters

Posted: Fri Aug 17, 2012 11:53 pm
by Stuey
Frailer, you'll see that little red arrow on the RH shifter points to either 'SIS' or 'Fric.' for indexed or not.

Re: Shifting with downtube shifters

Posted: Sat Aug 18, 2012 8:55 pm
by frailer5
Stuey wrote:Frailer, you'll see that little red arrow on the RH shifter points to either 'SIS' or 'Fric.' for indexed or not.
:thumbsup: Got it, thanks Stuey. Would have taken a while to suss that out. Couldn't see any 'SIS'/'Fric' markings (though I may in full daylight :lol: ) but twisting through roughly 90ยบ gives the appropriate feel in the lever. Thanks!