Downtube shifters

[328isport]

hi all,

i've recently purchased my first bike, a 1980's Raleigh Elan, however it's been rebuilt, powdercoated light blue and has prolite rims and conti ultras on it, really happy with the bike and enjoying it as such as i thought i would, however i'm after some advise on downtube shifters, my gearset is a mixture of tiagra and exage components, i have 8 cogs on the back and two upfront, at the minute i've mostly been using it in what i believe is top gear, big chain ring on the front, smallest one on the back, however i've found if i change down after a while the bike will change back up by itself and then sometimes back down again, i'm assuming this is could be me not using the shifters right, when i looked at it the other night i found the front derailler was right against the chain which i think was causing the chain to shift gears at the back, so i moved this off the chain slightly and it's now fine in top gear, but if i drop a gear it'll do the same again, that is switching between one off the top gear and the top gear at the back.

Any ideas? i'd appreciate a little crash course on how to use downtube shifters if anyone has one! my other question is do i need to go though all the gears on the back wheel on the main chainring - i'm assuming 8-16 before i should be dropping down to the smaller chainring upfront and starting again?

thanks!

 

[Bigsharn]

Are the levers friction levers or indexed? Simple way to tell is if it clicks into gear, or you have to "feel" your way into a gear (ie, you move the lever until it changes gear, but no click to confirm this).

If it clicks, it's because your gears aren't indexed correctly and someone will be able to guide you through the process better than I can. If it doesn't click just feel your way into the gear, then give it a tiny bit more, as you may not be "in" the gear per se, but between gears.

Hope this helps.

 

[biggs682]

80's elan could be indexed if i rember rightly

 

[TonyEnjoyD]

With downtube shifters, you go over slightly then back off to align, so if going say 5th to 4th, you would shift to 4th then back it off towards 5th very slightly
It'll take a little bit to get used to it but once it's automatic it's a breeze.
As for gear ranges, use it like any double, for istance, if it's a 8-speed, the smaller chainring would most likely be ok on 1-5 and the larger ring on 3-8.
So with the crossover, a 16 speed is ostensibly 9-10 speed (if that makes sense).

From what I remember, I would would have my 2nd n 3rd fingers close to the base of the shifter and use my thumb and index finger at the top of the lever. This allows finite adjustment. If you just grab the top of the lever on a friction type, it's very hard to get fine adjustment needed.

Although I haven't used a downshifter for 20 years, I could probably get back into it in a few weeks.

Good luck.

 

[sidevalve]

Many many downtube shifters are indexed, mine for a start and it uses exage components If so and you can feel the "clicks" then you have an adjustment problem. If not and it's a simple friction shift then I would suspect the friction shifters are a little slack and allowing the tension to pull them back. The levers shoud stay put where ever you set them The front on these systems wont be index [no need with only 2 sprockets]. Often the "index" lever [the rear shifter] will allow both index and non index shifting. the front chainring simple shifting pattern is large front - smallest rear 4 then small front - largest rear 4, a very basic rule of thumb but it gives you something to start on. However I'm not too sure why the front mech even if rubbing the chain would shift the rear sprocket. Are you sure you don't have a more fundamental problem, ie I wonder if the bike should have a 6 or 7 speed rear hub [not many 80s bikes had 16 gears, most were 10 - 12 - or maybe 14] and the previous owner has "upgraded" and not set it up properly ?
As for using downtube shifters the big thing is to relax when changing, it's no more difficult than signaling or waving to someone. A bit more tricky with a non index system at first but some diehards prefer them [I don't but each to his/her own]. They are a very direct and once set up, pretty foolproof system.

 

[palinurus]

... I would suspect the friction shifters are a little slack and allowing the tension to pull them back.

Sounds very much like it.

 

[palinurus]

my other question is do i need to go though all the gears on the back wheel on the main chainring - i'm assuming 8-16 before i should be dropping down to the smaller chainring upfront and starting again?
!

No. Once set up correctly you should be able to select whichever combination you want, with practice it's possible to simultaneously change to the small chainring and drop to a smaller sprocket at the rear.