Bicycle Mechanics - Vintage (late 70's) Suntour Shifter Doesn't Stay in Gear

My late 1970's Lotus Odyssey road bike has shifters on the down tube and non-indexed shifting. There is a wire bail on the shift lever pivots - increase friction by tightening. This also makes it harder to shift. I really hate (HATE!) when the the bike changes the rear gear without any lever shifting! It will shift up one or two gears unless I have the friction bail adjuster set really tight. Naturally this happens when I'm grinding away on an uphill, exactly when I don't want to be reaching down and shifting back into a larger rear cog. This problem has existed since I bought the bike new.

Any suggestions beyond get a new bike (I actually have one, but the rear derailleur broke off and I'm waiting parts).

Thanks

My late 1970's Lotus Odyssey road bike has shifters on the down tube and non-indexed shifting. There is a wire bail on the shift lever pivots - increase friction by tightening. This also makes it harder to shift. I really hate (HATE!) when the the bike changes the rear gear without any lever shifting! It will shift up one or two gears unless I have the friction bail adjuster set really tight. Naturally this happens when I'm grinding away on an uphill, exactly when I don't want to be reaching down and shifting back into a larger rear cog. This problem has existed since I bought the bike new.

Any suggestions beyond get a new bike (I actually have one, but the rear derailleur broke off and I'm waiting parts).

Thanks

That's the nature of a lot of downtube friction shifters. Paradoxically, cleaning and greasing the washers inside the shifters will sometimes make them hold better and move more smoothly.

If you can find them, Suntour retrofriction shifters:
http://www.velobase.com/ViewComponent.aspx?ID=39B0C9B8-10D7-4324-8BF4-F65ECA2D209A&Enum=104&AbsPos=11
would work on your bike (although it's a little ugly if you have brazed-on shifter mounts), and would resolve your woes.

I second Jeff's recommendation for Sun Tour "retrofriction" downtube levers but the clamp-on version he referenced isn't the only one. Sun Tour offered these levers in braze-on type for several of their road groups and the "Cyclone" version should be available at modest cost.

Also, any Shimano indexed downtube lever set will work since they all have a friction option. Six and 7-speed Shimano lever sets are obsolete so many bike shops will be happy to sell atheir NOS stock cheaply.

Either Sun Tour or Shimano levers will solve your "ghost shifting" problems.

Sun Tour racheting Power Shifters were my favorite downtube (and thumb-) shifters.

I second Jeff's recommendation for Sun Tour "retrofriction" downtube levers but the clamp-on version he referenced isn't the only one. Sun Tour offered these levers in braze-on type for several of their road groups and the "Cyclone" version should be available at modest cost.

Also, any Shimano indexed downtube lever set will work since they all have a friction option. Six and 7-speed Shimano lever sets are obsolete so many bike shops will be happy to sell atheir NOS stock cheaply.

Either Sun Tour or Shimano levers will solve your "ghost shifting" problems.
Available where? Although I suspect your second suggestion might be easier.

Shimano levers like these (http://www.bikeworldusa.us/ACTION-SHIFTER-ROAD-SET-SHIMANO-7SP/M/B001L5W6W8.htm)? Do they need to be 7 speed (like my gears)?


That's the nature of a lot of downtube friction shifters. Paradoxically, cleaning and greasing the washers inside the shifters will sometimes make them hold better and move more smoothly.
What type of grease? Regular automotive?

Available where? Although I suspect your second suggestion might be easier.
Here is one source: http://cgi.ebay.com/NOS-Suntour-Sprint-Down-Tube-Shifters-Braze-On-Model-/270520534645?cmd=ViewItem&pt=Cycling_Parts_Accessories&hash=item3efc47c675


Shimano levers like these (http://www.bikeworldusa.us/ACTION-SHIFTER-ROAD-SET-SHIMANO-7SP/M/B001L5W6W8.htm)? Do they need to be 7 speed (like my gears)?
The Shimano shifters you referenced are the bottom of the barrel. Do you need a band-on type or does your frame have braze-on bosses? If it has braze-on bosses get better ones. 105 or Ultegra level are very good. Are your current shifters indexed? If not, then it doesn't matter what "speed" the shifters are since you will use them in friction mode.

OP here - I just want my back-up bike (which is my only bike for this week) to be more usable! I had hoped to do it without spending a lot of time or money. The $50 shifters referenced might work no better than my current shift levers - I had this problem when the bike was new. The Shimano shifters I linked to were the first ones I found when I did a Google search - I thought they looked very, very cheesy. I searched eBay - 105 Shimano shifters like these (http://cgi.ebay.com/RARE-VINTAGE-SHIMANO-105-DT-7-SPD-SIS-SHIFTERS-/290459510587?cmd=ViewItem&pt=Cycling_Parts_Accessories&hash=item43a0bc673b)? Even though they're "indexed"? Will they have better friction?

Gee, I feel like a monster! But I just am not enough of a vintage fan. I actually prefer riding my CF bike with STI 10 speeds and real brakes. I can easily shift gears and dial them in so I keep my cadence in my target range. I've ridden the Lotus about 500 miles in the two months I've been cycling (vs. about 700 on the 2007 bike) - my only issues with the Lotus are the brakes and the shifting, but those really are pretty big issues of safety and efficiency. [I have another thread about improving the brakes.]

I did dismantle the shift lever assembly on the down tube and cleaned out the "powder" - I will find out tomorrow if it worked. Depending on how that goes, I will probably experiment with greasing the friction washers. Meantime I guess I can resign myself to knowing that I now know more about the shifting problem and can probably fine-tune my skill at dialing in the tension on the bails - maybe even "wiring" the bails with safety wire so they can't loosen from vibration and normal shifting action.

Thank you all for your suggestions.

PS - I have braze-on bosses.

OP here - I just want my back-up bike (which is my only bike for this week) to be more usable! I had hoped to do it without spending a lot of time or money. The $50 shifters referenced might work no better than my current shift levers - I had this problem when the bike was new. The Shimano shifters I linked to were the first ones I found when I did a Google search - I thought they looked very, very cheesy. I searched eBay - 105 Shimano shifters like these (http://cgi.ebay.com/RARE-VINTAGE-SHIMANO-105-DT-7-SPD-SIS-SHIFTERS-/290459510587?cmd=ViewItem&pt=Cycling_Parts_Accessories&hash=item43a0bc673b)? Even though they're "indexed"? Will they have better friction?

Yes, those will work. Shimano downtube shifters have an "indexed/friction" switch on the right lever. Leave it on "friction" and it'll work like your old levers, only much better. They might look cheesy, but they're bulletproof. I have a set of Shimano bar-end shifters (same mechanism, different mount) that still work perfectly even though they're 20 years old.

I had replaced my Suntour DT cyclone shifters with Campy friction shifters for that same reason. I always thought they held betterthan the lower Suntour friction shifters. Some people also prefer the simplex shifters over the campy's. Next up would probably the Suntour Superbes.

I give another vote for Suntour Power ratchet levers. You should be able to find the DT version on the 'bay for $20-25. The stem version goes for more like $15 usually, and they're probably the exact same levers. I have a couple sets of the handlebar-mount thumby version, and they're the same levers as the DT ones. I think they'd probably mount to your current shifter mounts, but maybe someone else can confirm that.

People call Suntour Power ratchet shifters "retrofriction", but I think that term more properly applies to the functionally sort-of similar (but non-ratcheting?) European (Simplex?) levers, which are a lot more expensive.

Suntour Power ratchets: cheap, excellent.