[128]

'87 Specialized 600sis

Probably been asked a lot but if you will:

What is the trouble shooting sequence to address the problem of the chain slipping from a larger to smaller rear ring while climbing. I know I need a new bike but in the meantime... I get sooo frustrated going up hill.

I've tried the lube under the bottom bracket to solve 'frame-flex' shifting but still have problem.

Are there derailleur adjustments that are usual to make (I have not done that) or some part to try replacing? Is it hopeless??

I'll take it to the LBS but really appreciate any thoughts you bike nuts might have.

Thanks a lot.

 

[Fordy]

What do other posters see?

I think your cogs are shot. You need a new cog set and chain. It looks like the wear between the teeth is really wide. The only adjustment is on the thumb barrel at the end of the cable housing. Try 1/4 turn at a time and listen for the mechanism to smooth out.

 

[bimini]

I would agree

The chain popping out and slipping when in the large rear gears while under load is a classic sign of a worn out cassette (change the chain if it has not been replaced lately). I just went through this on my bike. I put a newer cassette on the rear and all problems went away. I've never seen one so worn that it pops down into lower gears, but I have always changed mine before they got too bad.

I think your cogs are shot. You need a new cog set and chain. It looks like the wear between the teeth is really wide. The only adjustment is on the thumb barrel at the end of the cable housing. Try 1/4 turn at a time and listen for the mechanism to smooth out.

 

[theOldMan]

Another thing to check is the shifters. Your bike probably uses friction shifters on the downtube. There is a screw that holds it all together. If that screw becomes loose, you could get the same effect.

It probably is a worn chain and cassette, but check the shifters. A friend of mine went through the same problem on his old rain bike. It turned out to be screw holding the shift lever together. He tightened it up and all was fine.

 

[tube_ee]

Another thing to check is the shifters. Your bike probably uses friction shifters on the downtube. There is a screw that holds it all together. If that screw becomes loose, you could get the same effect.

It probably is a worn chain and cassette, but check the shifters. A friend of mine went through the same problem on his old rain bike. It turned out to be screw holding the shift lever together. He tightened it up and all was fine.

Good call onthe retention screw. That's the 1st thing to check for auto-shifting. I think the 600 SIS group used a 6-speed freewheel. There is a way to get new life out of an old, square-tooth freewheel. Take the cogs off and flip them around. This reverses the teeth, so the chain pulls on the unworn side of the teeth. It's worth a shot. You need two chainwhips and a freewheel remover to do this. Put on a new chain when you're done.

--Shannon

 

[128]

Clever,

and resourceful: flipping the cogs. And replaceing chain. Worth a try.
I have tightended that 'd-ring' on the shifter many miles ago, i'll turn it again.

Not familiar with thumb barrel adjustment. I'll give it a try .

Since there seems to be agreement it needs replacement I'll plan on that. But knowing me if it costs over $100 I'll end up buying that new Bianchi instead....mmmm Bianchi.

Thanks people.

Good call onthe retention screw. That's the 1st thing to check for auto-shifting. I think the 600 SIS group used a 6-speed freewheel. There is a way to get new life out of an old, square-tooth freewheel. Take the cogs off and flip them around. This reverses the teeth, so the chain pulls on the unworn side of the teeth. It's worth a shot. You need two chainwhips and a freewheel remover to do this. Put on a new chain when you're done.

--Shannon

 

[racerx]

Agreed, buy the new Bianchi and best of all...

Get the Specialized fixed, fixed geared that is. Look at those drop outs, just calling for a 16 or 17 cog. You may not even have to re-dish... Is the current wheel a cassette or freewheel hub?

Ebay the "vintage" DA stuff to pay for the fixed conversion and $$$ towards new ride...

WEEE I love spending other folks money!

 

[Dave_Stohler]

Flipping cogs will not work with HG cogs. Sorry.

 

[tube_ee]

Flipping cogs will not work with HG cogs. Sorry.

From the picture. it looks like he's got a six-speed UniGlide freewheel. I don't remember if Shimano freewheels had separate spacers, or if they were integral to the cogs. Seperate spacers are needed for the cog-flipping trick to work. New, the only freewheel choices are Shimaon and Sunrace, both only come in one gearset, 14-28 IIRC. NOS Suntour New Winners abound, but I don't recall them indexing well at all with Shimano shifters.

--Shannon

 

[128]

Yup

Not going to make any heroic efforts to upgrade this ride. Would rather add to the stable.

Scoping the Bianchi Veloce double. Would like a higher end bike (components) but this is about my price-point. I want 'all Italian', steel, new and traditional geometry. The Veloce has Veloce/Centaur mix. A sensible step forward from the current bike I hope.

Either that or troll for a used rig. Just passed on a Maillot Juene (sp) w/record/chorus. Was a little big, had 20K miles on components and 200K on frame and sew ups. Seller was a serious racer but asking only $1K.

Would consider making this a single speed/rain bike after hearing how much fun they are.


Thanks again all.

Get the Specialized fixed, fixed geared that is. Look at those drop outs, just calling for a 16 or 17 cog. You may not even have to re-dish... Is the current wheel a cassette or freewheel hub?

Ebay the "vintage" DA stuff to pay for the fixed conversion and $$$ towards new ride...

WEEE I love spending other folks money!