AD-SLE

Bike is a mostly stock Annova Giant for commute/winter riding. Put on drop bars with new Shimano (non DA) barcons. For now I was going to run the original drive train Altus C20, same cassette, new SRAM chain and off to the races. On the stand each click gives me the next gear. Sweet!

Out on the road, attack a hill and the chain skips because (I believe) the chain is getting picked up by the next bigger sprocket. Easy enough, screw in the barrel. But then it grinds. Can't find the sweet spot while riding and just switch back to friction

Is this low end Altus just not going to work with new Shimano Barcons? The rest of the drivetrain is orginal (engineered to work together) except the chain, maybe the SRAM chain link is too wide?? Don't think so, not on non 10 spd. No sign of significant wear on 7 spd cassette. How do you simulate heavy load on the repair stand? What am I doing wrong other than feeling like a total amature? I can buy a new derailure but it may be me not the equipment.

Retro Grouch 

Are your barcons really designed for 7-speed?

7 and 8 speed cassettes are spaced almost the same but they're not the same. Lots of folks report that they can mix and match 7 and 8 speed shifters and cassettes but I've never been able to get that to work to my satisfaction. They are either better tuners than me or I've got higher standards than they do.

If it was my bike, I'd just ride it in the low maintenance, carefree, friction mode.

AD-SLE

RG: You could be on to something. From all I read, all Shimano indexed except 10 spd will work together. Guess I need to do some investigation in this area on Sheldon's site. I tried to fit an 8 on but there is not enough room/thread to get the lock ring engaged fully.

Little Darwin

I think you are misreading.... From my interpretation of the information I have read, all Shimano with the same number of gears are interchangeable... Other than early Dura-Ace and mountain versus road front derailleurs.

As an example, you can generally mix and match 8 speed Sora, Tiagra, 105, Altus, Alivio, Ultegra.... But you are going to have far less luck mixing 7/8/9 speed even if in the same group.

A 7/8/9 speed derailleur may work for any number of gears in that range, because derailleurs don't know gears... Where the match needs to happen for sure is between the shifter and the number of cogs on the rear cluster... 7-7, 8-8, 9-9

This is because the Shimano derailleurs all move the same distance relative to the amount of cable pulled, so as long as they can go from the inner to the outer gear, they are good... in theory a 7 speed derailleur will work on a 9 speed if the range of motion is far enough. A 9 speed rear derailleur will work on a 7 or 8 speed cluster, because the limit screws will limit the motion...

Where the gearing clicks between gears is controlled by the shifter pulling a specific amount of cable, which is designed to move a specific distance inward or outward per click...

dobber

Nicely summarized

roccobike

As was stated before, the derailure is dumb and doesn't know what gear to go to, it just moves as it is told to by the barcon.
I know there will be a slew of "no that can't be" when I post this, but I'm going to say it anyway. You mentioned the chain being a SRAM and asked if that could contribute. If you have a Shimano chain available, put it on. I've had excellent success changing from a Shimano chain to a SRAM, but I've had two instances where the SRAM would not shift correctly on the road (and did shift correctly on the stand). Went to a new Shimano and it worked fine. But keep in mind, I did not change anything else and the entire drive train, shifters etc. worked well together, it was just time to change the chain. Before anyone says I'm against SRAM, not true, they are my favorite chain, that's why I change over to them.
Besides, chains are cheap and I'll bet you have a good Shimano chain hanging around.

tellyho

The only other thing I can think of is chain width - is it too narrow?

barba

I agree with others; it is the bar end shifters not being compatible with the 7-speed cassette. So they have a friction mode? They should work in friction, but make sure you have limit screws set properly to avoid throwing the chain

AD-SLE

Wow. Great fedback. I suspected I was the problem. The barcons are SL0BS64-8 and say it is designed for Shimano Ultegra 8 sp system. Use in combination with RD06401. I gather they want to sell the RD too as I now understand the RD is "dumb" to shifter and cassette. Funny there is no mention of what cassette one should use, you would think they want to sell that too

Well, I have a 8 sp wheel/cassette which I can use. Don't want to use these wheels in salt but if I can isolate the problem to be a mis-match b/w the shifters and the cassette at least I know the solution without throwing $$$ down the drain. Friction on the 7 sp wheel, indexed on the 8 sp....I hope.

As for the chain....no Shimano chains lying around....I can't wait to have the $$$ to buy a real bike! Kids will keep you in the poor house....but I would have it no other way.

barba

Sheldon Brown also has a trick for alternate cable routing that he says will allow 8 speed shifters to index with a 7 speed cassette. https://sheldonbrown.com/gloss_aa-l.html#alternate

I have not tried it personally, but Sheldon is usually spot on. It very well may be worth a try.

grolby

Sheldon does not say that you should use the alternate cable routing to make 8-speed cassettes index on a 7-speed cluster. He doesn't say so because you shouldn't! That cable routing is specifically intended for matching the cable pull ratio of an old DA shifter to a non-DA or new DA derailer. It won't work as you describe, but would in fact make it impossible to make your drivetrain index properly. The cable pull ratio between non-DA 7 and 8-speed Shimano shifters is exactly the same, there is absolutely no reason that you would want to change it.

Just set up the shifters and tune as you normally would. I've done this myself, it worked fine. The tuning is a bit pickier than usual, but not much; shifting works just fine. You can get just about perfect indexing this way. It might make a little bit of noise somewhere along the cluster, but you shouldn't have a problem if you tune it right. If you still can't get it to your satisfaction, there's always friction, which works beautifully with modern shifters and cassettes.

barba

To quote from the page I linked:

"Shimano originally publicized this as a way to make older Dura-Ace shifters work with newer Shimano derailers, but it is also useful for other applications where you want to make the derailer move slightly farther for each click. This would mainly be when you wanted to use a 9-speed cassette with 10 speed shifters, or 8-speed cassette with 9-speed shifters, or a 7-speed cluster with 8-speed shifters."

grolby

Whoops, looks like this got lost in the shuffle. All Shimano indexed stuff including 10-speed will work together, with the exception that 8-speed and older Dura-Ace derailers and shifters are not compatible with non-Dura-Ace shifters and derailers. You can make a Dura-Ace shifter work with a non-DA derailer using the alternate cable routing, but if you have a DA derailer and want to use it, you need a DA shifter.

9 and 10-speed Dura-Ace are fully compatible with other Shimano derailers and shifters. Mix n' match to your heart's content.

grolby

My mistake, sorry! I'm still not sure that I would use it. Things worked fine without it. Might be worth experimenting with, though.

humancongereel

i've been spending too much time in ss/fg. all this talk of gears is making my head hurt.

AD-SLE

No I am wondering....the box said DuraAce. The instructions said ~SL0BS64-8 and say it is designed for Shimano Ultegra 8 sp system.~ And, there is a sticker on the barcon that says specifically it is not for DuraAce so I just assumed it was a new kit in the wrong box. But....any other ways to tell beside this little sticker? Some part number on it somewhere?

AD-SLE

Well, even in friction mode...heavy torque and the chain skips..jumps...over the teeth IMO vs falling back off a failed movement to a larger cog. One would think there were broken teeth but they are all ok.

So. Next step is to put on a new cassette. I still believe in the SRAM chain which has less than a 1,000miles. My concern....I won't be able to fit the various 8 spd cassettes I own and I don't have any alternative 7 spd cassettes.....so that is a new hub...wheel...which...I guess is an option. Before I do all that....I thought I would reach out to the board again...

Thanks in advance!

mrmw

Hope I've read this thread right...

OP states that you have some 7 spd and 8 spd cassettes, a set of eight speed shifters and a seven speed cassette freehub, no?

So use 7 of 8: i.e 7 cogs and spacers from one of the eight speed cassettes.

Bear in mind that you may need to use a 1mm spacer at the base of the 7 of 8 cassette stack. AND don't forget to adjust the rear derailleur limit screws so your RD doesn't run off the largest cog into the spokes and at the outer extreme shifts acceptably onto the smallest cog.

You will have seven perfectly indexed gears with no cash outlay, except possibly a dollar or two for the 1mm spacer.