toosahn

Forgive my ignorance, but I've been trying to get my Eisentraut to shift reliably into the larger chainring and the biggest and smallest sprockets. So far, I've been able to get it to work great on the stand, but poorly when actually riding the thing. The bike has Suntour Cyclone front and rear derailleurs, a Regina 6-speed freewheel, and Rivendell silver friction barcons.

Things I've done:
-Taken all the slack out of the shifting cables when in the smallest chainring and shifted out into the smallest sprocket.
-Adjusting trim levels to get more throw out of the rear derailleur and to a less extent, the front derailleur.

Hypothesis:
-This might seem obvious, but a bicycle's drivetrain will behave slightly different whilst under an actual load.
-I haven't taken enough slack out of the lines.
-The frame is flexing under load (body-weight) and messing up the shifting.

Any other ideas?

toytech

Could be a lot of things, some that come to mind are worn pivots, limit screws that are a little to close. Without ramped gears you might need to overshift/back off a little.

Doohickie

Just checking: Did you use shifter (i.e., longitudinal wrap) cable, or brake (spiral wrap) cable housing? If you used plain ol' brake cable housing, I would swap it out for some SIS or other shifter cable housing. It can make a big difference, even on friction shifted drivetrains- provides more consistent shifting.

due ruote 

What chain are you using?

toosahn

Shifter housing: I'm using the Velo-orange derailleur cable and housing kit. I just bought some shimano derailleur cables from my LBS today and they are much smaller in diameter than the derailleur cabling from velo-orange.

Chain: SRAM PC-850. Bought brand new. I didn't remove and links however.

RobbieTunes

Check to make sure the back wheel is in there tight.
Smooth shifting on the stand means all the relationships are right at that time.
Weight on the frame and resistance on the chain can change those relationships.
When you find the change in relationship, 3/4 of the time you'll find the answer.

I recommend letting someone else ride the bike, and you observe it while being shifted, etc.
Start by focuing on the rear wheel, then the cogs, then the RD, and slowly move forward on the bike.

Grand Bois

You didn't take any links out of the new chain?

randyjawa 

I too suffer from this delimma. And the question is why does it work in the stand but not on the road? At least that is my take on the concern.

I have run across this many times and try to understand why. The shifts are perfect in the work stand, jumping from one indexed position to the next. Or, the chain shifts to and from the large ring and small, with never a hint of dropping. But when I get the bike on the road...

There might be a need to adjust cable tension to achiever indexed shifts. Or, I might have to tweak a screw or two to prevent the chain from falling off.

Why is this so?

JReade

I've had the chains be the exact same size before. On my giant framed touring bike, every last link was required.

cudak888 

There is more tension on the chain on the road. The force put on the pedals (far more than one puts on the drivetrain in the stand), and the weight being moved - not to mention friction - is far more than a wheel with no load being operated by a crankset spun by hand.

Cheap components (especially front derailers) will show up the difference in their stiffness - the linear load on the chain is enough to cause the pusher plates of the FD or RD to bend, accommodating the now-offset chain rather than forcing it onto the next chainring or cog tooth. This is more common with upshifts, but a hard, jolting downshift with el-cheapo bits is often from this same phenomenon.

Good components that do the same thing are either poorly adjusted (FD not sitting on the right plane), badly designed and therefore hard to dial in (Nuovo Record pulley cage), mis-matched by virtue of a design difference (some pre-index era C&V drivetrains are picky about the chain you pair with them) or damaged (scored or bent pulley cage, pusher plate, or parallelogram).

------------------

But to the OP's problem:

Cyclone mechs - especially the FD - aren't generally known for this; in fact, they're my preferred substitute choice on nice flippers when this problem rears its head.

I'm shooting in the dark here, but I'd bet that your bottom bracket spindle is far wider than it should be, placing the crankset too far outboard. This can cause strange problems at both ends, but - more importantly - its the only thing I can think of that would cause an otherwise good Cyclone FD - one that has been aligned on the proper plane, mind you - from operating as intended. If there's one weakness to that FD, it is that the parallelogram doesn't care to travel farther than it has to.

-Kurt

due ruote 

Same here. It's vexing. I'd start with the chain length, only because that's the first thing you've said about the bike that sounds questionable. Put the chain around the large/large combination without going through the derailleur, see where the ends meet, add a link. Try that length and see what happens.

As to the fd, by how much space is it clearing the large ring? You may need to move it closer.

miamijim

1. Yes, there is more tension on the chain on the road.
2. Cheap vs. good components. Ummm, dont think so. I've said many many times on this forum that inexpensive all metal Z-series Shimano kills anything Campy made in the 60's, 70's, 80's and early 90's. Everything. There is something to be said for loose pivots and sloppy jockey wheels but expensive goods shift like crap if they're worn out.

Because there is so much tension on the drive train its common practice to back off on pedal pressure while shifting. Think of it as backing off on the gas pedal when shifting a stick shift.

miamijim

I despise that chain measuring method because your measuring for the shortest chain possible.....I use the small/small method which gives the longest chain and thus the least drivetrain tension. Add links until the chian drags on the RD then remove 1 link.

You want a nickles width of distance bewteen the FD and big ring.

Glennfordx4

The big big + 1" is Shimano's way of doing it,I just set up a Fuji with full Suntour and tried this method and it didn't work out very good,Suntour's way is small small and the RD cage should sit at a 45 degree angle or as close to that as you can get. I set it up this way and it shifts like butter both on and off the stand.

cudak888 

When I said "cheap," I was thinking of those stamped steel Simplex clones made by Falcon - the kind you find on Wally World bikes. The old Z-series is dressed-down 105/Golden Arrow in my book.

I even consider the Tourney RD-TX31 in the "good" category - because it works. Mind you, this doesn't necessarily extend to everything similar in the Shimano lineup. Case in point, the RD-TZ30 is a disaster - both in terms of function and life expectancy. It's arguably the worst adaption of the straight parallelogram design in recent years. I refuse to use them.

-Kurt

miamijim

I agree. Shimano does have alot of crap derailleurs. I'm was thinking of the light action Z-series....

due ruote 

You know, for years I had chain length set more like what you're advocating. Then I read something on here about the method I espoused in my post, and started doing it that way. But I like your point about less drivetrain tension, so I think I'll revert to that method.

dbakl

Back in the day, we called shifting into the big/big combo "crosschaining", and it was usually avoided. Seems like it no longer followed these days as I see it out on every ride...

As far as the front derailler, I like to get them down, clearing the large ring by 1/8" to 3/32" or so. I set the chain on the middle cog in the rear and the small ring in the front and use that position to align the derailler cage to the chain and spin slightly if needed from there. Sometimes you can add a tiny bend to the inside, front of the cage to help it climb the big ring. I run the chain through the derailler and make it just long enough to cover the big/big combo, though I'd never ride there.

Sometimes you need to open the derailler stops a hair to work well when riding over in the stand.

wrk101

+1 BB spindle might be too long. Post some pics.

RobbieTunes

I still say check the QR skewer first, then go to other things.

cudak888 

Pretty good RD's, but I'm antsy about using derailers that have spring-loaded cable pinch ends - both Suntour and Shimano. A weak spring can result in spongy (if not entirely non-responsive) shifting.

-Kurt

dddd

Have you tried doing your final adjustments while out on the road?

That's my preferred method since it optimises the shifting per my actual usage, and often uncovers hidden glitches.

I tuned up a suspension bike recently, and failed to provide enough housing length to allow for full suspension movement.
The test ride made for an immpossible task of adjusting the cable, but ultimately revealed the problem.
Woulda caused a broken cable if I had sent it out that way.

I'm assuming the SRAM chain you used has the Shimano-type bulged sideplates? The older ones were notorious for not providing robust shifting, especially under load. I used to have to bend a few chainring teeth to hasten the chain pick-up, and still do on certain older chainsets.