IGH and Quest 559 don't mix, is that right(?)

[crazy_ebot]

Hi all - it speaks volumes for my inability to maintain a bike, but ever since a crash couple of months back, I've been unable to get my 559 to smoothly change gears any longer than a day.

I had the bike looked at (and parts replaced) post-crash... No matter how I adjust the tension screws (and/or cable tensioner), the chain regularly slips on the rear cassette, most often in the middle gears.

As a result, I've been looking at Internal hubs as a possible replacement/solution, but after reading the 'Thoughts of a nervous buyer' thread, Internal gear hubs and Quests don't appear to be made for each other - is that a fair assessment?

I noticed that Chain Reaction have the " Shimano Alfine 8 Speed Centre Lock Rear Hub S500 " selling for $240... That seems like a pretty good price. I know it doesn't take into account the other parts I'd need, but all up I think I could get a complete setup (including labour) for around $500(?)

I do a daily round-trip commute of 28km... I'm getting really tired of the constant slipping and failed adjustments... But there doesn't appear to be much point to looking into changes if they don't work. : )

If anyone would care to weigh-in and confirm/deny/clarify the situation, I'd be grateful.

 

[Doug Burton]

Hi Toby,

I don't remember which parts you've replaced - is your derailleur hanger straight?

John and I had a discussion about chain slippage a few nights back. If you run the b-tension screw all the way in, it increases the chain tension, but at the expense of "chain wrap" around the cassette cogs, i.e. there's not enough chain engaging the cog teeth to prevent slippage. There appears to be a happy medium here, particularly if you have a short x-seam.

You might try running the b-tension screw back out until, in the lowest gear (largest cog) there's about 6mm between the cog teeth and the rear derailleur top idler pulley.

Let me know what else you find. It ran okay before; we should be able to get it to run okay again.

The issue with an IGH (SRAM I9 or Alfine) is the need to tension the chain without a horizontal dropout to move the axle fore-aft in; a chain tensioner a la "singleator" would be needed, and the torque arm won't mate with the fork very well. SRAM supplier a serrated washer to perform the torque trnasfer function, so this could work.

So we're not necessarily saying it won't work, just that it's not a complete bolt up and we haven't done any research to support the modification.

Best,

Doug

 

[JonB]

Doug Burton wrote: The issue with an IGH (SRAM I9 or Alfine) is the need to tension the chain without a horizontal dropout to move the axle fore-aft in; a chain tensioner a la "singleator" would be needed, and the torque arm won't mate with the fork very well. SRAM supplier a serrated washer to perform the torque trnasfer function, so this could work.

So we're not necessarily saying it won't work, just that it's not a complete bolt up and we haven't done any research to support the modification.

I have done 1 experimentation, Rohloff. I use the Rohloff speedbone mounted to the diskbrake eyelets, and it works fine. http://www.rohloff.de/en/products/speedhub/speedbone/index.html

 

[crazy_ebot]

Hi Doug, thanks for the reply.

I kinda came to the same conclusion about the b-screw / chain slippage info, thanks for confirming. If it's correct, then I just haven't found that happy medium yet. Sigh.

I'll try the 6mm distance - thanks.

The derailleur hanger wasn't replaced as far as I know, but on the other hand I don't recall seeing any scratches, or sign that is was... Oh, wait a sec.

About a week after the crash, my chain snapped twice in one day, at different points. The second time it snapped, I noticed that the base of the hanger had a metal 'snag' which appeared to be the result of the chain 'tearing' the hanger by being in contact with it. I thought at the time that I had just put the chain on incorrectly. Perhaps the damage was done during the crash... Hmm.

Anyway, all that was changed was the large front chainring. I think I'm going to have to change the barrel adjusters at the brake grips also (incidentally), as they're cactus (making fine brake adjustment impossible).

Last weekend I discovered another 'snag' (burr?), this time on the middle chainring. It was like a tooth had been split , and the metal had torn/bent off at an angle. I've since filed it down. Of course, I now have a tooth half as thick, but what the hell.

I kinda follow what you're saying about the Internal hub, not not enough to do more than nod my head sagely and say 'uh-huh, yeah.'

Thanks again for the advice, I'll have another go and see what happens. I have to admit I'm a little disappointed this stuff wasn't picked up when I took the bike in to be assessed after the crash, but I know this stuff can be hard to identity.

 

[crazy_ebot]

Okay, had another go on Sunday. Still haven't got it right, but I think I managed a step in the right direction.

I let out the B screw 'til it appears to almost fall out, in order to get the top pulley 6mm from the bottom sprocket.

I then tightened the barrel adjuster, either not enough or too much. I think it's holding on a little too much between shifts. Generally moreso when I'm shifting down into a higher gear. The worst affected are still the middle sprockets.

I also noticed something else, which, may or may not be my imagination.

I was watching the chain pass around the middle chain ring (where I spend all my time), and I noticed that there 's an ever-so-slight 'curve' at one point in the rotation.

What I mean is the chain 'bends' out, away from the front shifting thingo at one point in the rotation. It's not much... I wasn't sure if I imagined it the first time.

I'm thinking if it's real, it might have happened in the crash. The large chain ring was replaced because it was badly bent, 'enclosing' the middle chain ring.

I think I'll take it to a store to see if I'm crazy.