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View Full Version : shifting issue (advice, ideas needed


peacepeddler
08-28-2011, 06:34 PM
Hi,

I don't live in Portland, but travel to the area often. I read the forums, and the bike Portland blog regularly.

I'm having a shifting issue, and am running out of ideas to fix it. I thought maybe I should reach out to a larger audience for more ideas.

Earlier in the summer I bought a used sidewinder on craigslist. It is in good condition, but needed some good old TLC. Overall I'm real happy with it after doing various work to it. However a new issue creeped up recently. The trike has index shifting. The derail, and shifter is compatible with one another.

So in order to reproduce the problem the chain must be on large gear on the crank, or the outside gear. It is not a problem on the other two main crank gears. Then when you go to the cluster down by the rear derailuer the problem is with second gear. Going from first gear to second gear is the problem(which would be the largest cog gear as 1st gear). I can see the derail moving, but it is very inconsistent. Sometimes it shifts to second gear, but most the time it does not. If I go from third gear to second it is never a problem. The problem is only first to second gear, and only on the large gear on the crank.

It was working great after a tune up, but has been acting this way more recently. It all works fine if I have the crank on mid gear, or small gear.

I have done the following to try to fix it. Changed tension on cable, adjusted b screw both ways on derail, shortened chain a bit. None of those things are resolving the issue. I plan to add the links back that I took off cause I feel the chain is a bit too tight now.

For a few weeks I was monitoring the axle. This is a tad pole trike with two wheels on front, and one wheel in back. I found that the axle was slightly moving side to side. This caused a few problems by the axle moving in this manner. I wonder if the axle moving effected my shift issue, but I resolved the axle moving side to side issue. I put a spacer on both sides of axle between wheel hub, and outside bearing. So the axle can no longer move side to side. I don't know for sure if this created my shift issue, but I have not resolved it yet.

So I'm at a loss at this point. I'm looking for advice from some of you. I'm sure some knowledgeable mechanics read these forums. Does anyone have advice on how I can get the derail to shift properly from first to second gear while on the large crank gear ? It is driving me a bit bonkers. I really feel like it should work, and don't know what to do at this point. Any ideas very appreciated ! All the other gears/shifting works great. It is just this one little spot that is a issue

Below is a pic of my trike. That is me in the kinetic parade at Da Vinci Days 2011 in Corvallis, OR.
http://www.flickr.com/photos/barefoot_chris_pics/5956809062/

Alan
08-28-2011, 08:41 PM
When you say first gear, do you mean the largest cog on the cluster, on the left next to the spokes? If that's the case, then you're putting the most bend in the chainline when it's in its tightest position, on both big gears (chainring and cog). It's best to avoid both that combination and the little chainring/little cog combination (which at least has a bit more slack in the rear derailleur) because of that angle it puts in the chainline, and use some gear combo of the middle ring instead. I don't follow that advice religiously but I do try to minimize time spent peddling in either of those positions.

I'm not sure if that's related to why it won't drop into second but it might be. Are your shifters indexed or friction?

PS - Which axle is/was moving side to side? The front one? Is the cog cluster connected directly to that axle, so that the cogs are also moving side to side? Does that rear derailleur move side to side with the axle, or is it fixed to the frame? Seems like that could affect how it shifts, if the side play moves the cogs relative to the der.

Sidewinders (http://www.sidewindercycle.com/) are mechanically interesting with rear steering and front drive!

http://farm7.static.flickr.com/6133/5956809062_d818590995_z.jpg

wsbob
08-28-2011, 10:38 PM
'Cross-Chaining', is another word for what Alan is describing. As he said, either combination of 'little-little', or 'big-big' isn't advisable, because it puts a big twist on the chain that's considered to contribute to excessive chain wear. Maybe you could help make sure we were straight on what cogs on the rear gear cluster you're having difficulty with.

Here's a situation I'm having with one of my bikes; it sounds similar to the situation you're describing:

I've got a vintage road bike whose drive train has a lot of miles on it, which I'm working on getting taken care of. There's a problem shifting from the 15 tooth cog to the 13 tooth cog. Lots of things can contribute to such a problem (some of which I've already attended to.), such as worn or gummy derailleur, cable that's binding inside the housing, worn chain, but also...wear on the cogs, which I think may be the source of the problems I'm having.

To be specific, over time, the profile of the cog teeth changes because of wear to their back sides as they come into contact with the rollers on the chain. This type of wear might be limited to problems with auto shifting...which is another problem I'm having...but I'm wondering if it's not also related to the 15 to 13 shifting problem, the 15 being one I ride in a lot and exert a lot of power to.

I've heard tell that in the old days, some shops catering to serious racers, had wall racks with a wide range of cogs. People would bring their bike in and to create different gearing or correct problems with wear, the shop would change out individual cogs on the freewheel, rather than toss the whole freewheel for a new one.

My situation is kind of complicated and expensive to correct, since new freewheels aren't so readily available anymore.


You said your rig has recently had a tune-up. I'd ask those guys if the freewheel/freehub casette cogs were o.k. Might also ask at different shop with knowledgeable mechanics.

Other characteristics of freewheel/freehub casette cogs that I don't know about, but wonder if they could be contributing problems with wear, is the twist the cogs have. If I understand correctly, the cog's twist is the Uniglide/Hyperglide thing that Shimano came up with gradually over 20-30 years to make for smoother shifting. I'm not sure though whether wear in this area would prevent a shift from occurring, rather than just preventing the shift from being as smooth as the design intends it to be.

So, maybe figure out more specifically what running gear your rig has, and edit that info in your original post. Also, you could shoot a query over to bikeforums. It has a recumbent category, if I remember correctly. The classic and vintage category regulars include some real technical wizzes too, If they'd venture to present advice on a recumbent's drive train.

peacepeddler
08-29-2011, 04:39 AM
Thanks for your replies. Your were correct as the largest cog gear being 1st while using the largest gear on the crank. It has index shifting.

It was working fine with no problems for numerous weeks. Now I have that one minor shifting issue. So I just figured something changed that needed to be corrected. Thought maybe I was over looking something. I've already been back to the bike shop once for advice. They have spoke of similar things.

Since the trike has shifted fine in the past, and all my other bikes shift fine. I thought maybe I could correct this.

Obviously I may have to consider just not using first gear while on the big gear on the crank.

I tend to like to fix things when it is not working right, but I may just have to leave this one.

Yes the sidewinder has some unique features. I got a really nice break on the price from craigslist. Those types of rides show up in our area rarely so I got lucky. I've very happy with the sidewinder !

wsbob
08-29-2011, 09:13 AM
peacepeddler...okay, read your latest post. So, cross-chaining is what's going on here. That's a definite no-no from almost everything I've ever heard. Ask yourself why you're choosing the 'big-big' gear combination. It's most likely possible to get a ratio that's very close to what the 'big-big' is resulting in, if you choose, for example, the middle chain ring, and perhaps the third smallest cog.

A fairly simple means of understanding this better: Look for the gear calculator link at the top of the list on Sheldon Brown's page of gear/drivetrain related articles (if you haven't heard of the late, legendary Sheldon Brown, this is a great intro to some of his work.).

http://sheldonbrown.com/gearing/index.html

The link will take you to a form into which you can punch numbers closely approximating your rigs drive train. When punched in, click, and 'Oila'! You'll be able to compare numbers for each gear combination. I think for general use, it's maybe not so important to be overly concerned with some of the technical terms used in the form, or specific cassettes listed, so don't be thrown off by them. Just check a cassette listing that's as close as possible to what you've got, and click to calculate.

My bike's gear train for example: It's a 52/42 chain wheel, 13-24 freewheel, 700cm wheel. Numbers for 52 freewheel/23 cog(a freewheel-cog combo that shouldn't be used.)...sheldon's chart doesn't include a cassette with a 24... is 15.9. Drop down into the 42 chainring and the the third largest cog, a 19, gives 15.6. As you can see...very, very close to the same gear. So unless there's a reason unique to the use of your recumbent, you may well have similar options, and shouldn't actually have to cross-chain.


Idea, is to keep the chain running as straight as possible. As needed, going two or three cogs away is probably the best practice. This might not be something that people automatically recognize. Some bike manufacturers used to pitch their product by listing a number for every single gear combination the bike could produce. I suppose that was their way of getting people to think that for example, a 12 spd must absolutely be better than a 10 speed or my god! ...a 3 spd. Nowadays, with bikes commonly having triple chainwheels and up to 10 or 11 cogs on the back, that's like...technically, 33 spds by the old way of selling. Doesn't make any sense from a practical usage point of view.

peacepeddler
08-29-2011, 11:11 AM
Thank you for everyone's in depth responses !

I have not really had this as a issue on my other bikes so I never really looked at cross-chaining that closely. Obviously the ratio is different on my sidewinder then my other bikes. With that said I'm confident what I have I cam more then work with the current gear ratio.

I will certainly look at the links, and more info on the topic. So I can become more familiar with it.

Thanks again. Just the reason I came here for great advice........

Alan
08-29-2011, 01:29 PM
I have a similar minor problem on my indexed 3x7 Suntour gears, only it happens to me in the 5/6/7 small cogs, using the middle and big chain rings. It's not happening when it's cross-chained from the small ring. When I shift to a higher gear it wants to skip the #6 cog and jump straight to #7, but then I can shift back down and it drops onto #6 just fine. With friction shifters I think I could feel my way from #5 to #6 directly.

I'm not an expert to say if that could be tuned out, other than that I have not been able to do it in my limited attempts. My feeling is that it could be tuned out but (a) it could simply move the problem to jumped shifts between other gears and (b) it's likely to return again and again as things go just minorly out of that optimal tuning, and (c) undoubtedly some indexed systems will work better than others.

Chris, I think you're on the right track with minor cable adjustments of the rear derailleur. Also, if that cluster is moving side-to-side at all relative to the derailleur it is very likely to affect shifting. Careful shimming, as you describe above, seems like a good approach to fixing that.

Cross-chaining is good to be aware of and it could lead to worn chain or gears which might contribute to this and other shifting problems. While I consciously try to avoid it, I also think there's a huge difference in wear-and-tear between (for example) routinely hammering up hills for miles while cross-chained and hustling across an intersection for a few revolutions when the light changed before you were down-shifted properly (or simply forgot). Also, once you're aware of it, both the noise and the feel in the pedals tells you, "hmm...I bet there's a better gear combo for this cadence..." :)

wsbob
08-29-2011, 04:49 PM
"...I'm not an expert to say if that could be tuned out, other than that I have not been able to do it in my limited attempts. My feeling is that it could be tuned out but (a) it could simply move the problem to jumped shifts between other gears and (b) it's likely to return again and again as things go just minorly out of that optimal tuning, and (c) undoubtedly some indexed systems will work better than others. ..." Alan


3x7 Suntour gears sounds like late 80's early 90's indexed downtube shifters. Bikeforums is the other bike forum that I frequently read. Maybe you're familiar with it, or a different one that's particularly distinctive for having some regular people that are very familiar with older bikes.

The classic-vintage category over there has some regulars that seem to be very familiar with the Suntour indexing shifters. You might consider posting a question over there. I wish portlandbikeforums had some of those people posting here more often. Jeff Wills is one of those guys that is also a portlandbikeforums member. He's posted here in the past.

I hate to say it, but I don't know much at all about adjusting indexed shifters. Too bad too, because I've got a bike whose brifters, I'd like to check out. They're low end Sora. Gears all work, but right side brake lever action has a bit of dead travel before brakes begin to be engaged. Something inside the lever may be worn or broken. It's working, just not very well.

Brifters...brake-shifters...whatever they're called: They work good, are fun to use, but they seem complex. Expensive too. I'd have to check before saying how much they cost. I think even Sora's must be more than a $100. Some of the classic-vintage guys have their eyes out for the indexed downtube shifters...ebay, craigslist, garage sales, garbage dumps. Never used them, but heard they work very well.

Alan
08-29-2011, 06:36 PM
Yep, I know of BikeForums (http://www.bikeforums.net/). Good place for lots of info and it seems to index well in Google for searching. Downside is there's also a lot of disinfo but hey, it's Teh Intarweb so that's expected. Consumer beware!

I hadn't tried to date my Univega (http://bikeportland.org/forum/showpost.php?p=20974&postcount=125) before, but turns out it's very likely a 1990, possibly as late as '93. That's because it has X-Press shifters as in this advert (http://mombat.org/90Suntour2.jpg) or better shown in this photo (http://mombat.org/90Suntour8.jpg) (lower right). There are separate levers for up and down shifting, so you only push to shift, never have to pull back on a lever. It's easy enough to get used to; the big (longer) lever moves toward bigger gears, small lever to smaller gears. Each gear is one click (except when it isn't...) and you can rapidly "click-click-click" through any number of gears if you're in a hurry. There's also a little bit of friction adjustment around each gear, so if there's a little chain buzz you can maybe dial it out with a light push on the lever. It's quite a user-friendly system and works well despite its age.

Looking at that Suntour page (http://mombat.org/Suntour.htm) on the Mombat.org (Museum of Mountain Bike Art & Technology), it seems Suntour had some pretty wild stuff back in that era. Check out the push-button shifter and the Browning-designed (http://mombat.org/286Browning.jpg) automatic front shifter using hinged chainwheel to engage both rings at once, allowing shifting under heavy load.

Brifters...cool! I haven't had a chance to try them but I'd like to. They're definitely pricey (about the same as my whole Univega fixed up to its present touring/utility rig ;) ) but they are showing up on more mid-range touring bikes like the Salsa Vaya. I wonder about the ruggedness of all that complexity and what would happen if something in them broke in the middle of nowhere, but it seems like most people have good experiences with them.

peacepeddler
08-31-2011, 06:28 AM
Prior to posting this thread. My tendency on this trike I have only had a few months. Was to mostly use the big gear on the crank. Or use the small gear on crank for a hill.

Now I'm experimenting with changing that, and using the middle gear on the crank more. In a effort to avoid the cross chaining issue.

I find having the front derailleur in the middle gear. 3 or 4 gears down the cluster the front derail wants to rub the cage. So it kind of limits how much I want to use the mid range on the crank.

Anyway the boys know me very well at the bike shop. I'm weak on derail adjusting. Hopefully the cage rubbing is something they can adjust. Think once I get that I'll be much happier with the shifting.......

Though I also find if I go mid range in front. Once I get to like 3rd or 4th gear on the cluster. I like to go to the big gear on the crank. At this point I'm out of the cross chain region.

My legs are strong. Kind of like the big gear on crank. My head is thinking about if maybe I should get a different gear ratio on the front crank. The small crank gear is great for hills. The large crank gear is great for general use. The mid range crank gear I find too slow, or not enough power for my legs. So I'm thinking about it.

I think first I want to see if I can resolve the chain rubbing on the front derail cage in mid gear on crank. If that can be resolved ride with it corrected, and see how I like it. I don't like making big changes at once. I'd rather fine tune when possible. The front derail does have some side to side adjustment within each gear, but not enough to compensate for the rubbing on cage in mid gear.

wsbob
08-31-2011, 11:03 AM
peacepeddler...it's definitely advisable to keep changing the position of the chain rings to get a lower or higher gear as the case may be, rather than just staying on one chain ring as long as possible, and going further down or further up the cog block to get a comfortable gear combination to ride in. Keeping the chain as straight as possible is the easiest way to avoid problems with the front derailleur rubbing.

How many cogs do you have in back? 6 or 7? or 8,9,10? The latter speeds are associated with designs component manufacturers achieved by resorting to thinner, closer spaced cogs and thinner chains. I have little experience with this sort of thing other than having read about it, but I'm assuming that closer tolerances would inevitably result with the latter system.

When on the middle chain ring, what cog(s) in back can you be on in which the front derailleur doesn't rub? Where on the block of cogs are those no-rub cogs located?

Here's the way I think of this: When on the big chain ring, the smallest three cogs on the cog block will probably give the best drivetrain action. Middle chainring...middle three cogs. Small chain ring...biggest three cogs.

Maybe though, the front derailleur just needs to be twisted a bit on its mount. Maybe the leading or trailing edges got bent in somehow, and need to be put back into their original position. Hope the guys in the shop you go to can eventually get you squared away.

You could take a look at the gearing your chain rings and cogs offer you, maybe getting a higher gear by switching out the middle ring for a bigger one.

peacepeddler
08-31-2011, 11:51 AM
I have 7 gears on the cog. Of course 3 gears up front on the crank.

I like your ideas on how to use the gears. These ideas would be a new practice for me, but I like it.

I could see having the crank in the small gear with 1, 2 on the cog.
middle gear on crank>3, 4, 5 on cog
large gear on crank>6, 7 on cog

I really feel like with the front derail in the middle gear. It already starts to rub chain/front derail a little once I go to second gear. Certainly at third gear, and above. So my first step will be to see if this can be corrected. The boys at the bike shop are busy with the students just getting back in town. I'm not in too much of a rush. My issues are minor, and is just fine tuning at this point.

Today I really want to note in my head for sure what gears are making the chain rub on the front derail. Ride, and really pay attention since I will change how I use the gears. Then I can go discuss it with the mechanics. I just want to get things straight in my head on what I want to do. This thread has been helpful in deciding what I want to do before I go back to the shop.

I think the current crank will be fine once things get squared away. Since I bought this sidewinder used. It has been a nice learning experience. Have not really put much money into it after buying it. More time of me working on it tweaking things, identifying noises and eliminating them, personalizing things, etc. I really think I'm down now to just the shifting. So I'm just taking time to figure things out in my head before going up to bike shop.

The front derail has been rubbing for a while now. Though since I was not using mid gear up front it never bothered me. Now I'm using mid gear up front so it is something I need to address. The bike shop gets more money from me then average customers. As I visit more often due to my kinetic race hobby. So they are more then happy to help me along with these things. Bribes go really far with the mechanics as well. A trick learned in kinetic racing !

peacepeddler
09-01-2011, 07:39 PM
Well I ended up fine tuning the front derail myself. Loosened the derail from frame, and did some slight rotation changes. It is much better now. I like the ideas on the new shifting technique. Thank you ! Really never had to think about it as much with my other past bikes.

Believe my shifting is good to go now. Went down to marsh for sunset. Gears shifting well with derail fine tune, and newly introduced shift method to me. Understanding cross chaining much better now.

wsbob
09-01-2011, 10:01 PM
Well I ended up fine tuning the front derail myself. Loosened the derail from frame, and did some slight rotation changes. It is much better now. I like the ideas on the new shifting technique. Thank you ! Really never had to think about it as much with my other past bikes.

Believe my shifting is good to go now. Went down to marsh for sunset. Gears shifting well with derail fine tune, and newly introduced shift method to me. Understanding cross chaining much better now.


Bingo! There you go...managed to get things worked out. Has to be a good feeling. Happy riding!

Alan
09-02-2011, 10:48 AM
Glad that worked out, Chris, and thanks for letting us know. Sounds like you find it as satisfying to do your own repairs as I do.

peacepeddler
09-03-2011, 02:12 PM
I rode the sidewinder in a parade today. Where I live, but inland in the mountains. It was a bigfoot weekend festival. As usual the sidewinder is a huge hit. For a slow parade I can disengage the main steering, and do circles on a dime. The brakes allow me to do this as secondary steering for circle spinning.

Very fun, shifting well.....