Bent chainrings,broken spokes and other woes...
We have a new Burly Rumba but these issues are putting quite a damper on our new found joy of tandeming. For the second time we have bent the inner chain ring of our Tracer 52-42-28 triple. Both times I shifted to the inner chainring and the chain jumped and became jammed. Either in the process of it getting jammed or my unjamming it, it bent. My LBS had not seen this happen before. Let alone twice. I know I can prevent this by installing a stop device but my concern is that the real issue is with the drivetrain. I had to keep loosening the the stop in order to get the bike to shift. It seems that by getting it loose enough I was causing the chain to jump. But when it was tighter it wouldn't shift. I thought I had it dialed in, when we wanted to down shift on the front, I would call "easy" and wifey and I would ease way up on the pedal pressure and it would shift pretty quickly. (NOTE: FD and shifters are Sora)
The chainline alignment does not look right to me. On the large chainring, I can use all 8 cogs in the rear (RD is a Deore) without any rubbing. On the middle, I get rubbing on the 6th cog! On my 1/2, I can use all the cogs of my Ultegra 10 spd when in the middle CR. I would think that would be the normal expectation. Is that unrealistic? On the small CR, it rubs on the 5th or 6th cog too. It seems like the FD is too far inboard compared to the the rear. One of the guys at the LBS didn't like the chainline either but the mechanic wants to just upgrade the chainrings. (Not sure how that will help the underlying cause) Any suggestions on what to do here?
Another issue they mentioned was the the 28t cog in the front should be changed to a 30t. I always thought 28t's were pretty standard on tandems. Will this change help the shifting?
On to the spokes...2 broken spokes in the past 3 rides. One front, one rear, both at the hub. Having never broken one before, is this unusual? We are a big team, 380+. Do we need to upgrade our wheelset?
Any input is appreciated.
When I was running 3x7 Sora brifters, I think that the front shifter had three simple positions -- low, middle, high. I recall that the chain would rub the front derailleur when used with the 6th and 7th cogs. I now have 105s, and they have several trim positions in the front. I'm running 8 gears from a 9speed cassette, and, with trimming, I can go all the way out to the little cog with just a wee bit of rub when the chain is on the middle ring.
Not much help with your issues overall, but, if your Sora triple shifter is like mine, it just may not have the flexibility of trimming that other models have.
I'm just kinda taking a stab at it here, but based on the fact that you can't hit the larger cogs while in the middle ring, your derailleur cable might be too tight. Because there is no trim adjustment on the lower-end shifters like the Sora, the derailleurs can get very sensitive to cable tension. It could also cause the derailleur to perhaps not drop low enough to engage the granny gear.
So I would try making sure that the low-end limit screw is properly set (almost touching the chain in little chainring/biggest cog) and then let up on the cable tension a hair at whatever barrel adjuster is in your cable system.
I hope this helps--I know how frustrating mechanical problems can be, especially starting out. Don't lose heart!
First comment - 28 lower is not normal standard on tandem road sets they are a 30 and a 32 - Shimano and Race Face - if your inner ring is a 44 then your jumb is 16 which is normally alittle tough with Shimano STI shifters. That being said I am running a Salsa 28 on my set - 54, 44,28 and yes I've broken chains with a jam and killed a xtr der when it broke. Several solutions - go bar end shifting, I switched chains Connex, I also now run two second eyes so the chain jump theorectally can't happen and I have trained my stocker to back off on gear changes appoaching a incline. To start with though you have make sure your chain alignment is correct - yours really seem off from your description. As for broken spokes we are 350ib team and have never broken a spoke in three wheel sets - we run staight guage 14 on out 700c wheels with 48 in the back and the same on our 26 inch wheels with 36 spokes in the back and I regularly true wheels every 1000 miles or so. Hang in there. Mike
On a stock bicycle I always look for the simple answer.
In your case, the first thing that I would do would be a complete checkout of the front derailleur adjustment. Park Tool has the complete drill on their website. The trick is to disconnect your shift cable and start from the very beginning as if you are installing the derailleur for the very first time. The sequence of the adjustments is very important because every adjustment affects all of the subsequent adjustments. I think that a "Third Eye" or a "Jumpstop" is a good idea, but my bet is that the front derailleur adjustment will fix your shifting problem.
As to the wheels, I'd have them both retensioned using a tensiometer and retrued. Just replacing the broken spokes simply returns the wheel to what it was previously. What it was previously was a wheel that was about to break a spoke.
Sounds like some improper shifting may be part of the problem.
Are you shifting onto the granny ring before you hit the hill or mid-hill? It's best to get in the ring you are going to climb the hill in ahead of time.
Also you should only be using the largest three cogs on the cassette with the granny rings, so rub should not be an issue.
As for broken spokes, are these new wheels? if so it sounds like the spoke tension is too loose. The wheels should be trued and tensioned under warranty. If they are old wheels and properly tensioned and have not been crashed, then the spokes are fatigued and the wheels need to be rebuilt.
Time Out: While it’s encouraging to see all the helpful feedback, I’m not sure why you (or anyone else for that matter) believe you need to “fix” a new tandem at your own expense.
Originally Posted by JohnnyCool
Let’s do a quick recap here:
You bought this thing on August 9th and your LBS, while being helpful and all, has still not been able to fix the shifting issues that were persent from the start. Moreover, they have even suggested “upgrading” the components that Burley has tacitly guaranteed to work properly for a specified time. Note: Off hand I don’t know what their warranty provides beyond the lifetime frame for the original owner but I’ve got to think you’re still covered UNLESS you’ve been jumping curbs or riding this thing on technical single track.
Burley and your dealer need to properly diagnose and adjust the components so they work as designed and/or offer suggestions on how to improve your shifting technique which I suspect may also be an issue. If they can't make the components they sold with your tandem work, then they need to provide you with ones that will and they should also make sure your frame is properly aligned before going down that road.
If your dealer hasn’t been on the phone with Burley in your presence then I’d suggest you give Burley a call to let them know that you and your dealer are struggling with a problem related to one of their tandems. If nothing else, this will put you on Burley’s radar and also give you a feel for how responsive Burley is to your situation. Moreover, they’ll be in a better position to recognize if this is a common problem with either your model of tandem or the specific components in question. Remember, you paid for this type of support from Burley when you bought your tandem, regardless of how much of his margin your local dealer was willing to shave off the bike when he sold it to you.
Same thing goes for the wheels; unless you rode the thing through pot holes and damaged the rims, your spokes should not be breaking, even if your team weight was 450lbs. This is indicative that Burley delivered an improperly tensioned wheelset to your LBS who apparently doesn’t spot check tension during assembly or pre-delivery inspections. Burley and your LBS need to “fix” your wheels, either by doing a complete rebuild** or by providing you with a new set of properly tensioned wheels. **If they simply replace the spokes that broke the likelihood that you will have further spoke breakage in the future is fairly high as the damage to the remaining spokes has already been done.
Bottom Line: Unless there is a product defect with your tandem or the components, your tandem “should work” once it’s properly adjusted and the wheels should remain strong and relatively true (a spot check & adjustment at 100 miles for bedding-in is normal) for several thousands of miles so long as they are not damaged by impacts or during a crash. Any product defects need to be addressed to your satisfaction at your LBS' and Burley's expense.
Other minor issues:
Chain rub in the middle and small chain rings: This is normal on tandems which, due to their wider than normal rear drop-out spacing have sub-optimal chain lines. In many cases, much of the rubbing noise is caused by the chain running up against the next larger chain ring and not the derailleur cage. It is noted that Derailleur rub is more common on older STI shifters that only provided 3 stops and more recent upper-end models now have intermediate positions that eliminate that particular issue; however, always confirm the source of the interference before assuming when working on tandems. Regardless, Burley has most likely taken this into consideration in the specification of your tandems components. I say most likely in that if they are struggling with component availability or suppliers, substitutions can sometimes fall short on performance. Can you “make it better”. Well, sort of. You can use Santana’s off-set front derailleur bracket & a bolt-on front derailleur to move the front derailleur outboard, but then you’ll also need to get minimally a new rear bottom bracket with a longer spindle to move the drive side crank further outboard as well. This will increase the tread width (aka, Q factor) of your stoker’s cranks which can create some “fit issues” for certain riders.
52/42/28 is not at all unusual for tandems but it is different from what Burley shows as the spec for the Rumba at 52/42/30. There would be a marginal difference in shifting performance between the 28t and 30t but, again, I suspect the problem is a combination of adjustment/alignment along with some shifting technique issues on your part. It would need to understand more about your cadence and what rear cogs you were shifting between when the chain was "kicked" pass the granny ring before making any further assessment.
Brake performance on tandems: In general, the more a bike weighs the more time and distance it takes to stop (period). While you can fit brakes that will perform better than some stock set-ups, you must ultimately "adapt" your riding style to how a tandem performs, which includes certain expectations regarding tire wear, shifting, acceleration, deceleration, and cornering. Short of solving a brake squealing issue with a stock set-up, the search for the "perfect" tandem brake will be a life-long pursuit where even marginal improvements will be great cause for celebration... although discs are showing great promise at making the quantum leap to tandem brake nirvana. In the end, the more you ride a tandem the more "normal" even what were wimpy brakes will seem and, conversely, you'll often times be surprised by how much excess brake capacity your 1/2 bike has once you return to it, noting that I always find myself skidding the rear wheel on my 1/2 bike after primarily riding the tandem.
Last edited by TandemGeek; 11-09-05 at 06:58 AM.
Tandem Geek and others, thanks for the replies. I will definitely call Burley today and let them know about the issues I'm having. Hopefuly, between the LBS and them, we will get it resolved. I will go to the LBS this afternoon and talk about it with them too. TG, to respond to one point, no curb jumping and the bike has never been off of pavement. I actually have tried to treat it very gently.
RE: my shifting. Let me tell you what I'm doing and hopefully, if that is part of the problem, it can be corrected. Generally, I try to keep us right at 90 rpm. I frequently shift the RD to maintain that cadence. At the extremes, if we fall much below 80 or over 100 or so I definitely will shift. In the front, when the middle chainring rubs, I shift to the large one. I will normally stay on the large until we come to a stop or a hill. When I shift the front to a smaller gear, I call "easy" and we apply just enough pressure on the pedals to keep them turning. This was working great, even when going to the small chain ring. I would try to shift to the smal chainring ahead of time but occasionally we've had to shift part way up a climb. The issue I do have with the shift from middle to small is that the jump was so big, we would slow to maybe maybe 60-70 rpm and would still be unable to spin fast enough to catch up to the smaller gear. I then started shifting up 1 or 2 gears in the back prior to shifting down in the front. I understand the concept of having adequate cadence to shift, but we also need to be able to pedal after shifting. Would it be better to drop to the small ring and then quickly upshift in the rear until we could catch up?
The other shifting issue with going to the small ring was that it would shift great on the stand but would not shift when we rode. That's why I kept opening up the limit screw. It seems like the point where it would shift adquately is very, very close to the point where it would jump off.
Actually, your shifting technique sounds just fine. The key is getting to the alpine or granny gear before you need to and generally doing so from one of the four upper cassette cogs: it sounds like you're doing that. Unfortunately, without seeing what it's doing or how it's set-up I think I'm at an impasse.
Originally Posted by JohnnyCool
As others have noted, there are any one of a number of things that it could be or that could resolve it, even something as goofy as discovering that your LBS routed the front derailleur cable to the wrong (right) side of the front derailluer cable fixing bolt. However, if this was the case you'd have also found shifting up to the middle and large rings seemed quite sluggish and heavy.
Keep us posted on their feedback, suggestions, and the final resolution.
Last edited by TandemGeek; 11-09-05 at 05:59 PM.
Usually, if I'm going to drop from the middle to a much smaller granny, I'll drop a cog or two in the back first (or even almost at the same time). Otherwise, there's the terrible huge increase in cadence required to maintain your current road speed if just dropping the front.
Originally Posted by JohnnyCool
If I have a big jump going from the middle up to big ring, I will usually prepare to shift up to a bigger cog immediately on the tail of putting the chain up on the big ring -- or two cogs if I've already been at a happy cadence, and am just going to the big ring in anticipation of needing it soon.
This all depends on the spacings of your rings and cogs, and your tolerance for cadence ranges, but I look at it as doing what needs to be done shifting-wise to put the chain in a reasonable gear combination for your desired cadence at the given road speed.
Of course, I barely know what I'm doing; this is just what works for me. I can usually find a happy combination for me. My daughter will call out for a shift with a shout of "pedal pace!" if the cadence crosses into the 100s for very long, and the adult stoker just says "I don't know what you're doing with that shifting, but after you do it, it's better."
Three tandems and 1000's of miles later I can say getting the shifting done in advance of a incline is an art. A Tandem' shifting is alot more complicated than a 1/2 bike - more cables longer chains etc. I have even on occasion had to check der. hangers to make sure they were straight and not slightly bent. (TG) - I must disagree with one point though, all my bikes brand new had issues coming from the dealers. Whether it be cable stretch, der ajustments that couldn't be foreseen on a stand, squeacky brakes, wheels out of true at 50 miles etc. What makes the difference is the customer service from the LBS who sold you the bike. Just a general comment though - there is a great diversity in the shop talent in tandem shops and I will shop till I find a good one who in knowledgable about tandem issues- luckily there are several good ones here in Seattle.
Not to be argumentative, but I'm not sure I understand where we have any disagreement. In re-reading my novelette I directed my comments at the post-delivery experience, the customer service aspects of our friends three month history of problems with this tandem, and what his expectations should be. The main thrust of my comments was, quite simply, a tandem buyer should not have to pay out of pocket to make a stock tandem function properly (front derailleur issue) or to fix components that should not have failed (wheels).
Originally Posted by vosyer
Specifically, this tandem has gone back to the dealer for a shifting problem that has existed since the buyer took delivery and despite at least one attempt, they have failed to correct the problem. Moreover, since just about every bicycle sold requires a one month / 100 mile check-up where things like wheel true / spoke tension and other problems can be addressed, one must wonder if those checks were performed on this tandem while it was at the dealer given the reported spoke breakage under normal use.
I wholeheartedly agree with your observations regarding bike shop expertise in tandem maintenance and often times note that just because a bike shop sells tandems it doesn't necessarily know much about their subtle performance nuances. Moreover, if the people you are dealing with at the bike shop don't regularly ride tandems they'll also have no appreciation for the level of frustration that a couple experiences when the relatively expensive bike they purchased to enhance their quality-time together becomes a barrier to enjoying their time on the bike. There are a lot of first time tandem owners who give it up for this very reason, i.e., more trouble than it's worth, loss of interest by the stoker when they get tired of listening to their captain rant about the "stupid" bike, etc... The point here being, a tandem-savvy dealer will go the extra mile to make sure the stupid bike does work properly going out the door and, missing the mark, will make sure they get it right -- to include taking the thing for a test ride with another employee from the shop as stoker or even the customer if they are a one-man show -- to make sure it works properly on the road as well as in the workstand. Your average LBS who happens to sell tandems may or may not do these things.
Bottom Line: If the dealer and the manufacturer can't make it work as delivered the ownus is on them to made any component changes needed to correct the condition (period). Shaking their head and saying "never seen it before" doesn't hack it if they don't find a work around and the work around shouldn't cost the customer money for "better cranks" if they had no inclination to upgrade in the first place.
Just my view... and yes, Seattle with it's deep tandem culture (R&E Cycles, Elliott Bay, Rodriquez tandems, Erickson Tandems, Bushnell Tandems, Davidson Tandems, etc...) and higher than normal tandem ownership & ridership does tend to have some very tandem-savvy shops.
Part of JohnyCool's shifting issue my lay with is chainring combinations. Because of the 14-tooth jump (instead of the normal 12-tooth jump) from his middle to granny rings, he may have to shift up further on the cassette to find a gear that is not too easy for his speed, which may promote cross-chaining and undue stress on the granny ring.
If I was running a 28-tooth granny with a 52-tooth big ring, I would consider switching the 42-tooth to a 40-tooth middle ring.
And I'm a struggling art student - certainly not an artisan. At least not yet.
Originally Posted by vosyer
Here's what the LBS did: Installed 30t cog replacing the bent 28t. (BTW, the Burley spec is a 30t) Installed a 3rd eye chain watch to prevent a reoccurance. Readjusted the der.
The result: well, mixed I guess. We rode some hills Sunday and it was a bit tempermental to coax it onto the 30t. If we had no pressure on the pedals and the right cadence (not too fast or too slow) it shifted with a slight delay, meaning there was a second or so of clicking before the 30t engaged. That was acceptable. I was always early, per the advice here which helped. The one exception was turning left at a light directly to an uphill. I was on the middle CR and depite trying to get up some speed to have time to shift, it wouldn't go. We actually made the climb on the middle. When we got to a plateau, I tried to shift to the 30t but no luck. Just I said "let's stop" to my stoker, our cadence slowed slightly and it jumped down. Not sure if we were exerting pressure prior to that or not.
Now my thought is to back out the limit screw 1/4 turn at a time until the shifting gets quicker. Make sense? Another question..we're going on a ride organized by some forum members this Saturday. I know part of the route is some fairly steep up and down hills. Should I stay on the 30t and just coast as our speed gets up? Assuming we've got a fair amount of speed on the downhills, if I go to the 30t early, and we can't spin fast enough, will it shift OK? Let me describe what I mean. On the downhills and on the flat portion between hills I would obviously like to go to the bigger gears so we can keep some speed going into the hills. Shifting to the small CR early will mean that we won't be able to spin fast enough to apply pedal force. I'm thinking about the flat part just before the incline. Do we spin enough so we can shift and then coast until our speed slows? Is that the proper technique for shifting early when transitioning from downhill to uphill. My concern, based on my previous experience, is that it's very easy to wait too long and if there's any delay once I hit the shifter, I'm afraid it won't go at all.
PS - any tandems going on the ride being organized by OC Roadie? Check the road bike form if you're interested.
The bike should shift from the middle to the granny within 1/4 of a pedal turn. Something is wrong. Either your cadence is to low and pedal pressure to high, or something is wrong with the front derailleur, like the return spring is weak.
As for the transition from down hill to up, I would suggest going down the hill as fast as you can in as big a gear as possible, then shift across the cassette for easier gears keeping a high cadence while in the big ring as you loose momentum, than a clean double shift to the middle ring and back up the cassette 1-2 cogs, all the while keeping a high cadence. Then when you are in the middle ring and the 1st or 2nd largest cog in the back and loosing speed, make another clean double shift onto the granny and back up the cassette 1-2 cogs and climb the hill.
This is assuming the hill is to long to just stand up and sprint over.
Yes, that makes sense. The first or second 1/4 turn will probably do the trick.
Originally Posted by JohnnyCool
Success! I had no troubles shifting on a hilly 65 mile ride after making the adjustment! I now feel confident in my shifting and the bikes ability to do what I want it to. Now on to broken spokes...
Originally Posted by TandemGeek
2 more on the aforementioned 65 miler. The bike shop just checked the tension on them too. What gives?
From my earlier post....
Originally Posted by JohnnyCool
They can retension the spokes until the cows come home but it won't do a bit of good. Again, the damage was done when the first spokes broke.
Originally Posted by TandemGeek
My original recommendations still hold: Bent chainrings,broken spokes and other woes...
Last edited by TandemGeek; 11-20-05 at 08:12 PM.
LBS/Burley should fix/pay for new spokes all the way around on the offending wheel as if they do not rebuild it, you will continually have problems later on. Next, a good wheel builder will also have to come into play.
Warranty should cover this. Dealer makes a certain percentage of profit, and service and good results pay off for them in the long run.
Never had an issue dealing with Burley on warranty stuff.
Ah ha, asked and answered. Thanks again TG. I just got off the phone with the LBS. Their policy is 3 broken spokes on the same wheel. They did agree to contact Burley though to see if they would agree to the rebuild. Hopefully it won't be any more of a hassle and they will simpy take care of it.
Originally Posted by TandemGeek