So the wrench says it's supposed to make noise...
I have Ultegra Double crankset. The chain always rubs against the front deraileur. I have adjusted it. I have had two mechs at two diff. shops look at it. No joy. They tell me the derailuer I have is for a triple but the specs say it can be used for double or trip. Any thoughts? The noise and the thought of the bike running inefficiently are bugging me.
No longer in Wimbledon...
Have you checked that the chainrings are not bent?
I hate it when shop folks cannot admit they are having trouble with some adjustment and just pull the customer's chain( pun intended). Front derailleurs are just about the simplest functioning part on a bike. They are also just about the hardest part to get adjusted just right. In my shop we run into difficult Front derailleurs all the time. The problem has increased exponentially with each increase in the number of cogs in the rear. The cages narrowed as the chains did. Combined with a more dramatic cross chain problem created by more gears and sometimes it is magic that solves the problem. Or dumb luck.
I could run down some of the techniques I use to dial them in. But I admit that sometimes, what I did to fix them makes no sense. And I admit that on occaision I am unable to completely dial the rub out. But before I make a suggestion, first some questions:
~In what combo's does the chain rub? Big in the front/small in the back? Small in the Front/ Big in the back? Big in the front/Big in the back? OR Small in the front/ Small in the BacK?
~What shifters are you using? Do they have a trim feature?
~Is your Bottom Bracket the correct length for the crankset you have?
~As womble asks, is your crank or chainrings bent? That is, does the rub happen consistently or intermittingly?
Several factors come into play. Cable tension. Vertical position of the derailleur. Horizon position of the cage. Using the set up instructions will often work just fine. But often they factory speced set-up is but a starting point.
Licensed Bike Geek
If your dérailleur is correct and in good condition, no it shouldn't rub the chain unless you are 'cross-chaining' (big/big or small/small combos)
Originally Posted by derwagon
Park Tools has a wonderful tutorial on how to set up and adjust the front dérailleur, here: http://www.parktool.com/repair_help/...railleur.shtml Follow the instructions from start to finish and in the order presented. You should be up and running in no time!
(29 Stumps eh? My son is stationed there.)
Thanks for the responses
To answer a couple of questions:
- the BB is the right size
- the problem is not inter. it is constant in most of the combos
I will try the park tools tutorial in a couple of days when I get some time with the bike
Davet, I just took orders to Frederick, MD. I was in the Stumps for 3 years. Hope your son is well. Semper Fi.
Ill ask a question along the same lines. I noticed my bike chain rubs only on big/small or small/big. I am riding an Ultegra Double, and these are the only two combos that the chain rubs in. I have had my bike for about a month now, and my LBS said that I should bring it back in about a month or so and get everything dialed in after the initial riding period.
Also, when in my small chainring, I notice that there is a clicking every time my pedal stroke makes on complete revolution. This only happens in my small chainring.
What kind of shifters are you using? Ultegra shifters have four positions which gives you a trim position for each ring. That should solve your problem.
mscycler, check the limit screws they are probably a little too tight. The clicking could be the shifter cable hitting the cramk.
Sounds like it could be limit screws to me, making the derailleur not move quite far enough in either direction. If you're willing to give it a go adjusting it yourself, just step through the adjustment on the Park Tool repair help - Front Derailleur adjustments page. Should be an easy fix.
Originally Posted by mscycler
i think that you should just replace the deraller or get rid of it all together..
if you have any parts lying around or a cheap bike
build a new one
i am currently working on one
i just need a new tire
Replace the derailer??? The thing has about 300 miles on it. If a derailer is only good for 300 miles, thats absurd.
Originally Posted by robthebiker
I will check the limit screw this evening and see if that is it.
If I can work the technology you can check out above link to see what some of the folks on the vintage threads think about the index shifting.
John E has some prettty stron feelings about it.
I kinda agree but I'm pretty new, and I don't really race. and ultegra is out of my $$ range anyway.
One things for sure,tweaking the DR's on mw Schwinn is alot easier then on my Jamis.
oh yea, mabye the cable is streched and the shop just doesn't want to "waste" man hours on what should be a free adjustment on a new bike when they could be getting paid to overhaul someone elses.
I drink your MILKSHAKE
Originally Posted by robthebiker
You hav to give a bit more info. Does the chain rub during an entire revolution, or only at certain points in the rotation. What is the chainring combo and what is the cassette range (also is it 7-8-9-10 spd)?
Originally Posted by derwagon
The PArk tutorial is a good start point, but each of those adjustments need to be 'customized' in some cases. The new, wider hub/cassette combos can make the adjustment really touchy.
If the bike is 'stock' and comes from a well-known company, is midrange or better, then the componentry is prolly OK as a working combo. If it's other than stock, due to shop customization, either at your behest or some other reason, then the components in question may not be the best working combo for your bike.
If stock, I suggest finding another bike on a showroom floor that is the same model, check compare the adjustments of height, derailleur angle of the showroom bike against yours - try to mimic those settings.
If it rubs on the showroom floor, Oh well...
Derail height - I use 2mm at the point of the outer cage plate that is closest to the chainring, which is a bit diff. from the park instructs. A particular derailleur, put on a particular seat tube (and itz angle) may find the closest point at the rear of the cage, not the front as in the pic. Use the closest point and set that to 2mm.
Angle - depending on chainline, you may have to 'finetune' the angle.
IF THE CHAIN RUBS ONLY DURING PART OF THE REVOLUTION, then check how much variance. If the chainring, in a sighting test looking down at the ring under the FD, 'wobbles' 1 -2 mm, that prolly manufacturing variance. 3 ,4 or more mm and its a defective crank. BB or both. I;d ask to have either/both replaced.
If the chain runs straight and smooth without any pressure on it, but rubs under your pedaling pressure, then itz likely the crank to BB spindle interface OR the BB moving within the retaining cups.
For that reason I really dislike sealed BBs. Give me a good open bearing Campy or other quality BB any time. But you may not have that choice.
Is the crank/BB combo square taper, octalink or ISIS? If Square taper, then take it off and put it on in a different position, that may resolve the wobble. If its Octalinl or ISIS you can try that but less likely to have much affect - with these you;re at the mercy of how closely the tolerances of Male/female splining match from spindle to crankarm.
Check that the cups are snugged well against the BB cartridge. Play of just a tenth of a mm at the cup inteface will translate into 2 -3 mms at the outer edge of the large ring.
You may also be rubbing the chain against the outer ring (while chain is on the small ring) not the FD, check for that condition. I;ve found that my new compact crank, 50-34, rubs the outerring if the chain is on the 34 and I;m trying to go to the smaller rear cogs (higher/taller/larger gear ratio).
With the modern frames I'm hoping that BB flex is not the issue, but if it happens while you're mashing the pedals, then it may be frame flex.
Good luck - I really dislike FD/chainring/chain problems.
cycles per second
Sounds to me like the cable length might be maladjusted. If you were using a double lever to shift, this would manifest itself as difficulty getting onto one of the rings (too much slack to get to the big ring, or too much tension to get to the little ring). But if you're using a triple lever, you can maybe still get to both rings but the FD is not properly aligned with either.
Originally Posted by derwagon
If it's close, you can use the barrel adjuster to adjust cable length. If that doesn't do it, you can try detaching and re-attaching the cable to the FD. But before you reattach, first adjust the lower limit screw to put the FD in the right spot for the small ring. Then put the shift lever in the correct position for the small ring. Pull the cable taut and attach to the FD. Use the barrel adjuster to fine tune.
Note: When I first put my bike together (Ultegra double w/STI), I attached the cable on the wrong side of the fixing bolt. This meant that the FD did not move enough with the cable travel and I had problems with rubbing until I reattached the cable on the other side of the fixing bolt. You want to attach the cable on the side that has a slot.