Payton1221

I bought a bike a few years ago with a 3x8 setup. I never could get the bike to be perfectly adjusted where there was zero interference with the front derailleur in all 24 gears. I eventually turned it into a 1x8 and was very pleased with it performance wise (gave up some topspeed but it suited my purpose fine) and it was super-smooth and quiet!


Through a program with my health insurance company at work, I accumulated enouth points to enable me to get a Trek Verve 1 (a 3x7 setup) for free. I had the bike professionally adjusted, and it's quiet in most gears, but there's still some sound/rubbing with the front derailleur in some of the uppermost or lowermost gears. Is this somewhat common? How many of you have truly quiet gearing in ALL gears with 2X or 3X setups?


I'm tempted to remove the front derailleur entirely and turn it into a "manual transmission" and choose the appropriate chainring for the ride before starting: 38T for hills, 48T for flatter terrain (I've never needed the granny). Would chaindrop be likely in this scenario? It was on my first bike before I fully committed to a single chainring with tube mounted chainkeeper.

jefnvk

It is called cross-chaining. In short, you shouldn't be in big-big/little-little combinations. The bike is not meant to work in ever possible gear combination, although sometimes it can be done.

Milton Keynes

I only hear that chain grinding sound if I'm running in gears I shouldn't be, like big ring to big ring, or small to small.

corrado33

No no no no no.

You will never get 0 rub in all chainrings with all gears in the back. What you are trying to do is "cross chain". You should never go "small small" (meaning the small chainring with the small cogs in the back.) Likewise you should never go "big big." Both of these will often result in derailleur rub because of what's called "cross chaining." Google it if you want to know more.

The general rule of thumb is that you avoid big big and small small, sometimes the 2nd gear in those directions as well (so big/2nd biggest cog and small/2nd smallest cog.) The middle ring SHOULD be able to get all gears without rubbing, but sometimes you have to eliminate the biggest and smallest cogs. But on a 7 speed that shouldn't be a problem. You're not losing any gears this way, there are better combinations that'll produce the same gear ratio without rubbing.

With that said, if you really wanted to eliminate front derailleur rub, put a friction shifter up front.

Sy Reene

So dumb question. Why aren't 7 or 8 speed cassettes made with the same cog to cog distance as 11 speed cassettes and use an 11s chain? Wouldn't cross-chaining be mitigated more so if this were the case as the overall cassette width would narrower?

PepeM

My Sram Force setup does not rub in any gear combination. Fully cross-chained and everything. My previous 105 setup would only rub on the big ring in the two biggest sprockets, but it didn't really bother me.

corrado33

$$$$$$ Cheaper to build them with larger spacing. Besides, 11 speed chains are expensive.

Double vs. triple.

Doubles have trimming, most triples do not.

Also, decent groupset vs. 7 speed. You make your own conclusions.

fietsbob

Friction shifters let the chain run with an adjustment you make to be at its quietest possible ..

But as the chain roller, steel , contacts the chainring and cogs, both metal , there is that sound..

Iride01 

3 speed chain wheels are probably always going to be worse for noises when small to small or big to big. But no matter what you have, some will not have an issue and others will. If it's not making a lot of racket, then it's not an issue to be cross chained. Though if I were riding cross chained most of the time, I'd change out my chain wheels to more or less teeth.

indyfabz

My friction shifting triple on my LHT is as quiet as a mouse.

dedhed

Because they were designed long before 11 speed existed.

Sy Reene

So they aren't used any more on new bikes? I.e. Why not update the design-- seems it could streamline and reduce the number of tooling lines in the factories

FrozenK

Because it wouldn't be backwards compatible. And if you are going to use an 11spd chain and spacing there is little reason to use only 7 cogs*.

If you were to change the spacing on a 7spd cassette, you would need to use different shifters and possibly derailleur (for index shifting). You may be able to get away with it for friction shifters. But again, why bother?

*an exception being downhill racing where they don't need the range and running a 7spd means less weight in the back, and tighter chain line.

Jon T

It's called friction shifters with infinite adjustment. I run a 3x6 and I can ride noise-free in ANY setting. Some old school stuff just can't be beat.
Jon

manapua_man

That or if I need to adjust the front shifting mech.

Wanderer

My 9 spd Deore on my Crosstrail, nor the 9 spd 105 on my Sirrus, do not rub - quiet other than normal running chain noise!

Payton1221

Good discussion and it prompted a few more internet searches with one that included Shimano's manual that states:


When the chain is in the position shown in the illustration [note: figures show both big:big and small:small combinations], the chain may contact the chainrings or front derailleur and generate noise. If the noise is a problem, shift the chain onto the next-larger sprocket or the one after.

Yellowbeard

Wide 8-speed chains and cogs are very cheap, robust and hard-wearing compared to 10-11 speed stuff. And the wide spacing between cogs makes them very tolerant of imperfect adjustment and dirty cables.

BlazingPedals

Not sure if you're serious.

BlazingPedals

In my book, indexed shifting was the single most beneficial bike invention in the past 50 years. Adjustments are a little more fiddly, and you have to worry about compatibility with other standards; but it's SOOOO much nicer to use.

Although even with indexing, I wouldn't like going back to my old 2x5 gearing.

Iride01 

if the cost benefit ratio of changing the design was there, they would. But if most people are going to 11 speeds and what ever the future may bring, the cost of changing the manufacturing processes and then convincing the masses that this eight speed is better than the others is probably not on the good side of the bell curve.

Iride01 

You are probably correct. But I still use friction shifters on a 2x7 combo. I'm just about to start using 2x11 speed indexed shifters with the levers on my brakes. I guess you still call those "brifters". But I'm tempted to hook them up to the down tube friction shift levers one day when I go to a century ride just to see everyones faces.

coominya

I prefer 2* chainring setups but a 3* is basically a 2* anyway since the granny gear is hardly if ever used. I adjust my front derailleurs on my 3* bikes so they have plenty of clearance on the big ring. I don't care if they rub when on the smallest one.

Barabaika

1) Take out the small chain ring.
2) Get rid of the left trigger shifter and replace it with a micro-indexed twister shifter, which can move the front derailleur to any position.
3) Get a double front derailleur and try to expand the cage, so it never rubs.
---
But I would just get a bike with the Shimano Alfine 8.

Viich

I also love indexed on the back - but friction on the front derailleur works - a 'trim' position is necessary to avoid what annoys the OP, and it's tough to do on a triple.

Disclosure - I run 2x8 with DT friction left and index right on my favorite bike (105 1056)

My advice to the OP is find a left friction shifter (probably thumb shifter for flat bars, or DT if you have a boss for it) that you don't mind, and give it a try.

Or Universal Cycles has a clamp-on downtube shifter that's friction front and 7sp rear.