chuanito

hi everyone,

I just got my Kuota Kiral 2015 that i bought to spend more time/energy with my hobby..

Now my issue...I went around 5 times back to the dealer to report chain rubbing or noices coming form the chain region...He explained me how a Shimano Ultegra set works with trimming etc. but told me not to use the two smaller gears of the casette and explained the cross chain issue.

My question to you guys: Is my expactation that NO chain rubbing should happen if i trimm correctly wrong? Why do i have the two highest gears in my casette if i cannot use them?

LesterOfPuppets

Yeah, you don't wanna use the big chainring with big cog(s) or small chainring with small cog(s).

There are some overlap gears, so the gears are still there, but they're on the other chainring.

So for instance, instead of using the 34x11, use the 50x16 or 50x17. They're very similar.

Usually on 9-speed setups I can get it so that I only rub in one cog. 10 or 11 speed would probably make that a little more difficult, however.

steve_cay

I concur, cross chain is a fact of life!

The highest front with lowest rear, and lowest front with highest rear will often not be smooth. They are also redundant with other gear combinations that will be smooth.

Why do you have those highest gears if the are not smooth with your low front? So that you can use them with your high/middle front!

In fact the Shimano tuning instructions for my front drailleur, state to adjust so that the chain has 0-0.5mm clearance to the derailleur arm at the cross chain combinations. 0 clearance, i.e. the chain touching a piece of metal will make a sound.

alcjphil

I am not sure about what Shimano says, but both SRAM and Campagnolo claim that you should be able to use all 11 rear cogs with either chainring. However, just because you can do something doesn't mean that it is a good practice. One reason for not using your 2 smallest cogs with your small chainring is accelerated wear. An 11 tooth cog will only have maybe 5 or 6 teeth engaged with the chain at any time. This puts tremendous force on each cog wearing them quickly. If you use your big ring and a cog that gives you about the same gearing you will have about 50% more teeth engaged lowering the load on each individual tooth.Since there are many more teeth on the cog as well the cog would wear at about half the rate of the smaller cog used with the small ring

steve_cay

Sure you can use them all with every combination ... the bike will work fine. But you may hear a bit of a rubbing sound. That is what OP is complaining about ... and that is not unusual.

Stucky

I run Shimano, and I use all my gear combos- With careful adjustment, and the trim function, it's not a problem (at least with 9 and 10-speed. Don't know about 11-speed)

alcjphil

That isn't what SRAM and Campagnolo say, the claim is that with proper adjustment there will not be any rubbing against the derailleur in any of the gear combinations

steve_cay

Was bored so looked this up.

First Ride: SRAM Red 22 | road.cc

"SRAM call this ‘True 22’ because you can cross chain with their system – you can run the chain on the larger chainring and the largest sprocket, and the smaller chainring and the smallest sprocket. They don’t encourage this but it can be done, whereas Shimano and Campagnolo tell you specifically not to do this."

So some lines have technology to improve cross-chaining, some don't. So to OP's question: "Is my expactation that NO chain rubbing should happen if i trimm correctly wrong?" ... The fact is the maker of your group set says don't do this, Campagnolo also says don't do this. SRAM has designed some lines to handle this, but still don't encourage it!

Trakhak

When I worked as a bike mechanic in the '70s, I noticed that every bike that came in for repair of a broken chain had the derailleurs set for the big-big combination. Chains have improved since then, but cassettes are wider now than freewheels were, so I still avoid the two innermost and two outermost cross-chain combinations.

On the other hand, riding around in either cross-chain combination makes it easier for experienced cyclists to spot a raw recruit, so there's that advantage.

alcjphil

Actually, when Campagnolo introduced 11 speed the company I worked for was a distributor and they did tell us that it was acceptable to use all 11 cassette cogs with either chainring. As chains become narrower and narrower they also become more flexible side to side so that riding in the extreme positions is possible. However, that doesn't mean that using those combinations on a regular basis is wise.