2WheelWilly

I'm borrowing a friend's Canyon Grail (with Shimano 105 groupset) and in some gearings there's inevitably chain rub. He says that he's found that, with brifters (instead of bar-end shifting that would give a tension option), there's basically no way to calibrate the indexing such that no gearing suffers from chain rub. Some combination of front and rear sprockets will inevitably rub. Is that difficulty idiosyncratic to his setup or is it just generally a problem with 105 shifting/gearing systems?

Thanks for any insight!

Iride01 

Considering 105 has come in many versions since it debuted in the previous century, you seem to be asking a pretty broad question that likely applies to most any component group name out there.

It's more the issue of what bikes will rub. Differences in the length of the chain stays and whether the most ideal chain line was given by the bike probably has a lot to do with what one person says over another.

105 is a good shifting group set. If it rubs some, that's never been an issue other than those that have to have a stealth bike. My Ultegra rubs sometimes.

Steve B.

Only place I see chainrub is small ring, smallest cog. That's often a result of shorter chainstays that sees the chain rub on the inside of the big ring. No escaping that and as Shimano would point out, you shouldn't use small/small anyway, there are other options to get that gearing using the big ring with larger cogs. You cannot compare this with a system using bar-cons as typically a bike using these shifters would be a touring bike with much longer chainstays that might eliminate rub on inside of big rings.

icemilkcoffee 

This is pretty much the case for all road bikes with mechanical brifters with 8+ speeds. That's why you have the trim function on your front brifter.

deacon mark

My r7000 groupset has no rub in any gears. I can trim the small-small to not rub. I easily can ride the big-big and no rub at all. Naturally this is considered cross chaining and most road bikes can be set up to no have any rub. I am a mechanic that probably helps and I take my time to get everything dialed in but chain rub can be taken out of the equation with proper set up. On my disk bike with r7000 I can ride in the 50-34 gear no rub.

2WheelWilly

Thanks, all; these answers are very helpful. And Iride, this is a relatively recent 105 groupset--I'd say 2018 or later. My apologies for not specifying in the original message.

mpetry912 

Long time cyclists will tell you that the small cog / small ring, and largest cog / big ring combo, should be avoided for several reasons.

The ratios in those gears can be approximated in other gear combinations.

yes, the FD can be trimmed, but better to solve the problem another way.

Like taking off from a stoplight in 4th gear in a car with manual transmission, yes it can be done, but there are other options that are kinder to the mechanism.

/markp

ARider2

Long time cyclist and mechanic here to agree with above.

Iride01 

What you are looking at might be a version later, but the 105 5800 group that came out circa 2016 that I put on my 1991 Scwhinn Paramount was the best shifting group I ever had. Not that I've had a lot. I was friction shifting till I made that switch. I'd even go so far as to say that it shifted faster and more responsively than my current Ultegra 8000 series Di2. However the 3 plus years maintenance free aspect that I've had with Di2 goes a long way to give it more favor if everything else about a bike is equal. But I do miss the more perfect shifting when the front and rear of my 105 5800 were shifted at the same time.

I was always able to trim out the rub in the big/big combo with the 105. But that Paramount had longer chain stays than my current Tarmac and other bikes I've check the length of.

Between Ultegra and 105, weight is the main difference between the two. Ultegra is quite a bit lighter.

dsaul

It's not specifically a 105 or even a Shimano problem. Any modern 2x drivetrain installed on a bike with short chainstays will have some issues in the small chainring and smallest cogs. The chain angle necessary to reach from the small chainring to the smallest few cogs at the rear will cause some contact with the large chainring. There is no amount of tuning that will get rid of this, short of altering the parts involved.

2WheelWilly

Super helpful, thank you everyone. And Iride, yeah... up to this point, I've only ever used friction shifters.

sweeks

Nothing wrong with that. Friction shifting requires a little more attention to what's going on. Like many things (think: stick-shift cars) these days, it's getting to be a bit of a lost art.