(Need Help) Shimano Ultegra gear setup problem/oddness

Skonk

Hi

Bit of a long story but essentially; my brother purchased a Boardman Pro Carbon SLR from Halfords and while everything initially seemed fine, it soon became apparent that there was an issue setting the gears up to work correctly.

This is the bike: http://www.boardmanbikes.com/road/road_ ... n_SLR.html
Bikeradar review: http://www.bikeradar.com/road/gear/cate ... -14-48135/

It has a full 11 speed Shimano Ultegra group set.

So here is the problem…..

It’s has proven impossible to make both 1st gear and 22nd gear work without one of them catching (and catching in the 1 or 2 closest gears to it).

If you set it up perfectly in 1st gear (small chain ring, large ring on the rear cassete) then by the time you get to gears 20, 21, 22, the chain will be catching (this is obviously with the chain now on the large chain ring, and the front mech in its outer most trim setting).

Getting it perfect in 22nd reverses the issue and it catches in gears 3, 2 and 1.

Limiting screws are set correctly but obviously this has been repeatedly tested with them wound out so the limits aren’t affecting it.

This isn’t an issue of silly gear selection, such as big cog at both the front and back, or small at the front and back.

It appears that the front mech doesn’t have the required range from its lowest to highest position (with the trim settings etc.) to cover the extremes of the 11 speed cassette at the back.

Both my brother, myself and the store he bought the bike from repeatedly tried to make it work and in the end the store replaced the bike with a new one, which had the exact same problem and was replaced again.

So he is now on the THIRD bike and it still does the same thing.

In all 3 cases, the only way to get the proper range of gears was to take a set of pliers to the front mech cage and physically widen it.

We understand that on any given setup there will always be gears that aren’t fully usable and gears you simply shouldn’t try to use but surely specifically gear 1 and gear 22 should be attainable?

Has anyone else encountered an issue like this or would anyone like to offer some advice as to what may be the problem?

Thanks.

meanredspider

I don't understand the issue. Why does the FD width affect the indexing of the rear gears? I assume you've checked the position and alignment of the FD?

Is the issue the indexing across the rear cassette?

mitchgixer6

This sounds like an issue which is difficult to explain. I'm certainly struggling to understand what the issue is. Any chance you could take a video and upload it to YouTube?

t4tomo

When you say "catching" what is catching on what? Chain rubbing on front derailleur cage?

If so It sounds like the trim function isn't working correctly. As you move up (to more teeth) on the rear casssette you should be able to click the front shifter to move the FD. Cage over a tadge so it doesn't rub.

farrina

t4tomo wrote:

If so It sounds like the trim function isn't working correctly. As you move up (to more teeth) on the rear casssette

Forgive me if I am misunderstanding, but does not the trim function come into play when you are on the inner chain ring and moving down the block ie less teeth on the rear cassette? ie the effect of the trim function is to move the FD marginally towards the outer chain ring (without obviously causing the chain to shift onto the same) to allow for the increasing chain line offset.

trailflow

The ultegra 6800 front derailleur has a trim function on both the big AND the small ring.


To set the 6800 front derailleur correctly an inline barrel adjuster should be used. It will make set up much easier.

When clamping the front derailleur make sure the gap between the big chainring and front derailleur cage is 2-4mm. (4-8mm can sometimes give better leverage).

Toe the cage in very slightly (2-4mm) when clamping. Then use the support bolt to align the cage with the chainring. The support bolt is a small screw that pushes up against the seat tube to add stiffness to the front derailleur when shifting. It also moves the front cage outwards as you screw it in. (see page 8 of the shimano pdf below)

So first , with the cable de-attached. Put the chain on the small front ring and 25t (or biggest) back cog. - Make sure to click the downshift lever into its lowest postion.

Adjust the inner limit screw (closest to the frame on the front derailleur) so the gap is 0.5/1mm from the chain. and not rubbing on the chain.

Clamp the cable (finger tight - not too much). Then shift the chain onto the 11t cog at the back, and shift the front onto the big ring. There should now be some chain rubbing on the cage.

Then wind the inline barrel adjuster (adding more cable tension) until there is a 0.5/1mm gap between the inner front cage and chain, and no chain rub.

Then wind the outer limit screw in until it just touches the stop. (start off with the outer limit screwed almost fully out)

Now it should all be set. Check all gears and trim settings.

The 11t will always rub (when still in the small ring). This is cross chaining.

Read this. Shimano 6800 front derailleur set up guide.
http://si.shimano.com/php/download.php? ... 03-ENG.pdf

Skonk

Sorry for taking a while to reply; I posted this last night and I've been out on the bike pretty much all day today.

I should have been a bit clearer; the catching/rubbing is on the FD cage vs the chain.

Keep in mind that we didn't install any of these parts; this is what's happening with the bikes as they come from the shop and we're on the third bike now since the shop has replaced it twice due to the issue.

I'll try to explain the issue again and maybe I'll make more sense this time

If the FD is on the small chain ring and in it's inner most trim position and you put the chain on the large ring at the back (so first gear); then set everything up perfectly on the FD so it doesn't catch the chain but the gap isn't too big etc...

...then start changing up the gears, moving the chain onto the large chain ring and into the out most trim position (so now at the extreme opposite of it's original position), by the time the chain gets down to the last 2 or 3 small cogs on the rear cassette, the chain will be rubbing on the FD cage.

If you set it up in reverse, it will rub by the time the chain is on the 2 or 3 largest cogs on the rear cassette (again with the FD down on the small ring and in the correct trim position).

It's as if the FD doesn't have enough range of movement between the inner most position (and inner most trim) and the outer most position (and outer most trim) to accommodate the range of chain movement you get across the 11 sprockets on the cassette. As if the limiting screws are set to limit the movement too much but it does this even with them screwed all the way out.

As I said in the earlier post; it's not an issue of being in silly gears (big > big or small > small) but rather that the setup will not run without the FD cage catching the chain in both first gear and top gear (22nd in this case) and a couple of gears closest to those.

The trim positions appear to work; the FD is clicking into 4 separate positions (2 for the small ring and 2 for the large ring) and can clearly be seen moving correctly. Limiting screws have been opened so as not allow the FD cage to move freely.

I'd love to post a video but it's my brothers bike and he's now back down south where he lives (I live up north). I'm posting this for him simply because he doesn't really do the whole internet forums thing

term1te

I've not experience with an 11 speed set up, but have had similar issues in the past with 8 and 10 speed (I missied 9 out). Have you checked that the front mech is correctly lined up with the chain? I'm not familiar with that bike to know if it has a braze on for the front mech or a band on variety. Either way if the "arm" of the mech is not parallel with the chain (when the chain is on the middle of the cassette) you'll catch the chain at the extremities. It might be worth adjusting the position , by rotating it slightly around the seat tube at the clamp, to see if it is resolved?

Skonk

That's something we can take another look at; it did look right but can't hurt to re-check it.

It has been noticeable that on the 3 bikes he's had, the FD has been in a slightly different position each time (height-wise at least).

Thanks to everyone who has replied for the input btw

clogg

There is an extra adjustment on the front mech with the 6800. It adjusts the cable angle. Have a look at this link and also the shimano tech docs. Insert a 2mm allen key in the hole on the other side and turn to adjust.


http://forums.roadbikereview.com/compon ... 14980.html

mitchgixer6

Nor sure if this will help but I was getting a rub whilst in the bigger gears (big ring, small cogs rear). Fixed it yesterday by tweaking the cable tension slightly using the barrel adjuster.