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Shimano ultegra r8000 front mech?????

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 im off 24 Oct 2020

This thing baffles me😂. Bike shop mechanic tried to explain how to adjust but basically said he tells people not to try as they end up completely out.

So its rubbing on the inner side when in small ring front and 2 smallest rings on cassette. Bike shop mechanic says yeah it will do....🤔....well it never has for 9 bloody months. It's just been serviced.

Something to do with if you move mech setting in any more it no longer will be able to push chain to big ring. Theres a compromise with this mech????

Are these mechs just abit naff?

Can someone recomend a good quality front mech that is easy to alter....like they used to be 20 years ago.

Campag look like they're still like front mechs have always been.

I think shimano have overengineered this thing????

I've just bent the cage a little which seems to have worked.

Post edited at 18:27
 Yanis Nayu 24 Oct 2020
In reply to im off:

Sounds like bullshit to me. 

 Yanis Nayu 24 Oct 2020
In reply to im off:

Ive just re-read - you’re cross chaining like mad. I’d imagine if your front mech is right when you’re in the 11/12 it’ll be out when you’re in a gear you should be in. Use the big dog and the middle of the cassette instead. 

 im off 24 Oct 2020
In reply to Yanis Nayu:

I've read the instruction manual. I dont understand it😂.

Oh well. Think I'll look at a camag mech in future.

Is this the sort of shit that starts to happen when u hit 50....easily confused

Post edited at 18:30
 im off 24 Oct 2020
In reply to Yanis Nayu:

Sorry...2 biggest on cassette. I refer to them as small.....erm.....not sure why......

I think of the small cogs on back as the big ones cos it's a bigger gear.....😂

Oh dear

 robert-hutton 24 Oct 2020
In reply to im off:

Mostly it's because the cable is too tight put a front mech adjuster barrel they easy to install and tighten or loosen so no rubbing on both rings.

You could loosen the cable a touch only needs a mill or so.

But also check the front changer arm is level with the Chain and not got bashed in the service or by putting in a car.

Post edited at 18:40
 nniff 24 Oct 2020
In reply to im off:

It shouldn't do that - something is not right.  It should be aligned in the first place so that with the cable slack it should have a clean run to the largest sprocket.  the limit screw should hold it in that position.  When the cable is attached, the shifter should stay in that same position when the limit screw is eased off (else the indexing is out).  With the cable connected, the chain line should be clean from the big ring to the smallest sprocket - use the barrel adjuster to make sure that this is the case.

Shimano front shifters have middle positions to move the mech a bit so that it doesn't foul the mech when cross-chaining, even if Shimano say you shouldn't really do this. 

Cheap FSA cranksets can be a PITA and are more trouble than they are worth with decent mechs (no idea what you have fitted though).

Your bike shop mechanic sounds like the Saturday boy.

Bending it is not a good answer, unless it was bent the other way in the first place. 

It's also possible that it has slipped on its mounting and is no longer pointing in the right direction

Contemporary Ultegra is state of the art from not that many years ago.

 wbo2 24 Oct 2020
In reply to nniff:  Without wishing to sound condascending, I'd imagine there's a full tutorial on youtune somewhere..  

 JimR 24 Oct 2020
In reply to nniff:

It can be complicated to get completely right, I’d take it back and ask him to fix it or get your money back,buy a bike stand visit YouTube and have hours of fun😀

 im off 24 Oct 2020
In reply to nniff:

It's all shimano ultegra. 

I wonder if it has just slipped on mounting. It looks straight though. 

The cable tightener screw (the barrel I guess) has been set with this screw loose. I've been told to stay away from this screw by the mechanic. I guess if this is loose....the cable is tight. Yeah....loosening the cable may be the answer and then using the cable tightening screw to get it to the right tension. 

Unfortunately my brain ain't state of the art hence this mismatch.

 im off 24 Oct 2020
In reply to JimR:

Yeah...I'm getting that😂

I could go them when they were more simple

 im off 24 Oct 2020
In reply to wbo2:

Oh jesus....yes there is. I'm sure I looked in past. Anyway I'll have a look.


 kevin stephens 24 Oct 2020
In reply to im off:

The R8000 is a great groupset, I love mine.

Like any modern group  set it will not respond to cross chaining; chain on big front cog and big rear cog or chain on small front cog and rear small cog.  It is not made to do this and there is no need to do this it will grate, sound horrible and ruin your cogs and chain

The front mech works really well but is sensitive to fine adjustments, this can be made more difficult by initial cable stretch until used for a few rides. If it has been installed correctly there are only 3 adjustments; cable tension (in line cable barrel adjuster), top stop and bottom stop. 

When I fist fitted mine I had similar problems to those you are having, this was down to me cocking up the barrel adjuster, and was fine after I corrected it.  Check barrel adjuster and cable routing first.

With the chain on the small cog (lowest gear) tighten the barrel adjuster to take up all of the slack in the cable  until just before the derailleur arm starts to move.  Adjust the low gear  stop until the chain runs smoothly when using the 3 or 4 larger cogs on the rear block.

use the shifter to double shift to the big front cog, adjust the top gear end stop so the chain runs smoothly on the smallest cogs on the rear block.  The two intermediate stops on the shifter should handle the middle of the rear bock whether in high or low on the front

The end stops are very sensitive, a quarter of a turn makes a big difference.

Take your Allen key on a couple of rides to get the adjustment just right, also tweak the barrel adjuster as the cable goes through its initial stretch

Once set up you should have no more problems and enjoy the smooth and effortless shifting

 due 24 Oct 2020
In reply to im off:

Cable tension is really important with new Shimano front mechs and you don't want too much. Hate to say it but read the instructions - there is a cable tension indicator on the built in adjuster that will line up when correct.

 im off 24 Oct 2020
In reply to kevin stephens:

Yeah sorry. I've not been cross chaining. I got mixed up. It rubs with front small to back big.. ie smallest gear. It rubs just slightly with no cable tension and mech as far in as will go. If I angle cage slightly off parallel it stops.

Maybe it's the plastic buffer bit on inside of cage sticking out to far. It's a new chain to. Do they vary in width at all. 

The cable tensioning screw head is gnarled and stripped....by the bloody bike shop. You can manage without I suppose but it's more fiddly.  

 JimR 24 Oct 2020
In reply to im off:

There’s also a screw on the fixing which controls height and angle. As well as the limit screws. YouTube really can be very helpful 

 Dave Cundy 24 Oct 2020
In reply to im off:

Don't delude yourself into believing that campag front mechs are any easier to adjust.  I still find mine a bugger to adjust and I've had it for ten years.  As Kev says, they are VERY SENSITIVE to adjustment.  I reckon its harder to get my front mech right than the rear mech.

 im off 25 Oct 2020
In reply to JimR:

You tubed it. Got my head round it. 


 GrahamD 25 Oct 2020
In reply to im off:

My only gripe with it was a stupid plastic cap intended to tidy up the cable end which constantly fell off leaving a scratchy bit of cable to catch the calf when on small ring.  Finally just got rid of it and cut the cable as short as I dare.

Have to admit to expecting better on this sort of detail. 

Post edited at 08:04
 im off 25 Oct 2020
In reply to GrahamD:

OMG  so it's not the front derraliur rubbing at all. It's a new chain and cassette. Grinds when only going up steep hills....any gear.

Just needs time to bed in maybe.

Can chains be put on backward.

 JX0 25 Oct 2020
In reply to im off:

Shimano brand chains are directional, the writing should face away from the bike. SRAM chains don’t have a direction (but are noisier, some say). 

New chains on not-as-new cassettes can be noisy, wouldn’t expect it if the chain and cassette are both equally new though. Obvious things to check for drivetrain noise are for stiff links and that the chain runs correctly through the rear mech round the guards etc. as it can be surprisingly easy to get wrong. Neither of those would be noisy going uphill only, it would be all the time. Is the rear mech cable tension dialled in correctly? Everything cleaned and lubed? 

 kevin stephens 25 Oct 2020
In reply to im off:

If your chain only grinds when going up steep hills, ie when pedaling hard, but not when you're spinning easy the the problem may well be your bottom bracket. If it's worn the play will misalign the front cogs when pressing down hard

 im off 25 Oct 2020
In reply to kevin stephens:

Just had that replaced too. It's a 2018 trek emonda press fit bb. They have problems I think. Be fitted with an oversized bb that trek do for this fault

 im off 25 Oct 2020
In reply to JX0:

It's a KLM chain...new. on a ultegra new cassette. Only does it when really forcing it....up hill.

If it dont stop....back to the grumpy shop mechanic.

 lpretro1 25 Oct 2020
In reply to im off:

Are you aware that there is a 'trim' facility on both rings - this helps to prevent rub when in extreme (though if you ride big/big or small/small then you likely will get a  little rub). The trim is achieved by a short click on the downshift lever and you will see a small movement in the front mech - so for example, if in big front and gradually moving up to the bigger sprockets on rear when you hear rub a little click on the front lever will allow the cage to move a tad inwards; similarly if in little ring and moving to smaller sprockets  a little click on the upshift lever will move it outwards a tad. Also if you move to smaller front ring whilst in smaller sprockets and then as you move to bigger ones when you get rub then another click on the downshift lever - you get the picture...

 JimR 25 Oct 2020
In reply to lpretro1:

Is the back wheel on firmly enough? 

 daWalt 26 Oct 2020
In reply to im off:

>  Grinds when only going up steep hills....any gear.

Sounds like it's your knees, try some cod liver oil dietary suppliments. ;-)

 dovebiker 26 Oct 2020

Former bike mechanic - I've done lots and they are probably one of the trickiest parts to set-up correctly. Follow the online tutorials, but if you have internal routing it's unlikely that simply adjusting the tension as a normal front mech will get the cable tight enough for the trim function to work. Set the inner stop to a 'wide' position, clamp the cable and then slackening off the inner stop gave you sufficient tension and then use the grub screw to fine-tune. Once you get the trim to work, the rest is a doddle.

 im off 28 Oct 2020
In reply to JimR:


 im off 28 Oct 2020
In reply to daWalt:

Tell me about it. 

 im off 28 Oct 2020
In reply to dovebiker:


Well I eventually broke it. Now invested in a torque wrench and new mech. I over tightened a bolt and it stripped.

The grinding...I'm sure its coming from chain cassette....maybe rear mech. It is getting quieter. It's a new rear mech, chain, and cassette.....oh and front mech now too😀. I think it's the chain settling in to the cassette. Maybe a new bike would get rid....

If not then I'll start trying to fix my knees. Any one out there good at DIY knee surgery advice.......

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