I purchased a Cube LTD a few months ago and decided to upgrade the chainset for one that had 48 teeth on the outer ring because 42 was just not enough.The crank I took of was a FC-M780 and I replaced it with a FC-T781;

https://www.bike-discount.de/index.ph...ils&pdid=47443

I realised I would also need to replace the front mech so I purchased a FD-T781 thinking that this would be compatible;

https://www.bike-discount.de/index.ph...ils&pdid=47442

I could not set it up and I put it down to being crap with gears so I took it to a LBS. They could not set it up either and said that that it looks like it is incompatible even though they looked it up on shimano website and shimano says it is compatible.

So, they recommended a XT-M770 with states it goes up to 48T;

https://www.chainreactioncycles.com/M...?ModelID=52285

Today, when I have gone to set it up, I can shift into all 3 front ring but I get rubbing when at either the biggest 3-4 biggest cogs on the cassette. If I adjust to eliminate this, I get rubbing on the 3-4 smallest cogs. This happens in all three front rings. Also, the H limit screw does not allow the FD to go far enough past to stop the chain rubbing the outer plate on the FD when in the biggest ring up front. This is similar to the problem they had at my LBS, they could only set up the other FD in the middle and out or the middle and inner as it would not even shift into the inner when the outer and middle where set up.

This front crank is only available in Germany and the USA, no shops in the UK stock T780 components which is making it harder to find completable components.

The shifters I have are SL-M780 which are also used for trekking components according to Shimano website as I though this could be a compatibility problem regarding the shifters but it does not seem so because the FD-T781 should be compatible.

What do you think the problem could be ? This is giving me such a headache and the LBS are going to be confused when I go back with the recommend much but still having a similar problem.

If you need to know what other conponets I have relating to the drive train I can post them too but please recommend me a front mech that will fit a FC-781 chainset.

Would be looking for a new bike shop who know there stuff, if the T780 series should all be compatible with each other, and if they are having issues, Madison are only a phone call away for assistance.

For getting parts in the UK vs Germany, it's not hard, and most of the time shipments from Germany are quicker than from the UK, so don't understand why you are saying that it's hard to get T780 series parts.

For getting compatible parts, would be making sure that you are going by Shimano compatibility charts, these are on the SI tech docs https://techdocs.shimano.com/techdocs...&bmUID=jBaDCs7 you can see an example of a complete bike with the parts you are looking at here https://www.rosebikes.co.uk/article/r...669/aid:562671

Not sure why you need a 48t on an MTB, if you are pushing that sort of gear, your aren't riding of road, and probably have the wrong sort of bike for you riding needs, for MTB gearing, would expect a question related to loosing the larger chain ring, and what bash guard to use rather than what to increase it to.

Are your shifters and rear derailleur Shimano 10-speed mountain type?

i was thinking of doing the same think on my 2010 Cube Acid. So, it seems that the 48T clears your frame?

i admit it is a little strange to have 48T on an MTB, but it's really common on German trekking bikes.

if you read german, this link shows a bike equipped with what you're trying to do (but with 622 wheels)

https://www.fahrradmanufaktur.de/prod...00-xt-30-gang/

send me a pm if i can help.

in short, it looks like VSF fahrradmanufaktur is using a touring crankset, fd and rd (T in the part number) with a hyper glide cassette and chain (HG) and a mountain shifter (M).

finally, it appears that you can order a shimano xt-t780 on amazon.co.uk but get a german listing. that may be the simplest way to get it.

however, it's all theoretical as I haven't ever used these parts in combination with a CUBE LTD frame, which may cause an issue.

however, however, VSF has a stellar rep and i guarantee their bikes don't rub in any gear combos.

also, keep me posted.

also, also, it looks like there are two model 63-66 degrees and 66-69 degree.

this is slightly (majorly) beyond me but good luck.

one last thing krobinson103 (or something similar) did the same thing 48T front ring on an MTB and i think he needed 4 more chain links and posted in this forum about getting it tuned right.

Yes, shifters are sl-t780 the same that are on some trekking bikes and in the trekking and mountain section on Shimano website. Rear mech is a RD-M780 Shadow.

https://www.cube.eu/en/hard/special/ltd-cc/

jimc101, I don't need to justify but I want a 48T on a mountain because I do road and cross country off-road paths. My cadence is too high with 42T and I always felt like I need more higher gears. The Cube LTD CC is a cross country bike anyway and not all mountain. Also, didn't say parts were hard to find or deliver as I have the parts obviously, bike shop said they could only find information from USA and Germany, making it harder to get answers I suppose.

This is what I have; https://www.cube.eu/en/hard/special/ltd-cc/

acidfast7, the 48T fits perfect, the 42T and 48T chain sets fit up to 50mm chain line but other parts will need to be swapped as I am finding out. I did use a bike with a similar set up as a template and this bike, as you said, does have the same set up as what I am trying to achieve.

https://www.bike-discount.de/shop/k17...-anodized.html

or as you said;

https://www.fahrradmanufaktur.de/prod...00-xt-30-gang/

My set up is

M780 shifter
M780 shadow rear mech
XT M771 10 Speed casette
FC-T781 crank
FD-T781 front mech and I have a FD-M771
HG94 chain

What's causing the front mech not to be adjusted correctly ??? I'm 110% sure the guy in my LBS knows how to set up a front mech ...

My FD-T781 is 63-66, would this cause issues as I read they are for 29ers or full suspension. 66-69 are for hardtails, apparently. Also, the chain length is not the issue, it is the correct length.

i read that the 63-66 is for smaller bikes. i never heard of it before that, but it sounds like the 66-69 is much more common.

but i have no practical experience and am learning through you because i agree that on the flats a 48 would be nice so that i could stay in the middle of the cassette rather than at the smaller end.

The outer for straights and the middle and inner for off road, perfect set up for me. I can ride the bike but I have to stay away form the largest cogs at the rear. So much faster than the previous 42T. I would recommend it if it were not for this PITA front mech issue.

Will be seeing the LBS again on Saturday and waiting for a reply from bike-discount.de which is where I got the bike and components. I do not understand if other trekking bikes have are sold with the same set up and obviously they do not have any issues. Even some of the Cube trek bike have the exact same geometry as the LTD frame.

It seems the majority, including Shamano and my LBS say these parts are compatible, so what is there massive amounts of rubbing ... very annoying ...

i really like the concept and can see why the germans really like the 48T on their trekking/expedition bikes

edit: bring it to bike shop that sells CUBE in the UK and they'll have the set up you want on the bike in house. my guess in that running a 48T is possible on an MTB frame ... but it probably requires the equipment to run at the outer edge of its operational window, therefore a CUBE dealer would be better suited to deal with it, as they use it on their touring/trekking bikes.

I have been reading a lot of shimano tech docs and I am quite sure that I ordered a FD-T781 for a trekking bike with a 63-66 angle when in fact I should have got the 66-69 version. I have ordered the the 66-69 FD-T780 version which Rosebikes.de specifically states that it is to fit mountain bike frames and it is suitable for angles from 66-69.

Shimano says that M870 shifter, FC-781 and FD-780 are all compatible and recommend that these are used together. Shimano also say that for my BB width (68mm), I have the correct spacer set up so this only leaves the angle issue. The 63-66 T781 did look weird when fitted as the cage did not follow the outer ring, that is that there was a 1mm gap the top and the distance at the end of the cage had a larger gap from the chain ring. Also, the 63-66 is designed for trekking bikes as the BB is lower and so effects the angle of the seat tube and chain stay. All seems to lead to the incorrect angle size purchased.

I will report back and let you know how it worked out.