project -Shimano XTR 40-11 11 speed cassette onto Di2 road bike

I was mulling over whether this would be possible without going to the huge expense of getting a full XTR Di2 kit. Well it is for very little outlay except for the Shimano 40-11 cassette. The problem obviously clearance over the 40 tooth sprocket.

My set up is Boardman CXR Di2 with 50-34 chainset and 11-32 cassette. Shimano Di2 6870 with a 'GS' rear derailleur.

I bought the xtr cassette and fitted it without any modifications, the bike could cope upto 35 tooth sprocket just and would go into the 40 tooth but catch the top jockey wheel. I increased the B screw tension which allowed me to get into the 40t but it was noisy.

I tried to get a longer hanger from the usual suppliers but no one was prepared to help other than sell the standard hangers.
So I set about making one myself, I am pretty practical and not averse to modifying parts to suit my needs. After a few hours in the garage, well 4 hours, I have a prototype hanger made out of high strength aluminium. All fitted to my bike, and it works brilliantly, the gear changes are smooth and I can even cross chain either way and the bike doesn't complain or drop off the gears.

Early results from logs are, I can maintain 80 rpm and keep the power output below 300 watts even on 20% gradients, my original setup would of seen my cadence drop to 60 rpm or less and my power to maintain that would of been 350 or more watts, just not sustainable by me on long climbs.

Requirements are a modified hanger and xtr 40-11 cassette and away you go, a longer chain is NOT even required!!. The prototype hanger is so close to perfect I will be having an engineering company copy, make a couple more to smarten up the rough edges for anodizing.

I will be using this setup when I can get to go to Tenerife and cycle up mount Tiede