Am thinking on putting this groupset on my bike
https://www.merlincycles.com/shimano...set-85890.html
Its on sale now and wondering if this could be good groupset for touring?
I have 50/34 (11-32) on the bike now, and I now the grannygear will be much better(i hope?)
But will I lose much of the top speed?

Thanks

Not sure what size wheel/tire you run, but there would be about a 6mph/11kph difference running on a 15 tooth cog at a cadence of 90rpm's. (50t=23.2mph/38.3kph; 36t=17.15mph/27.6kph) The wheel size I used was 700x28c on typical 172.5mm cranks.

You may not be able to fit that MTB crank in your Sirrus (is that the bike you're considering upgrading?)

The Sirrus should have a 68 mm wide bottom bracket, but the XT M8000 should be designed around (and include) a 73 mm bottom bracket.

The front derailleur wouldn't have the correct reach from your seat tube to the crank, either. Again, because it's designed around a wider bottom bracket.

I'm not sure if you could re-space the XT M8000 crank (with a shorter spindle) and fit it in a road bottom bracket. Probably not.


Regarding speed, you would lose a ton of top speed because your large chain ring would go from 50t to 38t.


If you want lower gears, you could:
* replace your current rear derailleur with a 9-speed Shimano MTB RD (XT-M772 is a favorite of mine), which would index perfectly with your 10-speed shifters, but allow you to fit an 11-36 cassette, giving you a granny gear lower than 1:1.
* replace your "compact" crankset with a "subcompact" crankset, like a 46/30. The IRD Defiant is an example. That would lower your top gear a little but lower your granny gear significantly. This would probably require a different bottom bracket; most available subcompact cranks use a square taper spindle.

If you want lower gears, you could:
* replace your current rear derailleur with a 9-speed Shimano MTB RD (XT-M772 is a favorite of mine), which would index perfectly with your 10-speed shifters, but allow you to fit an 11-36 cassette, giving you a granny gear lower than 1:1.

this is great info for me
So If I get the 9speed mtb rear derailleur then I can put on a 11-36cassete and all I will miss 2gear? From 20to18 gear?
Or do I have to do both and change the crankset to?
And again thanks a lot for the info cos I want to do some touring with my sirrus but i need better grannygear

If your bike currently has a flat bar and you are willing to run all of the pieces from the XT group, you shouldn't have a problem with it all working together. But if you want to run STI or even barend shifters on drop handlebar, the XT stuff doesn't work with any road components.

As for the top gear, this gear calculator lets you compare gears from two different systems. A 36/11 top gear spins out below 25 mph at 90 rpm. A 50/11 top gear spins out at 33 mph at the same cadence. That may not seem like much but from my experience, a bike that spins out that low can be frustrating. It doesn't take much of a downhill to reach 25 mph and that can be a lot of coasting.

Now compare a triple 48/36/22 to your current set up. You have almost the same high and have a much better low than you currently have and a wider range of gears. You'd have to change your shifter to one that is capable of shifting a triple and you'd probably have to change the front derailer. Chain Reaction has a Deore Trekking crank for about $75 US (get the 48/36/26 and a 22 tooth inner ring). This route would be cheaper than a whole group and would give you a better gear setup.

All of Shimano's Hollowtech external bottom bracket cranks are designed around a 73mm bottom bracket. You just use spacers to move take up the space.

This isn't a problem either. Again, you use spacers to move the crank to the position that it needs to be. Spacers come in a variety of widths so while it's not infinitely adjustable, it's pretty close.

You may need something like these to put Shimano cranks on it...These came with my S-Works Tarmac frame, not sure if they're the same size for your Sirrus though...

I doubt that the Sirius uses the same crank/bottom bracket as you S-Works. I suspect that your bottom bracket is a BB30. I fairly certain that all of the Sirrus line uses a threaded bottom bracket which uses a flat spacer behind the cup on the bottom bracket.

Yeah, I wasn't for certain whether it was a pressfit or not considering it is a Carbon frame, but Que Sera Sera, it is what it is...

Rohloff Hub alone is a whole group-set..

I can gear My Rohloff in a 20" wheel Bike Friday pretty Low ..

whats the Hills like from Bergen to the southern Norwegian coast, say Larvik, I Only used the Stavanger to Kristiansand section

2 sets of ferry ports in 1991 .. the Newcastle to Stavanger then Bergen one is gone Now.


A double using the Middle and granny and a chain guard (Or a 3rd chain ring) is another option.