[Closed] 50:34 chainset / 11-36T cassette / med cage rear mech ?

Shimano don't recommend it, but you can just about get away with a short cage mech on a 32T rear sprocket.  You'd defo need medium cage for a 36T.

there are 2 things you need to check - the maximum sprocket size for the mech and the max capacity - which for that set up would need to be 41T

if its for a bikepacing / touring bike do you really need a 50T chain ring? Surely a 46/34 or a sub-compact would be more practical

Depends on the frame. Some gear hangars are longer than others.

If it's 9 speed Shimano it's pretty easy, just use a long cage Alivio derailleur as it will work with road shifters (10 speed I'm not so sure). Works great on my touring bike. As said above, a 50t chainring is pretty useless most of the time on a loaded bike, switching to 46t will make better use of the gearing and make shifting a lot smoother.

yes, 9 speed shimano MTB mechs will work with 10 speed road shifters.

I'd even suggest going to sub-compact such as 44/30, then you can get away with a 32 block and have smaller jumps between gears than with a 36.

Not sure about your combo but I currently run a 36/52 and 11/32 with a medium cage 105 mech, 11 speed.

Many thanks for replies

Bit more info about the bikes

Both 11 speed

Bikepacker is a Cannondale SuperX with 650b wheels - (46/36 rings) - so could change inner ring to 34 easily enough

Partners tourer is a Canyon Roadlite with 700c wheels - (50/34 rings) - would like to keep this as is if possible

SRAM's compatability chart shows a long cage mech being necessary for 11-36t with a double chainset. (I've just been looking into this). Not sure about Shimano.

I've done 46/36 and 11/36 successfully with a 105 11 speed mid cage mech.

I suspect you may struggle a bit with chainlength on the 50/34 combo. Its going to be very, very slack in the small/small combo.

Jonny,

so for the Canyon, would your feeling be that if you avoided using the 34x11, then it should be ok ?

what if I got an 11-34 cassette - would slackness still be an issue ?

as mentioned above, you need to know what the capacity of the mech is - that's the number of difference in teeth and corresponding chain slack that it can take up. To work out the capacity you need it's

(Large Chainring + Large sprocket) - (small chainring + small sprocket) e.g.

50+36 (86) - 34+11 (45) = 41

so you need a mech with at least 41T capacity to handle all the chain slack - that's probably going to be a long cage mech. GS medium cage shows as 39T capacity

https://bike.shimano.com/en-EU/product/component/ultegra-r8000/RD-R8000-GS.html

Just trying to avoid certain gear combos is possible but not a great solution when you drop a chain, it gets jammed and stuff gets broken miles from home.

Cheers, Joe

So, if I'm reading this right, then it looks like the SuperX set up will be fine but the only options for the Canyon are to:-

a. replace the outer ring to a 46

or

b. get a long cage rear mech

If you want to fit an 11-36 to the Canyon then I think so, yes - but you need to check the mech you have on the Canyon will work with a 36t sprocket too.

Thanks everyone for the help

It's OK I'm here now, the bloke that's done it 😀

I'm running 50/34 and 11-40 on a 5800 105 SGS mech with a goat/road link to clear the 40 and the B screw reversed. I can get all combos and there's no sloppy slack in little/little or nasty binding in big/big.

Phew - 🙂 - where've you been ?

what's a goat/road link ?

It's the little thingumybob that extends the derailleur hanger so the top jockey wheel clears the largest sprocket. Google 'goatlink' or 'roadlink' (the first is apparently for mtb the second for road but I don't know what the difference is) then buy a copy off evilBay for less than a coupla quid.

Normally I'd ask why you need a 34-40 on a road bike but on my ride today I was desperately looking for easier gears. Right now a 40 on the back sounds good 😂

I get running a big cog on the back when 1x as you ditch the front mech but on a road bike wouldn't it be easier to just use a triple front and have the close range rear cassette ?

It would be a more expensive option as you'd need to change the left STI as well.

But you could sell the current shifter?

I know, triples are un cool but they do make sense.

Agree that triples are great when it comes to touring - just not cheap if you have to change most of the gearing

@Boblo - will have a look for those - thanks.

Aye to move to triple you'll need the front and most likely rear derailleur, left shifter, triple chainset and cassette. The change is then a faff to undo if you want to use the bike for 'normal' riding.

Mine is set up 50/34 11-28 for normal duties and then 50/34 11-40 for offroad/gravel. I leave the SGS derailleur, Roadlink and slightly extended chain on all the time. So road to gravel is just a cassette change or in my case, I bought a duplicate set of wheels and tyres so I just swap them. A little derailleur twiddling is usually required for perfect shifting and that's it.

It's the cheapest, quickest and most flexible way of rapidly converting road to gravel and back again. I don't find the gaps in the 11-40 an issue either.

just to highlight one of the other options that was glossed over - you could fit a 'sub-compact' chainset which allows for a smaller inner ring or to get the same result, though with a slightly less ideal chainline, fit a triple chainset and just use rings on the middle and inner positions. That will allow you to run a chainring as small as 28T. You could fit a 44 on the middle position and have a good range.

Couple that with a 11-34 cassette and you've got the low gears with smaller gaps in between.

I looked at the Praxis sub-compact chainsets but was put off because they have a non-standard chainring set-up, so instead I have a Sugino OX901D chainset (and herself has the same now) with 44/30. I have been riding with an 11/28 block but recently changed to a 11/32 block as I was a little undergeared on Gravel Dash. But previously I've ridden Tuscany Roads bikepacking event on it with 11/28 with absolutely no problems - 11,000m of climbing in three and a half days.

There are different versions of the Sugino cranks (ie cheaper), but they have standard BCD fitting chainrings and come with a bottom bracket whereas the price of that Praxis chainsets doesn't include BB.

ah right, I wondered what the BCD was on the Praxis one. That and the Sugino are not cheap for what they are though. I reckon you could get a 2nd hand triple and new rings for a lot less for pretty much the same result.

The Sugino chainsets are basically a triple with the outer taken off. If you want to do it on the cheap go to Spa Cycles website and do the same with their Sugino/Stronglight no brand cranks.

@ap & breatheasy - I'll have a look at that option too

@aP - Me and a few mates went bikepacking in Tuscany in May and did the L'Eroica route while we were there (3700m climbing in 130 miles) - all told it was 450 miles and gearing was 50:34 - 11:32 and that worked perfectly

34/32 is close to 30/28 if actually just under 1% lower... 😉

🙂 - like it