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planning on switching one of my gravel/road bikes to 1x mainly used for gravel but also doubles as a road bike when i ride with my son.
it has a gs 105 med cage rear mech presently and runs 30-46 and 11-34 cassette
hoping to go 11-46 and single ring up front, does anyone know if the mech will handle that.
i was going to get 2 single rings one for gravel and one for road duties for things like holidays to the alps. but would an oval negate the need for this. Read a bit an i think an oval 42 chainring can make it seem like a smaller chainring when climbing and a bigger chainring when going hard so essentially acts a bit like a 40 and 44 chainring, this could be absolute rubbish from me.
any advice greatly appreciated
I would guess that a GS mech that is rated for max of 34t is not going to work with a 46. I would also say that running 1x is not a great idea if riding in the alps.
I run 1x on a road bike and use a 45 tooth chairing with an 11 speed 12 - 25 cassette which is perfect for the relatively flat New Forest but if I needed more lower or higher gears I would stick to 2x
No chance that mech will work, get a GRX rear mech it will work with your existing shifters.
105 wont work. Ultegra RX or GRX.
Depends upon how much road use, but 1x would drive me mad with the gaps in the gears. My CX is 2x10 34/44 front and 12-32 cassette with 105 long cage mech. It won't go more than a 32/34T at the rear as it won't clear the sprockets.
No, that mech won't work. You'll need the right GRX mech for that (RX812 is 1x specific), the Ultegra RX only slightly more capacity than your 105 and not up to 46t probably even with a link range extender. Oval rings tend to feel like a slightly smaller ring than it is, but not bigger, so you'd still need 2 rings. But as others have said, if you're doing road and alps too, i'd stick with what you have. Much better spread of gears for road hills. I run 1x on my gravel bike but i don't do much pure road riding; but wouldn't want that for alp climbs, when you need to find just the right cadence at the low end, which on a 1x is where you have the biggest jumps.
I would also say that running 1x is not a great idea if riding in the alps.
I’d disagree with that.
I’ve done a couple of week long Alps trips, a week in the Pyrenees and the Cingles challenge on Ventoux all on a bike running 1x. The bike was running 42t chainring and a 10-42 cassette. Absolutely no issues on the climbs and only ran out of gears a couple of times on descents.
I guess it just depends on what you’re used to.
Well you have the low gear covered with 42/42 but have massive gaps in the gears on a 10-42 when not riding 42/42. That may not bother you so good for you but I run a cassette that is 12,13,14,15,16,17,18,19,21,23,25 and find it great for road riding as the gears couldn't be much closer and I only use the 25 for the odd steep short hill with most of my riding between 12 and 19 with most down towards the 12. I simply have no need for 2 front rings.
http://www.gear-calculator.com/
The gear calculator lets you see how much difference changing setups makes. Usually not as much as you would think.
Single ring on a gravel bike works well for me and I do convert it for use on the road in winter.
Oval chain ring wont make much difference.
I use a GRX chainset with 36T for gravel and 42T for road.
This is matched with a 10-42 cassette.
Again, it doesn't make much difference at the maximum and minimum gears due to the huge range cassette but that compromises having the right gear for fairly constant speeds.
I can't recall what chainrings were used, but I think I've read claims that the 105 7000 GS mech will do a 40T sprocket, possibly with a hanger extender like a goatlink.
Doh I'm meant 11-42 but still sounds like I'd need a different rear mech, probably go 40 or 42 on front. Other bike is 34-50 that's the bike I'll be riding in alps, son will be on 1x if I go that route!!
Max capacity on a 105 GS mech, is 40T total difference, but as Kerley wrote it is the max sprocket size that's the problem, the guide pulley will clash with the 46T sprocket, even with a Roadlink fitted the max sprocket size is 40T according to WolfTooth Components. Besides Shifting with a link fitted is never as good as Shimano intended.
If your 105 is 11 speed the shifters will work with a GRX long cage derailleur that's designed to work with an 11-42T cassette and hen you couldsize the front chainring to get the low climbing gear you need. I ran a 30T front ring for a while with an 11-42, it was good for 34.9kph at 100 rpm on the flat and 7.2kph at 60rpm uphill( just a bit taller than 40:46 6.7kph at 60rpm)