Upgrading to 1x11 gearing

markskinner89

Hello CXers, another newbie looking for help/opinions

My 2015 Merida cyclocross 500 currently has the original 2x11 Shimano 105 5800 groupset, with FSA Gossamer 46/36 chainset… (with English threaded bottom bracket)

But the chainset is in need of a replacement - half tempted to just upgrade to the ultegra BB and chainset (46/36), but wondering, if I was to upgrade to a 1x11 set up, what would people suggest I use to do this?

A large amount of my use means I end up staying on the smaller chainring anyway (that and weak legs)

So thought I'd entertain this idea before just replacing with a slight upgrade

Cheers,
Mark

Jterrier

What cassette does it have at the back? Basically make that a bit wider if poss (an 11-32 if the mech allows) then put a 38 or 40 or 42 up front dependent on your fitness. Ebay is great for unbranded narrow/wide rings in a variety of sizes so you could get several.

markskinner89

Jterrier wrote:

What cassette does it have at the back? Basically make that a bit wider if poss (an 11-32 if the mech allows) then put a 38 or 40 or 42 up front dependent on your fitness. Ebay is great for unbranded narrow/wide rings in a variety of sizes so you could get several.

It's 11-28 at the back, so agree would probably look for something wider to account for the change up front… Currently imagining 40 up front, with 11-32 at the back…

Wondering what decent chainsets there are for 1x as this is something I'm completely unaware of… (or how does that even work?) and do I need anything else to help with the change?!

And if I changed to an 11 speed, 11-32 ultegra cassette would I need to do anything with the rear-mech (which is 105 11 speed currently)?

Basically, I have no idea what I'm doing

trek_dan

You don't need to change your chainset, just buy a new ring and shorter bolts. Lots of people say they get away with using a 32 cassette on 105 short cage mech no problem.

Jterrier

Dont need an ultegra cassette. A basic road 11-32 will suffice as long as it is 11spd. The front ring can be a 40 mounted INSIDE the crank spider usually. You may need shorter bolts as previously mentioned. Change your chain too for a new one; its cheap (£8) and you may as well.

If you want to understand the effect on your gear range get your calculator out and work out your current one - your fastest gear is 46/11 and your slowest is 36/28 presently. A 40t with 11-32 would mean your fastest becomes 40/11 (i.e less top end) and your slowest becomes 40/32 (which is roughly the same as 36/28). If you ride road mainly get a bigger chainring. You did say you stay on the smaller ring mainly though so maybe that isnt the case.

Jterrier

Might be an idea to chat to a local shop too.

bold seagull

markskinner89 wrote:

Hello CXers, another newbie looking for help/opinions

My 2015 Merida cyclocross 500 currently has the original 2x11 Shimano 105 5800 groupset, with FSA Gossamer 46/36 chainset… (with English threaded bottom bracket)

Hi Mark,

Wonder if you could add your experience of the Merida 500?

There is a local one for sale nearby and I'm thinking of it as my road winter trainer, bit of tracks over the South Downs, and a general run around (I tend to commute to meetings into Brighton etc. around 4 - 8miles each way each time). I believe it is easy enough to add mudguards and turn it into a true allrounder - plus my cycling club do X training every Tuesday which I could join in with, and maybe even the odd race! (without the mudguards... ). It's for sale with both road and x tyres, and it doesn't look like it's been ridden much.

joey54321

Jterrier wrote:

The front ring can be a 40 mounted INSIDE the crank spider usually. You may need shorter bolts as

Are you sure about this?

Sheldon Brown states the chainline of a standard double/compact chainset as 41mm inside, 46mm outside.

http://www.wiggle.co.uk/sram-rival-1-1x11-gxp-chainset-with-x-sync-chainring-1/

Wiggle gives the SRAM 1x chainsets a chain line of 45.5, therefore much closer match to the outer chainring of a standard double than to the inner.


It is something I am toying with too to be honest. I would say you might also have to consider the rear clutch derailleur to help keep the chain on over tricky terrain (probably not an issue on the road) but having never used one I am not sure if this is essential or just a nice to have.

tgotb

joey54321 wrote:

Are you sure about this?

I've played around with this quite a lot; this is my third season on a single ring setup. I just mounted the chainrings (38T Absolute Black on the normal setups) on my old compact double spiders. Optimum mounting position will depend which part of the cassette you use most; I tend to use the lower part, so mounting on the inside works for me. Think about it - chainline will be exactly the same as being in the small ring of a double. My 3 Peaks setup was a Superstar 34T chainring mounted on the inner position and an 11-36 cassette (you can go to 36 with a short cage SRAM MTB mech); it worked very well, including in the 11. For normal racing I use 38x12-32, and the 12 is perfectly usable.

If you're on Shimano and constrained by the largest sprocket your mech will cope with, consider using a smaller chainring to get the range of gears you need; you can go down to 34T on a compact. 34x11 is 83", which is likely to be plenty for any CX race. My experience is that 83" is plenty for commuting and recreational riding too; after all, most track bikes are geared aoun 86". It's not too hard to wind it up to 30mph if you have the legs. A smaller cassette and smaller chainring should give you the same range for a fractionally lower weight.

Remember that, with a single ring, the effective chain length varies less, so you should be able to use a short cage mech (which will be less vulnerable) on pretty much any combination.

VamP

I have arrived at similar conclusions as TGOTB. I mount my single on the inside position of a standard double crankset, although I do offset it by 1.5 mm with a spacer on the HTii bottom bracket. This seems the best chainline of all the positions I have tried (inside/outside with and without spacers).

joey54321

Well at £20 I thought the Superstar narrow-wide chainring was worth a shot. If the chainline works well I might invest in a 1x SRAM rear mech. I went for the 38 which was a bit of a guess really.

Jterrier

joey54321 wrote:

Well at £20 I thought the Superstar narrow-wide chainring was worth a shot. If the chainline works well I might invest in a 1x SRAM rear mech. I went for the 38 which was a bit of a guess really.

38 should be fine. You should find that in general you stay in the middle of the cassette which is good as it means you have a bit to play with either side.

joey54321

I found this from SRAM

https://www.sram.com/sites/default/file ... _rev_b.pdf

which seems to back up what you are saying but also implies that inner ring on their doubles (excluding SRAM Red 2012) is exactly the same spacing as the 1x groupset...am I reading it right?

The Rookie

I'm running a Truvativ (aka SRAM) Rouleur crankset with the single NW ring in the outer location for a 46mm (measured) chainline, that's fine as the disc rear end (135mm) would normally want a 47.5mm chainline but I use the lowest gears more than the highest.

As its for commuting duties I run a 44T and that won't fit on the inner mounting tabs anyway as it fouls the frame (Chain stays - I think a 40t would just fit - PX London Road frame).

I run an 12-28 on mine (suites my commute duties) but have run it with an 11-34 for road rides with more gradients when needed.

Its running a cheap ebay NW ring (J&L) for now as I was trying to reduce the initial outlay when building the bike and its been faultless despite running a traditional 9speed undamped rear mech.