One of my mtbs is sram 1×11 with a 32t front.

I’d love to have the range of 12spd (like my other bike)

Instead of spending a few hundred on a new group would chaining the front to a 30t work ok? I guess I’d lose some top end speed but not that bothered as its only road sections I’d be in my tallest gear

http://www.gear-calculator.com/?GR=DERS&KB=24

You can compare your proposed setup with a 12spd here.

I used to run a 28T on my 10spd. It was the most appropriate for my riding. If you’re content that straight-line pedalling speed will suffer a bit, you’ll be fine.

Well you aren’t going to get the “range” without getting an 11spd cassette that matches the range of the 12spd. Changing the chainring just moves the range up or down, it doesn’t alter the size of the range itself. So if your 12spd is 10-50T then you need an 11spd 10-50T cassette.

If you just want a lower climbing gear then going 32T to 30T reduces everything by roughly 7%, which is slightly less than going 42T to 46T or 46T to 50T on the cassette. These jumps are both 9%, whether you’d notice a 2% difference in practice?

Wait, I can get an 11spd cassette with a 50t? Will my current rear mech reach

Sunrace do a 10-46 cassette that your sram 11 speed mech will probably be ok with. Much bigger and it’s probably not going to work (there are 11 speed 11-50 cassettes from Suntour and possibly Shimano – m5100 – but you need the biggest range Shimano mechs to reach those).

I’d ran my 10-42 11 speed cassette with a 30t chainring the whole time I had it. That kit is going on my new hardtail in exactly the same configuration too. I went 12 speed Shimano on my full suss for a lower gear and a bigger range (10-51 cassette with 32t ring). I think with Sram direct mount cranks you could even go to a 28t chainring for a lower gear – at the expense of high end speed.

On my mtb the top end speed isn’t really an issue tbh – apart from the occasional road section joining bridleways or really long fireroad descents the highest speed cogs don’t get used.

Thanks, sorry I meant I miss the 50t for climbing. The 32/42 is just a bit over geared for me on the steepest climbs

That’s what I assumed. Do you could go 30t or 28t on the front if you don’t mind giving away some range. If you have a direct mount Sram crank it was less than £20 for a steel x sync 2 chainring last time I bought one.

Other than that I think the biggest range cassette you can run with Sram 11 speed is probably the Sunrace 10-46 cassette. It runs on the Sram xd driver.

there are 11 speed 11-50 cassettes from Suntour

From Sunrace, and from many others. VG Sport, ZTTO, Sunshine and several other on ebay, AliExpress and so on.

Not sure about Sram, but friend of mine was using standard SGS SLX 11 speed mech with 11/50, 11 speed Sunrace cassette.

That was on V2 Banshee Spitfire and I’m sure he have it still running OK on V1 Banshee Prime.

Cheers!
I.

Yeah direct mount. I think a 30t might be ok…my other bike is sram 12 with 50

So wonder what the equivalent gear a 30/42 11spd would be on my 12 speed bike?

Calculate it and see. Someone posted the link above. You just need to know cog sizes across the cassette (which the manufacturer will publish or you can count). That will give you the whole range of gear ratios for you 12 speed. Do the same for your 11 speed and then compare.

Wait, I can get an 11spd cassette with a 50t?

My Sentier came with a 11 speed Sunrace CSMS7 cassette; 11T-51T. It is specced as being equipped with a 32T chainring, but it actually came with a 30T ring. Very happy on the climbs!

..these x sync rings…which offset do I get? Trek ex9.7

3mm boost offset I would think.

I can recommend the Sunrace 10-46t cassette, I have those with 28t and 30t rings on my MTBs.

The 30t one is a fast trail bike and I found the top end ok for cranking along on the flat.

My previous bike was 1×11 on a 32T, which I changed to a 30T. Made climbing easier and I didn’t miss the reduction in speed from the highest gear.

So based on my experience, if all you want is to give yourself easier gears for climbing then yes, it’s the easiest and cheapest way to do it.

By comparison, my new bike is 1×12 with 34T chain ring. Doesn’t feel noticably different to 1×11 on 30T, although I appreciate there’s other factors at play with it being a different bike.

That sunrise 10 46 looks great. Cheap, good reviews some say just tweak the b screw a little and it runs perfect. Will my current chain be big enough?

@nixie – the gear calculator site has a drop down list of most cassettes which gives you the tooth count for each of the cogs. No need to count them yourself. Assumes you know what cassette you have.

@sefton – depends what you are changing from and how old your current cassette is.

Will my current chain be big enough?

Flog it with your old gear and get a new one if you’re fitting a new cassette and ring.

It’s pointless everyone comparing ratios without mentioning wheelsize remember – that’s the “final drive” ratio!

I run 29inch wheels, 11speed GX 10-42 block and a 28tooth chainring on my ‘big’ bike as it gives me the climbing gear I need, and still allows me to do 20odd mph on the flat.

And the amount of time I really want to do 20mph on the flat on a 33lb suspension bike are negligible, so there’s no need for further top end!

It also (fractionally!) improves weight and ground clearance too.

I’m baffled by people running 28t chainrings with modern cassettes, spinning out on fast descents feels awful to me, and I love a good sprint on the flat sections so a couldn’t live with anything under 32t. Amazingly Nino Schurter runs 36 and 38t chainrings, that guy is a machine.

If you’re putting on a new cassette and new chainring then get a new chain at the same time. An old one (even if the right length) will prematurely wear your new components.

Around £20-25 normally gets a decent mid range X1 11 speed Sram chain. That’s what I’ve usually gone for, although I fancied some bling for my new build so picked up a gold coloured X11E KMC chain. But then I’m running an oil slick XX1 chain on my 12 speed so the bling isn’t a surprise!

I’m baffled by people running 28t chainrings with modern cassettes, spinning out on fast descents feels awful to me, and I love a good sprint on the flat sections so a couldn’t live with anything under 32t. Amazingly Nino Schurter runs 36 and 38t chainrings, that guy is a machine.

Whilst I’m no pro mountain biker I don’t think I’m slow either. What kind of fast descent are you spinning out on with say a 30/10 gear combo?

Even on a fast road descent the other day with 32/10 I didn’t spin out – can’t say 30/10 caused any issues previously either.

Different folks/bikes like different gearing. Run a 36 with 11-42 on my 650b Hardtail and 34 11-46 on my 650b full suss.
Like to stomp bigger gears on the HT but spin more on the full suss.

Ultimately some get on better with higher cadence, I don’t but others do.

@greeny30 – I run with a 26T chainring on my fat bike but that’s a slightly different scenario especially in the snow. I do have a 28T for it as well. On the HT and FS I’ll run either 30T or 32T, both are 29ers. Of course the fat bike is also essentially a 29er.

This is for the Dales, Lakes and Scotland.

I’m baffled by people running 28t chainrings with modern cassettes,

28t is just right with a 10-46t cassette on an enduro bike.

I managed on 30t and 10-42t, but it bloody hurt sometimes – and now I can winch up more long techy climbs.

I’m talking about riding Pennines, Lakes, Scotland etc

FWIW I’m comfortably above average fitness, but a way off Nino still.

I’ve just changed my ring to a 28T. Now running 28/51
😁

I ran 32-34 (possibly 36) top end for years on my hemlock. It did suck on steep stuff 😃

Just going to 1x on my Jeffsy (for simplicity more than anything), so that will be 30-42 as keeping the rest of the X2 GX drivetrain

The Gear Calculator app allows you to input all values, easy to understand output, as per screenshot in this blog post from a couple of days ago. Comparing different people and bikes requires you input wheel/tyre diameters for a meaningful result.

I’m baffled by people running 28t chainrings with modern cassettes, spinning out on fast descents feels awful to me

I think a lot of this depends on where your priorities lie.

I’d argue that any descent where you need to pedal at the bottom of the block, irrespective of chainring size, is probably not worth the effort/fun ratio. YMMV.

I spin out on the road and sometimes on fire roads, but why would I want to waste my effort there?

If you got a 32 absolute black oval it would feel like a 30 uphill.
I’ll explain my experience

As I stand to pedal a lot, in Summer I use a 34 (Sram 11s 10-42 cassette).
I had a 28 round ring on for Winter 2017 and 18 as its so muddy and slow going here.

28 spun out a bit easy, so for Winter 2019 I decided I’d try a 30 (and this time went oval), I was surprised (although I’d read the ring size / feel, oval -v- round stuff on their website) in that it certainly felt as easy as the 28.
But smoother, of course, so much nicer AND didn’t spin out as easily.

Might be an idea for you I hope. They seem expensive chainrings but are very hard wearing in my experience. Last ages.

If anyone tells you they didn’t like oval, ask if it was AbsoluteBlack oval, the clocking and ovality differs a lot between manufacturers

-Bit confusing, but here’s the link
https://absoluteblack.cc/size-guide/
“32T oval ring will suit best someone who uses 31 or 32T chainring currently. While pedalling, you will feel similar effort to the one riding round 31T ring, but you will gain the speed similar to riding 34T chainring.”
neil

greeny30

I’m baffled by people running 28t chainrings with modern cassettes, spinning out on fast descents feels awful to me

Having to pedal on a descent sounds awful to me. Are you riding down fire roads?

Whilst I’m no pro mountain biker I don’t think I’m slow either. What kind of fast descent are you spinning out on with say a 30/10 gear combo?

30/10 is OK, 30/11 isn’t, but..

The thing I noticed moving from 30-11 to 34-11 was that while I could attack fast descents my strava times didn’t change and rather than having a rest I was destroying myself.

I’m with scienceofficer, pick a gear that gets you comfortably up the hills as once you hit a certain speed downhill then you should be pumping or speed tucking. Unless you’re riding mammoth mountain eliminator…

I’m baffled by people running 28t chainrings with modern cassettes, spinning out on fast descents feels awful to me

I’m not.

But I remember the olden days when people cycled to the trails on their mountain bike, or used it to link up bits of bridleway on the roads, not just drive to a bike park or trail centre.

I realise this is wrong now, and you should buy a gravel bike for this.

😉

I think some people just live in places where the small end of a cassette isn’t that useful, and others ride along flat stuff/downhill on roads occasionally.

Most of my descents are both steep and rocky. So pedalling isn’t really that important. For me, I could probably be quite happy losing the smallest 4 sprockets off my 11speed setup. I should probably change to a smaller front ring but I perversely like being forced to climb hard. YMMV of course.

I’m baffled by people running 28t chainrings with modern cassettes, spinning out on fast descents feels awful to me, and I love a good sprint on the flat sections so a couldn’t live with anything under 32t.

Just depends on where you ride surely? I don’t spin out with a 28/30t because all the descents I usually ride are way too steep to require any sort of peddling. The only time the top gear gets used is on road sections.

For that reason a 10-42 11s cassette has enough range for me, but I can see why other people might want more.

p.s. I also wouldn’t be able to get up the steepest parts of the climbs with a bigger chainring 😀

I realise this is wrong now, and you should buy a gravel bike for this.

But what size chainring?

Some of the issue may be that people “spin out” at vastly different cadences. Some people are happy at 110rpm and others won’t want to go over 80rpm.

Look at a BMX racer and then see if you’re legs are going too fast, they know how to spin. It’s actually quite a good thing to learn to spin a low gear and is surprisingly easy once you get used to it.