1x11 - 34T vs 32T

[Andrew Buckley]

4 hours ago, throttles said:

Hi all.. 

Resuscitating this thread..

what's the standard ratio for a 1x12 setup on a 29" dual sus?

I have a 10/50 cassette and need to buy a chainring.

I weigh 100kg if that helps?

The standard, i.e. what a bike with a 10/50 cassette will come with, is 34 tooth.  I think it is also sensible for Mr Average.  34 x 50 will be easy enough for most climbs, and 34 x 10 is fine when you are going fast.

With a 32 tooth chainring you will spin out at speed.

Some pros even use 36 and 38 tooth chainrings.

[ChrisF]

4 hours ago, throttles said:

https://enduro-mtb.com/en/gear-ratios-mtb-drivetrain/

this is one of the articles i came across that were useful. but still left me questioning between 32/34t.

Maybe i should try out the 32t and if it's too light get the 34t?

thought perhaps posting the question here would save me some school fees.

 

To echo @Ozzie NL, I have spoken to Joburg riders after doing a couple of Cape Town trails, aka climbs.

 

34 is their normal ring up there.

 

for the climbs we have they often comment they need a better climbing ratio ....

 

EDIT  @Andrew Buckley has a very valid point about spinning out though .... but this depends on your type of riding and terrain.   If you are doing tar stretched to the trails, or long dirt roads, you may well want to ride at 40km/h .... now you need a 36-10 combination.  Which in turn means you want a 52 dish at the back ....  only your knees and the hills in your area will know if this is practical for you

 

Serious hills and the need for some higher cruising speeds .... there IS a market for 2x setups.

Edited August 1, 2022 by ChrisF

[Frosty]

5 hours ago, WIPEOUT 1000 said:

I ride 2x because despite all the marketing hype, 1.) it is more efficient (both theoretically and empirically) and 2.) I have the cognitive abilities to both understand this and also operate a front derailleur.  

I agree, I did the Fast One the weekend before. While I inherited the drive chain as a 2nd hand buy, I'm inclined to revert to a 2x setup.

• I find the jump in cadence between two adjacent gears is too big for my liking. 11-50 on an 11-spd setup is about a 3 gear jump between shifts.
• I have a 34T oval ring, and I'm climbing hills in the middle of my cassette, where others are climbing in granny. My cadence is the much the although I am going faster as a result of pushing that bigger gear.

[mecheng89]

16 hours ago, TyronLab said:

At the point where you "need" to be in 32x50 (i.e. you're riding up a hill that is so steep you can't maintain a usable cadence in a harder gear) you're crawling along at 5.8km/h at 65rpm at which pace you might just be quicker walking anyway. 

Unless you have multiple 8%+ grades you regularly ride where you want to be spinning with relative ease at 85rpm I wouldn't go for a 32 chainring. 34x10 is also enough to stick with the majority of roadie group rides in my experience (unless you're in the 35km/h+ boat, at which point if you're riding a mountain bike you should be fit enough to not need 32x50 anyway).

 

9kph for a walk? I'd call that a jog. 

[throttles]

10 minutes ago, mecheng89 said:

9kph for a walk? I'd call that a jog. 

I'd call that a run 😅

[eala]

18 hours ago, throttles said:

Hi all.. 

Resuscitating this thread..

what's the standard ratio for a 1x12 setup on a 29" dual sus?

I have a 10/50 cassette and need to buy a chainring.

I weigh 100kg if that helps?

Get a 32 oval

[guidodg]

32T is actually more the norm on new downcountry and trail bikes now...even with a 10-52

[TyronLab]

52 minutes ago, mecheng89 said:

9kph for a walk? I'd call that a jog. 

These okes would disagree:

12km/h pappie, daar gat jy!

[mecheng89]

56 minutes ago, TyronLab said:

These okes would disagree:

12km/h pappie, daar gat jy!

Bit more than 12kph for these gents.

[madmarc]

I run 1 X 12 with 10/52 Cassette with 34 oval chainring - I just went down this rabbit hole - I suck at climbing and find when i no longer have the power to turn the cranks while in the 42 and change to 52 my cadence increases and i start to bounce - the jump from 42 to 52 is too big, i need something in between. so i  changed to a 32 oval and only done one long ride where i never went near the 42 or 52 so for me the jury is still out.

Next week i will ride SBR which we did 2 weeks back on the 34 and will be a good test on the 32.

I think no one can tell you which chainring to use - Every rider is different - I would do a hill on 34 and then do it again on a 32 - measure your speed / time / HR & perceived exhaustion - this will give you a good indication if its better for you. I even got a 30 oval but haven't tried it yet.

a lot of riders are always concerned if they drop the chainring size they gonna spin out on the downhills - For me, by the time I'm hitting 40-50km/hr I'm freewheeling anyway so it more about getting that sweetspot on the climbs. This weekend we rode to Vaal & back, did some good long downhills and fairly long stretches on the tar flats, not once was i looking for higher gears to turn on the 32.    

Edited August 2, 2022 by madmarc

[117]

Run a 34 oval on 11sp 11/46 cassette - its about the best you can get for percentage spread

Most times you'll climb on the 37 (on both cassettes) anyway, and the needed 46 granny is there if you decide to climb a steep slope, instead of the 42. Its a big jump for the deraillieur from the 37 to the 46 (compared to the 42), but most XT style der's can handle the jump if you have a long cage - just set your B screw nicely and have the correct chain length. With the 34 oval it's (in theory) the same as a 32t when climbing

You still get the joy of the 11 on the flats and downs (on both cassettes) but the added advantage of the 34 oval (36t when you need the extra on the flats - in theory)

I tried a 36T round on an 11/46 11speed and died on the flats. The 36 was just too much

Now I'm stupid and run a 38t 10/51

 

edit: I see you're on Sram - I'm out of my depth on those components

[TheoG]

4 minutes ago, 117 said:

Run a 34 oval on 11sp 11/46 cassette - its about the best you can get for percentage spread

Most times you'll climb on the 37 (on both cassettes) anyway, and the needed 46 granny is there if you decide to climb a steep slope, instead of the 42. Its a big jump for the deraillieur from the 37 to the 46 (compared to the 42), but most XT style der's can handle the jump if you have a long cage - just set your B screw nicely and have the correct chain length. With the 34 oval it's (in theory) the same as a 32t when climbing

You still get the joy of the 11 on the flats and downs (on both cassettes) but the added advantage of the 34 oval (36t when you need the extra on the flats - in theory)

I tried a 36T round on an 11/46 11speed and died on the flats. The 36 was just too much

Now I'm stupid and run a 38t 10/51

 

edit: I see you're on Sram - I'm out of my depth on those components

Nope, 38 x 10/51 is not stupid, its perfect .... 🤪

[ChrisF]

29 minutes ago, 117 said:

Run a 34 oval on 11sp 11/46 cassette - its about the best you can get for percentage spread

Most times you'll climb on the 37 (on both cassettes) anyway, and the needed 46 granny is there if you decide to climb a steep slope, instead of the 42. Its a big jump for the deraillieur from the 37 to the 46 (compared to the 42), but most XT style der's can handle the jump if you have a long cage - just set your B screw nicely and have the correct chain length. With the 34 oval it's (in theory) the same as a 32t when climbing

You still get the joy of the 11 on the flats and downs (on both cassettes) but the added advantage of the 34 oval (36t when you need the extra on the flats - in theory)

I tried a 36T round on an 11/46 11speed and died on the flats. The 36 was just too much

Now I'm stupid and run a 38t 10/51

 

edit: I see you're on Sram - I'm out of my depth on those components

 

I am looking for a 38 104BCD chain ring .... (for the e-bike)

[Andrew Buckley]

1 hour ago, madmarc said:

I run 1 X 12 with 10/52 Cassette with 34 oval chainring - I just went down this rabbit hole - I suck at climbing and find when i no longer have the power to turn the cranks while in the 42 and change to 52 my cadence increases and i start to bounce - the jump from 42 to 52 is too big, i need something in between. so i  changed to a 32 oval and only done one long ride where i never went near the 42 or 52 so for me the jury is still out.

Next week i will ride SBR which we did 2 weeks back on the 34 and will be a good test on the 32.

I think no one can tell you which chainring to use - Every rider is different - I would do a hill on 34 and then do it again on a 32 - measure your speed / time / HR & perceived exhaustion - this will give you a good indication if its better for you. I even got a 30 oval but haven't tried it yet.

a lot of riders are always concerned if they drop the chainring size they gonna spin out on the downhills - For me, by the time I'm hitting 40-50km/hr I'm freewheeling anyway so it more about getting that sweetspot on the climbs. This weekend we rode to Vaal & back, did some good long downhills and fairly long stretches on the tar flats, not once was i looking for higher gears to turn on the 32.    

That is the problem with SRAM 1 x 12.  A 42 to 50 jump is not great. A 42 to 52 jump is ridiculous.

[TheoG]

26 minutes ago, ChrisF said:

 

I am looking for a 38 104BCD chain ring .... (for the e-bike)

They are not easy to find.  I have a 38T Race Face on my one bike, looking for another for the other bike but so far cant find.  36 no problem, but 38 is so skaars soos hoender tande  .

Edit:  Only option:  https://csixx.com/products/tt-chainring-104-bcd?variant=42978786672869

Edited August 2, 2022 by TheoG

[DuncanDoughnuts]

51 minutes ago, TheoG said:

They are not easy to find.  I have a 38T Race Face on my one bike, looking for another for the other bike but so far cant find.  36 no problem, but 38 is so skaars soos hoender tande  .

Edit:  Only option:  https://csixx.com/products/tt-chainring-104-bcd?variant=42978786672869

38t

I find that with a 38 I hit the motor cut off point so fast that its not even worth it. 

Happy with a 36 for jhb and a 32 for CT