Chainring size

[Nestus]

Hi guys.  I am fairly new to mountain biking.  Currently i am still riding a 3 x 7 setup and struggling a lot uphills with this setup.  So now I am in the process of buying a new bike with a 1 x setup.  The new bikes are coming out with 1 x 12 with a 34t x 50t setup.

 

At the bike shop they can swap the 34t chainring for a 32t or 30t.  For a newbie, which chainring is the best to go for, without upgrading the chainring in the near future?

 

Thank you

[ChUkKy]

Hi guys.  I am fairly new to mountain biking.  Currently i am still riding a 3 x 7 setup and struggling a lot uphills with this setup.  So now I am in the process of buying a new bike with a 1 x setup.  The new bikes are coming out with 1 x 12 with a 34t x 50t setup.

 

At the bike shop they can swap the 34t chainring for a 32t or 30t.  For a newbie, which chainring is the best to go for, without upgrading the chainring in the near future?

 

Thank you

 

If your battling with a 3x7 it might be advisable to stay with that for now and get stronger first before going 1x12.

 

I see youre from WC so that means lots of climbing. Get stronger then go 1x12

Id say 32 in front with 10-50 at the back, this shouldnt break you.

 

But as I said, get stronger, ride more.

[Red Bird]

Even though the granny gear could be big enough to assist in climbing, the jumps between gears could be too big for someone not strong enough to handle it yet. Try to borrow a bike with 1x12 to see if it works for you. If it does, you could start on a 30t especially if you’re riding steep terrain.

[Martin PJ]

What is the wheel size on the 3x7, also the maximum teeth on existing rear cassette, number of teeth on existing front small cassette? You can then work out if the 32/50 on the 29er is better or worse than what you have already in terms of gearing. My guess would be that it would be a lot easier with the 1x12 setup and 50t at the back, 32t in the front.

[Nestus]

What is the wheel size on the 3x7, also the maximum teeth on existing rear cassette, number of teeth on existing front small cassette? You can then work out if the 32/50 on the 29er is better or worse than what you have already in terms of gearing. My guess would be that it would be a lot easier with the 1x12 setup and 50t at the back, 32t in the front.

 

I have a 29er.  Front is 24t smallest.  Back is 28t biggest.

[100Tours]

I have a 29er.  Front is 24t smallest.  Back is 28t biggest.

 

I think I see the problem :-D

 

24x28 is hard work (1.16). compare that to 32*42 (1.31) or 32x46(1.44). 34t is probably too big for a 29er. 30 or 32 depending on how strong you think you are.  I have both and swop them around for different events.

 

24x28 is close to 32x36

[gogo@]

You can play around with this gear calculator to see what different options will do for you.  I've found this very useful for comparing different set-ups.

Just select the speed (KPH) and cadence (RPM) options where it says Gear Units, so it makes relative, real-life sense.

Then you can compare what you had with what you might get to decide what works best.

https://www.sheldonbrown.com/gear-calc.html

[LuckyLuke]

haha, If you were running eagle that 24-28 is basicly a 42-50, if you weigh less than 85kg stick with the 34...more go for 32

 

https://www.bikecalc.com/cadence_at_speed

 

check the link for gear ratios

[MORNE]

snip

 

24x28 is close to 32x36

...which some of us ride just fine

[100Tours]

...which some of us ride just fine

 

depends on the hill you're climbing. 5-6% that's OK; 10-15% you probably need a little more. 

[Nestus]

haha, If you were running eagle that 24-28 is basicly a 42-50, if you weigh less than 85kg stick with the 34...more go for 32

 

https://www.bikecalc.com/cadence_at_speed

 

check the link for gear ratios

Yeah, i am a tall guy 1,92 and about 87kg.

[Martin PJ]

I have a 29er.  Front is 24t smallest.  Back is 28t biggest.

 

Wow, that is hard. next question is how fast are you on the flats. The 34/11 spins out at around 45 km/h, 30/11 about 40 km/h. I would guess you are pretty fast on the flats being big and light, so that is something to consider.

[Eugene]

I'm going to get chastised for saying this, it's all too easy to keep changing ratios every time you are struggling on hills. We all struggle on hills.

 

Keep your current setup and spend more time training on hills.

 

As previously mentioned, once you've built up some leg strength for those hills, then start thinking about a 1x setup.

[coppi]

32 oval.................

[peetwindhoek]

34T. The 34x50 will be a lot easier than the 24x28.

[Grease_Monkey]

32t is a pretty good middle ground. You have enough top end and enough granny for any hill. 30t gives you the ability to spin up anything, but you run out of top end, 34t gives you massive top end speed, but you will be grinding up a lot of hills.