33T on bcd 110 Rotor 3D?

Discuss light weight issues concerning road bikes & parts.
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Posts: 58
Joined: Tue Nov 05, 2013 1:56 am

by Nozes


I've been taking a long look at my gearing choices lately,and came to the conclusion that I want to make it more compact,saving weight and having a closer ratio cassete.

Here's my current setup:


Rotor 3D bcd 110
48 TA Syrius outer
34 Rotor NoQ

SRAM Red 10s FD

PYC 1101 chain

Ultegra 11-32 cassete

SRAM Rival Wifli 11s RD

I know,big mixup,but it works :)
So,my idea is going for a 33t inner chainring and a 11-30 cassete. I didn't found a 33t 11s chainring,will a 10s TA Zephyr present any problem? It's the only 5 arm bcd 110 that seems available apart from the boutique brands.

A 33-30 would give me a 1,10 ratio,while my current 34-32 gives me 1,06.

Opinions welcome!

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Joined: Fri Aug 10, 2018 6:40 pm

by Karvalo

Ok, but a 34-30 is still only 1.13. It's pretty damn close.

Why not just put the 30 on and see if it's ok before pre-planning more funky mismatched chainrings? :noidea:

by Weenie

Posts: 296
Joined: Fri Jul 30, 2010 7:08 pm

by motorapido

33 tooth are available 11 speed STRONGLIGHT CT2, i'm running 33 47 on my gravel bike at the moment with an 11-28 for road and 11-34 for gravel and am happy with the gearing, run an 11-36 for proper offroad fun with 27.5 x 2.1" tyres, gives me all the range i need just by changing the rear wheel.

Posts: 58
Joined: Tue Nov 05, 2013 1:56 am

by Nozes

The 30 should work ok, but I'm willing to try different things if it means having a transmission tuned to my specific needs. Plus it's not a big investment, I can get the TA chainring for under 25€,it's worth a try.

Thanks. I can't find the CT2 as cheap as the TA, so maybe I'll go for the latter. I hope the minimal width difference won't present a problem.

Here's what the gear charts says, in meters per revolution:

34-32 2,24m
33-30 2,32m
34-30 2,39m

It may doesn't seem like much, but we all know how it really feels when hitting a steep climb, don't we...

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maddog 2
Posts: 363
Joined: Wed Feb 25, 2009 7:58 pm
Location: Lancaster, UK

by maddog 2

I've run 33/48 in the past, no problem.

33 was a TA and the 48 was a Praxis. I prefer Praxis shifting to TA on the 48. This was on 10spd but I'd be very surprised if 11 was an issue.

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Joined: Mon Aug 29, 2016 11:19 am

by alcatraz

The difference between 34 and 33 chainrings is smaller than half of the difference between a 30 and 32t cassette which is nearly nothing.

If you want more range you either put an 11s 36t (with or without a sram 10sp mtb rd = 11s compatible), or you get an adventure crank like a 46/30. Fsa has some cheap 11s 90bcd road cranks where you can swap the small chainring to something smaller than a 34.

Another thing is to get a powermeter and keep your current gears. The fifness you'll gain after a while is like having another gear or two.

Posts: 58
Joined: Tue Nov 05, 2013 1:56 am

by Nozes

I guess you didn't catch my first post.
I want a closer ratio cassete, not more range. In fact I can get away with a bit less than the 32,but the 30 may make change my mind, so I'm considering the 33 chainring. I'll keep the 2 cassetes and may swap them around.
Very little differences, I know.

As for powermeters and getting stronger, thanks for the tip but that's just not for me.

Enviado do meu G3311 através do Tapatalk

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Joined: Fri Jan 29, 2016 12:54 pm

by jih

33t 110bcd chainrings exist but they are VERY marginal and the chain is liable to touch the crank spider arms. This probably isn’t a problem, but it could be.

Why not get a 50/34 and 12-32? This gives you closer spacing and only a slightly shorter high gear, while also using standard components

Posts: 2415
Joined: Mon Aug 29, 2016 11:19 am

by alcatraz

To get the 16t cog you usually need to step down to an 11-28t cassette. 30 and 32 are basically the same.

So how about a 46/34 and 11-28, or as the previous poster said 50/34 and 12-32t or a 12-30t or 12-28t.

Different brand cassettes will offer different jumps. I like how the 28t cassettes from sram offer a ton of 1t jumps for cadence adjustment at speed.

by Weenie

Posts: 58
Joined: Tue Nov 05, 2013 1:56 am

by Nozes

Thanks for your suggestions.

As it isn't a big investment,I'll try my first idea,the 48-33 x 11-30. My only concern was if the 33t ring would clear the Rotor crankset,but I don't think it will present a problem.
If it doesn't work,I'll keep you posted.

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