guadzilla

Hi peeps -

Are there any issues with using 53/39 chainrings on 110BCD cranks? Specifically, a Quarq D-Zero PM, which supposedly does not require factory calibration if you change chainrings. Reliability, stiffness, whatever.

Thanks!

Dean V

It is standard on any modern Shimano road crankset so it works for them.

guadzilla

Ah cool, i didnt realize that. I was under the impression that 53/39s were 130BCD cranks. Good to know - thanks!

Kimmo 

Yeah, except Shimano uses crazy expensive 3D big rings to get stiffness at 110BCD.

Use something like BBB, and you'll get mad flex.

delbiker1 

I believe 53/39 chainrings are available in both 130 and 110 BCD. They are not interchangeable

Bah Humbug

Yes, the Shimano four-bolt cranks are all 110BCD, so it's doable. Your DZero (there are two of those in my household, so good taste!), however, has a traditional five-bolt pattern. That's still not an issue, but means you can't use Shimano chainrings for 53/39. I use Rotors on mine, though they're 52/36 Rotor has options in 53/39 for 110BCD. A quick search shows that the options for 110x5 53/39 rings are reducing, though - Praxis and Wickwerks used to make them, but now appear not to. Even Rotor seems to only make them in aero form now.

RiceAWay

Until maybe 5 years ago they were 130. But with the burgeoning popularity of compact cranks almost everyone has now changed to 110. Though Campy, as usual, was still a holdout last time I looked.

noodle soup

Are you saying all non-Shimano 4 bolt chainrings are very flexible, or just BBB brand chainrings?

tony2v

In 2015 Campagnolo came out with a new carbon spider for Super Record, Record and Chorus that accept 53x39, 52x36, and 50x34 tooth rings on the same crank arms.

guadzilla

Ha, i am a Quarq ho (with this, i will have 2 D-Zeroes, 2 Rikens and an Elsa, spread out over 2 domiciles) - I briefly considered dabbling with other power meters but Quarq just freaking *works*, whereas my wife has been having issues with her Vector 3s (to the point of getting a pair of Assiomas).

Figures - my last crank purchase was around then (also a Quarq, funnily enough) and it was a pretty clear 130/110 divide.

redlude97

Can you go with 52/36 110bcd which are readily available?

guadzilla

I figured there was a reason they went with 130BCD back in the day for the 53/39s. Do you have suggestions for stiff rings? Rotor aero rings arent a bad idea, actually...

noodle soup

I've used 53t Absolut Back 110bcd (Shimano compatible) and 54t Osymetric chainrings (110bcd Shimano compatible), and never experienced a flex issue. YMMV

FWIW, Bradley Wiggins used Osymetric chainrings on his TT bike.

guadzilla

What's the skinny on oval chainrings? They were quite the rage a while ago - are they still popular? I was rooting through my spare parts bin and have found a pair of unused Rotor Q-Rings, in 130BCD. Wonder if i should try them on my TT bike.

Kimmo 

I'm saying if you use an aftermarket five bolt 53 ring on a 110 crank, you'll probably realise why 130 is a thing. As for four bolt rings, I'd imagine most companies would make at least a half-arsed effort to emulate the lateral stiffness of Shimano rings; IIRC the BBB ones, although of traditional construction, use these big cosmetic blobs on the nuts that would probably offer a reasonable amount of bracing. I think maybe they did something similar for their replacements for the five bolt 3D rings too.

Bah Humbug

I liked Q-rings, but definitely had shifting issues on them (which is probably largely a setup issue). They felt great, though be aware they'll cause issues for many/ most power meters getting an accurate reading.

I don't know that 53-tooth 110bcd chainrings can really be noticeably worse than 52-tooth 110bcd chainrings, and those are common (and were prior to the new Shimano 4x110bcd).

noodle soup

+1

I've never had an issue, or heard of people having flex issues with 52-53t 110bcd chainrings.

noodle soup

I really like Osymetric rings on a TT bike, but I could never get the front shifting to work as well as standard Shimano rings. On a TT bike it's not an issue, but with a 50t ring on my road bike, it wouldn't allow me to cross chain on short climbs.

guadzilla

Yeah, a 52/36 might be something to consider, to split the difference between the standard and the compact - it would let me stay on the big chainring for a bit longer, and also give me a little extra spinning room for moderate climbs (for serious climbs, i'd just use the 50/34 with a 32t dinner plate at the back).

And noted re the accuracy issue. Apparently, it is a 3% error on Quarqs. I'll give it a go on the next TT and see how it goes - if the inaccuracy throws off my pacing, then back come the regular rotors.

I have decided, my next TT/tri bike is going to be SRAM 1x with a 48t and a 10t cog at the back. My 70.3 speeds are around 35-36kph, and that would give me sufficient gearing for any course which i would ride on this bike - any steeper, and it is aerobars on my road bike.

WhyFi

I thought that TTists favored bigger rings and cogs to avoid the frictional losses from the tight(er) bends in the chain path? 48/10 sounds like a combo that would give SlowTwitch the collective heebie-jeebies.

Bah Humbug

Yup. There's a reason the serious ones will use a 55-tooth - not only does using a larger chainring let you use a physically-larger cog with a looser bend in the chain, it also lets you use a cog one more inboard for a straighter chainline. You'd rather use an 11-2X cassette than a 12-2X cassette for a TT, even if you never use the 11-tooth. And it's not just the 'Twitchers - Froome did that as well, at least some years.

guadzilla

Man, that's a level of OCD that i havent descended to. I am not convinced that ceramic bearings, OS RD pulleys, etc make a difference. Besides, I only wish I could be hammering a 48/10 - that's only for descents at most - I can spin out a 48/10 on a descent, I'd rather push harder on the climbs and use the descent to recover (that's more efficient for overall speed).

Even during a TT, at 39-40kph, a 12-13t should be sufficient.

Anyway, this is just early thinking right now... the simplicity appeals to me, and when i get closer to a purchase, i'll probably try to figure out the gearing and see if it makes sense, or even if it is worth losing the flexibility of having a small chainring.

True, but (a) they put out a lot more power than my fat ass is capable of and (b) they have the luxury of setting up their bike differently for different events. I use the same bike for tris and TTs, just tweaking the height of the aerobars a little between events. So would prefer a one-solution-fits-all. A 55 is going to break me if there are any steep climbs.

noodle soup

So why use 48-10?

Bah Humbug

More importantly, why throw away your FD?

noodle soup

Because SRAM.