Chainring and gearing sizing advice

[benp1]

Chainring, chain and cassette need to be changed on my Solaris. Think I have changed the chain, but the chainring and cassette have been on it 6 six years now...

The cassette is an XT cassette with a Hope 40t T rex on it, 40t cassettes weren't a big thing back then. But I haven't been able to get into the smallest cog for a while, so might be running 12-40 in practice.

I've secured myself an 11-42 cassette, which if it works OK will be great. Otherwise I'll be looking for a new rear mech, currently running an XT non clutch mech.

Now need to think about the chainring. Currently running a 104bcd 30t Raceface NW chainring, what oval chainring should I go for to give myself another gear? Rarely need it where I am but would be grateful of it on some of the big climbs when loaded

I know I can use a gearing calculator, but I also heard of folks moving to a bigger ring when going from round to oval.

So not sure whether to go for 32t oval, or go for something different? Any good value recommendations also welcome. Went to works components but they're out of stock

[slarge]

Hi Ben
I've used Absolute Black oval chainrings - you might be able to get a 30T to fit your cranks (their website should tell you if it fits), or stick a 32T oval ring on - that will give you a slightly easier gear. I think that the mech you have should be fine but use a narrow wide chainring - it does make a big difference in retaining chains.

[Bearlegged]

I *think* the suggestion with oval rings is that if you're happy pushing a (e.g.) 32t round ring, you'll feel much the same pedalling a 34t oval. This seems to be based on the idea that the 34t oval gives you the same torque/leverage(?) as the 32t round when in the pedal dead-spot (where you're least effective).

The alternative approach (it seems to me) is to use the same number of teeth, and you'll find it easier to pedal the oval ring, but get the same gear development (i.e. distance travelled per revolution).

[redefined_cycles]

Ben... I put some thought into what chainring for the front on my setup. Contwnders were Praxis, Wolftooth and Absolute Black. Ignored the likes of PlanetX, Uber and them other lot who are famous for giving good service and value for money (I forget the name... erm... anyway).

So I needed a ring that wouldn't wear the rest of my setup as its gonna be a pretty-penny cassette (Dura Ace that'll cost a pretty penny or few). So I need a ring that won't wear prematurely. Decided on Absolute Black as I've been running it (non oval but narrow-wide) on Stan (the Sonder) in 1x XT/SLX gearing and its been absolutely fantastic.

Reading up on their website I finally understood too why most of the contenders (ignoring Planet X and the likes cos they don't worry too much about patents I suppose) don't actually advertise Narrow-Wide so obviously. According to AB they have the patents on their specific design. In about 2 years of use (arguably abuse but I'm kind to my drivetrain I think) I've not dropped the chain once AFAIR and thats without the clutch engaged up back.

Impressive chainring indeed and being alloy you'd expect at least some wear over about 2000 miles. I haven't looked with a magnifying glass but I'm certain no other alloy ring could do that through grit and grime (though I do change the chain in time). Designed in UK and made im Norway or summat. Get it and hopefully be impressed.

NB. Sorry for the story... but just to top it off, I'm going narrow wide on the road now too and if it works out, next on the mtb

[Bearbonesnorm]

I've a 32t AB oval on my Stooge and I'm fairly sure (in absolutely no scientific way) that there is a difference when climbing. I'm not sure I'd class it as an 'extra gear' but I reckon it suits my low cadence style - 'spinners' maybe not so much but I don't know. I see they now also do a 30t 104 ring - uhm

[Dyffers]

I see they now also do a 30t 104 ring - uhm

My superstar 30t non-oval ring is spaced out from the spider to allow the chain to fit inbetween the ring and the arms. How oval is oval ie how much less diameter is the narrower width than a round ring? A mm or two probably still works.

[redefined_cycles]

I see they now also do a 30t 104 ring - uhm

My superstar 30t non-oval ring is spaced out from the spider to allow the chain to fit inbetween the ring and the arms. How oval is oval ie how much less diameter is the narrower width than a round ring? A mm or two probably still works.

That was the word I was looking for 'Superstar'... how longs that chainring been going for please Dyffers

[Dyffers]

That was the word I was looking for 'Superstar'... how longs that chainring been going for please Dyffers

Only a couple hundred miles in the last two years or so; it lives on my 'big' bike which only sees occasional use but did get moved across to the XC bike for the BB200 but I never made it to Wales.

I have a couple of other NW Superstar rings that I've been very happy with - performance and longevity - especially having waited for the offers and got them for about £25 each.

[Bearlegged]

How oval is oval ie how much less diameter is the narrower width than a round ring?

I think the rule of thumb is usually +/- 2 teeth.
So, a 32t oval ring will be the same diameter as a 30t round ring in the short axis, and the same as a 34t in the long axis.

[benp1]

Thanks all

Absolute Black chain rings have shot to the top of the list. Think i'll stick with a 30t and see how it goes!

[mattpage]

I don't use NW any more, but when I did there did seem to be a difference and I think it felt smoother at lower cadences. Pretty much what Stu says.

I don't think it's like an extra gear and don't think it's giving any extra performance/power.

[benp1]

Thanks folks

I bought a 30t absolute black chain ring, went on nay bother. Put a new cassette and chain on too, even putolined the latter.

So shiny new drivetrain (still the old mech though), will see how I get on