Best Chainring Size for XC Racing

I have had a few rides on the 32 Oval now. My opinion is that it feels really, really good on singletrack, and slightly bobby on the tarmac heading to the trails. It felt smoother on climbs although I didn’t notice any super increase in traction.

This is all for a 32 AB Oval on a 2012 Giant Anthem 11-42.

I need to do more trialling to see the effect on Power readings, but I have changed back down to a 30T round in preparation for my A race in a few weeks time. I’d like to try the 30T AB Oval ring but it’s getting a bit excessive having so much money in chainrings on the shelf.

Thanks for the feedback. I think I’m persuaded to try and AB Oval.
I’m on a hardtail but have a race next July with alot of climbing so figure any slight advantage will be good :wink:

I’m half tempting to do a ramp test on a std chainring and a couple of days later repeat with an OB to see if it has any impact.

Edit: has anyone any experience of an oval chainring on a trainer whilst using TR?

Went to 34 with a 10-48 this year and love it. IIRC I measured the clearance loss at about 2mm from a 32.

Lots of punchy climbing in New England but nothing mega.

3.9 w/kg. I run a 1x 30t oval, 11-36 in the back. Riding in my area is quite steep and punchy, but I ride a single speed most of the time, so it feels like plenty of gearing.

Absolute Black Oval?

Relax dude. Who died and made you the local forum traffic cop? Jeez.

I ran ovals for a couple years on my singlespeeds.

Benefits:
Strava showed I was faster
Seemed to have fewer traction issues on climbs.
Very low cadences were a little easier to maintain

Downsides:
I had to adjust my chain more often (singlespeed problem)
It was significantly more difficult to spin smooth at high cadences above 100 rpm.

Mine oval chainring is from Wolftooth. I really like it. When I first started using it about 5 years ago, I wasn’t as fit, and it immediately made the difference between clearing and not clearing certain punchy sections. Traction is much easier to modulate at slow speed. I just run a normal round chainring on my single speed (34 over 20). I think an Oval would be awesome on the single speed. (P.S. I climb much faster on my single speed…which is probably no surprise)

Hi,
Can you tell me how much clearance to the chainstay you have with your 36t oval Garbaruk?
I have tried a Sram 36t oval chainring (3mm boost offset) but I only have about 1,5mm clearance to the chainstay, so I’m worried about hitting the chainstay when the frame/crank flexes under load.
What is the offset of your Garbaruk chainring? Or did you fit any extra spacers between crank and BB to create more clearance? Or do you also have very little clearance, but it’s not an issue when riding?

Thanks!

This thread got me thinking. Im currently building up a XC hardtail and was going to go for a 36T but it seems the general consensus is 34T is better. I thought with a 9-50T cassette i’d need the 36T to get hard enough gears.

Anyone got any thoughts?

How big are your quads, and climbs?

Not huge and hills im in Yokrshire.

That said around 4.3 w / kg. Maybe 34T would be best! Just coming from the last bike i build being a road one maybe got me thinking i need a larger one!

Unless you mostly ride your MTB on the road I don’t think at 4.3 and with a 9 tooth high gear you would need a 36T.

All guesswork though. My suggestion is to gear yourself for where you spend the most amount of time, not for the one offs.

I went from a 32T to a 34T to shift myself up the cassette for more of my riding.

The reason most the Pro’s use 38 and 36T cassettes is mostly to do with chain alignment with the middle of the cassette than needing a taller top gear.

With the important caveat that they’re still able to get up all the hills they have to in the 50/51/52t without grinding at 30rpm :smiley:

Agree with most people here, for most of my races I’d rather have an easier gear to climb at a reasonable cadence. Rarely am I spinning out of gears on non-paved surfaces.

Yep, I think you’d be fine with that!

Hi everyone!
Short question for the ones swapping between 32 and 34 teeth.
Do you use the same chain length? The two extra teeth will theoretically require an additional link or two. My RD seems to not be on it’s limits currently with my 32 tooth setup.

I went from 30 teeth to 34 teeth with the same chain, and chain length was not an issue.

Ideally you should do a test fit. In theory you could do it with the same chain depending on the amount of slack and the amount of chain growth (if full suspension).

My preference and recommendation would always be to drop the air out of the rear shock and measure at full compression.

No, different chains. My 34 chain is too loose on my 32 chainring. I’ve never tried my 32 chain on my 34 chainring though.

I will give it a try, I don’t think the chain growth on my bike is that large, I ride a Supercaliber and the rear travel is not that long. Last week I adjusted the b-screw setting and noticed that there was no noticeable difference if the bike was at sag or not, so I gather it behaves almost like a hard tail in my understanding.