Osymetric chainrings (mountians)

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guttengeo
Posts: 6
Joined: Wed Mar 27, 2013 5:24 pm

by guttengeo

Hello everyone,

I'm thinking about buying a pair of the Osymetric chainrings. I've seen Wiggo, Froome, Brajkovic and others go with the rings.

But i have some questions to "the smart Osymetric guys".

I have a 130mm crankset and that means I can get a 42t chainring as the smallest one!

- I normally ride with 39t in mountians and with my crankset I can only get a 42t. Have anyone ridden with an Osymetric 42t in mountians?
- Instead of buying a compact crankset and get a 38t OSymetric, will a 11-28 cassette equalize the different?
- What do the pro riders like Froome etc. do? compact or 42t chainring?

- And finally: have you ever got any knee/ankle problems by riding on Osymetric chainrings?

Geoff
Posts: 5395
Joined: Sat Dec 13, 2003 2:25 am
Location: Canada

by Geoff

I can't do it...

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trysixty
Posts: 12
Joined: Tue Jul 14, 2009 5:41 pm

by trysixty

42t osymetric is easier than a 39t standard. with an 11-28 you should be able to climb any mountains in this country.

make sure you have a chain guard, the chain goes off both outer and inner rings at several shift points........and dont tell me i need the thing adjusted
because i ve had the best mechanics look at it and they all say the same thing, fast but shifting with the osymetrics is a nightmare. best suited for a flat tt course with minimum shifting

GatoQuatro
Posts: 5
Joined: Sun Mar 24, 2013 10:49 pm

by GatoQuatro

I rode osymetric 42-52 (what Wiggins uses) for about 4k miles in the past 6 months. I'm in my 20s 180lbs and don't live in the mountains so can't speak about how well they do on a continuous climb but short steep climbs I miss the 39 even with an 11-28 cassette. The feeling is different because you push and pull but don't have to carry over the top or bottom stroke with your legs. dead spot is virtually eliminated making it seem faster to get back into power phases. It took me 80 miles to get used to them. Idk about a football between your legs but essentially gaining muscle memory allows the pedal stroke to smooth out over time. However, while its great to have more teeth in the power phase you will notice how this benefit plays a roll in climbing. While one may use less muscle but recruit different smaller muscle fibers overall yada yada whatever the website says there's still the extra teeth to deal with even if you're saving energy in the dead phase essentially you're still pushing a bigger gear. A 40 would be perfect as a small ring for climbing while the 52 is more then adequate. Yeah I've had so much trouble with them running on an SRM DA crank on a BBright (30 pressfit?) Cervelo R3 that I'm back on Dura Ace chain rings. Chain would come off alot fixed it by inserting spacers,tiny plastic washers, but chain drops from big ring if I shift into the last two or three low gears (21,23,25) which is not cool. And I had to let up on the pedal stroke more so than any other chain ring when going from small to big. Every time.

Now I'm back on dura ace 52,39s getting ready for Tour of the Gila in New Mexico. Have a buddy on the junior Slipstream Craddock team that spent a week in silver city area and is from the same area I'm from meaning he knows how to compare terrain and he mentioned I should use my 39 instead of the 42 osymetric. Also, have a buddy Jason Reinhardt from Brownsville who is making (with engineers and all) the same chain rings with new specs. i.e. 4mm instead of 2mm chain ring widths for strength and some other stuff plus anodized versions but don't quote me on that. The only reason I bring it up is because he's machining a 40T out of titanium. Yes, he's spoken with the owner of the company in Europe I don't know the details but it's legit. Also, Thomas Craven mentioned 2 months ago that his company/website was going to carry the updated chainrings but looking at his site I don't see anything.

CarpetFibre
Posts: 556
Joined: Thu Apr 01, 2010 10:24 am

by CarpetFibre

I run the 52/42 osymetrics and I'm a devoted climber (125-130lbs). Most of the hills around me are short, around half a mile to a mile long and anything from 5% average to 14% average. I don't think I'd want anything less than the 11-29 I run at the back. To be fair when I'm really caning it I'll be down in the 25T sprocket but the 29 is very useful for when the gradient hits 13-25% or I just want to go a bit steadier on the hill.
The 42T ring at the front is 38T in the dead spot and 46T in the power phase, but this doesn't mean a great deal as once you get used to the chainrings, it just feels like a 42T round ring. Climbing with osymetrics are worth it, I feel like my pedal stroke is much smoother and more efficient - I always stay seated on climbs and sustain my effort rather than sprint like hell out of the saddle and die towards the top. They really work for me.
I like to keep my cadence up at around 90-100rpm and hate it when I have to drop below 70, so the gearing is important for me.
As for getting used to them then it took me about 20 minutes. It felt really strange at first but the really strange feeling goes away. Then after that you don't quite feel your old self - it doesn't quite feel efficient but at least the really odd sensation where you can 'feel' the odd shape of the rings has gone away. By my second ride I was really getting on with them, third ride I was loving them, and then after that I could never imagine myself going back to round rings.
For a longer climb like Mt Ventoux then I think I might just be able to keep my cadence up at around 80-90rpm in 42x29 for the steeper parts. On a climb like that you can't really grill yourself as you'll find the gear even harder later on.

If you know what sort of speeds you can pedal at for various different gradients I suggest you work out your cadence for that given speed using a gear calculator.

tdudzik
Posts: 47
Joined: Sun Sep 02, 2012 2:17 am

by tdudzik

Im running a 52/38 compact 110bcd. Took only about one ride to adjust to the feel, and like CarpetFibre said, climbing on them is MUCH better. You don't do the usual side to side rocking as much. Also, with the new sram red yaw FD, you can get your shifting set up really good, for what it is. No spacers, and I get no chain rub in the big ring. In the small ring, the chain rubs against the outer ring in the last three cogs. It still doesn't touch the FD, though. As far as shifting, I've gotten mine to not drop it anymore. Make sure you run the chain spotter really close. I wouldn't shift when doing over like 225 watts though. The chain doesn't drop for me, but when the chain section from 11 o'clock to 4 o'clock shifts down, the remaining section from 5 o'clock to 7 o'clock stays on the ring and gets sucked up on the outside of your chainstay. Hard to explain, but if you pedal forward slightly it will snap back into place on the ring. Any ideas on how to fix this? It's on a cervelo S5, with beefy chainstays. Once I get my R5 set up, it might not even come into contact with the chainstay.

But that doesn't really answer what you're asking... Yes, I like my 38. Coming from a 34 round and a 25 in the back, there is a small difference. I'm probably going to pick up a 27 for races like Gila anyways.

I still ask myself whether I want to keep the rings everyday. But if Wiggens...

guttengeo
Posts: 6
Joined: Wed Mar 27, 2013 5:24 pm

by guttengeo

Thank you a lot for the answer guys!

On my bike I have Sram Force 2012

- Do you think there will be problems with the FD or is it just how good I am to adjust it?

- On my city-bike i have regular round rings. Will it influence my ride on my road bike when I chance from round to Osymetric almost everyday, or is it just getting used to it?

guttengeo
Posts: 6
Joined: Wed Mar 27, 2013 5:24 pm

by guttengeo

Please help me, cause I don't want any cons by using Osymetrics.

tdudzik
Posts: 47
Joined: Sun Sep 02, 2012 2:17 am

by tdudzik

You can get it set up with the force FD. I've done it before, when I had it on my TT bike. It's going to be harder than with the newer Red, and you'll have to use the included washers to open the cage. I can't guarantee you wont get chain rub, but if you do, it's mostly from the chain hitting the outer ring, not the FD cage.

Whether or not having round rings on your other bike will affect you depends on the person. For someone like me who got used to the Osymetrics in only like 10 minutes, I could probably switch back and forth. If you're not doing any super hard riding on your city-bike, i guess it doesn't matter.

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grid256
Posts: 362
Joined: Tue Dec 15, 2009 8:32 pm

by grid256

I've put extensive miles on Qrings and tried endlessly to get Osymetrics set up on my TT bike but eventually gave up. The shifting was awful but the feel was great. Enter the new QXL rings. In my mind they're the best compromise of all the non round rings. They produce a feel similar to Osymetrics but shift smooth with zero problems especially with the new Red.

guttengeo
Posts: 6
Joined: Wed Mar 27, 2013 5:24 pm

by guttengeo

Why is it so hard to set the FD up to Osymetrics? Is it because the shape is oval or are the chainrings just different from round rings?

Geoff
Posts: 5395
Joined: Sat Dec 13, 2003 2:25 am
Location: Canada

by Geoff

I don't think it is. It may depend on your derailleur, though. I have set it up on Di2 and 7900 with no problems. It is a bit more finicky to do, for sure. Once it is set, it seems to be fine. Don't expect it to shift like stock rings, though. O-Symetric have no ramps, etc., like the stock rings. Also, the validation makes it weird. I will say that the Di2 front derailleur would probably make short work of just about anything...

Sisbud
Posts: 54
Joined: Mon Oct 15, 2012 3:43 pm

by Sisbud

Geoff wrote:I don't think it is. It may depend on your derailleur, though. I have set it up on Di2 and 7900 with no problems. It is a bit more finicky to do, for sure. Once it is set, it seems to be fine. Don't expect it to shift like stock rings, though. O-Symetric have no ramps, etc., like the stock rings. Also, the validation makes it weird. I will say that the Di2 front derailleur would probably make short work of just about anything...


+1. Osymetric and Di2 is just the best combination.

guttengeo
Posts: 6
Joined: Wed Mar 27, 2013 5:24 pm

by guttengeo

Okay thanks, but is it impossible to set Osymetric up to Force FD or can a good mechanic do it?

I mean so it shifts good (not perfect, but not bad too), cause i've heard many people talking about the FD and Osymetric. Some say that they have many problems with the FD while others have no problems at all!
Last edited by guttengeo on Sat Mar 30, 2013 7:49 pm, edited 1 time in total.

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natefontaine
Posts: 249
Joined: Wed Mar 31, 2010 3:37 am

by natefontaine

Make sure you order the "Time Trial" version of the outer ring. It's thicker and solves most of the problems of the shifting issues. I like to think of myself as a climber and I decided on the 56/44 with 11-25 it suites me well. The 44-25 is tough at 13+% for 2km or more, rpms around 50, but standing feels so much more natural with the O' rings. I feel like the 44 is easier to keep putting power down on the big climbs than the 39T round rings I was using before.

As for setup, I would suggest a FD with a steel cage and <1mm clearance, set the limit screws so that when in big-small and small-big the chain just barely taps the FD, you'll see what I mean when you install them. Shifting under full load is not much slower than DA up or down with the thicker rings, the standard "thin" O' ring is horrible.

Whenever i'm in the small ring and 11-13 in the back I throw the chain over about 1 out of 10 times. So I just make sure to shift up in the back 3 gears and shift to the big ring at the same time, which solved the chain throw issue. I can count on one hand the times I dropped it on the inside, but that's more to do with bad limit screw adjustment.

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