kandui Posted August 20, 2012 Share I have an XX 39/26 setup on my Air 9 HT and an XTR 40/28 on my Jet 9 Alu Full Sus. Both have an 11-36 cluster.No need for ratio graphs here. I want to know whether I should be feeling a big difference in leg power applied or whether my legs are just poked at the moment? I am talking climbing gears. At yesterday's Oude Molen my legs were toast after 60km of riding the XTR rig. Perhaps I should move the XTR to the lighter bike? Link to comment Share on other sites More sharing options...
Captain Fastbastard Mayhem Posted August 20, 2012 Share Those extra 2 teeth do make a marginal difference, yes. It's small, but it's there! Moving the "lighter" crankset to the heavier bike would be logical, due to the extra weight you are pushing up the hills. And there's quite a difference in weight between the Air 9 and the Jet 9 IIRC! TheV 1 Link to comment Share on other sites More sharing options...
kandui Posted August 20, 2012 Share I felt I had to ask. I think I'll move the XTR crank over to the Carbon bike . Probably leg fatigue, a slight cold and the terrain yesterday made it feel so hard to turn the crank over yesterday. Link to comment Share on other sites More sharing options...
Ryan Posted August 20, 2012 Share a slight cold That can make any ride horrible... Edited August 20, 2012 by Ryan Link to comment Share on other sites More sharing options...
Captain Fastbastard Mayhem Posted August 20, 2012 Share I felt I had to ask. I think I'll move the XTR crank over to the Carbon bike . Probably leg fatigue, a slight cold and the terrain yesterday made it feel so hard to turn the crank over yesterday. I know what you mean... I'm running 1x9 at the moment (32 at the front, 11-34 at the back) and my chain snapped halfway to tokai. Luckily it was just 4 / 5 links away from the quicklink, so a fix was possible (left my chain breaker at home) but I lost my top 2 gears. Eish, I suffered... Link to comment Share on other sites More sharing options...
NINER_boy Posted August 20, 2012 Share Hi Kandui Especially on 29ers, the bigger chainrings need more torque to turn. The recommended size for 29ers is 26/39 and smaller. I have recently moved over to Rotor crank and Qrings on my Niner RIP9, size 25/38.My bike feels like a nimble little beast.Yes the Q rings make a difference, not acceleration but more on the power-drive part. Yes my gears are all "shorter" and I top out at around 55km/h, but then again, how much of your time do you spend at these speeds. Go smaller, you will not regret it. PS, this is probably the ONLY instance where going smaller is beneficial... Happy Hoopin Edited August 20, 2012 by NINER_boy Link to comment Share on other sites More sharing options...
kandui Posted August 20, 2012 Share Hi Kandui Especially on 29ers, the bigger chainrings need more torque to turn. The recommended size for 29ers is 26/39 and smaller. I have recently moved over to Rotor crank and Qrings on my Niner RIP9, size 25/38.My bike feels like a nimble little beast.Yes the Q rings make a difference, not acceleration but more on the power-drive part. Yes my gears are all "shorter" and I top out at around 55km/h, but then again, how much of your time do you spend at these speeds. Go smaller, you will not regret it. PS, this is probably the ONLY instance where going smaller is beneficial... Happy HoopinI want to go 56km/h uphill. i have been eying the Rotor cranks , but just got the XTR a month ago. Would the Q rings fit either XX or XTR? Would dig to give them a try if anyone has some second hand ones. Link to comment Share on other sites More sharing options...
Overlord Posted August 21, 2012 Share Running 40/27 Rotor Crank on my 29er and it is absolutely awesome. Link to comment Share on other sites More sharing options...
Andro Posted August 21, 2012 Share I want to go 56km/h uphill. i have been eying the Rotor cranks , but just got the XTR a month ago. Would the Q rings fit either XX or XTR? Would dig to give them a try if anyone has some second hand ones. Morning Kandui. Running a Rotor system, re your question... not sure but call this no, Burry's dads shop, friendly service and will be able to assist. 031 762 1416 or speak to Naas here on the hub. He operates from Durbanville. He was selling some new blades. Best Regards Andro Link to comment Share on other sites More sharing options...
kandui Posted August 21, 2012 Share Thanks Andro. I had actually spoken to Mr Stander last year about Rotor cranks, but was put off by the price and went for an XX rig instead.I would however like to try the Q Rings on the XX crank and see what it feels like. Buying new just to try is not what i want to do so I am looking for a second hand set. 40/27 or 38/26. Link to comment Share on other sites More sharing options...
Edge_Design Posted August 21, 2012 Share Definitely a big difference for climbing... I have 42/28 on my Anthem 29er and it was deadly when I first got on it (changed from 26/39). I've gotten used to it now and prefer having the top-end/cruising speed available - the strength will come from training on the bigger gear (all of my training is in Tokai so no shortage of climbing!). If I was doing ultra marathon stuff then the 26 would definitely be necessary, but 60 to 70km's is my max on the MTB. Link to comment Share on other sites More sharing options...
Johan Bornman Posted August 21, 2012 Share Yes. A 29er wheel moves forward 2280mm with every revolution. If you turn the crank in your 39/26 gear once, your bike goes forward 3420mmIf yo turn the crank in your 40/28 gear once, your bike goes forward 3257mm. Thus, the 39/26 gearing is 5% harder than the 40/28 setup. If you're a glass-half-full type of person you would put it differently: the 39/26 gearing is 5% faster. Link to comment Share on other sites More sharing options...
NINER_boy Posted August 21, 2012 Share Hi Kandui The XX BCD is much different from the XTR, so you will need to decide witch ones to get and then buy for that system. Here is a website where I got my cranks and Q rings from... http://www.velotechs...co.uk/index.asp Sram XX BCD is 120/80mmXTR BCD is 110/74mm Edited August 21, 2012 by NINER_boy Link to comment Share on other sites More sharing options...
NotSoBigBen Posted August 21, 2012 Share Perhaps just check out Rule #5 RacerX and Chro Mo 2 Link to comment Share on other sites More sharing options...
kandui Posted August 22, 2012 Share Running 40/27 Rotor Crank on my 29er and it is absolutely awesome.Do you need a longer chain for the Rings? Link to comment Share on other sites More sharing options...
kandui Posted August 22, 2012 Share Hi Kandui The XX BCD is much different from the XTR, so you will need to decide witch ones to get and then buy for that system. Here is a website where I got my cranks and Q rings from... http://www.velotechs...co.uk/index.asp Sram XX BCD is 120/80mmXTR BCD is 110/74mmBought a set of second hand 40/27 Q Rings from a fellow Hubber yesterday. I'll stick them on my XX Crank which is on the Air Carbon.Doing a ride from Grabouw to Greyton on Sunday, that should give me enough time to get used to them and evaluate.If I like the Q Ring, I will probably go one smaller, because I spend more time climbing than I do on the flat roads. Link to comment Share on other sites More sharing options...
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