XO 2 x 10 Chainring combinations, what's yours?

[Izak]

Hi Guys

 

I am running out of speed on my current setup:

 

SRAM 1170 Casette with 38/22 up front.

 

Was thinking of cranking it up, so to speak, with a 42/28 combination.

 

What do you guys think? Oh and it's on a 27.5.

 

Will this be too much when I get to serious terrain or should I be able to push it?

[V12man]

Use this, and you can see the impact it will have - there is an option for speed at 90 rpm.

 

http://sheldonbrown.com/gears/

[jcza]

29r running 39/26 and 11-36 cassette. Never run outta gears.

[Rudi Pollard]

I have 26/39 which works very nicely for my on a DS 29er, but to be honest I very rarely go into the 26. I used it at Sabie quite a lot but you dont get those types of hills in Gauteng. If you are looking at riding stuff like Sabie, I wouldnt go to the 28/42 unless you are proper strong...

[Jakkals.]

i ride 42/28. climbs are tough but manageable.

[Izak]

I have 26/39 which works very nicely for my on a DS 29er, but to be honest I very rarely go into the 26. I used it at Sabie quite a lot but you dont get those types of hills in Gauteng. If you are looking at riding stuff like Sabie, I wouldnt go to the 28/42 unless you are proper strong...

That's my problem I never get out of big chainring but have not done massive and technical climbs so not too fussed about that but I run out of speed on flat sections and downhills is a free only zone at the moment.

I'm fairly strong and it is on a 27.5 so will decide between 42/28 or maybe 39/26 - Think 39/26 might be the best overall solution for me.

 

Thanks for all the feedback and cool link.

[Sitting slip]

 

That's my problem I never get out of big chainring but have not done massive and technical climbs so not too fussed about that but I run out of speed on flat sections and downhills is a free only zone at the moment.

I'm fairly strong and it is on a 27.5 so will decide between 42/28 or maybe 39/26 - Think 39/26 might be the best overall solution for me.

 

Thanks for all the feedback and cool link.

i will trade you my xtr 40/28 for your xo cranks?

[Izak]

i will trade you my xtr 40/28 for your xo cranks?

 

bwahahahaahaaaa

 

XO or nothing for me thanks

[DC Carbon]

If I understand Sheldon Brown's gain ratio which is in Miles per hour I've converted the below into km/h

 

What cassette gears do you have? 11/36?

 

If you have 13/29 I would understand how you would run out... the difference is 38.4km/h(13/29) as apposed to 45.44km/h(11/36) using the 38 chainring at 100RPM! You would probably spin out at 110/120RMP which is 56km/h using a 38 tooth chainring 11/36 cassette at 120RPM..Sheldon doesn't have a 27.5" wheel but if I do the above calculation with a 27" wheel it equates to roughly 1km/h slower than a 29" wheel...

Edited March 12, 2014 by constada

[Izak]

If I understand Sheldon Brown's gain ratio which is in Miles per hour I've converted the below into km/h

 

What cassette gears do you have? 11/36?

 

If you have 13/29 I would understand how you would run out... the difference is 38.4km/h(13/29) as apposed to 45.44km/h(11/36) using the 38 chainring at 100RPM! You would probably spin out at 110/120RMP which is 56km/h using a 38 tooth chainring 11/36 cassette at 120RPM..Sheldon doesn't have a 27.5" wheel but if I do the above calculation with a 27" wheel it equates to roughly 1km/h slower than a 29" wheel...

Yes that's seems to be correct.

However I am a mountain biker and like to spin at around 95 - 100 rpm. Doing so at 120 will firstly tire me out and secondly make me look like a chop!!

 

I have gone for the 39/26 combo and already works quite well. But I can see that on flatter races I would just like to try the 42/28 combo just as a matter of interest ... .regardless of any calculations.