GRG Posted April 14, 2017 Share Some gear maintenance has to be done..currently have a 2x10 shimano system on a 650b hardtail, mainly do marathon races (trailseeker, ashburton etc) and train hilly routes offroad and on tar (Wolwespruit, Waterkloof area). Should I change to a 1x10 system, 32/34 chainring, 46 cassette or keep what I have?My feeling is leaning towards sticking to the 2x system which I know works but I do notice that the 3 largest cogs on the cassette are hardly used..therefore maybe the 1x. Im not sure about the wheelsize debate and how it affects gear ratios and gear systems and keeping up on the flats with guys on 29inch bikes? Changing wheelsize is not an option for me at the moment. Any advice from guys riding 650b mtb, doing the same kind of races etc would be appreciated! Link to comment Share on other sites More sharing options...
ChrisF Posted April 14, 2017 Share Wheel size vs gear ratios : I have a 29er and 27,5. The maths shows a 5,2% change in gear ratio. Going from the 34 to the 36 on the back cog is a ration change of 5,56%. The typical 22/36 of a 3x10 on a 29er has an effective gear ratio of 0,611. The typical 24/36 of a 2x10 on a 27,5 has an effective gear ration of 0,629 (adapted for the change in rim size; 0,667 before adapting it) Thus the "climbing" part is pretty much on par. BUT, then you loose out on top-end .... depending on the group set, more than 10%. The smaller tires takes some more away from your top-end .... Your riding style and needs will determine if this 10km/h on the top-end is an issue for YOU .... YES, very possible to choose a different group set to give the top end, but then you need strong legs for the climb Going 1x11 (or 1x12) the game changes and there are some hard choices to make ... and enough threads here to show that the current 1x riders are still finding their optimal setups ... You need to go extreme down to 32/46 to get the low down climbing gears - IF that is what you need. Going extreme to the other side - 32/10 still leave you slightly short on the top end of the 2x10 options .... IF you go for extremes the gaps between gears become very noticable ...... This may not suit the average rider ..... 2x10 or even 2x11 may be the future, for now at least .... I dont want to loose too much top end, though this is less and less of an issue off road for me, but I do need the granny gears .... Link to comment Share on other sites More sharing options...
BaGearA Posted April 14, 2017 Share stick to 2x10 Link to comment Share on other sites More sharing options...
gummibear Posted April 14, 2017 Share stick to 2x10What he said ^^^^^^ Link to comment Share on other sites More sharing options...
GRG Posted April 14, 2017 Share Wheel size vs gear ratios : I have a 29er and 27,5. The maths shows a 5,2% change in gear ratio. Going from the 34 to the 36 on the back cog is a ration change of 5,56%. The typical 22/36 of a 3x10 on a 29er has an effective gear ratio of 0,611. The typical 24/36 of a 2x10 on a 27,5 has an effective gear ration of 0,629 (adapted for the change in rim size; 0,667 before adapting it) Thus the "climbing" part is pretty much on par. BUT, then you loose out on top-end .... depending on the group set, more than 10%. The smaller tires takes some more away from your top-end .... Your riding style and needs will determine if this 10km/h on the top-end is an issue for YOU .... YES, very possible to choose a different group set to give the top end, but then you need strong legs for the climb Going 1x11 (or 1x12) the game changes and there are some hard choices to make ... and enough threads here to show that the current 1x riders are still finding their optimal setups ... You need to go extreme down to 32/46 to get the low down climbing gears - IF that is what you need. Going extreme to the other side - 32/10 still leave you slightly short on the top end of the 2x10 options .... IF you go for extremes the gaps between gears become very noticable ...... This may not suit the average rider ..... 2x10 or even 2x11 may be the future, for now at least .... I dont want to loose too much top end, though this is less and less of an issue off road for me, but I do need the granny gears ....Thanks for the detail ChrisF! So to summarize, a 1x11 system offers smaller gaps between gears and has the climbing side covered but still falls short at top end speed, even with a 34 chainring? Therefor, although I am more suited to climbing than power on the flats (so maybe a 34 chainring..), a 2x10 system would benefit me more when competing against guys riding 29inch bikes while I'm on my 27.5". Link to comment Share on other sites More sharing options...
GRG Posted April 14, 2017 Share Do you guys find larger intervals between drivetrain maintenance with 1x compared to 2x? Link to comment Share on other sites More sharing options...
BaGearA Posted April 14, 2017 Share Do you guys find larger intervals between drivetrain maintenance with 1x compared to 2x?I think its too subjective to get accurate data. OP keep your 2x10 adn maybe go for A 40t or 42T big ring , keep the 26/28 small ring Link to comment Share on other sites More sharing options...
ChrisF Posted April 14, 2017 Share Thanks for the detail ChrisF! So to summarize, a 1x11 system offers smaller gaps between gears and has the climbing side covered but still falls short at top end speed, even with a 34 chainring? Therefor, although I am more suited to climbing than power on the flats (so maybe a 34 chainring..), a 2x10 system would benefit me more when competing against guys riding 29inch bikes while I'm on my 27.5". Do check very carefully what the shop wants to sell you !! A qucik glance it may appear "similar" ... but when you start crunching the numbers you quickly pic up some setups are aimed at "climbing", while others are aimed at top-end speed .... the choice is very personal to your type of riding. Speak to the shops near you. Test ride the various gear combinations .... The maths only helps once you know your requirements PS - there are some nifty apps to calculate gear ratios - http://www.bikecalc.com/gear_ratios Link to comment Share on other sites More sharing options...
ChrisF Posted April 14, 2017 Share and when you KNOW what works for you it is very easy to say I want "that bike" but I want this or that on the front or back ..... Link to comment Share on other sites More sharing options...
GRG Posted April 14, 2017 Share Thanks for the info and suggestions Link to comment Share on other sites More sharing options...
eddy Posted April 15, 2017 Share So to summarize, a 1x11 system offers smaller gaps between gears and has the climbing side covered but still falls short at top end speed, even with a 34 chainring? Therefor, although I am more suited to climbing than power on the flats (so maybe a 34 chainring..), a 2x10 system would benefit me more when competing against guys riding 29inch bikes while I'm on 27.5. No. Gaps are BIGGER on a 1x11. Also, unless your chainring is as big as your big ring on your current setup, you will struggle even more to keep up with guys riding 29" bikes on high speed sections (ceteris paribus). Link to comment Share on other sites More sharing options...
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