bigger crank on scott scale?

Discuss light weight issues concerning mountain bikes & parts.

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qwpy
Posts: 46
Joined: Tue Aug 04, 2015 6:34 pm

by qwpy

Hello there

i have a scott scale 35 frame i wish to upgrade, so the crank has more teeth on the outer ring.

parts on bike:
front dérailleur = xt 9 speed, E type(bb mount) triple
crank = xtr m970 triple (largest ring is 44t.)
rear cassette = 9 speed dura ace 11-21 ( i hope to keep its got lots of life left in it)
rear mech = xtr 9spd (medium cage)

I hope to get a larger crank ring 50+? but the front mech is almost maxed out at 44t. ( 46 might be largest i can go)

this is a link to the frame

https://bikepedia.com/QuickBike/BikeSpe ... l=Scale+35

maybe i can change the chain to 10sp and the front mech to a racing bike double 10sp, and then use a larger ring?

thanks for any help

mattr
Posts: 3506
Joined: Fri May 25, 2007 6:43 pm
Location: The Grim North.

by mattr

Road double will foul the chainstay as the chainline is smaller. Unless you get an old octalink bottom bracket about 10mm too long and chainset to match. Then the front mech won't reach.
46 is probably the largest, unless you try and get a compatible XT trekking front mech, that goes to 48 i think. Much bigger than that, you'll start sawing through the chainstay.

Any specific reason you want to turn your scale into a hybrid?

qwpy
Posts: 46
Joined: Tue Aug 04, 2015 6:34 pm

by qwpy

mattr wrote:
Wed Jan 31, 2018 9:11 pm
Road double will foul the chainstay as the chainline is smaller. Unless you get an old octalink bottom bracket about 10mm too long and chainset to match. Then the front mech won't reach.
46 is probably the largest, unless you try and get a compatible XT trekking front mech, that goes to 48 i think. Much bigger than that, you'll start sawing through the chainstay.

Any specific reason you want to turn your scale into a hybrid?
thanks I will look into the XT trekking front mech you mention or at least just get a 46 ring and see how that goes.

I very rarely use the 22t inner ring and regularly wish the outer ring was larger. So I thought it might be an easy modification, or to go to a dura ace racer gear set up on this frame.

I can get to maximum pedal speed quite easy on this bike. But I do not want a racer bike as i do go over bumpy ground a fair amount. i like the bike allot but the 44t is just not the perfect gear. i upgraded to a 11-21 race cassette which helped though.

thanks again.

mattr
Posts: 3506
Joined: Fri May 25, 2007 6:43 pm
Location: The Grim North.

by mattr

Maximum pedal speed?
About 35mph at a quite reasonable 110rpm on a 44x11.

qwpy
Posts: 46
Joined: Tue Aug 04, 2015 6:34 pm

by qwpy

forgive, but your message appears to suggest that a 44t ring is perfectly adequate for everyone and that my needs are not justified.

if this is so, why are there larger rings made above 44 teeth? Why would companies bother making them? and people install and use them?

Could it be perhaps some people have stronger legs that prefer to pedal at a slightly slower frequency, but harder, to reach top speed?

maybe i am not comfortable at a higher rpm and can give more power at a lower rpm?

Or perhaps when going down a slight incline with the wind behind me pushing me along and i am frustrated that there isnt another higher gear to click too, maybe that is when i thought to get rid of this 22t i never use and hope to modify the crank to a more racer type set up?

wingguy
Posts: 3829
Joined: Thu Mar 08, 2012 11:43 pm

by wingguy

To be perfectly honest it kinda sounds like you either need a road bike alongside your MTB, or to replace it with a gravel bike.

qwpy
Posts: 46
Joined: Tue Aug 04, 2015 6:34 pm

by qwpy

or maybe just have one large crank ring with no front dérailleur and a long cage rear mech and mtb cassette 36-11. might work. : )

thanks for all your help everyone.

happy cycling : )

mattr
Posts: 3506
Joined: Fri May 25, 2007 6:43 pm
Location: The Grim North.

by mattr

qwpy wrote:
Fri Feb 02, 2018 5:25 pm
forgive, but your message appears to suggest that a 44t ring is perfectly adequate for everyone and that my needs are not justified.
not really, i just have some concerns with your reasoning.

Mainly that changing from the standard XTR/XT cassette to your 11-21 Dura ace cassette almost certainly got you exactly no extra gear inches, as the stock cassette that would ship with a 44t big ring 9 speed triple would be an 11-32. (the 12-34 used to come with the 46 tooth big ring triple. I've had both set ups)
if this is so, why are there larger rings made above 44 teeth? Why would companies bother making them? and people install and use them?
Getting a better chainline (for touring). Using different sized tyres/wheels. Using a larger cassette (13 up are still available i believe, tourists like them for smaller ratio steps).
Could it be perhaps some people have stronger legs that prefer to pedal at a slightly slower frequency, but harder, to reach top speed?

maybe i am not comfortable at a higher rpm and can give more power at a lower rpm?
Even going down to speeds achievable at ~70 rpm your regular running out of gears would require between 300 and 330 watts. Which is not insignificant.
Or perhaps when going down a slight incline with the wind behind me pushing me along and i am frustrated that there isnt another higher gear to click too, maybe that is when i thought to get rid of this 22t i never use and hope to modify the crank to a more racer type set up?
Get into a tuck?

ooo
Posts: 528
Joined: Sat May 21, 2016 12:59 pm

by ooo

3x9 mtb fd will work with trekking crankset with 48-46-26 chainrings
'

mattr
Posts: 3506
Joined: Fri May 25, 2007 6:43 pm
Location: The Grim North.

by mattr

ooo wrote:
Sat Feb 03, 2018 8:58 pm
3x9 mtb fd will work with trekking crankset with 48-46-26 chainrings
Don't think there is enough adjustment on an etype mech. IIRC My old m770 was as high as it would go on the 44T (with the insert adjusted as well.)
You'd need to find a trekking e-type mech. Or get a 38mm SRAM band on mech and lose the e-type plate.

ooo
Posts: 528
Joined: Sat May 21, 2016 12:59 pm

by ooo

Sorry, I didn't notice that it is e-type. FD-M660-E official spec is 44T, to find real spec try to move it to top height adjustment and measure clearance over 44T

Chainring diameters:
44T = 182mm
48T = 199mm

Most likely biggest chainring for all e-type FD is 46T
@mattr advise to "get a 38mm SRAM band on mech and lose the e-type plate." is a good idea
'

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