Installing a 40T chain ring with an XT FD-M8020 Side Swing?

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Xico
Posts: 49
Joined: Mon May 19, 2014 10:09 pm

by Xico

Hi All,

For the riding my father's Canyon 29er hardtail is having at the moment (road only), he would like to change the biggest ring for a 40T.
At the moment it has a 2x11 (28-38T rings with a 11-40T cassette) with a Shimano XT FD-M8020 Side Swing front derailleur installed.

According to Shimano information the FD specs are:
- Maximum Capacity: Total capacity 10T
- Top Gear Teeth: 34-38T

Does anyone knows if it will actually work:
- by installing only a new 40T ring and keeping the 28T ring (exceeding the Maximum Capacity by 2T and recommended Top Gear Teeth also by 2T)?
- by installing new 30-40T rings (exceeding the recommended Top Gear Teeth by 2T)?

If not, what are the available options?

Which chain rings do you recommend for a XT M8000 2x11 Crankset, not sacrificing the shifting performance?



Cheers!

by Weenie


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Xico
Posts: 49
Joined: Mon May 19, 2014 10:09 pm

by Xico

Anyone has some information on this? :noidea:

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F45
Posts: 1077
Joined: Wed Jun 08, 2011 6:08 am

by F45

I'm probably going to do a similar thing....why don't you try it and report back how it worked out?

Xico
Posts: 49
Joined: Mon May 19, 2014 10:09 pm

by Xico

I want to try it, but I'm having some problems finding 4 bolt chainrings with a BCD of 96mm and 64mm, for the FD-M8020 crankset.
On this crankset, the 4 bolts are not equally spaced. They "make" a rectangle, instead of the usual square.

Image


Does anyone know of a source for this kind of chainrings, in bigger sizes (30 and 40 teeth)?

BikeAnon
Posts: 399
Joined: Sun Mar 02, 2014 6:36 pm
Location: NY USA

by BikeAnon

Is it really worth the effort?

If it's road-only, buy a commuter slick that is as large as you can fit in the rear. The larger diameter will help for the time he spends spun-out at 38x11.

Even without changing the tire, running 38x11 at 90rpm is only about .3mph slower than 40x11.
http://www.bikecalc.com/gear_inches

Meanwhile, picking up cadence by 1-2 rpm is more effective. Is he really spending enough hours at 38x11 to make it worth hunting down a questionable "fix"?

by Weenie


Visit starbike.com Online Retailer for HighEnd cycling components
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TheKaiser
Posts: 653
Joined: Thu Sep 05, 2013 3:29 pm

by TheKaiser

I know this is kind of a wacky suggestion, but is the bike equipped with a through axle or open dropouts? You could get a casette with a 10t smallest cog (or even a 9t), if you built up a wheel with an alternative cassette body. Expensive options would be use Sram XD casettes, but you could also look at some that are compatible with the Shimano Capreo commuter cassette which you might be able to find cheaper. I think the Capreo was only made up to 10 speed, but it's possible that you could make it work with some creativity. Here is an example of a modified Capreo setup that Canfield did: http://singletrackworld.com/2013/12/can ... -cassette/

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