Raleigh Roker Comp gearing question

NoCoGreg wrote:Zman - The difference between gears on your cassette vary between 12% and 18%.
42/36 = 16.7%
19/17 = 11.8%
13/11 = 18.2%

So if you split the difference and say there's an average of 14% difference then to get one gear lower you'd need to buy a 37t chainring:
42/1.14 = 37t 

If you want 2 gears lower you'd need to get a 32t chainring:
37/1.14 = 32t

Conversely going to a 44t cassette will only get you about a third lower gearing:
44/42 = 4.8%

To get a full gear lower by moving to a larger cassette you'd need to get:
42*1.14 = 48t

Note that if you do get a smaller chainring (say 38t), you'll may be spending more time in the smaller cogs on your cassette, which is where the gear-to-gear changes are larger.

Also note that you may need to shorten the chain if you go for a 38t chainring. A shop should be able to guide you on this.  If you think you'll want to move between setups you can get a 2nd chain and masterlink (Shimano chains use a special pin that is expensive to replace, instead consider consider SRAM, Wipperman or KMC chains - all are good quality and have master links).  

Hope this helps,
Greg

dangle wrote:Narrow wide rings (used for 1x systems) have to be evenly numbered so there's always a narrow, then a wide tooth. You would have to choose between 36 and 38 and it looks like you chose 38.

I'm 93% sure nobody makes an 11-44 cassette, but even if they did, that 44 cog would be the only difference and it would be less than 5% lower than a 42......which is why nobody makes one.

The 11-42 and 11-46 from Shimano are identical, except they throw a 46 on instead of the 42. It's 10% lower. It's really up to you to decide if spending nearly $100 to have a slightly lower bail-out gear is worth it. A 38 front and 42 rear is already really low. If you were pedaling in the 38/42 at a cadence of 70, you're approaching walking speed.

"Run what ya brung." and "Don't try anything new on race day." come to mind here.

Enjoy!

Zurichman wrote:
When I was reading the comparison between the two I read this. Available with 110mm/148mm boost option what is that?

For only $53.27 I can justify buying the Shimano 11-46. The higher gears look better than what I have on the bike stock right now. Yes the lower gears have some big jumps in them but I won't be mt. bike with the bike that often so this should work. In the future probably over next winter I will be buying a lighter wheel set but not int he cards right now.  

clarksonxc wrote:The other statement caught my eye.  Why would a cassette be advertising a Boost/non-boost spacing option?  What does the dropout spacing have to do with the cassette width?  Does the Boost spacing allow the largest cog to not be dished, and require an 11sp road freehub?  I haven't heard any details on this before, so I'm curious.

dangle wrote: There's no such thing as a Boost spaced cassette (yet). There's Boost "spaced" chainrings for 1x applications that moves the chain line slightly. It's not relevant for this conversation though.

I ran the AML400 (417 miles because I made a run to Covington, VA about 5 miles off route on night 3 for a hotel room vs. camping) back in April/May of this year on a SunRace 11-46 rear & 38T chainring. Bear in mind I never ran out of gear except in one section, which was hike a bike anyways and I was left on day one with the bike packed down to the tune of 63 pounds! I can vouch that you are hard pressed to descend an 8% grade in excess of 42 MPH 😃

I'm going to be running the AMLX in October (yo-yo route with much more forest roads and more elevation - 502 miles, 46-47K of elevation) and I'm currently look at getting a new lighter GX MTB Crankset with a direct mount 36T chainring as it has steeper sections 14+% in parts. I'm currently researching the chainline differences out of the box vs. getting an offset direct mount chainring.