School Me on MTB Cranks- worth an upgrade?

[gunniride]

Short- go to direct mount RF Next crank from Sram 1000?

Long- I have a Yeti SB5 with the Enduro build. That translates to lesser components which is fine, but if I replace anything, I hope to upgrade and keep the weight down. I have three reasons I might switch cranks, which I can likely get for fairly cheap, if not the Next, the Turbines

1. Running a 28T for the good old fashion climbs around here like Canyon Creek, not a must, but wouldn't mind trying it over the current 30T
2. The front derailleur mount chainguide I recently got isn't playing well with the current chainline.
3. Weight, not too concerned, but new parts other than tires are going to less rather than more.

Any reason this switch is silly and superfluous?

[evdog]

Personally cranks are one of the last thing's I'd upgrade. You should be able to get a 28T rign for just about any style of crank, so that should not require a change. Chainline can be an issue but you may be able to space the BB to move things outward or space the chain ring inward using spacers on ring as needed. As for weight, how much would you save? I would not call this switch silly, but definitely superfluous. I'd put money into lighter wheels, upgraded or tuned suspension, or better brakes, maybe lighter drivetrain but only when it wears out.

[FlimFlamvanHam]

Well if you want to run a 28t you'd have to switch, no? You have a 104BCD crank so 30t is smallest you can run.

The stock chainline on the Cinch with a RF chainring is too outboard in my opinion. All of the aftermarket rings for those cranks have a more inboard chainline.

Also, if you want to run an oval ring the smallest you can run on 104BCD crank arms is a 32T.

edit just to add: the Next cranks are filthy. They are crazy stiff and weigh nothing. So if you are going to "upgrade" your cranks, you may as well actually upgrade them.

[Dantheman]

Well if you want to run a 28t you'd have to switch, no? You have a 104BCD crank so 30t is smallest you can run.

AbsoluteBlack makes 26t and 28t N/W rings that mount to the 64BCD spider.

http://absoluteblack.cc/xx1-style-shimano.html

[gunniride]

/\/\/\ Thanks that link is helpful.

Regarding weight savings, its hard to calculate.
Next w/ 28T = 425g (but no BB)
Sram 1000 = 930g (but presumably with both original rings)

So would that really look more like 600g vs 850g? Guess half pound is in the significant range.

[Dantheman]

Guess half pound is in the significant range.

For frame weight, no.

[ShoNuff]

If it is a weight thing, it's not worth the money. That is pretty much the best place to carry weight on a bicycle. Center and low. The $ is far better spent on wheels/tires or suspension.

[gunniride]

Agreed. Though I'd never pay the retail for those, could pick up from a friend for $120

Susp is 36/floatX, Tires are butcher/Slaughter, wheels could be better DT 1900, but upgrade for that will be putting a wider rim hand built on a hadley if I can convert the old 135 to 142.

[mfa81]

I'd say shock is the first thing I'd upgrade on sb5, but you seem to be covered!

got a dropper?

but for $120 I'd be all over a next sl!

[grinch]

Next sl's are pretty sweet. Fair bit of weight savings in comparison to any other. They spin like crazy too. Generally I have my cranks for more yrs than other parts as well. I think my xt cranks on my rune are 8 yrs old.

[jimmyjames11]

Those absolute black oval rings are tits! I have it on a face face turbine cinch and it's slick.

[Dantheman]

Can't go wrong for $120.

[FlimFlamvanHam]

AbsoluteBlack makes 26t and 28t N/W rings that mount to the 64BCD spider.

http://absoluteblack.cc/xx1-style-shimano.html

Truth but your chain will rub the next largest cog when in the two smallest cogs as your chainline is now around 46mm. Hope that makes sense.

And it looks ridiculous unless you run a bash where the 104 holes are. And who wants to run a bash (especially with a 28 or smaller ring)?

The reason AB does not make a 30t oval for the 64 bcd position is because it would rub the chainstay.

To the OP, those next SL's your buddy has, are those cinch? I assume they are the older ones with the integrated spider (104 bcd). If they are cinch grab them for that price.

Bear in mind the added expense of a bb that will accommodate the 30mm spindle if you go to a cinch crank.

[gunniride]

Thx all

Will put in a 30mm BB as well with order.

Advice appreciated

[Dantheman]

Truth but your chain will rub the next largest cog when in the two smallest cogs as your chainline is now around 46mm. Hope that makes sense.

And it looks ridiculous unless you run a bash where the 104 holes are. And who wants to run a bash (especially with a 28 or smaller ring)?

Just pointing out that it's an option. That's interesting about the chainline and rubbing the other cog. One of the reasons AB says they even make those is that the chainline is better in the 64 BCD position.

[FlimFlamvanHam]

i too think it's better. But it will still rub in the small cogs. I believe it's like 46mm?

Look down at a chain on a dedicated 1x (like on a Cinch or SRAM crank made to run one ring) and look at the chain line when in the large cog. It's stupid. Now pedal backwards. Notice how the chain drops down the cogset? It sucks. That would not happen with one of the AB 64bcd rings. Nor does it happen with a single mounted on my M985's or the 30mm N/W rings with the built in 2mm offset for 104bcd cranks (which yield about a 48 mm chainline which I find ideal).

i would prefer to have no rub at all in any cog and I'd also like not to have the chain drop when I pedal backwards, but as long as manufacturers say 50 and 51mm is optimal that latter will happen.

[gravitylover]

Are those AB rings online purchase only?

A little rub in the smallest cogs is mostly meaningless to me because I almost never get there. I want things smooth from 1-~8 and hate when the chain tries to drop in the largest cogs.

[panchosdad]

If you're going down to a 26T single, wouldn't you be better off getting a front derailleur? Seems like you're going to be spinning like mad in flatter terrain.

[ticketchecker]

[QUOTE=Johnny Sizzler;4691667]
Look down at a chain on a dedicated 1x (like on a Cinch or SRAM crank made to run one ring) and look at the chain line when in the large cog. It's stupid. Now pedal backwards. Notice how the chain drops down the cogset? It sucks. /QUOTE]

I'm about to buy a 1x11 complete setup and wanting to run 28T, was going to get the Turbine Cinch. Should I be looking at something else to get a proper chainline? WWMD?

Planning on an AB oval too

[gunniride]

[QUOTE=Johnny Sizzler;4691667
Look down at a chain on a dedicated 1x (like on a Cinch or SRAM crank made to run one ring) and look at the chain line when in the large cog. It's stupid. Now pedal backwards. Notice how the chain drops down the cogset? It sucks. [/QUOTE]

So if you have a direct mount crank, such as the NEXT, what is the solution? Would an aftermarket ring bring the chainline inboard?

[radam]

If you're going down to a 26T single, wouldn't you be better off getting a front derailleur? Seems like you're going to be spinning like mad in flatter terrain.

It all depends on your terrain. I'm running a 28T ring and I only get into my 11t cog once a ride (on doubletrack) and I am far from spinning out. Our local trails just don't let you open it up in anything but short bursts and even then it's more likely that I'm just letting off the brakes rather than pedaling. But that's my trails.

[FlimFlamvanHam]

So if you have a direct mount crank, such as the NEXT, what is the solution? Would an aftermarket ring bring the chainline inboard?

I have the Next SL cinch on my current bike with an AB oval. The AB ovals on the cinch make a 50mm chainline.

Stock Race Face ring on the cinch is 51mm

WolfTooth and OneUp are both 49mm. Oneup goes so far as to promote that chainline, "Perfect 49mm chainline corrected from stock 51mm."

When I backpedal with the AB when in the big cog the chain drops down cogs. I run 10 speed, BTW. I never had the chain drop down running a single 30t (with the built in threads and offset) on 104BCD cranks (~48mm chainline) and certainly never on my M985 cranks running a 28t (will only fit on inside location =~47mm chainline).

RF puts it at 51mm because, as far as I know, they have this measurement as center of cogset. But in actual use I find, for me anyway, most of the grunt work is being done in the bigger cogs thus more stress and wear on drive train when in those gears.

Plus, the "free amount" of chain is much less when 21 links are wrapped around the 42 cog than 6 links wrapped around the 11 so why favour a centered chainline? You have a shorter available chain trying to make that cross-chained angle from the chain ring to the large cog...it makes no sense. Instead, why not allow a more extreme chain angle when in the smaller cogs and try and limit it in the larger ones since when in the smaller cogs there is more "free chain" to work with and thus "bend" to that angle. At least that's how I see it. And that would be via a more inboard chainline. One caveat: I think 48mm is the limit though since my chain rubbed the 13t and the 16t when I was in the 11t and 13t when running a ~46 - ~47mm chainline with my XTR double crank.

the longest lasting NW ring I have had thus far was my 28t NSBillet (which is pretty much identical pinner tooth profiles as a RF) on my M985 cranks. It should have worn the fastest (relative to the 30's and 32s I've used jsut because it's smaller). I attribute the fact it lasted so long because the chainline favoured the cogs the drivetrain was seeing the most abuse and use in.

So knowing what I know now. I'd go WT (or Blackspire if they make one yet and CL is 49) just because of the big squared tooth profiles. I went AB because of a more aggressive oval shape. i just really think a chainline favouring the larger cogs would be most beneficial unless one rides in an area where the large cogs see limited use.

The ultimate solution is a gearbox. One day. Some year. This whole derailleur thing is archaic and pretty much junk.

[ticketchecker]

Thanks Johnny, I know what I must do now. Preesh

-ride on