Cranksets - Bog standard or something different?

[Jim Junkie]

Hi All,

So on my recent trip to Thredbo, I managed to total my SLX crankset, chainring, chain and quite possibly bottom bracket, all at the same time. Basically an unlucky shot of the flow trail, clipping a rock on the inside of a turn and folding the end of the ring over, breaking 2 tabs on the crankset at the same time.

My first inclination was just to replace, like for like (or maybe XT/Zee). I had it set up with a 32T Raceface NW ring, so it would mean buying the ring and the cranks, then stripping off the stock rings to replace them. I've never had any troubles with the Shimano gear, it's affordable and it works (until confronted with a large rock at speed).

It occurred to me though that there are other options out there and I've never even considered them as an option. Mostly because it's been a case of progressive upgrades/mods which meant the stock cranks just keep getting re-used. I looked into it and realised I have no idea where to even start & what the pitfalls might be.

So, any advice? It's a SC Blur TRc it's getting put on, 73mm BB(70?) with 1x10 NW set-up. I'm not overly fussed about weight, just performance & good-value.

And just for fun, a shot of the destroyed one:

Thanks.

 

[moorey]

I can't recommend SRAM removable spider cranks enough. X9 for most of us, XO if fancy. Just avoid the carbons. Get a DM ring, and bobs your uncle.

 

[Knuckles]

I'm with stoopid^

 

[Jim Junkie]

I can't recommend SRAM removable spider cranks enough. X9 for most of us, XO if fancy. Just avoid the carbons. Get a DM ring, and bobs your uncle.

So excuse my ignorance here, but it looks like you buy the whole crankset, rings & all, then you can remove the spider & buy a ring (DM: Direct mount?) that mounts directly onto the spline? Like this: http://www.mountainbikesdirect.com.au/wolf-tooth-drop-stop-chainring-direct-mount-gxp-4

From what I can tell, the technical term for a threaded bottom bracket it GXP these days?

The best I could find with the usual suspects (Wiggle, Pushys, MTB Direct, CRC, Jenson) was something like this:
http://www.chainreactioncycles.com/au/en/sram-x9-10-speed-chainset/rp-prod84849
http://www.mountainbikesdirect.com.au/wolf-tooth-drop-stop-chainring-direct-mount-gxp-4

 

[The Duckmeister]

From what I can tell, the technical term for a threaded bottom bracket it GXP these days?

No, GXP is Truvativ/SRAM's take on the two-piece crank design with the spindle permanently attached to one crank arm (typically the right, but some other manufactuers' take on the concept has it on the left). It's available in both threaded and press-fit variations.

 

[99_FGT]

No, GXP is Truvativ/SRAM's take on the two-piece crank design with the spindle permanently attached to one crank arm (typically the right, but some other manufactuers' take on the concept has it on the left). It's available in both threaded and press-fit variations.

Pretty much, GXP refers to the drive side axle being 24mm and the non drive side being 22mm, whereas Shimano are 24mm on both sides.
Good to know the TRc is up to the abuse! That is a much bigger hit than the previous owner ever gave it....

 

[Jim Junkie]

Pretty much, GXP refers to the drive side axle being 24mm and the non drive side being 22mm, whereas Shimano are 24mm on both sides.
Good to know the TRc is up to the abuse! That is a much bigger hit than the previous owner ever gave it....

Thanks for the clarification. The TRc definitely did well under the circumstances! I had a quick look over it at the time and everything looks good, although I'll give it a closer inspection once I get to removing the BB itself. Absolute cracker of a bike though, I was having a great time down the flow trail for the previous 2 days until that happened.

 

[moorey]

So excuse my ignorance here, but it looks like you buy the whole crankset, rings & all, then you can remove the spider & buy a ring (DM: Direct mount?) that mounts directly onto the spline? Like this: http://www.mountainbikesdirect.com.au/wolf-tooth-drop-stop-chainring-direct-mount-gxp-4

From what I can tell, the technical term for a threaded bottom bracket it GXP these days?

The best I could find with the usual suspects (Wiggle, Pushys, MTB Direct, CRC, Jenson) was something like this:
http://www.chainreactioncycles.com/au/en/sram-x9-10-speed-chainset/rp-prod84849
http://www.mountainbikesdirect.com.au/wolf-tooth-drop-stop-chainring-direct-mount-gxp-4

People often list them as just arms alone, but if they come with spider/rings, sell them off and recoup some dollars to put to a DM ring. Arms just listed and some on here yesterday for $50. DM ring is still there for $30. They are $90ish new.

 

[Alo661]

Raceface Turbine? Come setup as single ring config with a NW ring and BB, plus you don't have to bother with buying cranks, removing stuff, selling useless rings.

 

[Flow-Rider]

I think you have had one of those unlucky, "one in a million strikes". Slx cranks are cheap enough, I would just buy another one and fit a good bash plate to it. Heaps of other options, I like being simple.

 

[moorey]

I like being simple.

coulda just left it at that, qld boy....

 

[scblack]

coulda just left it at that, qld boy....

He does the simple thing so well too.

 

[Flow-Rider]

coulda just left it at that, qld boy....

Haha! Works fine for me, I will just have to get that grass straw in my mouth, like a hillbilly.

 

[The Duckmeister]

Pretty much, GXP refers to the drive side axle being 24mm and the non drive side being 22mm, whereas Shimano are 24mm on both sides.

Sorta, but not really. Yes the stepped spindle is the major feature that distinguishes GXP from others, but the term GXP (Giga X-Pipe) specifically refers to the type of construction rather than the step.

 

[slippy]

I'm with the simpleton. Replace with same SLX crank. Next time have a bash ring.

 

[99_FGT]

I'm with the simpleton. Replace with same SLX crank. Next time have a bash ring.

As has been mentioned, it was one of those strikes that just happens. A bashy might have soaked up some of the impact, but at the same time would have transferred more of the impact to the frame.
Al..

 

[cramhobart]

Raceface Turbine? Come setup as single ring config with a NW ring and BB, plus you don't have to bother with buying cranks, removing stuff, selling useless rings.

I have turbine cinch cranks on my blur tr and love them- just be aware that you need an old shimano splined bb tool to change chain rings and the threaded RF turbine bb(30mm spindle) requires a race face tool, that isn't compatible with any other bb tool.

 

[Jim Junkie]

As has been mentioned, it was one of those strikes that just happens. A bashy might have soaked up some of the impact, but at the same time would have transferred more of the impact to the frame.
Al..

Yeah, I'm with 99_FGT on this one, I don't think the bash ring would have helped much given the extent of the damage. That ring is fractured on the back side, as are the 2 tabs on the facing side as well, so the force was considerable and I'd prefer to sacrifice the cranks rather than transfer that to the frame.

Being a simple Qld'er, I think I'm leaning towards some SLX or XT cranks at the moment. There doesn't seem to be a considerable benefit to the SRAM DM system, and it does seem to be considerably more expensive and harder to find. That, and given all the spare parts & tools I've got match up with the Shimano Hollowtech set-up, I'm not yet convinced there's enough benefit to make the change.

We'll see though. I've got a little while before I push the button, so if something pops up on the sale threads I may try it out. Thanks for all the advice everyone, turns out I've got a bit to learn about cranksets.

 

[teK--]

i don't know if many cranksets would have survived that. usually the DH spec ones have steel axles and uprated strength on the arm, but the chainring and spider is similar to your standard spec of crank. FWIW Renthal chainrings are meant to be very strong but you really need a bashring to protect against something like that. (ISCG tabs would have probably been snapped clean off)

 

[silentbutdeadly]

Basic option is to go with what you destroyed. Other option is the SRAM system that Moorey and Knuckles pointed out (though I personally have never had much luck with GXP even when using a Hope BB and the metal spacer).

Then there's the dedicated 1x systems like Raceface (already mentioned), Hope (new!), E13 and Middleburn...which all seem to run a Hollowtech style BB. But these can get nasty, price wise. There's also the new Shimano XTR 1x but the prices for that are eye watering!

I really like the look of the Middleburn but can't get over the practicality and value of the basic Shimano SLX.

I've been burned somewhat by a bling 1x crankset (White Industries ENO with SRAM XX1 adapter on White Industries titanium square taper BB) already due to its relatively narrow Q factor...so I'm loath to do it again (or suggest others do the same).