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Building up a new scandal.
I normally use an old triple crankset with a narrow wide chainring and run a stealth granny
Is this doable With boost spacing?
Would I be able to get ye olde square taper crank and space it out with a wider BB?
My friend has a non boost xt 2 part crank I can have . Can this be spaced in some way?
Hope this makes sense.
I do something very similar on a boost SolarisMax. Old XT triple with a 30t ring but it does put ring and chain very close to stay. It's been fine but I think a larger chain ring would give problems.
I have been looking for a new boost chainset and have been puzzled by conflicting chainline advice. Some say 52mm for 135/142 hubs and 55 for boost, others say 52mm for boost.
What is the STW view?
I've been running a non boost chainset on a boost frame for a while. Singlespeed though. I have tried it as 1x12 but not with a granny. Do you perceive the issue to be granny/frame clearance or chainline? I think I'd loosely fit the existing parts to the frame and eyeball it.
On my 1x12 setup I did have the chain touch the tyre, so there's no way I'd have got a granny in for that reason alone, but that's more about tyre width, not suddenly created by the old standard I think. Is bottom gear on 12x closer to the centreline than pre boost? And, my non-boost chainset is a double, so outer ring on that I suspect is already close to boost single ring chainline.
Sorry - that's garbled - but I suspect a chain line from 3x non-boost granny to a modern cassette bottom gear would be far enough inboard to trouble a lot of mtb tyres, even if nothing fouled the frame. But too many variables, so I'd be tempted to experiment if you have the bits.
Some say 52mm for 135/142 hubs and 55 for boost, others say 52mm for boost.
Yep, I've been looking recently as well and it's really confusing. That one up link up there says that boost chainline is 51-53mm but some info says thats for 135/142 hubs. Are the likes of wiggle just displaying the wrong info??
I'm currently using an XT M785 chainset on a boost frame, again the one up stuff says, "104BCD with one up spacers in WIDE chainring position", what does this actually mean?...
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Actually, ignore me, I've just actually read the whole page and seen the massive pictures!!!....
If the XT is a triple then you might get away with the chainring in the outer position. Especially if you went with something like a 30T which are usually offset slightly.
If it's a double it'll be very close to the chainstay if it works at all. The new scandal has very little chainring clearance (the upside is masses of tyre room).
It's quite a chunky chainstay too, so a granny ring might be difficult to make work.
I’m currently using an XT M785 chainset on a boost frame, again the one up stuff says, “104BCD with one up spacers in WIDE cjainring position”, what does this actually mean?…
I think it's referring to hub boost spacers. If you're converting a rear hub you can either put 3mm on each side which effectively leaves you with a half-boost chainline that will work with non-boost chainsets. Or but the spacers on the disc side, which pretty much makes it as good as boost.
As above - depends on the frame. I'm running a 30T oval on my boost MkV Soul on non-boost cranks, and that clears OK. I'd argue it gives better chainline in the gears you're actually tending to spend most time in too.
On the other hand, 28T oval on my Rocketmax needs boost cranks to clear.
Cant help with the stealth granny!
My understanding when Boost came out the Shimano 1 x recommended chainline was 51.8mm. I have noticed that newer Shimano chainsets are now suggesting 55mm as a boost chainline. Its a bit confusing and I haven't seen a reason for the change.
My guess was that was to allow greater chainstay clearance and also to optimise the chainline for the smaller higher wearing cogs. Its only 3 mm so I am not sure whether it makes a huge difference on a geared bike.
I actually have been using an old 49mm chainline crank on my boost frame for the last 5 years.
On my XT 756 triple chainset I run the 30t ring on the middle position. Tried the outer position but it threw the chainline completely out. This set up is actually the best shifting on my 3 MTBs
I'll be in this position when I swap to a v3 Scandal frame from an old 26" Spesh sometime this winter. I'll be running a set of XT 2x 10 speed cranks, that I currently have the chainring spaced in by 4mm to get the right chainline. I'm kind of assuming that running the chainring on the outer tabs with no spacers should put it in the right place...
Hmmm as said above see here for comment on chainline change for boost frames https://bikerumor.com/aasq-142-why-are-brands-moving-boost-frames-from-52mm-to-55mm-chainlines/
And none of this accounts for whether the rider is in hillier terrain and so using the bigger cogs for longer periods so would benefit from a narrower chainline. I will stick with my M785 with single ring at a 49mm chainline.
I've been running a non-boost 2x crank on my Boost Occam for 6 years or so.
I found 49mm ideal for 142mm, as for boost running 55mm that just seems and looks wrong to me, boost rear end with 51mm seems the best chainline for me, oneup and blackspire snaggletooth even made their chainrings 1mm offset closer to the stays for better a chainline, if your frame allows it I'd go closer, but they seem to be making frames to have terrible chainlines nowadays.
Sounds like (to within a mm or so)
49mm (not boost) would line up with gears 1-10 in about the same chainline as a 1x10 drivechain.
51mm (boost) lines up with 2-11.
55mm (superboost, but now just boost) lines up with 3-12.
But in the real world it makes no difference unless you're back pedaling. As long as it clears the chain stay.