A new Litespeed titanium goody has arrived...of the Monster Cross variety

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RyanH
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by RyanH

A shop in South Orange County had a brand new Litespeed Ku:wa sitting on their shelf in my size. While I was on the lookout for the T5g, a Monster Cross bike had previously crossed my mind so I figured I'd make the drive down there an pick this up. This will be an interesting and challenging build.

Litespeed Ku:wa in size Medium without bolts and hanger @ 1543g

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Measured out iLinks for the rear caliper (TRP Spyres), mocked up the seatpost and threw on my spare Quarq cranks:

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Clearance is questionnable. A 36t DM chainring should fit fine, I'd really prefer a 40t but 36t should be good. The chainstay clearance though...

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For the MTB guys out there, does chainring clearance increase with true MTB cranks? Meaning, can most frames accommodate a 40t direct mount ring?

As far as the build, I have a Enve Mountain rigid fork en route. I need to decide on wheels. Enve m50 seems a bit too de rigueur. Besides, for the price of a used set, I could do Mcfk 29er laced to Carbon Ti hubs with an XD body.

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godzuki26
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by godzuki26

Did you get that at Adrenaline bikes? Ryan you buy more stuff than me!
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mrgray
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by mrgray

I'm very interested in the wheels. I know nothing about what mountain bike wheels are considered good or what sort of weights one might expect for reliable robust wheels. Also are you going to run tubular? Or is tubeless the go in this space?


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Fuchspk
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by Fuchspk

Nice frame :) will be an interesting bike

RyanH
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by RyanH

Haha, sometimes I feel like I should ask UPS to setup a shipping receiving satellite location in my place.

@godzuki I got the frame in Dana Point at Cycloligcal.

This will probably be my slowest build as I have so many options that are all foreign to me. I'll try to do a short writeup on each component selection a la Calnago. MTB gear selection is just so much different.

Has anyone run ilinks with mechanical disc brakes? I'm concerned they won't be initially compressed enough. However, I'd prefer to avoid the 240g full housing run of Yokozuna that I just did on the Caadx.

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by nobuseri

Nice frame! Have fun with the buildup. I second the hydro option.
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dwaharvey
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by dwaharvey

I third the hydro option... much better modulation and feel than a cable-actuated.

Hard to tell from your photo Ryan, but the clearance between the chainstay and the crankarms and the chainring both look like they are a concern. It looks to me like you have a set of Red cranks on there with chainring in outer position (?). I looked around online for Sram road crank clearances and found this pdf for Sram 2012. According to table on page 8 you should have a crank-arm spacing of 59.9mm from center (to inner edge), and an outer chainring inside edge at 48.1mm from center.

Here's an equivalent sheet for mountain cranks
That has the inner edge at 46.5 (page 12). So a switch to a standard mountain crank from Sram would actually lose you a tiny bit of chainring clearance, although the crank clearance would go up to 64.5mm for the "narrow" version... so 5mm, which is an option if you need wider. Direct mount rings tend to preserve the chainline of the original so won't buy you any extra clearance on a mountain crank, unless you had something custom made. I believe that with Sram the 1x setups (and direct mount rings) have a chainline that is the middle of the 2x setup, so probably buying a CX1 direct mount ring and putting it on will lose you about another 4mm of clearance.
Last edited by dwaharvey on Thu Feb 02, 2017 7:34 pm, edited 1 time in total.

RyanH
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by RyanH

@dwaharvey, thanks that's really helpful information.

If I go hydro, can I run SRAM or am I stuck with Shimano? From what I've gathered, the new SRAM hydraulic is flat mount only. The fork is post mount (160mm) and the rear is flat mount*. I think it's flat mount that's been designed to run with an adapter.

Regarding the cranks, I have a SRAM 36t Direct Mount 0 offset ring coming which should bring the ring outboard by a few mm compared to where the road spider puts the big ring. Crank arm clearance is only a couple of mm on each side. I'll run it and see if the cranks hit the stays, then reluctantly order a true MTB crankset.

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by Gullholm

The chainline you're running now seems to be 47,5mm, a regular Sram 1x mtb chainline is 49mm and Boost has a 52mm chainline. But with this not being a Boost frame the 49mm should be perfect. Almost any mtb frame will fit a 36 1x setup, most a 38, but 40 can be pushing it a bit so has to be tested.

Hard to say for sure but I think you're out of luck with that crank clearance though. Tried a similar (as in very little clerance) fit on a Trek carbon fully and the crank would at times hit the frame, for example when pedaling hard up a hill. But of course, give it a try and see how it works!

If you end up getting a mtb crankset, two lightweight (weighed by myself) options are Tune Blackfoot at 332g and Sram XX1 Eagle at 391g for arms only. A 38 direct mount Sram chainring is 93g but there are lighter ones out there around 80g.


As for wheels, I haven't tried them but the MCFKs do look great and the price isn't too bad at least. Nice and wide rims.
And to answer some of mrgray's questions, I'm quite sure that around 1070-1090g is the lightest you can build when it comes to clinchers. Bike Ahead's top of the line full carbon wheelset is a claimed 1080 but the only confirmed I've seen is just above 1100g. Most wheels these days are around 1300-1500g though, and a nice quality wheelset at that weight will definitely hold up for most riders gravel and xc use and abuse.

Honestly don't know much about the road hydro side of things, but for Sram mtb you can often mix and match calipers and levers. Maybe that's an option for road too? To get an IS and not flat mount.

Anyway, looking forward to see how this turns out! :beerchug:

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dwaharvey
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by dwaharvey

@Gullholm: Where are you getting the 47.5mm chainline number from for his existing setup? Based on the sram pdfs I linked, I expect his photographed chainline to be more like 50.5mm with chainring mounted in outside of spider.

@RyanH: I believe Sram continues to offer Red shifters/brakes in both PostMount and FlatMount. FlatMounts are designed so that with an adapter you can install a PostMount brake. The compatibility doesn't work in reverse though. Does Litespeed offer proprietary adapters for the rear mount? Because it looks like a regular flat mount and I struggle to see why they would do something similar but different and proprietary... If it were me, I'd probably opt to go flat mount if the fork I wanted to use was available with it.
Where are you getting your zero offset ring from? It sounds like a good first step, though your chainline is likely to be a little wider than optimal for the rear shifting in largest cog. But I've used a RaceFace crank with 51mm chainline on an XX1 135/142 rear for a few years and never had any issues, so I expect you'll be fine also... assuming you're not banging the arms into the stays on hills. I wonder if there are wider Q road options than what you have that would give more clearance but not be as wide as a normal MTB crank...

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dwaharvey
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by dwaharvey

Also Ryan, realized I messed up my math (sorry!) and the narrow mtb crank option is only 5mm (64.5 - 59.5) wider each side than the red road, so not that bad an option after all if your arms are hitting on this one.


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Gullholm
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by Gullholm

@dwaharvey: Sorry, my mistake, 48,1mm for Red. But, correct me if I'm wrong, wouldn't 48,1mm already be on the outside when measured on a Red crankset?

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dwaharvey
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by dwaharvey

@Gullholm: I think the 48.1mm number for the outside position on Red is to the inside edge of chainring though. I think the chainline in that position is about 2mm or so larger. So a little bit wider than the Sram 1x mtb chainline of 49mm.

RyanH
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by RyanH

Fork Selection

As a roadie, we don't give forks much thought. With the introduction of disc and increased tire clearance, forks may get a little more attention as to their affect on geometry. Frames are designed around a certain fork dimension. One of the most critical design aspects of that is the Axle to Crown length. This is the measurement from the axle to where the crown sits. Seat tube angle, head tube angle, bb drop, reach and stack are all affected by this. So, before we select a fork, you need to figure out what the geo table was based on.

In the case of the Litespeed Ku:wa, it was a Rockshox Sid 3 650B fork with 100mm of travel. Axle to crown is 487mm for that fork. For reference, a Enve road fork is 367mm, so this fork will bring the headtube roughly 120mm higher (it moves at an angle, not vertically) and the Caadx cyclocross fork is 400mm. So, the geo table has the HTA at 69.5* with this fork.

If we chose an Enve Mountain fork, which is meant for 29er, the AtoC is 470mm. That will steepen the HTA some and decrease stack while increasing reach. Some 650B rigid forks have an A to C of 435mm. So, which do we choose?

I think we can work backwards on an ideal trail number but keep in mind it will vary based on tire width and wheel size we choose. BMC targets 63mm of trail for all of their Roadmachine for all sizes and adjusts the HTA and rake to get that trail. Long trail numbers will be more stable at high speed but slow handling at low speed. I'm not sure what's appropriate for a monster cross bike, but we could maybe look at gravel bikes as a proxy:

Medium Litespeed T5g has roughly a 66mm trail with a 40mm tire on a 700c wheel.
Medium Open UP: 69mm of trail with 40mm on 700c and the same with 650B and 59mm tires (650B with 2.35in tires is the same diameter as 700 with 40mm).
53cm Niner BSB: 71mm of trail with 40mm on 700c

Mocking up the Litespeed with an imaginary fork having an Axle to Crown of 435mm puts the HTA at 71.1*. Trail with a 50mm offset fork would be 69mm on 700c/40mm tires. I think I previously calculated the trail for the Enve Mountain fork in the high 70s, so that's probably a tad too much, even with its adjustable offset since it maxes at 52mm. So, to get road okay handling, I'm going to need a 650B fork with an axle to crown of 435 and 50mm offset. To China I may have to go.

EDIT: Made a mistake on the angles when I mocked up the fork, redid everything in photoshop and got everything digitally straightened.

RyanH
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by RyanH

It looks like I'm searching for a unicorn fork. The resulting trail for most forks that I can find will probably be in the high 70s, if not 80s. For the geo experts out there, is that too much trail for a gravel bike?

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