headtuber
Tech talk

Getting Inside The Digit Datum

Words Mike Ferrentino
Photos Mike Ferrentino
Date Jan 19, 2023
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Getting Inside The Digit Shock

Tim Lane’s Digit Datum, previewed here, is a reductive design that aims for modern suspension kinematic performance with fewer moving parts. It features a strut/shock absorber integrated into the top tube. This is either a bug or a feature, so to speak, depending on your personal feelings about non-universal componentry and potential design redundancy. This piece is not an attempt to reinforce or dispel one set of beliefs or another, but it is an up close look at the individual parts that make up this suspension.

Normally, by now, a month or two into taking delivery of a test bike, I’d have ridden the thing enough to have either broken something or at least find something to really love or hate about it. Instead, I got about three rides in back in November on an initial well-used, pre-production tester, then swapped that out for a new production frame, then swapped with Tim for his personal bike because I liked his Lyrik better than the Mezzer on my test bike (sorry Andrew). We went for a ride together to decide that we were headed in the right direction, and then I got one more ride on it, and then California just got shellacked by mother nature while I went to Mexico. Soooo, we are a long way behind schedule for the riding of this thing.

I did, however, manage to snap a few pics back right before the weather went berserk. This was right as I took delivery of bike number two. I was focusing (poorly) on the shock and linkage parts while Tim was spinning wrenches on the bikes. So, here’s a slightly random not-really teardown of the Digit Datum, in mostly picture and caption form.

Then you do something like that, only in reverse...

allsploded

And you end up with something like this. A relatively easily accessible, simple to work on shock absorber. There are some structural benefits to using the shock as a strut; it allows for a high load integrity that doesn't suffer as much torsional or side-loading forces as some other designs. The design negates the need for an upper link, which reduces the number of bearings and axles in play. And the size of the strut itself means that it carries about six times as much oil as a regular single can air shock. This means lower operating temps, less contamination, longer oil lifespan, and ultimately less internal wear and tear.

That, more or less, is what goes on inside the Digit Datum. It's a pretty cool exercise in component integration and mass reduction, without any glaring weaknesses that make the danger/fear parts of my lizard brain light up. My areas of concern are less about the shock/strut, and more based around whether or not the bottom bracket will start to creak. But that is total conjecture on my part. The rain has stopped, and the next month is going to be prime riding here. We shall see how this goes.

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Comments

bishopsmike
bishopsmike
2 weeks, 2 days ago
+10 OneShavedLeg Kos Mammal ohio Tim Lane Metacomet Tremeer023 Nologo imnotdanny vunugu

10/10 would definitely ride.  Slight concern about future serviceability of the shock, but I would probably purchase a few additional parts with the bike, and call that safe for a decade or so.

Reply

tim-lane
Tim Lane
2 weeks, 2 days ago
+1 bishopsmike

A few people have bought complete spare shocks with their Datums.

Reply

xy9ine
Perry Schebel
2 weeks, 2 days ago
+8 OneShavedLeg Todd Hellinga Tim Lane kcy4130 Pete Roggeman Tremeer023 Nologo Velocipedestrian

yep, i still think these bikes are neat.

Reply

FlipFantasia
Todd Hellinga
2 weeks, 2 days ago
+1 Pete Roggeman

agreed, would love to demo one! My brother lives in the Irvine area, maybe need to go visit and pay Tim a visit! haha

Reply

tim-lane
Tim Lane
2 weeks, 2 days ago
+1 Todd Hellinga

I'll likely start doing some demo rides in spring.

Reply

kfowler100
kfowler100
2 weeks, 2 days ago
+6 Lynx . OneShavedLeg Tim Lane Mike Ferrentino Todd Hellinga Velocipedestrian

Mike, thanks for reviewing this bike.  It is on the top of my short list for my next bike, and your helping me make that decision!  I am super stoked you joined the NSMB team!  Keep the posts coming. 

Tim, its super rad that your proactive in the comment threads.  I want to see more of your bikes!

Reply

Jotegir
Lu Kz
2 weeks, 2 days ago
+3 Mike Ferrentino Niels van Kampenhout Andrew Major

I can't quite put my finger on why that completely blank piece of black material just might be the best head badge ever, intentional or not. Is a logo supposed to go there eventually? I hope not.

A datum to traditional marketing efforts!

Reply

Jotegir
Lu Kz
2 weeks, 2 days ago
+4 Hbar BadNudes Mammal Metacomet

Actually, I didn't intend to highjack this post for self-advocacy reasons, but I think the headtube logo I modelled after my cat might be in the running...

The badge

The model

Reply

tim-lane
Tim Lane
2 weeks, 2 days ago
+7 Lynx . Todd Hellinga Lu Kz bushtrucker Pete Roggeman Blofeld Andrew Major

I figure if a tiny red tag is enough branding for Levis, a simple sticker on the top tube is plenty for me. To me, too many bikes look like they just crashed into a dumpster full of stickers.

That blank black material is 3D printed and Cerakote'd for durability.

Reply

velocipedestrian
Velocipedestrian
2 weeks, 1 day ago
+1 Lu Kz

Your badge gives me Totoro vibes.

(edited to add badge image).

Reply

Jotegir
Lu Kz
2 weeks, 1 day ago
+1 Velocipedestrian

That's good, the rider for that one is a big My Neighbour Totoro fan.

Me: What names/logos do you want on the bike

Her: None.

Me: Ok, but it doesn't give me a lot of room to break up the colour since we're just doing a simple fade.

Her: How about the cat?

Reply

xy9ine
Perry Schebel
2 weeks, 2 days ago
+10 Lu Kz Tim Lane Mike Ferrentino Mammal Metacomet bushtrucker Pete Roggeman Dave Smith Andrew Major Velocipedestrian

now that i'm seeing it as an anti-logo headbadge rather than an access port cover, i love it.

Reply

kos
Kos
2 weeks, 2 days ago
+2 Mike Ferrentino 4Runner1

Just waiting for Tim to offer a "29er corrected" rear triangle for the Datum.......

Reply

tim-lane
Tim Lane
2 weeks, 2 days ago
+2 Lynx . Metacomet

I don't see the Datum ever evolving into a 29er, at least in the short term, or in sizes other than XL or above. An industry wide ban on long drop dropper posts, or riding steep terrain, or people shorter than 6'4" would certainly make me reconsider, but I don't see these in my crystal ball.

I plan on launching the shorter travel Ring this year which will have 29" wheels.

Reply

ohio
ohio
2 weeks, 1 day ago
+1 Andrew Major

As someone that prefers longer chain stays than pretty much every current spec, I wish you'd reconsider. Chainstay lengths still haven't caught up proportionately to the new long front centers created by slack head angles and lengthened reaches. From my calcs and hands on experience, ~445mm is now appropriate on a medium (larges and XL should be at least 10mm and 20mm longer), and that leaves plenty of room for 29" rear wheel and a straight seat tube...

Reply

tim-lane
Tim Lane
2 weeks, 1 day ago
+4 Lynx . bishopsmike ohio vunugu

With "As someone that prefers [something different to] pretty much every current spec" you've self-identified as an outlier. There are so many challenges already in launching Digit Bikes, the Analog Suspension, the Integer Strut, all of it really, that introducing outlier geometry would only hamper my chances of getting this boat off the ground.

Also, perhaps most importantly, I made the bike which I most want to ride - it would be pretty weird if I hadn't done that.

I'm not saying I won't at some point make a model which more closely matches your desires, just that the Datum is the model which I want to ride.

Reply

tim-lane
Tim Lane
2 weeks, 1 day ago
0

@Ohio, I notice in another thread below you asked about a 170mm travel bike. Are you talking about the 29" rear wheeled 140 travel bike which @Kos proposed above, or your proposed 29" rear wheeled 170mm travel bike here?

Either way it'll be a few years until I get around to these, so it's a bit of an abstraction at this point.

Reply

grimwood
grimwood
2 weeks ago
+1 Tim Lane

Tim, this bike is so cool on so many levels. I’ll definitely keep an eye out for your longer travel version in the future (I love over-biking). I think you nailed everything for a trail bike, including the mullet.

ohio
ohio
1 week, 2 days ago
0

First, thanks for the response and engagement. You're definitely doing it right as a small upstart and I hope folks appreciate what it means to have the builder directly involved in a forum.

Second, yup, I am an outlier but I don't expect and wouldn't ask companies to build the chainstay lengths I'm proposing*. My point in this scenario is that chainstay lengths that are still well within the mainstream will support a 29" rear, and chain stays so short they will only fit a 27.5" are actually bad for handling when coupled to modern head angles and reaches. The goal of shortest chainstays that we've been sold is hack science that was barely a benefit in the days of 69deg head angles on size small frames, and definitely isn't a benefit anymore for handling.

And I hope the enduro isn't tooooo hypothetical. Because I really will buy one if you build it.

*I actually considered starting a new brand in order to introduce this approach to geo... but bailed as I decided it was too niche and esoteric to sell with any significance. So instead it's just a rant I share with every industry pro in my network, and maybe eventually it will sink in.

tim-lane
Tim Lane
1 week, 2 days ago
+1 ohio

I hear you. And I see where the trends are going, it's just not where I wanted to go with this model. I'm not dogmatic about much in bike design, the geometry will be be different for each model based on anicipated use. 29ers will certainly have a longer rear-center than the Datum.

ohio
ohio
2 weeks, 2 days ago
+2 Tremeer023 Tim Lane

Love it. Hope it sells like crazy, because when he comes out with a 170mm version I'll trade in my Spec Enduro for one.

Reply

Hawkinsdad
Hawkinsdad
2 weeks, 2 days ago
+1 Tim Lane

Dang, that unpainted frame and simplistic design make this steed appealing. It reminds me of my Rocky Stratos, one of my favourite bikes out of many. I'd love to swing my old legs over that thing. Thanks for the timely review Mike. I hope your state gets a reprieve from the biblical atmospheric rivers soon.

Reply

Lynx
Lynx .
1 week, 2 days ago
+1 Tim Lane

Awesome little update Mike, thanks. Tim thanks again for jumping in and participating in the forum/site. Can't wait to hear/see the geo for the short travel 29er, but personally, I'm hoping that it won't have a STA steeper than 75, a HTA slacker than 66 and clearance for at least 29x2.6" tyres on i35 rims, Large would have a 475-485 Reach and Stack of around 430mm.

Reply

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