Digger Goreman

Could/would someone donate a new/good used, single speed, square taper mtb crankset and bolts, 104 bcd? Together, or separately, with a new/lightly used 104 bcd, narrow/wide, round 30 tooth chainring? Super if it is in black (but doesn't have to be pretty, of course). 170/175mm. Going on my 1995 Trek 800 Sport all-rounder.

Unless you're feeling super generous, I'll pay shipping to Atlanta, GA.

Many thanks!

DG

veganbikes

Why not just stick with the 130 BCD you have? No need for a 104 when there are 130bcd narrow wide rings. If you are just trying it out you can just take off some of the rings on the current set up and give it a try while you await a ring.

Digger Goreman

Thanks, friends. The bittersweet facts of my current bike life is that I have a riveted triple. 22/32/42. Can't experiment with drilling without stranding the bike. So, hoping for second hand handouts to extend my depleted bike budget. I found an old mtb site post that 1x'ed in the exact same profile as I have: 95% pedaling in the second ring (32 tooth) with occasional "punchy" hill climbs. Same 11-34 cassette. This is my solution till the newish cassette wears out. I expect that to be years in the future. By then I should be on a tight, modest retirement. If I economize enough, then, I hope to go 36 in the front, and 11-46 in the rear (depending on how I navigate post 60 age). One related thing I have noticed is my growing desire to simplify within my permanent hilly circumstances. Love "doin' it" on a bike! Very economical too.
Thanks for all kindnesses.

Digger Goreman

Thanks!

Digger Goreman

As an update, I got a windfall and can/could go ahead with this little project. I had already tested my endurance with (front chainring) 32/11-34 (rear cassette) (24.5 - 75.6 Gear Inches), and done the "poor man's version" by setting the lower limit screw to dial in just the middle and removing the left shifter. I do have to pump/push/stand on my steepest local hill, but it's still doable at my age (60) and conditioning. I still miss that access to 20 gear inches. As stated before, my triple gave me 18-99 Gear Inches and I almost never used the two extremes (well, one can always go down faster). So I wanted to replicate that range in a single. I decided to go for the greatest equivalent range and will have a 40 (Narrow/Wide)/11-50 at the end. This will give me 20.8 - 94.5 G.I. Ditching the rivets, of course, allows reducing tooth count in the future, as I age (thus making climbing easier, at the expense of downhill speed). My rear derailleur is rated to 45 gear teeth, but I read somewhere that you can exceed comfortably by 10% (49.5). So, either it will handle the increase OR I will make the minor investment in a derailleur extender.

Now, I know a great deal of you wise and smart cyclists knew all this. But, just in case there are less experienced riders that can share positively in my experiences, I included them.

SoSmellyAir

Congratulations!

According to Wolf Tooth (Chainring Diameter by Tooth Count – Wolf Tooth Components), going from a 32T to a 40T increases chain ring diameter by 32.3 mm, which corresponds to a 16.15 mm increase in diameter. So measure the clearance between the 32T chain ring and the right chain stay before you buy that 40T chain ring.

See my thread (Bike Forums - View Single Post - Converting Trek FX2 to 1x) regarding the installation of (a) a bottom bracket with a shorter spindle to install the chain ring on the outer ring position for the cleanest look, and (b) chain guide to prevent dropping chains.

Digger Goreman

Thanks! This is what I love about cycling is learning something new nearly every day.

Digger Goreman

SoSmellyAir Just a hypothetical curiosity: Could the ring be spaced away from the chainstay, if necessary? Changes the chain line, of course.

Edit: In retrospect I can see that is a slightly ignorant question on my part. Wish I had the bike with me at work to measure and muse. If I'm wrapping my mind properly around this, then the chainring is sitting roughly parallel to the chainstay and outside of it. So it would be a matter of where the crank/spider is spaced (spindle length?) in relation to the chainstay?

Digger Goreman

SoSmellyAir Took the time to read the whole thread and am encouraged. Thank you. The cranks you used look almost like the ones I have coming in. (Though, on second look, yours are 110bcd to my 104bcd. Will that matter?) So, I suppose if necessary, the ring could be mounted outside (as I believe you did) if the 40 tooth will then clear. If not enough clearance, could you safely use spacers on the outside? I'd really like the 40 to work IF possible, but will "get smaller" if necessary. I've been riding with the fd fixed in the middle, and LOVE not dealing with left hand fiddling. More than ready to send that derailleur to the parts bin though, unlike your case, the cage has JUST ENOUGH clearance to go from 1-9 on the cassette without scraping. I'm committed to the final production of a 1x9 in the best range possible. Given your sage counsel, we'll see what that ultimately details.

Digger Goreman

Looking at the Trek 96 manual for the 800 Sport, the original middle ring was a 38 tooth, so I'm hoping a 40 tooth won't be THAT much bigger in radius! https://www.vintage-trek.com/Trek-Fis...manualTrek.pdf

Found the wolftooth site and that would be 4.05 mm in radius over the original ring. (5/32").

shoota 

Maybe I missed it but why do you want 1X? If you're in a hilly location then 2X makes much more sense. Especially since you already have that.

Digger Goreman

Oh mostly the typical reasons: clutter/weight; possibly vanity and being a semi-obsessive tinkerer? All possibilities. My "official story" is that this matches my philosophy of simplifying my life. Doing more with less. A little bit of versatility in a smaller package? More concentration on enjoying the ride than considering shifting? I know so much of this might seem inconsequential but, as the song goes, it just depends on where you start.

Or maybe just my Decision Science degree impinging on life: how to get what I like (20-99 gear inches) with the least amount of gear/weight and (at least during the ride) bother. I kissed a shifter good bye, and I liked it! So, now this

In an oblique way I am pre-empting aging. Not that I am suffering. Once a season I might totally fudge a shift/space out and shift the fd the wrong way Sounds more like rationalizing. However, a simple ring change if/when I lose capacity will keep me climbing the hills as long as I can balance the bike, eh? One or more truths in here somewhere, maybe.

SoSmellyAir

Assuming that you are buying a triple (i.e., 3x) crankset, I don't see why you would want to add any spacers, because:

(a) If you add spacers to the middle chain ring mounting position for a 1x setup, it would move the chain line inward and thus further reduce clearance between the chain ring and the right chain stay.

(b) If you are using the outer chain ring mounting position for a 1x setup with the original bottom bracket, the resulting chain line is further outward than the original chain line, so why would you want to install spacers to shift the chain line further outward?

Best to install (a) the new chain ring onto the new right crank arm, and (b) the new right crank arm onto the existing bottom bracket, then evaluate resulting the chain line, then buy a new bottom bracket to shift the chain line inward or outward as necessary, keeping in mind the required clearance (while being conservative).

EDIT: You mention a 104 BCD MTB crankset; is that a single, double or triple?

Digger Goreman

Sorry SoSmellyAir , it is a Single crank that I will be going to. I am going away from my current triple. In the meantime (till parts arrive) I have used the limit screw to simulate a single, initially for testing, and as an intermediate solution as I do like the experience. All that you say is true and taken to heart.

As I recently measured on my current setup (and using the same brand to replace the cassette, if that matters) the chainline is right at 50mm and straight as an arrow to the 5th (middle) gear when in the middle ring. The incoming spider arms appear flat where the bolts go, so I assume the ring can be mounted interior to the spider (regular position), or exterior, whichever position gives the straightest chain line. THOUGH, as you pointed out, a new BB might be necessary. Fortunately they are not expensive. Though I LOVE this old frame, and it has been very good to me over the years, my bike remains a labor of utilitarian love, and not by any means a show piece. Again, something that clicks a huge box vis-a-vis bikes and life: from no frills beaters, to vintage, to fiber and titanium works of art (mechanical as well as visual) there is something for everyone. Thanks for helping me with my not-so-(but totally)-special artifice to an enjoyable life.

Digger Goreman

This week's update: Parts are almost all here.

>Generic "Action" square taper cranks, 170mm, 104bcd, 4 arm spider.
>40 tooth, 104bcd, Snail narrow/wide chainring
>11-50 JFOYH 9 speed cassette
>6.5mm chainring bolts

Question for the gallery: I am content to keep my Altus 9 speed RD. It has performed well for me, especially mated to a SunRace (Sturmey Archer) thumb shifter. The Shimano website rates the RD at 45 teeth max. I have heard you can comfortably exceed this by 10%. 50 is half a tooth outside of that. Has anyone run an 11-50 with an Altus successfully? Even with no Altus experience, do you believe an extender will be necessary? Hate to get my only ride to the shop and have an "oops" moment!
Edit:
Finally found the YouTube video that did exactly what I am doing and works with the extender. So, added to the acquisition.
50t cassette with shimano altus rear derailleur. cheap mountain bike upgrade. - Bing video

Thanks!

DG

SoSmellyAir

From what I have read here on BF, how much you can exceed the RD capacity by depends not only on the RD but also on frame geometry, i.e., chain stay length. So the only way to tell for sure is to gently try it out.

bboy314

I think the 9 speed Altus RD has a total wrap capacity (difference between smallest and largest cog + same of chainrings) of 45 teeth but is only rated for a 35 tooth largest cog. I’m using a 9 speed Deore RD with similar rating (actually 36 large cog, 45 total capacity) with a 10-42 cassette, doesn’t seem like it would work with a larger cog but I haven’t tried.

SoSmellyAir

Typo by bboy314? Max chain wrap of 45 teeth, but 34T max cog.

Shimano Altus RD-M370 Rear Derailleur (Silver) (9 Speed) (Long Cage) (SGS) - Performance Bicycle (performancebike.com)

Digger Goreman may have mixed up chain wrap capacity and max cog size.

bboy314

I had in mind the shadow version of the derailleur, which now that I checked has a 36t low cog limit. Not sure where I got my original 35! But either way, seems like op will probably need a different derailleur to work with the 50t cassette.

Digger Goreman

Yeah, I am seeing (as I dig deeper in various forums) that my approach was naïve (ain't too proud to admit that, either: my folly will be someone else's wisdom!). I also, most definitely, mixed chain wrap with max cog.

So my approach was to match numbers of GI I wanted and expecting there to be an engineering solution. Essentially I had/have a desired range that will not (normally) fit what is on the bike. Fortunately, an old-new-stock Shimano derailleur that someone else used in this application (with an extender) will only set me back another $25.

So, plan C (or is it D) is to touch base with my mechanic, trust his expertise (I really like his honesty, so far) and either lightly test the Altus (not leaning that way now, as the Utuber said his stressed out over time) and tap the kitty for the modest RD cost.

Keep the thoughts coming. By the end of this adventure, I/we should at least have a summary of how to approach such. Btw, if not already mentioned, I do understand and accept the gear tooth jumps inherent in a 9 speed 11-50. Looking at my gearing charts, there WILL be "sweet spots" that I am used to that don't exist (they are in between the jumps), so the future will be higher or lower cadence. I'll adjust.

Digger Goreman

Update: Finished the MTB Commuter 1x project and couldn't be happier! Old Altus 9 speed RD + goat link, handles 11-50 cassette. As a bonus to my simplification tendencies, I used my old Shimano thumb shifter to go silently non-indexed

So, 40T narrow-wide, 11-50 cassette, for 0.8 ratio on the climbs and 3.6 on the downhills. That's 20.8 to 94.5 gear inches. Rode the new setup home from Aztec Cycles in Stone Mountain (thanks Preston!!!) using my commute route. The bike performed within a whisker of the old triple setup.

At the moment, very pleased

Digger Goreman

Non-Drive Side: Japanese steel Minoura front rack (says it will not go on rigid forks but, flip the bracket and it lines up with brake bosses . Low rider section gets a pair of Ortlieb classic back rollers. I think the top of the rack (sans the blue bag that can easily transfer to a fanny pack) could take a traditional saddle bag. Blue bag is a converted golf novelty bag that I sewed on straps/buckles. Lowest bottle is an AirZound (horn) bottle. Cobb Randee saddle, light duty generic cable lock (almost never let the bike out of sight). Medium Topeak saddle bag (repair supplies/tools). Topeak Explorer rack. Crank Brothers Clic-Stick (under non-drive side of rack). Cygolite HotShot Pro 150.

Drive Side: 40 tooth Snail chainring. Fmpxtr 170mm cranks. JFOYH 11-50, 9 speed cassette. Shimano Altus 9 speed rear DR w/goatlink. Rhino Sun Rims (36). Shimano Alivio brakes.

Cockpit: Ergon GP2 grips. Shimano "050" brake levers. Delta AirZound horn. Bontrager Trip 4W "computer". Shimano "Malaysia" friction shifter (donated to me from this blog; found an example on something like an India fleabay for less than a penny equivalent ). Bucklos top bar bag.

Salsa and Topeak bottle holders; generic plastic partial fenders.

It's a "Beast" (heavy and strong) and I LOVE IT!

Digger Goreman

Forgot about the Topeak MTX (non pannier) bag that slots on the Explorer rack, and the Axiom Storm Front (waterproof) panniers that ride the rack rails. Helmet is a POC ski version, with plexi-shield, third eye visor clip mirror, and helmet mounted Cygolite (Metro 600 for night and Metro 360 in flasher mode for day). On the lightest work commutes I have the trunk bag with work clothes and rain slicker; front bag may carry extra gloves, but is a dedicated light med kit, spare light and charging cable carrier. Lunch is in an old Tamrac camera bag, belted around my waist. Typical spandex/Goretex gear according to weather.

Digger Goreman

A little over a month later and everything is Aces and Eights! Drive train is as quiet as the triple, even with largest chain line deviation. Old Altus is smooth and efficient, even with multiple cassette ring shifts. I definitely plan to keep it this way.

Did have to go with a new bb in the end.

Happy 😁

SoSmellyAir

Digger Goreman Looking good. You have inspired me to look into an AirZound; that might be worth adding a second bottle cage. What new BB did you get?