IslandTimePE

Hi All: Started working on my Miyata Two-Ten again. Plan is to use it as a gravel/dirt road bike this year. Converted to flat bars (yes, I know, my preferences for bars on a gravel bike run contrary to most ) and Claris 3x8 flat bar shifters. Cassette is 8 speed 11-32. Crankset and front/rear derailleurs are originals to the bike.

So far, so good. I've gotten everything put together and the shifting works well. The old 6 speed rear derailleur handles the 8 speed cassette with the 32 tooth cog with no troubles. Need to clean up the cabling, etc. but from a functionality standpoint it is all good. See pictures below.

My only concern is the gearing with the original crankset triple. It has 52/45/28 rings. This raises 2 issues:

1) The roads I typically ride are hilly and rough. I'm very happy to have a 28-32 low gear ratio and will need it on some of my rides. However, I will have very little use for the 52 tooth big ring.
2) I would like to reduce the gap in capacity between the second and third ring.

Ideally, I would like to remove the 52, move the 45 to the outer ring position and then get a new middle ring somewhere in the 39-36 tooth range to add in.

So I am looking for some advice:

1) Will the existing 45 work OK in the "big ring" position. I know I will nee to re-position and re-adjust the front derraileur. But will a middle ring work in the outer ring position?

2) Where can I find a new middle ring to fit this crankset? Am I limited to looking for vintage Sugino rings (or similar) or would a more modern ring work? I see listings for 39 tooth Shimano Ultegra rings. Would that work? Any suggestions of sites that might sell vintage/NOS rings?

Or do I need to think about replacing the crankset?...not something I really want to do if I can avoid it.

Thanks for any and all feedback.

mstateglfr 

The middle ring will work, but wont look the part.
Its aesthetic, but it wont be as nice looking in design.

If thst doesnt matter, toss it on the outer side of the crank arm.

simmonsgc

Great bike. Works great for a 'gravel bike' -- though I sorta loathe the marketing co-option of that term. Here ya go....same bike, same year, same crank. Mine's identical to yours, expect mine is 'sandstone.' I do the same kind of riding with mine, and here's a drivetrain shot with 28/36/46. Middle ring is a new Sugino 36, which I think I bought off ebay, can't remember. Just grab a Sugino 36 (or 38, whatever you want) x 110, and off you go.

miyata2.jpg

HTupolev

Probably. You'll probably at least need to flip the ring: they have a counterbore where the bolt or nut sits, and it needs to face outward for the outer ring and inward for the inner ring.

You need chainrings with the correct bolt circle. I *think* that your outer and middle rings sit on a 110mm 5-bolt circle, while your inner ring is on a 74mm 5-bolt circle. Lots of brands still sell 110BCD and 74BCD 5-bolt rings, including Sugino ("Sugino standard chainring"). Sugino's 110BCD 5-bolt rings don't come in 39T, but you can get 38T and 40T.
You'll want to make sure you get chainrings designed for multi-chainring road cranks, not BMX or narrow-wide chainrings.

I'm not sure what particular Ultegra ring you found, but most of the "Ultegra" chainrings out there won't fit your crank.

I don't see why you would. The style of crank you're using is great for the application. The only concern I would have would be shifting. Does the indexed Claris shifter actually shift the front very well? If not, you could always stick something like a friction thumb shifter on the bike.

Dfrost 

Your crankset uses the once very popular 110mm (middle/outer rings)/74mm granny ring Bolt Circle Diameter (BCD). Rings in that size are available from many mail order firms, such as my favorites, Universal Cycles and Harris Cyclery.

https://www.universalcycles.com/shop...hp?category=50
https://harriscyclery.net/product-li...1405/?rb_br=87

They are also highly likely to be available very inexpensively at a bike co-op or purveyor of used parts.

Ultegra rings are 130mm BCD, so won’t fit.

Don’t worry about shifting concerns. We used chain rings with no “ramps or pins” to assist shifting for decades.

IslandTimePE

Thanks. As long as it will work, that is the main thing for now. Need to keep the cost of this project to a minimum, unfortunately.

IslandTimePE

Awesome. Exactly what I am attempting to do. I love the C&V forum! Thanks.

HTupolev

I agree about pins and ramps, they're basically decorative if they're not designed around specific chainring matches. But chainrings designed for 1x systems should be avoided, their tooth designs can make them retain the chainring too well for good front shifting.

wrk101

I tend to “borrow” the two largest rings from a donor vintage MTB. There were a lot of 110 spaced MTB cranks out there. I often use them to make a thrifty compact double. 44 to 48 big rings, 35+/- middle rings. Looks a little odd but not as odd as the old guy riding the bike.....

1980s MTBs tend to have little value but they are full of tasty parts: thumb shifters, MTB/BMX pedals, triple cranks, long cage RDs and more. Eventually buyers will catch on. If the pedals are BMX type, and often they are, the sale of the pedals will pay for the bike if not more.

SkyDog75

If you're going to pick up replacement chainrings, you'll need to know a few things:

• The number of bolts on your crankset and its BCD (bolt circle diameter). If your chainrings aren't made for the same BCD and number of bolts, the mounting holes won't line up. We can tell by simply looking at your crankset that you need 5-bolt chainrings, and I think your crankset uses a 110 mm BCD for the outer two chainrings. If I'm right, the distance from the center of one bolt to the center of an adjacent bolt should be 64.7 mm (2.55 inches).
• Whether you want chainrings for a single-speed or derailleur drivetrain. Single-speed rings are made to interface with wider chains. Single speed chains are generally 1/8" between inner plates versus 3/32" for derailleur chains. You obviously need rings for a derailleur drivetrain, so I only mention this so you know to avoid 1/8" single-speed chainrings.
• Middle chainrings for a triple will have a recess for the chainring nut. Without that recess, the nut would stand proud of the chainring face and be likely to rub the chain when it's running on the inner ring.

You don't necessarily need the shifting aids and sculpted teeth on modern chainrings, but you can use those rings if you want ...so long as the BCD and number of bolts are correct. You mentioned modern Ultegra chainrings, but recent ones have an asymmetric 4-bolt pattern which won't fit your crankset.

Sugino sells reasonably-priced chainrings. Jenson USA is one of the vendors that carries 'em. Sugino specs the 46-tooth and larger as outer rings, while 44-tooth and under are listed as middle/inner.
Sugino Standard Chainring | Jenson USA

IslandTimePE

Thanks. For some reason, I was thinking it was 130 BCD.....which explains why I couldn't find any suitable rings when I was looking previously.

Unfortunately, very few local bike part sources in my neck of the woods so will look around online.

simmonsgc

I get it. I did 20 miles on gravel on my Two-Ten yesterday, and was 90% on the 36 middle ring. Just dropped to the granny for a couple of 'loaded' climbs before we stopped for lunch and boiled up some noodles. I also use the 46 on smooth flats. Up here in the Blue Ridge Mts, we have ancient 'dirt roads' that have been packed and ride like silent, smooth glass. My wife calls them 'velvet roads.'

You probably already know, but 34 is as small as you can go for a middle ring with the 110BCD.

Grab one like this, and you'll be in business.

simmonsgc

Yeah, I love this forum, too. I've often posted a question like yours, asking about the best way do to X on some specific bike. Usually, someone with THAT EXACT BIKE will chime in, and say..."look at this, here's what I did."

I've been on the receiving end a lot, so thanks for the chance to be on the other side for once!

fietsbob

110-74 crank, middle can be 34, innermost 24, outer 45,46 should be OK ..

bolt counter bore on the flipped over middle will be on the outside, as will be the scratches from the chain up shifting from your current 28t.

52telecaster

i love 110-74 bcd triples. they are so versatile. if it was mine i would put a 24 on th inside so that no hill is a problem. you could also do a half step in front for your 8 speed 11-32, if you use chainrings with an 8% difference in teeth the half step will work great.

bwilli88 

I would get a 48t ring and replace that 52t. Nice half step + granny.
check here for gear inches

Bicycle Gear Calculator

IslandTimePE

Thanks. As long as it functions well, I cal put up with the less than ideal looks.

IslandTimePE

Sorry, can you explain the half step concept a it more? That's a new term for me.

IslandTimePE

Thanks for the chart. I had been thinking mostly of overall total gear range. Hadn't really considered getting the gearing of the first and second ring to line up correctly.

SkyDog75

Half-step gearing, especially in the days of 5-cog freewheels, was a gearing setup that allowed riders to select finely-spaced gear ratios. In a half-step setup, you've got two chainrings on the crankset that are close in size to one another, like 47 and 49 teeth. The idea is that shifting from one chainring to the other on the crankset will give you roughly half the difference between adjacent cogs on the freewheel. For example, if you're on the small chainring and middle cog and want to upshift, shifting the rear would give you a 'full step'. Shifting the front instead would give you a 'half step'.

The up side is that you've ideally got 10 distinct but closely-spaced gear ratios on a 2x5 gearing setup, allowing you to find a 'just right' gear ratio. The down side is that shifting up or down from one gear ratio to the next involves shifting both the front and rear derailleurs. Another down side is that half-step gearing makes use of both chainrings across the entire freewheel, meaning you could be cross-chaining fairly often.

A common variation on half-step gearing is "half-step plus granny". Since the chainrings in half-step gearing are closely spaced, you won't have any extra-low climbing gears in a two-chainring half-step setup. Adding a smaller 'granny' chainring gives you those bail-out low gears. You can use the two larger chainrings to find cruising gears that are just right, then drop to the granny when you need help climbing a hill.

Half-step gearing has become much less popular in recent decades. With more and more cogs on the rear wheel, they can be more closely spaced to one another, negating the usefulness of closely-spaced chainrings up front.

clasher

I was using a sugino crank with 46/36/26 rings and an 11-28 9 speed out back, it worked well for me. The cassette was tight enough with the 9 speeds that I didn't need to use half-step gearing. I use the 46 for tailwinds and the odd hammerfest, and the 36 for riding into the wind, and the 26 for big hills. I like gear-calculator.com for playing around with ratios and such, you can compare your current setup to a hypothetical one before you buy your rings to see what changes will give you.

52telecaster

when you are using a 11-32 or 12-34 or even 11-34 8 speed cassette the individual sprokets average roughly being 15-20% apart step wise. if your front two chainrings are 7-8% apart you can have a half step between each rear cog.

in practice i generally just shift the rear derailleur for most commuting purposes, but if i am slogging thru a headwind for a long time i will fine tune with the front derailleur. to see what i mean i will post my gear ratios for a 12=34 8 speed cassette with 24-38-41

24 58.3 % 38 7.9 % 41>>>>>chainrings

12 54.0 85.5 92.3

16.7 %

14 46.3 73.3 79.1

14.3 %

16 40.5 64.1 69.2

12.5 %

18 36.0 57.0 61.5

16.7 %

21 30.9 48.9 52.7

14.3 %

24 27.0 42.8 46.1

16.7 %

28 23.1 36.6 39.5

21.4 %

34 19.1 30.2 32.6


the numbers are gear inches, the far left numbers are rear cogs.

IslandTimePE

Thanks. That makes perfect sense to me now.

IslandTimePE

I generally rear shift most of the time as well. I guess the relative usefulness of the half step setup versus more of a "maximizing total gear range" approach (for lack of a better term) would largely come down to the riding terrain? With more rapidly changing grades up and down, more likely to just stay on one ring and switch the rear. Versus using the front ring to fine tune effort on more consistent terrain/conditions like you mention re headwind.

IslandTimePE

+1 for gear-calculator.com (thanks bwill88 for introducing me to the tool). I just tried it with my potential 45/36/28 rings and 11-32 cassette. Doesn't look too bad. Would give me 2 extra high/low gears on the big/middle ring, plus a couple more on the low end with the granny 28. Could eventually drop down to a 26 or 24 for the granny if I need a bit more.