This summer, for reasons too complex to explain right now, I may have to temporarily gear down from my normal 73 gear inches to 65 gear inches.

I normally ride with a 130mm BCD Stronglight crank and a biopace ring.

I haven't found a biopace or regular round chainring that will fit on my 130mm BCD crank and give me the 65 gear inches I want (using the EAI cogs I presently have).

This gives me a good excuse to get a Sugino 75 crank with the track normal 144mm BCD bolt pattern, and which will give me access to the 47t chainring I want.

With a 47t chainring and my two favorite EAI 17t and 19t cogs, I can easily go back and forth between my normal 73 gear inches and my temporarily necessary 65 gear inches.
And all prime numbers, too!

Now I have to choose between a black or conventional silver Sugino 75 crank.

It seemed like a no-brainer in favor of a conventional silvery crank, until I saw a black crank with a silver chainring on a bike over at Fixedgeargallery.
Mmmm-mm.
Tasty.

I think I'd like to go with the black Sugino 75 arms, now, with a silver ring.
However, before I lay out the money, I'd like to see some more examples of black arms and silver rings.

I'd appreciate some pictures or links to pictures of bikes with Sugino 75 crank arms, black and silver, but especially black arms with silver rings.

Thanks.

Buy the 75s if you want them, but TA makes a 1/8" 130bdc ring that comes in 47t if you want to go with your original plan. They are not all that hard to find, really.

I roll with that exact ring; a guy on ebay is selling them all the time.

so in order to prevent buying a single new cog you are going to buy a new crankset, a new chainring, bb? and abandon the biopace system you have been such a proponent of... hmmmmm

yeah dude get a ta or a sugino messenger ring

Black arms, silver chainring, entirely different context :

I want to stay with 3/32's and I want to branch out into 144mm without getting a new crank bearing.

A Sugino 75 with a JIS taper will work with my the Ti Phil crank bearing I use with my present crank arms.

I presently ride a 53t biopace.
I can only find a 52t and a 42t biopace ring in 130mm, and those don't make a lot of sense to me.

As for the cogs, I like prime numbers for no special reason other than personal preference.
17, 19, 43, 47, 53

I like those numbers.

I would really like to find a 43t 3/32's chainring, as that would let me go all the way down to 60 gear inches if I need to.

I really don't know what to expect, meaning, how far down I will need to go, or if I can even go low enough.

As I have mentioned before, I have flown helicopters for 38 years, and EMS helicopters for 24 of those years.
Sometime during the first half of my EMS flying, I got Hepatitis C, as did about half of my flight nurses, from the constant exposure to human blood.
We didn't wear gloves back in those days.
Nobody did.
We didn't know about Hepatitis C and AIDs.

Anyway, my "numbers" have gone up, and I may need to do a chemotherapy type of treatment beginning in the next month or so.
This treatment knocks about a third of the people who undergo it literally into the dirt.
I want to keep riding my bike, if I can, and I thought it would help if I could gear down.

I had my heart set on a 43t ring, which would have given me the options of 66 gear inches and and 60 year inches with the prime cogs I like.

I noted at www.businesscycles.com that John has a broad range of 3/32's Dura Ace rings that would fit on a Sugino 75 crank arm, so I thought I'd try a Sugino 75 and Dura Ace combo with a 47t ring.
With my 17 and 19t EAI cogs, that would give me 72 gear inches and 65 gear inches, which might see me through a low energy period and the let me bounce back up to my regular gear inches.

I like to experiment.

I like going back and forth between biopace and round rings.

I don't seem to have as big a choice of 3/32's chain rings in 130mm as I do in 144mm.

If it appears to dutret as though I have not thought this sufficiently through, I remain open to his advice.

Consider the prime number thing an idiosyncracy.
I like playing with numbers.
I like prime numbers and sevens.

I may have to settle for "boring" numbers, not prime and not sevens.

Thanks to Jim-Bob for the picture.
I like the look.

why would you do that when you have way more options in 130bcd ths coming from a guy with three 144bcd cranksets on different bikes

no offense, but you sound absolutely crazy ...

hope you get well, though.

also, unless i'm smoking crack 47*17 & 47*19 will be close to 70(~68/69ish) and 76?

Nope you're wrong Jody. check your favourite gi calc. (47t ring user here)

You can get sweet ass 130bcd Dura-Ace 3/32 chainrings from anywhere between 46 and 50 teeth. Hope your treatment is not too ****** Cox.

you can get rocket rings in 3/32 / 43t / 130

yeah but rockets flex your better off just going 1/8" up front and running an 1/8" chain trust me it will work fine

nah, i'm pretty sure my math was at least close (i originally estimated 68.something high and 76.something -- don't remember cause i did it quick on my comp calc.)

this chart backs it up...

76.2 & 68.2

You should have lots of choice of 3/32 rings with a 130bcd since that is the standard for Shimano road cranksets. Most of the choice in 144bcd will be older chainrings for the old campy standard and some track chainrings.

You might also want to look into TA chainrings that are designed as road inners - there should be a range of sizes (I would expect there would be a 43) and they are ramped or pinned for shifting.

I don't have any advice for you, but you have my good wishes concerning staying out of the dirt.

There are far more 3/32 chains in 130mm bcd then in 144mm ones.

Also you are clearly bat**** crazy and should see a psychiatrist.

i think he's like eighty, everyone needs a hobby (ocd)
it's cool

I don't think he is crazy, I just think he is looking for a reason to buy a new crank. I am all for Wu-Tang style numerology when it comes to selecting gears. TA also makes a 3/32" 47 ring, BTW. The idea that there is a wider selection of 3/32" rings for 144bdc is mistaken, however.

Really 130bdc rings in a wide range of sizes & quality levels are not all that hard to track down. I would be inclined to change the cog, though. It is easier to have a collection of cogs around to change your gearing. I have probably 4 that see regular rotation (15-18t), depending on the time of year and how I am feeling. It is nice to have that flexibility (plus I can buy 2 cogs for the cost of one chainring). I just pick a ring that will give me a good range of options (45t for me). That gives me a range of about 66-79 gear inches with 4 cogs I have.

I hope you get better, and I hope that when I'm your age I'm still riding and killin' it!!

where can one find this? I am actually with ken cox with the numbers thing i also like sevens and primes...

Don't hate, he's supportin' the scene.

Facing a life threatening "treatment" isn't always easy to cope with in ways that seem rational to other people.
Plus, if you got the money, it usually means you don't need much of a reason to buy sweet sweet bike ****. Which I will do as well when I have that money.

Until then,

Ken I could really use one of those Phil bottom brackets with Ti spindle.

68x109 mm english threading JIS tapered... please?

yeah i totally only run prime numbers on my bike too.

i occasionally run a multiple of seventeen if i can't find a prime that appeals to my aesthetic sense.

"wu tang style numerology"

definitely using that one.

Last time I looked, Harris Cyclery sells them. They are road rings, so I think that have the shift assist ramps (not that it matters much).

Link: https://sheldonbrown.com/harris/chainrings/130.html#47

Universal rings from Dan's Comp ($13.00) or Rocket Rings from Harris ($17.99) come in the sizes you need with dual drillings for 110 and 130 bolt patterns. A true working man's component, no frills, no ramps, a solid part that gets the job done for a reasonable price. Someone early said the Rocket Rings flex, but I don't know where they are coming from - the things are solid. I've used them for years.

They aren't fancy, but you can pull out a Sharpie and write NJS on them if you need to feel cool (but I doubt you're that kind of guy).