Sugino crank help

[Cooker]

Hi all, I have a 1980's Sugino crank and it has 684 and 171 stamped on it.
The front chain wheels are a 52 and I think 48 or 49.
I think it's a Sugino Mighty but unsure.
I would like to change the small chain ring to a lower ratio then it's current high ratio of 48 or 49 to something around a 40 or 39.
I can't seem to find a wheel to buy, am I able to change the wheel?

http://m935.photobucket.com/albumview/a ... PxkQ%3D%3D

[HappyHumber]

Should be able to, unless it's an especially cheap Sugino with riveted/pressed rings.

Read up about BCDs and how to measure your crank and know which size chain ring to buy here

Seems a little odd that your existing chain rings are so close together in size - normally there's at least a 10 tooth difference. eg 52/42, 53/39 etc... etc. though this can depend on the age of the bike and the original ratio combinations with the rear cassette/cluster though.

[Cooker]

Any ideas on a website etc where I can find a chain ring?
The link in first post shows my bike with the crank.
Can't find any on eBay for my bcd.
It's quite large.

[HappyHumber]

chainreaction... wiggle... pbk.. "Specialites TA" as a brand have a good range of aftermarket 'rings.

It's not really the best photo for guaging by eye what you have. Odds are it's a 130mm.. or possibly if it's an older 70s road double maybe 144bcd. If the latter is the case.. you'll probably be limited to track chainrings in this day & age, which are meant for 1/8" chains - not multi-speed 3/32" geared set ups.

144 as a road (geared) BCD died out back when rear clusters were no more than 5 (or 6?) cogs at the back... but there are still a number of these 144 doubles (i.e. two chain ring) around.

[darkhorse75]

Just found these aftre a quick look, http://www.spacycles.co.uk/products.php?plid=m2b34s113p1744 , apparently 41t will require some filing of the crank spiders but 42t will fit fine.

[Cooker]

Awesome, thanks for that.

I've either got a 144 or 151 bcd.
I'll check tonight.

[Cooker]

My BCD is 151 aaaaah
I cant find an inner 44t chain ring for my bike.
Can anyone help out?
Thanks

[HappyHumber]

Spewin!

Probably just easier to swap your crankset for something more common.... Fish around on the market place.. should be able to get something suitable second hand.

[foo on patrol]

Can someone tell me how you work out the size of the chain rings please?? (not the teeth)

I have rings for the Sugino cranks from the 70s (2 sizes) and these used to fit campy, shimano and galli cranks from the era.

They changed the star size in the late 70s and I have the later crank size but still have some rings, from the earlier crank size but not the crank arms as I
sold these on a bike many moons ago.

Foo

[Cooker]

Yer measure your holes on the chain wheel as shown in the above link on post 3 I think.
If your holes measure 84.6 then it's 144bcd
If it's 88.7 then it's 151 bcd

[foo on patrol]

Thanks Cooker!

The later ones are 144 then and the earlier are 151.

Foo

[Cooker]

How many teeth are your 151 ones?
Lower then 48?
I might be interested to buy of you.
Cheers

[HappyHumber]

There's a limit to how small they can get depending on your BCD. I think the smallest 144bcds you can get are about 42/43 tooth ? (don't quote me) but it's a geometry limitation traded off with rigidity & strength.... so I'd wonder if you could ever get much lower than 48/49 on a 151 bcd.... let alone if can get one in this day & age.

The smaller the BCD, the lower the minimum tooth count. Physically there's no limit to the max tooth count (not taking into account frame clearances against the chainstays etc) but you lose rigidity as the crank spider gets smaller in relation to the larger chainring.

[HappyHumber]

I'd be dubious about buying an old second hand ring for any sum of money.... if you're heart is set on using your cranks, Cooker.... contact these guys, who do custom jobbies; www.cycleunderground.com.au or even Fyxomatosis (whom Cycleunderground apparently makes 'rings for)

[singlespeedscott]

Don't give up on your old 151 BCD Sugino's. Plenty of 3/32 151 rings come up on eBay. A small amount of wear is not a huge issue as these older rings are not ramped or pinned and generally have larger teeth meaning chain slip is not a big concern.

[foo on patrol]

How many teeth are your 151 ones?
Lower then 48?
I might be interested to buy of you.
Cheers

I am trying to find them at the moment Cooker as I have just moved house in the last couple of months!

When I locate them I will let you know the sizes.

Foo

[HappyHumber]

since I agree with singlespeedscott.. I'll correct myself.....

I'd be dubious about buying an old second hand ring for any LARGE sum of money....

no more than 25% or so the price of a new ring I reckon.... Entirely your call though

[Cooker]

Problem is, I need an inner ring.
My crank has 2 rings, 48/53.
I want an inner ring less then 48 and all the 151 rings I have found are for single speed that doesn't recquire changing gear.
Are yours inners?

[foo on patrol]

I ran 1/8 and 3/32 so as soon as I can find them I will let you Know!

Foo

[foo on patrol]

Sorry Cooker you've bumed out. The only 3/32 I have is 54t and my others are 1/8 including a Campy one.

I went to all 3/32 in the 144 and interchanged with my road bike.

Foo