FBinNY 

You're welcome, though I wish you'd mentioned the horizontal dropouts in the first place.

Since the chain wraps only halfway around a sprocket, and since the added length is divided between the upper and lower loops, each added tooth makes a difference of 1/8" in the rear wheel position. (1/2" /4)

Even the shortest horizontal dropout has plenty of room, and could probably accommodate more than 8 added or removes sprocket teeth.

bonsai171

I mentioned that the bike was a converted bike without track ends in post 420, but no worries. There is some room to go backward in the stay (away from the handlebars) though maybe not forward. Since the sum of the 45 + 17 and 44 + 18 gears is the same, it shouldn't move the rear wheel, right? Essentially i'm taking away a tooth in the front and adding one in the back. Not sure i can follow all of this, but worst case my lbs can bail me out if need be

Dave

Broctoon

Yes, it's as simple as that when you're figuring where the axle will end up in the frame for a given chain length.

FBinNY 

Yes, I knew it didn't have track ends, but for the last 20-30 years vertical dropouts were the norm, so I wasn't expecting older horizontal road dropouts, especially since you are worried about needing to move the wheel.

So, as I said, 1/8" per tooth + a smaller adjustment for the change in the angle of the chain based on the different sprocket diameters. To know what that may be consider a right triangle with one side being the distance between the rings, the other being the vertical difference equal to the change in sprocket radius, and the chain forming the hypotenuse. so you can solve based on the formula a*+b*=c* (* means squared, but I can't type that here).

Or you can solve this with a pencil sketch. Measure the distance between the sprockets (on center), and mark that off on a sheet of paper. Now draw a right angle and measure off the difference in sprocket radius. Now measure the new chain path connecting the two end points.

It'll quickly be evident that small differences in sprocket size won't make much difference.

epdarks

Been looking at Vigorelli's and I found this Red Hook Crit version... https://www.ebay.com/itm/Cinelli-VIG...m/372072058675


Obviously a bit more money than the regular bike but in doing searches I am not able to find much information on this version. I believe they were given to the winners of the 2015 Milano RHC race... are there really only 3-4 framesets in existence?? Cannot seem to find a duplicate of this color scheme other than one other that it is in London.


I tend to like all things rare and expensive... I feel like this one might hold it's value? Good buy, or stick to the regular version for ~$850?

REDMASTA

From the listing:

"Cinelli has been providing custom painted Vigorelli Track frames as first prize for the worlds premier track bike criterium since 2011 and you can own a replica of the frameset taken home by the 2015 RHC Milano Champion."

Apparently it's a limited-edition replica. Doesn't state how many are made but assume more than 3-4.

epdarks

Gotcha. I guess if Cinelli is making a "replica" of the bike given to the champion then I might be down. If it's some aftermarket paint job then obviously not. Would be nice to know the production numbers. Likely gonna pass. Thanks.

TimothyH

Ask yourself if you would pay $250 to have a regular Vigorelli painted that way.

I like the Italo colors way more but that's just me.

https://www.cinelli-usa.com/vigorell...set-new-italo/

phobus

Those look more like Belgio colors to me.

epdarks

I sent the seller a message about the bike and this is what I got back:

"Hi Dan,

This is a replica of the 2015 RHC Milano frame produced by Cinelli, manufactured and painted by Cinelli.
We do not have any information as to how many of these were produced."



So that is somewhat encouraging and also discouraging that they don't release the production numbers. Can't be many cause I still can't find any online.

Carcosa

The Caleido was the best Vigorelli paint scheme.

But if that one is legit, you dig it and have the money, go for it.

Scrodzilla

Corrected that for you.

Carcosa

Well I think we can agree on the best two at least.

bonsai171

If I ride a 42x17 gear combo on a road bike, and the same on a fixed gear bike, would the gear inches be equivalent? In other words, would the derailleur on the geared bike affect the gear inches?

Dave

FBinNY 

No, it's on the chain's return loop. Everything power related is about the upper loop and the sprockets.

Scrodzilla

Gear inches = how many inches your bike will roll per full revolution of the crank.

42x17 is 42x17 regardless of which type of bike it's on if the wheels on both bikes are the same diameter. Different tire sizes will change it a very tiny bit though.

SquidPuppet

No. Wheel and tire size do, though.

AlmostTrick

That's what I once thought too, but it is incorrect. The bike will travel much farther with one crank revolution than the gear inch number. Go measure for yourself. Gear inch is a reference to what a particular wheel/chainring/cog combination would be equal to on a 1 to 1 driven fixed wheel... like the original "ordinary's".

bonsai171

That's what I was hoping. Going to try some gear combos on my geared bike and then buy the same ratio for the fixed bike. Thanks!

Dave

SquidPuppet

I had to look that up. Seems that what we commonly (incorrectly) believed "gear inches" to be, is actually "Meters of Development" or "Rollout".

A bike set up with 70 gear inches will actually roll 220 inches (5.6 meters) for each full crank revolution.

The same distance as a Penny farthing with a 70 inch wheel.

What an antiquated system we've remained attached to, for well over a hundred years. Crazy.

Fahrenheit531 

Made the same discovery re: gear inches not too long ago.
It's our own little bizarro-retro measurement system with zero practical reference in the real world. I'd call that a win.

Scrodzilla

I only ride a pogo stick so I was just taking a stab in the dark.

Carcosa

Well, we appreciate you hopping to it.

Bandera

GI is the gearing-speak of the sport putting any chainring/cog/wheel/tire combo into a single numeric value.
Trackies speak in GI and optimize gearing for training as well as each event and log times/cadence/gearing.
A Masters Worlds competitor was discussing training and refereed to warm-ups in 82 GI and efforts in 90 GI, what the chainring/cog/wheel/tire combo was is irrelevant.
Speaking in GI may be arcane and traditional but it is clear, concise and easy.

50 X 16 or 47 X 15, which is a "bigger gear" on 700 x 23?
Both 82 GI

-Bandera

FBinNY 

Whether we use the US/British gear inches (diameter) or the European development or rollout (circumference), it's a very practical way of thinking because it makes direct comparison of bikes with different wheel sizes possible.

Historically both date back to when highwheeler pedals were attached directly to the wheel, like a modern child's trike, and if you wanted to go faster you got a bigger wheel (up to the limits imposed by your leg length).

So while many consider this way to think of gearing a relic, it remains the most practical way to predict speed and climbing capability.