bombicri

I have an old road bike, Dancelli, made in years' 80, with next equipment:
- shifters: Shimano Claris ST-2400, 2 x 8
- rear derailleur: Shimano Claris RD-2400
- freewheel: Ventura 8 speed (13/15/17/19/21/24/28/32)

After upgrading to 8 speed with Ventura freewheel the changing of speeds is not more accurate.
I aligned the rear derailleur hanger with a DIY tool very similar to ParkTool DAG-2.2.
I changed the chain (KMC Z8).
I aligned the wheel in drops measuring the distance between the two chainstays and wheel rim.
As the speed changing did not improved too much I thought that I have to verify if the freewheel is built in the way to fit Shimano shifters and derailleur.
I dismantled the sprockets from freewheel and I measured them as well as the spacers between them.
Results are presented in table "Original dimensions".

It is seen that the center-to-center sprocket distance is not 4,8 mm, as is recommanded.
So I decided to polish the spacers.
Results are presented in table "After First Spacer Polish".

Even if this new situation is more near the theoretical center-to-center sprocket distance the speed changing is not good enough, specially from sprocket 1 to sprocket 2.
If I tight the shifter cable to get good changing from 1 to 2 the other speeds are changing well but I have problems going back from 8 to 1, sometimes refuse to move down to next sprocket.
When I loose the shifters cable to get good changing up and down is most impossible to move up from 1 to 2.

After your experience please tell me if I have to go on with polishing the spacers to get exactly 4,8 mm center-to-center sprocket distance or I have to look some ware else.

Thanks.

Bike Gremlin

Options:

1) Get a freehub, instead of a freewheel. Either buying a new wheel, or lacing the current rim to a new hub. And a new 8 speed cassette.

2) Polish the spacers to get the correct spacing.

3) Make the shifter work with just 7 speeds, limiting the movement to the smallest sprocket with limit screws. Then, a click to go from 2nd to 1st will do nothing, because the RD would be stuck on the limit screw. Click back from 1st to 2nd will also do nothing - the RD will remain above the 2nd sprocket. The rest of the gears will probably work fine.

fietsbob

You have a different use of the term .. Standard 'pitch' for Bicycle chains is 1/2 inch..

Shimano tried to introduce a 1 CM pitch chain, but UCI ruled against it, so it went away.

the intended application was Pista - Track racing.

If I grasp the usage,, Above is where you go , Freehub..
Freewheels coming from separate sources will have an un avoidable Planar Wobble..

because the driver is part of the hub the sprockets all slide on and wont wobble in such a way .

I hated the last Sachs -Malliard Aris Freewheel.. adding the 8th speed was a folly to service
Because you needed to unscrew the last 3 cogs to remove It ..

but the 6& 7 speed ones were great.. and the removal tool was able to be gripped easily

staying wholly Shimano every thing was made to work together, so No lens grinding like polishing is needed.







./.

bombicri

@Slaninar
In Romanian language the word "slăninar" means a guy who is dealing with pork grease. I am curious if in Serbian language means the same ...
No, I do not want to change freewhell with freehub. I have on this bicycle nice and really thin Gian Robert hubs, I bought them two years ago being absolutely new, in original box.
I do not want to buy new wheel as my rims are Mavic MA2, made also around years '80, and they are in excellent status.
I do not want to reduce the capabilities of the bike from 8 speed to 7 speed, I want to make it work but for this I need some numerical information.

I want to know if 4,8 mm center-to-center sprocket distance is a critical distance and has to be very accurate.
I want to know if the center-to-center sprocket distance measured after first polishing and presented in table "After first spacer polish" is guilty for bad shifting, in other words if I shall make them exactly 4,8 then the shifting will be perfect?

@fietsbob
I do not understand which is the connection between "pitch" of chain and my problem. I am not using Shimano chain, it is KMC chain, I am not using a Shimano freewheel, it is a Ventura (which is calming that is compatible with Shimano products). Also my chain, KMC Z8 fit perfectly the freewheel and the chain rings. Terms are taken from https://en.wikibooks.org/wiki/Bicycl...ing_Dimensions, "TABLE FOR REAR SHIFTING ONLY", "Table 1: Cog-set Sprocket Pitch and Other Data by Size and Manufacturer".
As I already said, I do not want to change to freehub.
The Ventura freewheel has extremely low Planar Wobble, you have to be very attentive to notice it.
On another hand I could not find localy 8 speed freewheel made by Shimano. I agree that staying wholly Shimano all would be well but this is not a chance for me.
My question is very clear ... is so important to have exactly 4,8 mm distance between sprockets?
If I make it to be exactly 4,8 mm the shifting will become perfect?

fietsbob

pitch is used for speaking of the distance center to center of the pins of the chain,
in my language as applied to the subject, for the lst almost 70 years I've been around .
I dont know what it translates to from Romanian.


cricket pitch,. pitching horseshoes ..

good luck with your obsession with precision, might be overdoing it spending it on bicycles.

Or maybe the Campagnolo plant in your country needs Engineers ..

Andrew R Stewart 

The term "pitch' is the chain link pin to pin dimension. So the VAST majority of bicycle chains are of a 1/2" pitch. Now chain widths do vary from under 6mm to over 8mm wide to fit onto cogs with 1.6mm to 3.2mm thicknesses.


Indexed shifting is VERY dependent on the cog c-c dimension being both the correct one (for the shifter and rear der's spec)as well as being consistent across the entire cog set (freewheel or freehub). But other factors come into play too. (When indexing first came out in our life time [indexing is a very old idea but few people know it] Shimano claimed there were 17 design/dimensional aspects for a good working index system). Proper der cable clamping is a must as example. Andy.

bombicri

Thanks for clarifications.
Special thanks for very clear explanation are going to @fietsbob.

AlexCyclistRoch

"Polishing my spacers"? I'll have to use that phrase more often.

"Hey, what are you doing tonight?"

"Eh, sitting around, 'polishing my spacers'. You?"

bombicri

Thanks Alex, you are really good.

Andrew R Stewart 

Could be "Filing my centers" too. Equally lame activity to those who don't work on their own stuff. Andy.

Bike Gremlin

In the post I already told you what your options are. After reading this, it's clear the only option left is
2) polish spacers to get the appropriate cog pitch.

Sprocket pitch is a term used in some literature, though some use "center to center sprocket spacing".

Slaninar means a bacon eater, more than dealer, but it's a nick name for supporters of a football club from my city, Vojvodina Novi Sad.

bombicri

Yes @Slaninar, more or less is same meaning like in Romanian language. Even if Romanian is based on Latin language we have more than 20% words borrowed from slavish languages.
Which one are you from the three in the photo?
I shall make the spacers to give me 4,8 mm distance between cogs, it is obvious.
And when somebody will ask me ... "What are you doing, do you sit and polish your spacers?" ... I shall answer ... "I am just sitting" ... :-)
Thanks.

dabac

BITD when the industry transitioned from 7- to 8-speed, there were a few guys running mismatched drivetrains and claiming decent function. Even today some people mix Shimano and Campy parts and claim to be happy with the results.
With Shimano rear derailers, the sideways float of the top pulley makes the system forgive some amount of mismatch. I suggest you check yours.
Some aftermarket pulleys don't have that float, and sometimes top & bottom pulleys get swapped during service, which can influence function.

bombicri

I shall verify and clean the pulleys. Anyway the derailleur, Shimano Claris RD-2400, is brand new, was bought in spring and has only about 500 km. The pulleys were not changed.
Thanks @dabac for advise.

bombicri

Problem solved.
Thanks to all for good opinions and advises.
Back wind when pedaling!

fietsbob

The sideways wiggle of the top RD Guide pulley is an important part of Shimano's STI scheme ..

I makes up for imprecision in other portions of the whole Kit

Andrew R Stewart 

And what was the solution? Andy.

bombicri

The solution was correction of industrial product. The spacers where grinned to correct dimension, distance between cogs became in this way also correct.
This was the main reason of speed changing with hesitations.
Beside this I made also all verification recommended here, I cleaned and re-lubricate the derailleur even was enough clean, inclusive the two pulleys from cage, I changed the tube and cable which is coming from shifter.
It was not hard work, it took two days with maybe two work hours per day. It is a little dirty but I prefer to solve myself my bikes problems because I use to go in long rides (100 - 150 km) and I need some sureness.

Bike Gremlin

Top left.

Yes. "Sitting and thinking?"
- No, just sitting.

bombicri

@Slaninar, you are great ... you know the original joke ... nice.

davidad

Hello. My father was born in Pitesti in 1893. He left home in 1909 and finally ended up in Galveston, Texas in 1915.

bombicri

Nice to here this. Pitesti is a nice town now. There is the Renault factory and a lot of Pitesti inhabitants are working for Renault. So, @davidad, do you consider yourself being Romanian?

bradtx

Cristian, Most Americans are proud of their heritage. I'm 1/2 English and 1/2 Czech, FWIW. We have many different ethnic celebrations throughout the year representing most of the world's nations. Good times!

Brad

bombicri

Thank you @brad, I know enough well America (well, not really all America) and its inhabitants. And, in fact, what you are saying is pure normality. Also here, in Romania, are living different ethnics and they are proud of their roots. My question addressed to @davidad was just to provoke him to speak more about this feeling ... heritage ... roots ... .

Cristian

davidad

I am 1/2 Romanian on my father's side. On my mother's side it's more American. Her father was born on Naples and her mother was a German coonass from Louisiana.
My father's name was Demetrescu before he got here. Immigration gave him a more American sounding name that turns out to be Dutch. Sitting Bull was taken.
AS for me I consider myself to be American. We are the melting pot of the world even when we don't act like it.