Chain/ chainring advice

[SwissVan]

Mampara' date=' I like your pictures... They say a thousand words, but where can I get an "Imperial steel ruler that's longer than 12 inches."?[/quote']

 

Look up your local SNAP ON tool salesman, these guys sell steel inch rulers and other ?specialist tools" to the local aviation industry which still uses imperial measurements.

You might get a suprise  at the price though....<?: prefix = o ns = "urn:schemas-microsoft-com:office:office" />

Snap-on Africa (Pty) Ltd
6 Hippo Park
12 Kubu Avenue
Riverhorse Valley
Durban
South Africa
PO Box 40344
Red Hill 4071
South Africa
Ph: 27 (0) 31 569 7600
Fax: 27 (0) 31 569 6134
E-mail: enquiries@snapon.co.za

 

 

 

[madmarc]

Cut cut cut

 

1% rule seems extreme but consider 1% over the entire length of a 54 link chain (1 link = 1") this would be just over 1/2" or 13.716mm. With this amount of extra length would affect gear changing an the rear mech "B" screw would have to be set at max' date=' becuase your jockey pulleys would be bumping against the cluster when riding.

 

[/quote']

 

1% is not extreme, that's the design. Within that limit the chain does not damage the sprockets and none of the effects you describe happen.

 

 

One must also be carefull of LBS telling you to replace clusters and chainrings when replacing a chain. always inspect the profile of the teeth against a new gear before replacing. 9 times out of 10 ther is nothing wrong with the gears (LBS are simply trying to make money) when you consider the materials that clusters are made from (titanium and ST/ST) it will take many worn chains to wear out a cluster.

 

 

Inspecting the profile of the teeth will tell you nothing. The most sensible way is to simply keep on replacing the chain until eventually the new chain skips on the old cassette. Looking at the teeth will tell you nothing' date=' even if you are a dentist and used to profiles.

 

 

 

I recently changed my 9 spd cluster for a different ratio. The old one is approx. 5 years old and when comparing the tooth profile against the new cluster for wear there was absolutly no wear other than faint rubbing marks, so the 5 year old cluster is still in perfect condition.(But then again it is after all a Campag cluster) the chain was also replaced which when hung next to the new chain, the length had increased by approx. 1.2 links (just over 1%)

 

Telling us that your cluster is five years old and still good is meaningless. Cluster age isn't measured in years but in mileage, with hygiene and chain maintenance factored in. I don't have a unit for this but age it ain't.

 

My aunt Edna has a bicycle in her garage that's 40 years old and the tyres, chain and bearings are still perfect.

 

 

 

Mr. Boringman a worn gear will show on the profile of the gear tooth as well as the thickness. As a Mech Engineer i have a number of years fault finding and repairing bad chain drives on all types of machinary, almost all the faults i find are worn chains and in some instances worn sprockets as well, and inspecting and measuring the sprockets for wear is an exact science, not an assumtion we make when the chain is simply jumping.  BTW i thought we talking about gears here not your false teeth.

 

Furthermore if you are trying to tell us that an increase in chainlength of over 1/2" due to wear, will not affect the drive train, then i think we need to start a college fund for you to redo some of your engineering subjects, thats of course if you actually did any. 

 

My 5 year old cluster has approx. 6000km on it. and maybe someone should have taken the time to teach your dear old aunt Edna how to ride a bike instead of trying to teach you principals and practices of engineering. Because they clearly wasted their time

[Reg Lizard]

Popcorn anyone?

[Guest Big H]

What about the Rohloff tool to check cassette wear?????

 

 

 

[Johan Bornman]

Mr. Boringman a worn gear will show on the profile of the gear tooth as well as the thickness. As a Mech Engineer i have a number of years fault finding and repairing bad chain drives on all types of machinary' date=' almost all the faults i find are worn chains and in some instances worn sprockets as well, and inspecting and measuring the sprockets for wear is an exact science, not an assumtion we make when the chain is simply jumping.  BTW i thought we talking about gears here not your false teeth.

 

Furthermore if you are trying to tell us that an increase in chainlength of over 1/2" due to wear, will not affect the drive train, then i think we need to start a college fund for you to redo some of your engineering subjects, thats of course if you actually did any. 

 

My 5 year old cluster has approx. 6000km on it. and maybe someone should have taken the time to teach your dear old aunt Edna how to ride a bike instead of trying to teach you principals and practices of engineering. Because they clearly wasted their time

[/quote']

 

I dont find the "Borningman" moniker an insult. It's by now just plain boring and not very original.

 

Exact science? Perhaps you'd then like to explain to us what to look for so that we can all just look at the sprockets and declare them toast or terrific.

 

If you still find the 1% alarming, all I can say is just observe any worn chain and you'll notice that a 1 or 2% increase in length does not affect the drive chain. The jockey spring takes up the little bit of slack, unless of course the chain was just-just too long to start with and with the elongation it will rub  on the underside (Normally front side of a correctly-tensioned jockey).

 

I reiterate: the best way of testing for a worn sprocket is to put on a new chain and go for a ride. If it doesn't skip, the sprocket is fine and WILL NOT START to skip before the end of life of that chain. Also, being a driven sprocket, it will not deteriorate the life of the chain.

 

Now that you've volunteered your credentials and told us how many sprockets you've inspected in your life, how come you've never observed that titanium is not a great sprocket material? How is it that you've mistaken a shiny plated sprocket for a stainless steel one?

 

Many of us are waiting for your tips on spotting a worn sprocket with the naked eye.

 

 

[SwissVan]

 

JB - I agree with you 100%

 

Madmarc - Was wondering where the Mad in Madmarc comes from

 

Ive been riding bikes for fairly long now and follow the principal as described by JB (i.e. if its not f**ked broken dont fiddle with it).

 

 

[madmarc]

1st - i never indicated that by simply looking at a sprocket you could tell if it needed replacing - checking a used sprocket against a new sprocket will indicate how much it has worn and if it needs to be replaced. Comparing the tooth profile as well as thickness with the use of a vernier (i can send you a pic of a vernier if you need) against the new sprocket will give an accurate way of deciding to replace or re-use. This statement i made because many cyclists get conned by LBS into replacing sprockets when only the chain needs to be replaced.

 

2nd - WTF are you on about regarding the 1%/2% - i agreed with you on this statement and simply pointed out that many would assume 1% would be such a small amount of wear that it would not be noticed but when taken over the full length of the chain would equate to over 1/2". On a short cage this elongation would cause the jockey wheels to bump the big sprocket on the rear cluster.

 

You yourself made the statement that 1% change the chain & @ 2% the sprocket is toast. But now you say that even a 1 or 2% won't effect the drive train - are you having a senior moment!!!!!

 

3rd - i made the materials comment as an indication that in general sprocket matrerials on clusters were a lot tougher than they are given credit. I have re read my statement and i'm trying to find where it is i indicated that titanium was the best material for sprockets. If you want to include more BS just to add to the argument then stick to the statments made without adding to them in order to justify your point.

Furthemore i have seen, used and designed many St/St sprockets on applications for chain drives and do in fact know the difference between St/St & polished metal.

 

I find it strange that you would attack most of what i added to this thread as information from experience i have on drive trains. The topic originator can use it or not use it. In general i agree with what you say in your original post, but now you find it neccessary to challenge and attack this experience. You may also have many years of experience which i don't dispute or challenge. But please stop thinking that you are gods gift to bicycle repair, maintenance and design. There are many people out there that know the same or even more than you, if you can't accept that, then go get some therapy

[NotSoBigBen]

Enough waffling guys should I change the chain or the chainring

 

[linnega]

Enough waffling guys should I change the chain or the chainring

 

Clean it and then we'll let you know.

[NotSoBigBen]

I did ..........

[Tromps]

You have to replace your drive train. Your chain rings are worn to the point were it is impossible that your chain is still ok. If you replace your chain, boom, cluster too...

[brianj]

middle ring has to go, for sure... check chain separately.

Those are proper shark fins.

[Johan Bornman]

Enough waffling guys should I change the chain or the chainring

 

 

Change your degreaser, replace the middle chainring and measure the chain for wear. A shark fin profile like on that middle ring spells chainsuck and sooner rather than later, complete chainskip.

 

My gardner had a dikwiel once on which he came to work for me each day. One day he walked all the way from Wheeler's Farm to the other end of Walkerville where I lived. On asking him what's wrong with his bicycle, he said the bearings are shot.

 

"Why?" I asked. "How do you know?"

 

"It makes grrrr when I try to pedal."

 

"And that stop you from riding the bike?" I asked.

 

"Yes."

 

Eventually a friend with a car got his bike to me and I noticed that the grrr is from the chain skipping over the virtually smooth rear sprocket. Bearings were fine, or as fine as they get on an abused dikwiel.

 

To make a long story short, shortly your bike will have shot bearings. It'll go "Grrrr" when you try and pedal.

 

 

 

 

 

 

[NotSoBigBen]

[Johan Bornman]

You have to replace your drive train. Your chain rings are worn to the point were it is impossible that your chain is still ok. If you replace your chain' date=' boom, cluster too...[/quote']

 

Admit it. You work in a bike shop, don't you?

 

Why on earth would you want to change sprocket one and 3 when only 2 is worn?

 

Haven't you followed this thread? A worn chain does not necessarily mean the cluster is worn.

 

Edman used to have an avatar of someone banging his head on a brick wall. Please may I borrow it?

 

I have written a long piece on chain and sprocket mechanics. One day when I find my website password again I'll put it on there. It explains the difference between driven and driving sprockets, which worn components affects which good component etc etc. If anyone wants it, PM me and I'll e-mail it to you.

 

 

Johan Bornman2008-06-13 06:38:37

[Tromps]

Not arguing with that. Just stating for the record... There is a huge difference between Book Know how... and the real thing..