Worn drivetrain
 

Hi all

I know my drivetrain is worn, but not sure to what extent

I think you can see my jockey wheels are well passed their sell by date and definitely need replacing, as does my chain which has stretched more than 1/8” passed 12 inches. Which would imply that my cassette needs changing, but it’s not that old. Can anyone tell by looking at the photos if the cassette needs replacing aswell?
Adn the chainrings? The middle one looks knackered, but I wonder if I could get away with keeping the larger and smaller ones?
If I have to replace components, that’s fine, but not unnecessarily.

I couldn't attach photos as they were too large so here they are: http://www.thebreadcrumbtrail.org/ga...vel/Bike-parts

Thanks

I think that you have 2 choicces:

The first is to replace everything, chain, cassette, and crankset all at one time. The advantage of that is you get it all done at once and you get to work with clean new parts which is always more pleasant.

The other is to replace the chain, cassette and middle chainring and see how everything else works.

I recently replaced the chainrings on my most-used bike. The old one is on the left, the new one is on the right.

https://farm4.staticflickr.com/3676/...b3186c67_b.jpg

I would replace the the chain first and the 2nd cassette if you have the money. The secondary replacents would be the BB and then the chainrings no reason to replace a semi decent crank unless it has major issues.

Chain and pulley wheels for sure... cassette and chain rings might actually be OK. They don't look that bad to me, try a new chain and see what happens.

whoa... I think I could use that in my table saw!

It looks like you only ride in one gear... the cassette might be fine save for the small cog showing a fair bit more wear than the rest and the middle ring and jockey wheels should get replaced with the chain.

These chainrings are fine:

http://www.thebreadcrumbtrail.org/ga...g?m=1402916983

These jockey wheels are toast:

http://www.thebreadcrumbtrail.org/ga...g?m=1402917136

Some very practical advice. Thanks everyone. It's very frustrating when purists say that everything needs to be replaced at the exact correct time, and you can't go a little over the limits. Sure there the chainring like the table saw which is no good, but most people who work and live a busy life don't have time or money to forever maintain bikes at optimum performance. For most people, good enough is acceptable, so I really appreciate you guys taking that approach here.

The teeth on the jockey pulleys are pretty worn, but I don't know how much urgency there is to replacing them. They just get pulled around by the chain under low tension, and many early derailleurs had toothless pulleys. Wouldn't hurt to take them apart and clean/relube them, though!

You mentioned the cassette "isn't that old" -- it's a good idea to replace the chain right away when you install a new cassette. Otherwise, the worn chain will quickly wear the cassette to match its condition.

@Jeff Wills, how many miles on that 42T? :thumb:

5 years in all sorts of weather. It lasted through a couple chain changes. I think I let the chains go too long before changing them, too. :o

I'll add that since the harm is already done, and you cannot replace the chain without replacing other parts, you have a really simple decision now.

Ride it as is, if it still runs smoothly (reasonably), or replace the chain and at least the cassette, and probably the RD pulleys, and possibly but not necessarily the inner ring now.

If this were mine, I'd milk out all the "free" miles left before starting fresh, since it's to late to save anything. It's kind of like a 12 year old car with 200,000 miles on it. There's no resale value left, so it it runs you'll drive it until it's time to drive it to the junkyard, but not "invest" in any major repairs.

The RD pulleys could use replacing, but I've seen much worse. These are cheap, so if the rest of the drive is OK, you might spring for the small $$$ for those, and those only until it's time for the bigger purchases.

Some more great advice, thanks. yeah, well I work on a building site, hence me not bothering to replace anything, but now I'm parking the bike outside, and am sick of jumping gears, so I'm upgrading now the bike is out of the dust. So here's what I've done:

-Brand new jockey wheels and chain.
-Middle chain ring: I didn't realise this until I looked at brand new chainrings, but the middle one is not as square or rounded as thre large and small ones. The spikes are quite sharp, so I think my one has a little life still left in it. I was expecting it started life much squarer (if that makes sense). So I'll keep those for now

Having fitted the new chain, gears 1-4 on the cassette are fine, but 5-7 are jumping, probably because they are worn and I use them more than the others.

I could just replace the cassette, but I have 4 cassettes sitting in my shed. Most of which didn't get much life out of them (I have terrible post war mentality - waste not want not!!). Two of them, 8 speeds, the 8th gear cracked. But the rest of the cogs seemed ok

So I removed my 7 speed last night, and put on an 8 speed (with the 8th smallest cog missing).

I had to remove one spacer I had on the freehub, so the position may have shifted.

What's strange is that in 1st and 3rd chainring, all gears work fine, but in 2nd chainring, most the gears keep jumping


Terribly confusing I know!

here is the state of my 8 speed (now 7 speed) cassette:

20140813 083537
20140813 083549


If this is too much hassle, I'll just buy a new cassette

Thanks

So I ended up taking those 4 cassettes in my shed and dismantling them to make a franken-cassette with the best sprockets I had. Made no difference. And now I have noticed that the gears used with the small chainring are also skipping a bit, but no where near as much as middle chainring.

I would like to understand what is going on here. It's almost like, when the large chainring is used, the tension is greater and the chain sits in the teeth more firmly so it doesn't slip. In the small chainring, the tension is so low that it won't slip, and in the middle chainraing, it's just enough to make it slip. Dunno.

Long and short of it is (unless I'm missing something here), all my cassettes are too far gone in gears 5-7, and I need to replace it. And in future I need to change my chain more often.

Chainring selection makes very little difference in chain tension. The tension in the lower loop is set by the RD cage, and while there's a small change in tension as the cage angle changes, it's a very small difference. The tension in the upper loop is what drives the bike and is proportional to how hard you push the pedals.

You describe a bike with drive train wear, that slips under load. The slippage seems to be dependent on the chainring used, yet you refuse to consider that the chainrings themselves (middle an maybe small) may be worn also, and be the real cause of the problem.