Drivetrain issues

Commuter247

I am noticing that the drivetrain on my Boardman Pro 29er is becoming less smooth, which is worse when under load.  All 20 gears operate perfectly without hesitation and shift well, and the chain moves freely without juddering or skipping.  I only use this bike for commuting 28 miles each day on the road.

I have thoroughly cleaned the Shimano Deore M510 free hub, Deore CS HG50 10 speed cassette, XT Shadow derailleur, rear wheel ball bearings and axle, Shimano XT chain set and KMC X10 chain including replacing the missing link.  I also had a new ‘Wheels Manufacturing’ bottom bracket fitted about a 1,000 miles ago to replace a poor push fit variety, and this has been running perfectly since.  I have checked the cleats on my shoes and the pedals and crank arms which appear to be solid.  The only thing I have noticed on a recent service, was that the 9th and 10th gear on the cassette were slightly loose.  I have since tightened the cassette with the lock ring, albeit with a great deal of force, and the last two cogs have remained tight.  I have never seen a Shimano free hub spacer on the hub, or do not know if it should have been fitted with one.

Any advice would be greatly appreciated, as it’s driving me insane

steve_sordy

I once had a Shimano cassette where the rivets holding the gear clusters together had failed. So, no matter how tightly you do up the cassette lock ring, they will remain unstable. This would be a warranty claim if the cassette is less than 2 years old.

Another alternative is a worn chain; when did you last check the chain for wear? Even if you don't have a chain checker (cheap to buy), you can still easily check the chain. Remove the chain and lay it on a flat surface. Measure 100 links. In an unworn chain they should measure 50 inches (100 links at half inch pitch). If they measure 50.375" (50-3/8") or more then it needs replacing. If it is much more, say 50.5" then the cassette may also be knackered. You could try a new chain to see if it runs with the cassette, but if it starts clanging and jumping, then the new chain is slipping on the old cassette and you need a new one. Put the old chain back on until you can replace the cassette.

02gf74

Commuter247 wrote:

I am noticing that the drivetrain on my Boardman Pro 29er is becoming less smooth, which is worse when under load. 

...
What exactly do you mean by that. Describe what is or isn't happening.

Commuter247

Thanks for the helpful replies.

I will check the chain tomorrow Steve. I thought there was a little movement between the cogs so I removed the cassette but the rivets do seem tight.

In reply to 02GF24, I can only describe it as a click or slight knock which is noticed through my shoes It does happen in every gear about twice each pedal cycle. It's not affecting the way the bike rides, but it is annoying.

I am happy to replace components, but as it could be many things I want to try and identify the affected part first.

Thanks for your help

Commuter247

Just measured the chain.

I am getting 50 1/8 inches

02gf74

If the click happens at same position of the pedal stroke it is bottom bracket, chainset/chain wheels or possibly pedals.

Mad_Malx

steve_sordy wrote:

I once had a Shimano cassette where the rivets holding the gear clusters together had failed. So, no matter how tightly you do up the cassette lock ring, they will remain unstable. This would be a warranty claim if the cassette is less than 2 years old.

All the rivets do is make it a bit quicker threading on the hub. They're held in place by the hub splines and lock ring. Most of the rings are single and some people drill the rivets out the clusters to make unusual spacing.

I’d be very surprised if anyone replaced a 6month old cassette (never mind 2 years) under warranty. It’s a consumable item.

steve_sordy

Mad_Malx wrote:

................

I’d be very surprised if anyone replaced a 6month old cassette (never mind 2 years) under warranty. It’s a consumable item.

Buy pretty much anything from Shimano from Chain Reaction Cycles and you get two years warranty. Chains, jockey wheels, cassettes, whatever....... CRC state it on each individual web page.

Yes, I agree it's a consumable item and I would not claim if it was normal wear, but the rivets failing on a cassette is not normal wear, in my opinion. It is the only time it has happened to me in over ten years.