Renewing Drivetrain

[colinr]

I'm looking to replace my drivetrain due to the chainrings looking like a pool of sharks, but there are too many options. Please help!

Currently running Tiagra Double (9 speed) and plan to keep the same set up.

I know I need a 9 speed cassette, does it have to be Tiagra or would any Shimano 9 speed be ok?

Same for chainrings? I'm assuming it's 130mm PCD so mix and match any two teeth counts, or do I have to stick to certain things?

Chains, again can I stick any 9 speed on? I see Shimano chains mostly called HGxx, what do the numbers mean?

Finally, is it worth changing front/rear/both derailleur as well or do they not wear so much?



This is why I ride fixed most of the time. I don't need to know about so many parts

 

[byegad]

Its the bolt diameter that matters. As for teeth numbers you can tinker so long as you don't go too far.

 

[Cubist]

Any 9 spd cassette as long as the number of teeth don't exceed what the rear mech cage can handle. (so if you run a narrow range cassette now, say 12-25 or so, your short cage rear mech won't handle an 11-32)


Chains? Shimano chains increase in cost as the first number increases. HG53 is basic-ish (Deore), HG73 (SLX) is Middle of the road, HG93 (XT) is lightweight then there's Dura Ace/XTR high-end. Get them from chain reaction and you'll save a fortune over the RRP. (£14, £16,£20, £25 respectively)

However, Shimano chains use a spare pin link set which is a complete faff and has been known to fail . Get the equivalent SRAM chain, it'll be more durable with a powerlink connector included in the packaging.

SRAM chains are notated SRAM PC951, 961,971,981,991 again in ascending order of "quality", starting off at about 15 quid from CRC


When swapping out chainrings be sure that the bolts fittings are compatible. I had a truvativ chainring which someone said was compatible with shimano. It wasn't, the bolt lugs are stepped and faced differently, despite having identical PCDs, so they didn't fit on the spider.

The rear mech is unlikely to be knackered, but if the front chainring is looking sharky, treat your rear mech to some new jockey wheels. Front will be fine by the sound of things.

 

[colinr]

Thanks, that all sounds straightforward enough.

 

[mickle]

...and in future replace your chain long before it wrecks everything else. Chains are consumables.


If you replace your chain regularly your cassette will last for years and chainrings go on indefinitely.

 

[colinr]

I've learned this the hard way. Unfortunately in this case the bike was second hand so the damage had already started, figured I'd just wear it out and replace the lost.

 

[RecordAceFromNew]

To add to others' comments above, your front mech will have limits on the tooth count of and tooth difference between the chainrings. You might also want to check whether your existing rear mech (find out whether it is short or medium cage) will handle the new cassette (Shimano or sram) and chainrings if you are going to change their tooth ranges. You can look up the limits in manufacturer specs, or provide the info of existing to check here before ordering

 

[gannet]

...and in future replace your chain long before it wrecks everything else. Chains are consumables.


If you replace your chain regularly your cassette will last for years and chainrings go on indefinitely.

at what point should you replace your chains to avoid cassette damage?

maybe I have been unlucky in that I just replaced a chain at 0.75% stretch after 1200 miles (or so)... new chain kept skipping over two of the rear sprockets with a new cassette all is well again...

 

[Maz]

When swapping out chainrings be sure that the bolts fittings are compatible.

When you buy a chainring, do any bolts come with it, or do you just use the existing bolts on the bike?

 

[Cubist]

When you buy a chainring, do any bolts come with it, or do you just use the existing bolts on the bike?

Use the ones on the bike, or treat yourself to some bling off the 'bay
http://cgi.ebay.co.u...=item746adbc4a8

 

[colinr]

The cassette is either 23-25 or 12-23 (I counted and forgot) but looking closely at it, the teeth look pretty fresh as does the jockey wheel. Inner chainring looks ok too, hat tip to the previous owner for living in the big ring.

 

[colinr]

Right, before I make a cock up, is this a suitable replacement for an 9 speed outer chainring that says "Shimano SG 52-B" on it?

Looks like it should be, but doesn't specify A or B type. Maybe Tiagra doesn't have A/B?

 

[mickle]

'A' and 'B' refers to chainrings for double or for triple set-ups. (I can't remember which one is which!) It's to do with the existence and location of shift ramps. A 42t ring intended for a triple chainset has ramps to ease the chain up from the granny, a 42t ring for a double set doesn't.

 

[colinr]

It says it's for a 9 speed double setup, I'm sure it'll be fine, shall order it.
(I'm running a double setup, so guess B is for doubles)

 

[mickle]

It says it's for a 9 speed double setup, I'm sure it'll be fine, shall order it.
(I'm running a double setup, so guess B is for doubles)

innit