Retro Groupset Upgrade to something modern

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Joined: 28 Jun 2020, 10:14am

Retro Groupset Upgrade to something modern

Postby Iserlohner » 28 Jun 2020, 10:29am


I have a 2006 Giant XTC SX, yep 14 years old :D and I'm out in the Middle East so all parts have to be shipped in

I'm having problems with my LX Hollowtech II left hand crank, in short it keeps dropping off and spare parts are getting hard to come by

My thoughts we upgrade to a completely new Groupset, but I have a few questions

Bottom bracket Will that need to be changed?

Read wheel Freehub will that need to be changed?

Is this possible? Can you fit new parts into an old frame and wheels?

Is there another solution? My cranks have the old three chainrings, where as new groupsets only have the one, my rear cassette has 9 sprockets, whereas new ones 11 I believe

Any advice would be greatly appreciated

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Re: Retro Groupset Upgrade to something modern

Postby Brucey » 28 Jun 2020, 10:44am

If the rest of the bike is OK I would suggest that you just get another crankset. Plenty of choice of ones that will fit and work.

You can rebuild the bike with a different groupset but unless you have special requirements (eg you struggle with front shifts for some reason) it will (IMHO) mostly just be an expensive way of wasting your time.


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Joined: 26 Jun 2009, 8:21pm

Re: Retro Groupset Upgrade to something modern

Postby reohn2 » 28 Jun 2020, 11:03am

If the chainrings are in good condition with life left in them I'd be inclined to investigate why a crank arm is inclined to fall off.
If the correct torque settings are followed with a blob of thread lock on the two bolts on the left crank I can't see why there should be a problem,unless of course there are other complications.

You can of course replace the existing with a square taper 9sp (or even an 8sp will do,I'm currently running a couple of 8sp Alivio chainsets(cheap as chips on Ebay) with 9sp chains)and correct length(122.5mm) UN55 BB or a 9 or 10sp hollowtech II chainset and BB
I cycle therefore I am.

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Joined: 4 Jan 2012, 6:25pm

Re: Retro Groupset Upgrade to something modern

Postby Brucey » 28 Jun 2020, 4:57pm

FWIW in answer to some of your compatibility queries;

- shimano 11s HG type MTB cassettes (and all 10s HG type cassettes) will fit onto a 9s HG type hub. 11s HG type MTB cassettes all use 36T largest sprocket or bigger still.
- there are also two 11-34T 'road' 11s cassettes which fit these hubs
- Current chainsets can be sourced which fit into a standard BSC threaded frame (which is what I think you have)
- Current MTB rear derailleurs will fit onto your frame, but because your wheels are ~26" (vs ~29" in most modern MTBs) the RD will be ~1.5" closer to dragging along in the dirt than intended (which may be closer to the ground to start with because the large sprocket is larger). The RD has to be replaced for 10s or 11s because the shift ratios and capacities are different, and the RD will probably have an extra clutch in it too.

So if you did want to change to a newer groupset (1x11 or 2x10) you would need;

- cassette
- chain
- rear derailleur
- front derailleur (2x10 only)
- chainset
- bottom bracket
- shifters (and brake levers if they were originally integrated with one another)

Comparing a newer groupset with the present one;

On the plus side you might save a trivial amount of weight, not have to do as many (or any) front shifts, and no FD means no FD to get clogged up with dirt. You might get a slightly lower Q value.
On the minus side the gear range is less likely to be as wide and/or have gears with small intervals between them, the chain is probably more likely to unship from a 1x system, the gearing is less efficient in 1x form, chains tend to wear faster in a 1x system (esp if you use the extreme gears much) and all the consumable parts are more expensive than with a 3x9 system.

So it isn't the case that 'newer is better' in every respect, only some of them, and that is in the eye of the beholder. Also note that 11s is almost obsolete already; 12s is with us and that requires new hubs (meaning new wheels more or less) etc. So in two or three year's time 11s stuff you buy now will likely be NLA in exactly the same form, so you won't necessarily be any better off than you are with 3x9.