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Hi what is the correct freehub replacement part for Giant Defy 4 2013?

The bike is all original, 8s pg-850 cassette

thank you,

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  • Hi, welcome to bicycles. Are you specifically looking for the exact OEM part? For most bike parts simple mechanical compatibility is all that's required, but it looks like the SRAM PG850 is still available if that's important to you.
    – DavidW
    Jan 20 at 23:56
  • thanks, yes, hoping to replace the freehub with same part # for simplicity. If not the part should be compatible with pg850 cassette and Giant S-R2 wheel. this might do it: giantbikespares.com/product_detail.php?pid=3-41228 but only 2014 model is mentioned.
    – Jay
    Jan 21 at 0:15

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In my opinion, the act of replacing a freehub body on any given wheel--especially from older, generically branded hubs--is a ridiculous exercise in frustration. Knowing the brand or maker of the rear hub can go a long way to determining what's needed. The problem there is that many OEM hubs found on the vast majority of low to midrange priced bikes have zero identification markings on them. One cannot go by the brand of rim necessarily because any rim of appropriate size can be laced to a compatible hub. Said compatibility may simply be the correct number of spoke holes to match the holes in the rim.

While that would seem a bit of a tirade to the industry (it is) a larger point is that removing the current freehub is beneficial in a search for a replacement. This is due to the fact that what makes (for example) HG freehub bodies different and possibly incompatible is the method used to connect the body to the hub, the number and location of the pawls and their method of engagement (spring, magnetic, do they come from the hub and engage the body?, or do they come from the body and engage the hub?). There are also considerations as to the type of bearings (loose ball vs. cartridge) and axle size the hub is equipped to use (thru axle vs. solid axle vs. QR). These latter considerations can be determined with the freehub body still in place, but the meat of the information still lies hidden in the interface of the body to the hub and removal of the body is necessary to be certain what you're then looking for in a replacement.

How then does one remove the body? Well, that depends on the hub maker and their chosen design. (Are you feeling the frustration of the multitude of DIYers?) Take heart, we never give up that easy. A freehub body is secured by a right hand threaded bolt. This fixing bolt may be part of the hub or may be part of the freehub body or can be a separate, loose bolt that engages threads are either in the body or sometimes within the hub. Finally, many of today's freehubs are removable by hand when the end cap (end of a thru axle system) is removed by hand (where the thread engagement of the tru axle holds all together) or sometimes is threaded onto the inner axle and secures the hardware of the hub.

Removing the freehub body from your wheel will take a 10 or 12 millimeter hex wrench. The hex aspect should be long enough to engage the fixing bolt. It may be accessed by the hex wrench approaching the bolt from the right, drive side of the freehub. If you find you can't even begin to insert the 10 or 12mm hex from the right side, then access to the bolt is from the left, non-drive side. Either way the threads fixing the freehub body may be very tight. One trick would be to mount the hex wrench in a vise, then put the wheel on to the wrench and turn the rim around the wrench. Much more leverage. One caveat: you're dealing with a right hand threaded system (righty tightly, lefty loosey). The direction you turn the wrench to loosen the bolt is dependent on the direction you approached it from. If it's from the left, non drive side, you'll turn the wrench right, which from the hub body perspective is turning the threads left, loose.

Here's the most relevant aspect to your question. Thanks for listening. The Defy 4 from 2013 is specced with SLR-2 rims and has an 8 speed cassette on an 8,9, 10 speed HG (common, Shimano-style) freehub body. Utilizing a web-based tool from a Giant spares website one can muddle through the options to find either a direct replacement (for 8-10 speed road cassette OR a compatible--see above--11 speed freehub body if you want to be upgradeable. The 11s freehub body will work for your 8 speeds with the addition of a spacer which is typically provided with an 11s body). This freehub body is the one I would expect to be a direct replacement.

Again, I cannot emphasize enough that having the current body removed so it can be compared to a replacement option will save a headache later on. All this too is dependent on your bike still having the original, specced components, namely the SLR-2 rear wheel. The punt, of course is to take the entire rim to the shop and let them handle it.

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  • thanks Jeff, after more reading up I got the required tools (3/8 socket extension or 11mm allen) to remove the hub for a closer look.. And yeah, that part number - GDC102-301 - looks about right. loose bearing type etc Looks like will need bb's, cup and cone also. Thankfully there is a Giant shop in the area, so hopefully they'll have all the bits. Doesn't seem to be much to keep water out of these units. Basic maintenance is key with them obviously. Will report back on the outcome.
    – Jay
    Jan 23 at 23:25
  • @Jay I still like a loose ball hub and the satisfaction of a long spinning wheel after completing a hub overhaul. Regular maintenance--cleaning and fresh grease as little as once a year--increases the longevity exponentially. Shimano QR axle systems complete with cone nuts with attached seals, washers and lock nuts are available. They seem to seal the hub pretty well as the piece on the cone nut caps the center of a larger seal of metal and rubber that press fits around the inside perimeter of the hub covering the bearings. Happy trails!
    – Jeff
    Jan 24 at 10:13

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