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Compatibility [03] Rear hubs

Updated: 01/04/2021.

Note: this article explains compatibility in terms of rear sprocket mounting and proper gear shifting. For other important facts about rear hubs, read the following articles:
Rear hub
Freewheel vs Freehub

Before you start, to avoid any misunderstanding:
please take the 5 minutes needed to read the compatibility articles use instructions.

Compatibility categories will be sorted by number of rear sprockets. It is important to note that there are three major rear freehub standards – a) Shimano standard supported by most other manufacturers (SRAM as the biggest one), b) Campagnolo standard and c) SRAM XD standard that accepts cassettes with the smallest sprocket of only 10 teeth.

Campagnolo uses different spline design, so Campagnolo cassettes can only fit Campagnolo freehubs, while Shimano cassettes will only fit Shimano compatible freehubs.


a) SHIMANO standard

Stated compatibilities also go for SRAM (and most other manufacturers’) cassettes with the same numbers of sprockets – they’re compatible with Shimano, except the SRAM XD cassettes.


6 and 7 speeds, freewheel

All the current (since the year 1990) freewheel hubs are compatible with all the 6 and 7 speed freewheel sprockets.

Freewheel rear hub with threads, and freewheel sprockets that are screwed onto it.
Freewheel rear hub with threads,
and freewheel sprockets that are screwed onto it.


7 speed freehub

7 speed freehubs accept 7 speed cassettes.

Cassettes with more sprockets can also be fitted onto 7 speed freehubs, but some sprockets need to be removed. The smallest sprocket must never be removed since it is profiled to accept the lockring holding the cassette in place. When removing sprockets, if it is not the largest one, expect shifting between the two adjacent sprockets left to be a bit sluggish, since sprocket teeth are profiled to allow faster shifting, but removing one sprocket messes up that pattern.

8, 9 and 10 speed cassettes can be used if one sprocket is removed.

11 speed MTB cassette should also fit with just one sprocket removed, but here, along with the smallest, the biggest sprocket also mustn’t be removed – it is specially designed to take up less space on the freehub body.

11 speed road cassette – two sprockets need to be removed. Unlike with 11 speed MTB, here the biggest sprocket can be removed.


8-9-10 speed freehub

It accepts all the cassettes, except 11  speed road ones.

When placing a 7 speed cassette on such freehub, a 4.5 mm spacer needs to be placed before the cassette. Then check if the smallest sprocket engages the freehub splines. If it doesn’t, check if the largest sprocket has gotten over the spacer correctly (the spacer mustn’t be too “tall”). If this doesn’t help, try using a bit narrower spacer, to make sure the smallest sprocket is slit onto the splines properly.

This is important whenever mounting the cassette: smallest sprocket should engage the freehub splines, so it doesn’t turn freely, but it mustn’t be aligned with the freehub body all the way – it should be a bit “taller”. Otherwise lockring won’t be able to lock the cassette in place. If the last sprocket sits too deep, add a (thicker) spacer. If it turns freely, remove a spacer (or one sprocket, if there are no spacers used).


Pictures above don’t show a case when there are too many spacers (or they are too thick) – then the last sprocket would not be able to sit on the freehub splines properly.

8 and 9 speed cassettes are placed directly, without any spacers (9 speed cassette has narrower and more tightly spaced sprockets, so it has the same overall width as an 8 speed cassette).

10 speed cassettes have even narrower, more tightly spaced sprockets, so their overall width is actually smaller than that of 8 and 9 speed cassettes. That is why placing a 10 speed cassette on a 8, 9 and 10 speed freehub requires a 1 mm wide spacer.

11 speed MTB cassette is put straight on, just like 8 and 9 speed ones.

11 speed road cassette doesn’t fit this freehub. One sprocket needs to be removed (not the smallest one because of the lockring). Then a 1 mm spacer needs to be put before the cassette (do check alignment and put a thicker spacer, or remove the spacer if it all fits).

I demonstrated how to check whether spacers are just a bit too thick, or narrow in this video (watch until the end).


10 speed freehub

Shimano also used to produce special 10 speed only freehubs for a while, which are a few mm narrower than 8 and 9 speed freehubs. Only 10 speed cassettes can fit these freehubs. 10 speed cassettes are mounted onto these freehubs without any additional spacers. There are also 10 speed freehubs with aluminium body. Splines are taller, so that more material comes in contact with (narrower) 10 speed sprockets so they don’t cut into the freehub body under load. These hubs can not fit 7, 8, or 9 speed cassettes because of taller splines.

Shimano Dura-Ace 7800 "10 speed only" rear hub, with an arrow showing the "higher" spline section
Shimano Dura-Ace 7800 “10 speed only” rear hub, with an arrow showing the “higher” spline section
Source: VÉLO7 – veloseven.com


Another “catch” is that the newest 10 speed cassettes, Shimano Tiagra 4700 model, won’t fit these freehubs, because they are not cut deep enough for the taller splines. Just to make things more interesting. 🙂

In practice, when a term “10 speed freehub” is used, it is usually meant the 8 and 9 speed compatible one, not the exotic 10 speed only Shimano stuff!


11 speed road freehub

Since MTB 11 speed cassettes can be mounted on the 8, 9 and 10 speed compatible freehub, this one is meant for road 11 speed cassettes only.

8 and 9 speed cassettes can be used with a 1.8 mm wide spacer. Same goes for 11 speed MTB cassettes (thanks to Cristophe for the feedback).

10 speed cassette requires an additional 1 mm wide spacer (along with the 1.8 mm wide one) – just like when putting a 10 speed cassette on a 8-9-10 speed freehub.

7 speed cassette will require 4.5 mm spacer, in addition to a 1.8 mm wide one (used when mounting 8 and 9 speed cassettes).


11 and 12 speed MTB XTR M9100 freehub

From summer of 2018, new standard, completely different from all the others. Freehub splines and cassettes are mounted differently and can’t be combined with other standards.


New cassette teeth design is called Hyperglide+, while the new mounting interface is called “Micro Spline“. It has 23 deeper splines, where Hyperglide has 13. Detailed explanation is at the following links: Hyperglide+ freehub and Hyperglide+ cassette.


b) Campagnolo standard

Campagnolo hubs are compatible with Campagnolo cassettes only. Even there, they have different standards, by generations and by numbers of speeds, like it is explained here:


7 and 8 speed freehub – old standard

7 speed freehub is about 5 mm narrower, but all the old 7 and 8 speed cassettes will fit both 7 and 8 speed freehubs.


8 speed Exa-Drive freehub

Current Campagnolo 8 speed standard. There is also a discontinued 8 speed standard for titanium cassettes, that are no longer produced.

Old Campagnolo 7 and 8 speed standard.
Old Campagnolo 7 and 8 speed standard.
Ridge at 12 o'clock is wider, to ensure proper sprocket orientation when mounting them onto the freehub.
Current, Exa-Drive 8 speed standard. Ridge at 12 o’clock is wider, to ensure proper sprocket orientation when mounting them onto the freehub.
Obsolete Campagnolo standard for 8 speed titanium Exa-Drive cassettes. Ridges are wider at 5 and 7 o'clock, to ensure proper sprocket orientation when mounting.
Obsolete Campagnolo standard for 8 speed titanium Exa-Drive cassettes. Ridges are wider at 5 and 7 o’clock, to ensure proper sprocket orientation when mounting.


9 speed freehub – old standard

Standard for old, Exa-Drive 9 speed cassettes.

Old 9 speed Campagnolo Exa-Drive standard. Wide ridge at 5 o'clock and a stepped ridge at 7 o'clock.
Old 9 speed Campagnolo Exa-Drive standard.
Wide ridge at 5 o’clock and a stepped ridge at 7 o’clock.


9-10-11-12 speed freehub – current standard

Current Campagnolo standard – suitable for all the modern Ultra-Drive cassettes, whether they are 9, 10, or 11 speed (12 speed as well from 2018).

Left: Shimano cassette freehub Right: Campagnolo Ultra-Drive cassette freehub Source: www.eqnx.co
Left: Shimano cassette freehub
Right: Campagnolo Ultra-Drive cassette freehub
Source: www.eqnx.co


c) (SRAM) XD 10, 11 and 12 speed MTB standard and 11 speed road

Cassette carrier (freehub) has been redesigned and accepts cassettes with the smallest sprocket of only 10 teeth!

Left: XD freehub. Right: Shimano hyperglide compatible freehub.
Left: XD freehub.
Right: Shimano hyperglide compatible freehub.


XD freehub standard accepts only XD cassettes. There are 10, 11 and 12 speed cassette versions (same  XD freehub body).

Many wheel and hub manufacturers make XD compatible freehub bodies that can be screwed onto the hub instead of the old Shimano compatible freehub. Unfortunately, as far as I know, Shimano is not among them for now.

As of mid-2018, SRAM has introduced NX Eagle groupset, that includes 12 speed cassettes compatible with Shimano (and SRAM) standard freehubs (for 8, 9, or 10 speed cassettes). However, they don’t allow for the smallest sprocket to be smaller than 11 teeth.

SRAM have also made an XD road freehub, named XDR (XD Road), that is wider by 1.85 mm than the XD freehub.

Related post – Bicycle cassette compatibility:

Compatibility of bicycle cassettes (rear sprockets) - which shifters and derailleurs can they be combined with
Compatibility of bicycle cassettes (rear sprockets) – which shifters and derailleurs can they be combined with


Compatibility posts are also available in eBook (printable and Kindle) and paperback editions on Amazon:

Bicycle drivetrain compatibility book
Bicycle drivetrain compatibility book
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23 thoughts on “Compatibility [03] Rear hubs”

    • Wrote it for myself – too many stuff change, wanted it all in one place to remind myself when I need it. 😀 Glad you find it useful too. 🙂

    • Yes. A Shimano 11 speed road cassette is about 1.8 mm wider than a 10 speed cassette.

      Just to note that for 10 speed cassettes – there’s no difference between road and MTB ones: same width, pitch and sprocket thickness.

  1. I have formula hub 142×12 with non anti bite guard freehub feature. Now I want to replace it with different manufacturer Freehub Body but same measurement 142×12. Is it compatible?

    Reply
    • That would depend on the profile of the freehub part that gets onto the hub. These things differ from model to model for all I know.
      So do check, compare, but it’s not just the axle and width, but also the number of ratchets and the shape of the part going towards the hub.

      Not sure if I’ve explained properly, let me know if You need pictures and more clarification.

  2. According to Campagnolo, yes. That is – 10 speed wheel could fit a 12 speed cassette according to Campy docs.

    11 speed Campagnolo cassettes fit 9 and 10 speed Campagnolo freehubs. Source:

    https://www.campagnolo.com/US/en/Support/can_an_11s_sprocket_set_be_mounted_on_a_campagnolo_9_10s_compatible_wheel

    While 12 speed cassette takes the same space as 11 speed one. Source:
    https://www.campagnolo.com/US/en/Components/super_record_sprockets

    I haven’t tried this, not even seen a 12 speed Campy live yet, unfortunately.

    Reply
    • I don’t know.

      Will edit the text though. I think I see where the confusion was.
      The body is the same, for any XD cassette used. No different body widths.

  3. Thanks, this is a really helpful article. Sheldon Brown’s compatibility webpage is also helpful, though it is mostly text and a picture can help a lot.

    –> question about free hub bodies. There are several shimano hub bodies in the 8-9-10 family available at numerous retailers and I can’t figure out which one to buy. I am trying to mount on an older deore XXT mtn hub to convert it from 6-7 to 8-9-10. The older hub never shows up in the listings online. I tried to use a freehub I had and I would say it puts the largest cog perilously close to the spokes coming out of the flange. I could make a thin shim, but I was wondering if there is any documentation available that characterizes the width of the free hub drivers from the hub seat to where the cogs start? Or an overall width dimension so I can subtract off the cog region?

    Thanks

    Reply
    • For all I know, Shimano freehub body width comes in several dimensions (sorted from narrowest to the widest/longest):
      7 speed
      10 speed only (sold/made for a relatively short period)
      8-9-10 (any) – 11 (MTB only) speed
      11 speed road

      So old 7 speed freehub will be too narrow to accept 8, 9… speed cassettes. The main concern being the lockring not having enough threads to get properly threaded and engaged.
      Though I never tried replacing a 7 speed freehub mechanism with an 8-9-10 one, on a 7 speed hub. It is possible that the flanges are put too close for the 8-9-10… speed cassettes to clear the spokes. But I can’t confirm that.

      I can’t figure from the comment what exact model of hub you have, which replacement freehub body you are considering placing on it and which cassette is to be tried on. That info might help.

  4. It’s a deore XT FH-M732 mtn hub, 135mm axle. I am indeed trying to put an 8/9/10 body on this hub. Based on the flanges, which are approximately 60mm apart, I think it should be close. There is a lot of room with a 7 sp cassette. I may need a small shim under the free hub, depending though. Wish I could find drawings with measurements for the free hubs shimano makes today – there appear to be 3-4 different shapes with slightly different offsets from the mounting face.

    Reply
    • A few notes, just in case:
      When adding a wider freehub body, hub’s OLD will change. Solution would be making the left hand side spacing a bit narrower (replacing a wide spacer with a narrower one helps).

      Don’t have the measurements of freehub widths – but will measure when I find the time (adding this to to-do list).

      Likewise, I also think that freehub attachment profile/standards differ between models, not all will fit all, even “within” the Shimano brand.

      As for the spacers, with an 8-9-10 speed freehub, only if using a 10 speed cassette, a spacer must be added (1mm wide, often provided with the cassette). 8 and 9 speed cassettes don’t need any spacers. There’s definitely no room to add them with those cassettes, even if one wants to.

  5. Hey,
    Excellent article ! So useful !!!

    Will also be super useful to have a measurement of freehub. I am helping in a bicycle workshop and we have a box of freehubs but always take some time to figure out what models they are.

    Just to add that it is not clear that you can use a 11s speed MTB cassette on the 11 speed ROAD freehub with à 1.8 mm spacer.

    Thanks for the great work !

    Reply
    • Hi,

      Thank you very much for the feedback. I’ve edited the article to be more clear now. 🙂
      As for the measurements, I have made a hub dimension spreadsheet, noting the dimensions important for wheelbuilding.
      Do you think any other dimensions should be included?

  6. Yes

    Size of freehub : (From kstoerz website)
    7s freehub – 30.9 mm
    8-9-10s (and 11s MTB) freehub – 34.95 mm
    10s only freehub – ?
    11s freehub ROAD – 36.75 mm

    Otherwise I use this website for hub size. And calculate with Roger Musson like you do.
    https://www.kstoerz.com/freespoke/

    Reply
  7. Useful page! I am stuck with a Trek Marlin 7speed and trying to figure out if I can improve it or if I should just get a new bike. I was short sighted and changed to 1x in front, and now I live somewhere with more hills and wish I had lower gears. I had heard about the “8 of 9” or “9 of 10” method where you could supposedly fit other cassettes on this 7 speed hub. Your page here helped me understand it even a little better (I think). This is the first place that I heard the key information that you can’t just remove the smallest gear – I had assumed that would be the easiest way to do it! This leaves me wondering, how many other choices do you have though for other gears to leave off? How often does a cassette come with more than the smallest gear not completely attached to the cassette? Or in the case of wanting to remove the largest gear (aside from 11 speed where you should not), how would you ever take off the large gear? Aren’t these usually riveted together? Of course I am speaking of lower-end budget components; I have seen that a higher end cassette can come apart in many more pieces. Basically if I wanted to find an 8, 9, or 10 speed casette to use, but the rule is that you can’t just leave off the smallest gear, do I need to make sure it has the second smallest gear as a separate piece? I wouldn’t want to remove the larger gears anyway since that is where I am looking for extra range.

    My choices are to fit something on the 7 speed hub, buy a new rear wheel that has a hub for 8/9/10, or just start thinking about my next bike. (I’ve read conflicting information about just trying to get a longer hub body on the original wheel, seems like you shouldn’t really do that as the wheel dish isn’t correct etc). I’d like to keep the 1x up front so I’m not considering going back to a front derailleur.

    Reply
    • Hi,

      There are several solutions to this gearing problem. I’ll number them for easier reference in case of any follow-up questions:

      1) Custom cassette.
      Some cassettes have the largest sprocket go all the way to the freehub. While others have the largest 3, or more sprockets stuck together on a spider.
      For the former ones, you can drill out the pins, rivets, or unscrew the bolts – whatever is holding the sprockets together – and use the sprockets “separately,” as you please (just don’t forget to put a spacer between every two sprockets 🙂 ).

      My road bicycle has 53-42 cranks, so I just took an un-worn 34-tooth sprocket from an 8-speed cassette and put it first on the freehub, to allow me climbing long, steep climbs. It took place of a 25 tooth sprocket. The next, 23-toothed sprocket got replaced by a 28-toothed one, to make the gap a bit smaller and allow shifting. Most of the cassette is “edited” to make it “slower / easier,” but without such huge gaps on the “faster end” of the cassette. For the smallest sprocket, I went with a 12-toothed one (that’s the largest readily available) and used a matching locknut for a 12-T sprocket.

      Here’s a video, in my native (Serbo-Croatian) – you can play some music and just watch what I’m doing 🙂 (I’ll make a video in English once I find the time):
      disassembling a cassette – Serbo-Croatian version
      – You can use Google translate for the video description, because it contains a Table Of Contents, so you can skip to the parts of interest, not have to sit through the whole video.

      Lower end cassettes, especially the 8 and fewer gear ones, often have sprockets going all the way to the freehub.

      2) Triple, or double cranks
      This is a good solution as well. You would need to find a front derailleur and a shifter. In my city, 2nd hand ones can be sourced relatively cheaply. I strongly prefer friction shifters, but I know it’s not everyone’s cup of tea.

      If a frame fits you, you can mount practically whatever you want on it and make it an effectively new bicycle, matching your requirements.

      Relja

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