reroll

Apparently not all but many Shimano freehub bodies are interchangeable on different hubs. I have a FH-M570 8/9-speed HG hub and the next-earlier FH-M560 7-speed hub had a UG/HG conversion body having external threads near the RH end of the body. Yet there also was a later FH-RM30 7-Speed freehub body which was only HG without having the UG/HG conversion threading and, as my question, please, would the FH-RM30 freehub body fit and work on a FH-M570 hub?


TIA!

dmark 

No. The back of the body is different as well as the face of the hub.

reroll

Thank you, that is the answer I needed. I can find a parts diagram for the FH-M570 hub but not for the FH-M560 hub. Yet what stops me about the FH-M560 7-speed freehub body, even if would fit and work on a FH-M570 hub, is its having UG/HG conversion threads on it because cutting external threads onto the outer RH end of the body involves removing spline metal which weakens the spline's bearing surface for the outer RH sprockets, but the newer FH-RM30 7-speed freehub body is HG and so does not have those conversion threads.


My FH-M570 hub has the 135mm OLD needed for my bike and I am thinking that replacing the hub's HG 8/9-speed freehub body with a HG 7-speed freehub body and using the right combination of axle spacers could considerably reduce the RH spoke flange offset and get closer to building a zero-offset wheel.


Or perhaps I should rearrange my thinking and ask what/which 135mm OLD hub/s a FH-RM30 freehub body fits.


Again, thanks!

70sSanO

I've not heard anything good about FH-RM30.

Exactly what are you trying to do?

What freehub do you currently have?

Do you want to run a 7 speed freehub with an 11t or run a 12t first position cog? That part is important as you need a Shimano "C" freehub body to run an 11t.

If you want to research exploded views you can find them here...
https://si.shimano.com/#/

John

reroll

I am not familiar with these but apparently these freehub bodies were originally for Alivio FH-RM30-7-QR rear hubs.

Now using 8/9-speed hub, would like to reduce spoke flange offset as much as possible, flange offset on 7-speed FH-RM30-7-QR hub is only 5.5mm, so was wondering if something similar could be done to improve my hub by simply swapping parts around; https://bike.shimano.com/en-EU/produ...RM30-7-QR.html However, I have been informed that FH-RM30 freehub body is not compatible with my hub and on further investigation discovered that hub may have been available only in Europe and perhaps elsewhere but not in North America where I am. Shimano chooses where and where not in the world to sell its products and restricts its dealers from exporting them to other continents and nations. What is available in Europe is often not available in North America and that happens with Dia-Compe too.

I am in the commuter and medium-weight tourist category and get along fine with widely spaced gearing, just shift into the necessary gear and leave it there. On 700c wheels I run 12-34T Megarange 7-speed freehub cassette, 46-34-24T crankset, for ~19 gear inch low gear, ~105 gear inch high hear, with wide but even mix of ratios in between.

Since I already use 7-speed on 8/9/10-speed freehub body I could eliminate at least 4.5mm of 7-speed cassette spacer's width from spoke flange offset.

70sSanO

You can use a UG/HG 7 speed freehub and run a 12t HG and a lockring. You don’t need remove any of the external threads.

The caveats with any Shimano freehub swap are the rear flange thickness, the dust seal diameter, and the obvious one, cones. The RM30 and Dura Ace 74XX are the odd spline/attach ones. And I believe the latest 11 speed.

You can cheat a little if you have a deep recess hub (thick flange) and you install an 8/9 speed thin flange. It won’t reduce it nearly as much as a 7 speed, maybe a couple mm’s, but you’ll need a spacer to make the large cog work.

John

70sSanO

I've posted this pic a number of times, but it shows the differences in freehub body rear flanges and UG/HG vs HG.

The top row are the thick flanges. Left is a 7 speed UG/HG off an FH-M732, right is a 9 speed HG off an FH-7700.

Bottom row are the thin flanges. Left is a 7 speed UG/HG off an FH-MT62/M650/1055. Right is an 8 speed UG/HG off an FH-6402.



John

reroll

Thank you, yet there are a number of important details which I must learn more about. I just now contacted a dealer selling NOS LX FH-M560 7-speed freehub UG/HG bodies and who claims they fit SOME other Shimano hubs, so I asked if his freehub bodies can fit and work on LX FH-M570 hubs and that question is now pending a reply from the dealer. Apparently UG bodies were threaded with two different threads for lockrings but Shimano parts pages include no information about either of those two threads. Then I have other questions about, as you mentioned, seals, cones and other parts where information about them is often confusing, incomplete, wrong or unavailable. And so, this project could take some while to get to grips with.

70sSanO

I'm pretty certain that the dust seal diameters on the 8/9 speed "C" freehub bodies are a smaller diameter. Since the 1st postion 11t cog hangs slightly off the front of the freehub body, the 11t lockring is a smaller diameter and deeper (more threads). I'm not certain that a potential lockring interference with the dust seal drove the smaller diameter, but one issue of just buying a freehub body is not having all the DS pieces to make it work.

I'm always a little leery of blindly buying a freehub body and then hunting down the rest of the stuff. It can be a real pain going through Shimano docs playing mix-n-match trying to find all the compatible bits.

Wheels Mfg does/did offer aftermarket cones, but they seem to be limited to popular hubs that use the same cone. I have been able to find a few cones I needed. Loose Screws sells a few NOS axle assemblies. That is what I did when I swapped out a 7 speed freehub body for an 8 speed body.

But the "hopefully" more foolproof approach, but more expensive especially since NOS stuff is crazy expensive, is to figure out what freehub bodies will work and just buy a complete freehub. Use the existing NDS cone and dust seal and move the DS body, cone, and seal over to the existing hub..

John

reroll

Yes, Wheels Mfg has axles and cones for my stock 8/9/10-speed FH-M570 hub, but a substitute 7-speed freehub body could then require a different axle and RH cone.

The more I look and learn the more convinced I become that Shimano stopped backward freehub body compatibility between M550/M560 and M570.

70sSanO

Shimano never “officially” published any backward compatibility on freehub bodies.

Shimano did publish a listing of freehub body interchangeability between hubs using the freehub body part number. But that interchangeability was never outside of specific cassette speeds. Shimano never provided any guidance to replace a 7 speed with and 8-10 or vice versa.

The only backward compatibility has been the attach splines. For nearly 30 years it was possible to slap an earlier body on a later hub or a later body on an earlier hub; with a few exceptions.

The disadvantage you have is trying to make a swap to a 7 speed body 25+ years down the road. The knowledge from those who routinely did this in the 90’s, and could rattle off what to look for, is probably lost; along with available parts.

I can only provide a tiny slice of info because I have done a number of swaps in the last few years.

John

reroll

I thought eliminating a 4.5mm spacer to reduce spoke flange offset would be worthwhile, but 1x and 2x cranksets have largely wiped out 7-speed cassettes, making it less worthwhile to eliminate that 4.5mm spacer. A 7-speed, 12-14-16-18-22-28-34T cassette I got a couple of years ago is now out of production and its manufacturer offers only 11/12-28T 7-speed cassettes, a sign of retirement, about the same as what is available for 5-speed cassettes, barely enough gearing to keep them on the road.

However, that same manufacturer does make high capacity 7-speed freewheels, not freehubs but freewheels, as another option for reducing flange offset. BTW, I have put many thousands of miles on freewheels, which do work reliably well and are good, and maybe a slightly sidestepped 135mm 7-speed freewheel hub would work.

Truth be told, my bike runs on 8-speed chains, I like 8-speed components too and my 8/9/10-speed hub has less flange offset than the newer hubs. I will keep looking into a 7-speed freehub body conversion but not as a high priority. Yet I can not bring myself to give up on that idea completely as it is there to be done.

reroll

I chose the LX M570 hub because its 7+spacer/8/9/and later 10-speed design once was and could remain popular today, a series which went on for six years so there still could be a lot of new and rebuildable used LX M570 hubs to work with and in addition to its stock form it could also be updated into a new 7-speed form. Wheels Manufacturing currently makes an axle and left and right cones for the LX M570 hub or a different axle and cones could be selected. Then would be designing a new freehub body which would not be difficult to do as a new body would only need to fit other components which have already been developed and then would be rubber seals, a dust cap and other small parts. And reverse engineering could get a lot of this project done.

70sSanO

I hate to say this, but you've come to the end of the line. You do commuting and medium weight touring. The last thing you should do is to go to a freewheel.

Shimano still offers an 11-34 7 speed cassette, but the gaps (11-13-16-20-24-28-34) are not something I would want to ride; especially that 13-16-20 sequence.

I have no clue what is going on with Sunrace. They used to be a good source for decent cassettes at good prices. Their website has been completely changed. However, you can get an 11-34 8 speed cassette from Microshift that looks suspiciously like an old Sunrace cassette. It is possible to dump the 11t and re-space the cassette to 7 speed and run it as a 13-34.

Then again, why not just go to 9 speed. Swap out your shifters, get an 11-34 9 speed cassette. And if you "ever" want to go to a 7 speed freehub body, you can run 8 of 9 cogs and dump the 11t.

You are running a 135mm OLD rear hub. Personally I'd give up the ghost on zero offset.

John

ThermionicScott 

+1. Zero dish is nice in theory, but not necessary in practice.

reroll

Yes, I notice this thread has apparently been deleted from General Cycling Discussion.

On the one hand, having a longer axle provides room to shift the hub toward the right end of the axle after installing a shorter freehub body.
But on the other hand and although the hub could be modified as I suggested, the net flange offset gain would only be about 2.25mm, some gain but not much.

70sSanO

It’s still in the General Cycling Discussion.

I think 9 speed is becoming the old 7 speed. It is still supported with cassette and shifter options.

Getting the right cassette is probably the biggest driver. If you can’t find the right 7 speed you will have to move on sooner than later.

John

reroll

Yeah, when X-speed gets commercially retired cassettes often drop down to some size like 14-28T or some smaller capacity like that. 5-speed got retired long ago, 6-speed freewheels can still be found in MegaRange capacities but 6-speed freehub cassettes are practically unheard of in recent years, 7-speed freewheels can also be found in MegaRange capacities and a couple of years ago SunRace offered 12-34T 7-speed freehub cassettes but recently I looked at SunRace and while MegaRange freewheels are still available the SunRace 7-speed freehub cassettes available were only 11-28T and 12-28T and MicroShift now offers only 12-28T 7-speed freehub cassettes, so just in the past couple of years it looks like 7-speed has become commercially retired and as you said it looks like 7-speed is vanishing into the fog of history.

Edit: I think 8-speed will be around for many years and believe 8-speed is the lowest-speed chain KMC makes these days.

70sSanO

8 speed is the ugly step child. It never really found a home.

Of course half of our 8 bikes are 8 speed.

But over the years I have acquired a stash of enough various cassettes, individual cogs, and spacers that I can build just about anything I want by mixing and matching cogs and brands. My franken-cassettes include 8 speed 13-40 and 14-36.

If I were starting from scratch today, I’d just go to 9 speed.

John

reroll

You said a lot in this post and have said a lot in other posts too, which I do appreciate, thank you, but this website is not set up for detailed responses and I have been timed out a few times now, then having to circumnavigate some roadblocks where if I make one mistake then my return post vanishes, poof, gone, my time and effort wasted.

70sSanO

Sometimes the site gets temperamental, especially from my phone.

There is an Auto Restore Saved Content at the bottom of the reply box that helps a lot when you hit something and the site sends you off to another screen. If you just go back to the thread that seems to work well.

John

ThermionicScott 

If you have a long reply in mind, try composing it in a text editor first, then pasting it into your browser. Then if the website craps out, you can try it again.

reroll

I tried that, wrote it on Word and then copy/pasted it. Seems to be the website with excessive roadblocks and repeated needs to log in, probably for security reasons.

I appreciate detailed thoughts, which can require equally detailed responses, which can take time to write, which brought me to Word and copy/paste.

reroll

I have been timed out a number of times here, so my new strategy is to use partial quotes, requiring a faster answer, and repeat that process until finished.

ThermionicScott 

Funny, I always think of 7-speed cassette as that forgotten middle child. Bikes were largely 6-speed up to the late 80s, then Shimano would upgrade a group to 7-speed, only to bump it up again to 8-speed within a couple years. And frames and freehubs intended for 7-speed didn't provide as easy a path for upgrades as 8-speed... so 7-speed became a mid-to-lower tier thing pretty rapidly.