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Can my Shimano Fh-M756 hubs be converted to 20mm?

9K views 43 replies 6 participants last post by  Mr.Magura 
#1 ·
I bought this wheelset before I knew too much about them, and now realize that a 20mm through axle is what I want. These hubs have the 9mm QR. I have read that some hubs can be converted with new endcaps, but I can't find any info on the compatibility of these ones.

So, can my FH-M756 Shimano XT hubs be converted from a 9mm QR to 20mm through axle?

Also, it seems I cannot use a centerlock rotor on a 6 bolt hub, and there is no adaptor that will fix this. Is this correct? I have a nice Shimano Ice Tech centerlock rotor, but didn't realize until after the fact my Shimano hubs were 6 bolt. Boo! :(
 
#2 ·
Can't find much info on the discount rotors I found (goodbye Ice Techs, I will save you for another build!).

Basically, Torq-lite rotors or Ashima Airotor? From what I can tell, both are weight weenie rotors. I honestly just need something tough for a clyde-- weight isn't that big of a deal. They are just under $20, which is how much I have to fix this problem. I need a 203mm 6-bolt, which all seem to run much higher on average than centerlock? Any better suggestions?
 
#3 ·
I bought this wheelset before I knew too much about them, and now realize that a 20mm through axle is what I want. These hubs have the 9mm QR. I have read that some hubs can be converted with new endcaps, but I can't find any info on the compatibility of these ones.

So, can my FH-M756 Shimano XT hubs be converted from a 9mm QR to 20mm through axle?
No, they can not be converted.

Also, it seems I cannot use a centerlock rotor on a 6 bolt hub, and there is no adaptor that will fix this. Is this correct?
Yes, a centerlock rotor can not be used on a 6-bolt hub.
 
#5 ·
Hmmm... that's a good idea!

I imagine the Saint hubs are better than XT, correct?

Ack, just read the reviews. They say you need the OVERSIZED centerlock rotors. I am pretty sure I have a standard one.

I looked for more XT hubs, but they only come in the 15mm version. Need the 20mm if I am going to do this.

and... now that I am thinking about it... how expensive is it to have an LBS lace a new hub in? I sure don't have the tools or know how to. That will be a cost on top of everything else too :/
 
#11 ·
Damn, you guys are making this tough!

I chose the XT wheelset over a lower one he showed me based on how buttery smooth the hubs were in comparison. I don't want to lose the butter if I go with Zee! But, likewise, if XTs are a bit wimpy, I may be busting them. I haven't busted the hubs on my cheapo full rigid, so I guess I am not *that* hard on hubs...
 
#12 ·
Depending how heavy you are (the 200# mark is usually where things begins to fail left and right), you have the freedom to pick fairly light components.
I would be very surprised if you're able to overload a XT front hub.
In general the seals have been better on XT than the lower groups. That would be a deciding factor to me, as it cuts back on maintenance.
The difference in cost, is negligible.

Magura :)
 
#13 ·
Ok, I am having a WTF?! moment as I dug around a bit more to try to decide between the two. Check out the warnings on the left of this Shimano Tech Doc for the XT m776: http://techdocs.shimano.com/media/t...001/SI_26L0A_001_EN_v1_m56577569830616069.PDF

Not designed for off-road bicycle riding?! What the hell are XTs made for?! A jaunt around the effin neighborhood?!

I tried to find a similar document for the Zee, but there doesn't seem to be one. Is that warning like a default warning for all components to release Shimano from liability? I would expect to see such a thing on Acera level and below, but not on freakin XT components! I thought I had this figured out too, I was going for the XT (I looked up the tech doc just to find out the year of the hub, only to double check what multiple sites had...) :/ I haven't had my hands on the Zee, so I wanted to stick with something I know I already like.

I am over 200#, which is why I am making a big deal about this. A catastrophic hub failure is NOT something I need... I blew over components like the bars, stem, and derailleurs cause failure of those won't hurt me badly. Stressed much more over tires, hubs, crankset, and fork (seatpost was easy. Thomson, no questions. Done :)). But like I said, I haven't bombed my shitty hubs on the entry level bike with a rigid fork (yet), so I know I am not being *too* hard on anything (atm, the gentleness is mostly due to bike limitations preventing me from trying out very rocky and steep areas). The lack of failure on what I have been riding makes me think I just need something tough, but not necessarily something for hard-riding DH riders. At the very least, it should be intended for off-road use...
 
#14 · (Edited)
If you're hard on components, the Zee is the way to go.
It's either that, or cough up for a Hadley.

The "not designed for off road bicycle riding" seems to be printed on just about anything.

Magura :)

EDIT: or if you have a friend that's got access to a machine shop, have one custom made.
I can supply drawings if needed, as I make my own hubs generally.
 
#15 ·
Ya, I have seen no evidence I am hard on components, and I am more defaulting to my weight as the source of any stress I put on stuff. But people who weigh half as much as me destroy bike parts instantly that I have been riding on for months, so I am realizing that it isn't a very reliable gauge as to how hard I am on my gear.

*googles Hadley*

Hmmm... the NOS versions range from $100-$150... I will keep those in the back of my mind when browsing around the bargain bins. Might be able to pick one up stupid cheap one day :D They are way cheaper than Kings...

*raises eyebrow*
MTB GT Hadley 32h Rear Hub Disc 135mm | eBay

Used GT Bicycles Hadley Front Hub 32h Front Disc Mount 20mm | eBay

4 bolt? EH?! I don't know if I have seen that before... Good deal for someone out there though, better hurry! :)

I thought 'Not intended for offroad use' was limited to wally world bikes... sheesh. :p
 
#16 ·
Ya, I have seen no evidence I am hard on components, and I am more defaulting to my weight as the source of any stress I put on stuff. But people who weigh half as much as me destroy bike parts instantly that I have been riding on for months, so I am realizing that it isn't a very reliable gauge as to how hard I am on my gear.
By hard on components, I meant either by riding style or weight, or both ;)

A used Hadley can't be all that expensive in your neck of the woods?
If they get new bearings, they will be as new, and a set of bearings for the front, are like $20.
4 bolt rotors are hard to come by these days AFAIK.

Magura :)
 
#17 ·
I would grab that ebay one in an instant if I didn't also have to hunt down a 4-bolt 203mm rotor for it. So far, I am finding only Hope rotors, around $32, but nothing in 203mm. The auction is for a take-off. Cosmetic damage only, good as new as far as I am concerned!
 
#23 ·
Ok, maybe a stupid question, but I need to ask before I buy...

The auction for the Hadley says the axle is not included. Umm... that is normally part of the hub, isn't it? Are they cheap?

I don't know the finer details of hubs, so if axles are expensive, that might be a dealbreaker.
 
#26 ·
Pulled the trigger on the Hadley! Just need to fill up my shopping cart at chain reaction to get free shipping on the rotor and new adapter. Big problem is, I already have everything and am just picking up odds and ends right now (uhhh... I need slicks for when I convert my current ride to a commuter? And tubes/ tubeless system. That's about it...). Plus I over stretched myself when I made the decision to go with a 20mm through axle instead of sticking with what I have. The fork was $50 more, $50 for the new hub, $35 for the new rotor. $10 for a new adapter (I had already ordered one for a 203mm rotor) Ouch. Won't be able to afford to get it assembled for a couple months :(

I think it will work out in the long run! Better hub, and better performance from a beefier axle.

Thanks for all your help :)
 
#31 ·
Pulled the trigger on the Hadley! Just need to fill up my shopping cart at chain reaction to get free shipping on the rotor and new adapter. Big problem is, I already have everything and am just picking up odds and ends right now (uhhh... I need slicks for when I convert my current ride to a commuter?
Are you sporting wagon wheels or 26"?
If 26" DMR Moto RT is the ticket for commuting, and they let you go off pavement as well to some extent.

Magura :)
 
#27 ·
For a front 20mm hub, you don't really have to that particular. If you're a clyde and/or hard on your gear, the rear hub is where you will benefit from spending more money and shopping wisely.

If I was looking to build a 20mm wheel on a budget, I would jump on one of these in a heartbeat:

Sett'E Components 32h 20mm Front Hub | eBay

Wheelmaster Disc Front Hub Black 32h 20mm thru Axle Black | eBay

New Marzocchi QR20 Hub Front 110 x 20 mm Through Axle 6 BOLT32 Hole 240 G | eBay

I built a wheel for my son with one of the Marzocchi 20mm hubs a few years ago, and he has been beating the *s* out of it with no problems ever since.

The Hadley for $50 is a great deal. It will serve you well.
 

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#28 ·
I figure I will just ride the XT until I destroy it on the rear. I imagine it won't have an exceptional life, since it is the QR version. I hope to get a few years off it, I have read good things about the older ones (which this one is... 2008, I think?). From what people are saying, that Hadley was a purchase that will last for life :) I am hoping I can trade the spare XT for some credit towards the labor for assembly, since the wheelset came from him. He knows I haven't used it. I also have some extra new deore rim brakes I hope he can throw me a 20 dollar credit for. That should help me get it in sooner!

Still waiting on some parts and to hear back from a shop if they can get a hold of my fork for me.
 
#29 ·
It took me a while to get strong enough to give XT (756) hubs more than they could stand. For an inexpensive rear hub, they (the 756 XT hubs) are about as good as it gets. Most people aren't heavy AND strong enough to hurt them that often. Once you start laying waste to the XT freehub though, you may as well count on spending at least $200-$250 for a rear hub alone (Hope Pro II would be the minimum I would recommend). Hadley makes a great rear hub for strong clyde types.
 
#32 ·
I am chuckling at the mod, because I build computers and the tech industry does the EXACT same kind of stuff! Many times, their lower end items are just neutered or down tuned versions of higher end stuff, since it is cheaper to make a ton of the same things and just remove or omit a couple parts to designate lower end models. Many times, you can do stuff like turn on extra cores in a processor or flash the BIOS of a video card to get the higher end performer for the price of the budget stuff :) It seems Shimano did the same thing! Same levers, they just omitted one freaking screw. I definitely will give it a try! I don't have a lathe handy (if only!) so I am going to have to go ghetto with a drill and file for that one :p The knob is great too, but it is a bit overkill for me. I can bust out an allen wrench if I need to make an adjustment :) And what is the tool called for removing the blanking screw? I suppose I can grab a screwdriver at the dollar store and modify it if the tool costs some silly amount.

I had no idea the SLX didn't have both adjustments! I would have sorely disappointed when I went to set stuff up :D


On the bike I am currently riding and converting to a commuter (let's call it the Diamondback, much easier!) it has standard 26" mountain bike rims. I want to put slicks on it because everything around here is paved. There is no chance I will need to go offroad with it once I get my mountain bike going, and if I do (like, as a backup bike) I can just put the knobbies back on it :) I hope to get a road bike by summer, mostly because the desert gets deathly hot at that point and it is dangerous to go mountain biking in the heat. That is our off season!

Once I get that going, I am still undecided as to what to do with the Diamondback. I actually am really starting to enjoy the rigid ride, but haven't ridden a real mountain bike yet to compare to. If I find myself feeling that suspension is leaving a hole where the rigid used to fill, I might turn the Diamondback back into a mountain bike. If I am feeling like 'good riddance to rubbish', I will optimize it for an around town beater that I won't be afraid to leave chained up in the bad part of town (I work at a luxury resort and park my bike next to the security bikes in front of their office, which has a few cameras pointed at anyone who comes close. I have never felt a need to lock it up, and have never had a problem. Therefore I am not afraid to take a decent road bike to work and leave it there.)
 
#33 ·
I am chuckling at the mod, because I build computers and the tech industry does the EXACT same kind of stuff! Many times, their lower end items are just neutered or down tuned versions of higher end stuff, since it is cheaper to make a ton of the same things and just remove or omit a couple parts to designate lower end models. Many times, you can do stuff like turn on extra cores in a processor or flash the BIOS of a video card to get the higher end performer for the price of the budget stuff :) It seems Shimano did the same thing! Same levers, they just omitted one freaking screw. I definitely will give it a try! I don't have a lathe handy (if only!) so I am going to have to go ghetto with a drill and file for that one :p The knob is great too, but it is a bit overkill for me. I can bust out an allen wrench if I need to make an adjustment :) And what is the tool called for removing the blanking screw? I suppose I can grab a screwdriver at the dollar store and modify it if the tool costs some silly amount.

I had no idea the SLX didn't have both adjustments! I would have sorely disappointed when I went to set stuff up :D
Once you get your brakes, you can borrow my "stupid userunfriendly screw" driver (see pic in Zent thread).
I made one of a tool from an implant template, from a spine surgical kit, I was modifying for a client back then. Sending forth and back should be cheap.

Magura :)
 
#37 ·
Dont the coda 4-bolt fit? I seem to recall the auction saying the spacing was 50mm between holes. I couldnt find any info on how coda 4-bolts were spaced, but they look right.

Worst case scenario, I could get a centerlock rotor with lots of metal in the middle and drill some holes. Most likeley i can even rotate the coda one and drill new holes if the spacing is off. Rotors dont seem to be something to stress too much over. Cheap, lots of variety, buy one time. Something should fit!
 
#38 ·
Ok, never had a hub in my hand before, so how do I check a used hub for damage/ problems/ etc?

It looks perfect, listing said it was a takeoff, never ridden. I believe it. I spun it, and it does not spin freely like one laced to a wheel. I can spin a wheel and it will spin and spin, but this hub doesn't move unless I am applying force. The movement feels smooth, but there is a very small of 'bumping' or 'clicking' (no sound), like a tiny index in it. Nothing feels like it is grinding, and it is silent. The movement is smooth except for the micro clicking. If it needs service, I will ask for an exchange (they listed another one). Does this sound normal? Any other way to test out a new (used) hub?
 
#40 ·
Do I need to open it up?

The hub is squeaky clean, looks like new other than barely discernible scuffs on spoke holes. It looks like it was taken off years ago, wrapped up, and kept in storage. I looked up stuff about opening up the hubs, and it is pretty finicky. There are talks about clean rooms and such!

Because it was never used and it was stored well, is it possible it is clean and just needs some new grease? That sounds a lot less scary than disassembling the thing in a clean room :p
 
#41 ·
Clean rooms and stuff like that, is maybe a bit over the top ;)

You do need to open it up, and get rid of the old grease though.
I usually take everything apart, and throw it in a jar with some petroleum or lamp oil.

Once clean, a sheet of white paper and grease in a syringe does the trick.
Taking it apart is no big deal. Just be careful not to damage the seals.

http://www.sicklines.com/tech-info/hadley/H500145.pdf

Magura :)
 
#44 ·
I went with the Hadley because I thought I would be getting a much better hub for the money...
And that is what you got ;)
One of the best hubs out there.

Opposed to the El Cheapo hubs, they don't eat bearings for breakfast, and basic maintenance will keep them running.
Most of the cheaper hubs, are hit and miss. Some are ok, some are even quite ok, but most manufacturers of cheaper hub, make them with bigger tolerances, and have consistency issues.
A good example is Hope.
I have had a few of their hubs over the years. Most were fine.
The front hub from the last set I bought, eats at least a set of bearings a year.
Similar experiences are common.

Magura :)
 
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