Dirkitech Posted September 10, 2014 Share Hi all, As the title states I have no idea how to determine what my rear hub specifications are. My rear hub bearings still spin like new, but there is an off-balance somewhere with the rear wheel area. When I lift the back and step the pedal, the wheel spins well, but the bike rocks up an down slightly when holding it in the air. I tried searching the forum for hub and rear hub but to no avail. Could someone please advice me how to determine my current hub specifications and which of these are important to keep in mind when buying a new hub. I know the hub has the extra part for the disc brake rotor.It says "American Classic" on the hubI haven't counted the spoke-holes as I'm unsure if there are special things that needs to be taken note of.EDIT- added:Its a new tyre with a new slime tube (well, it rocks heavily whether I have the road slicks on or the mtb tyres).A spoke was recently replaced and therefore the whole wheel was trued. Edited September 10, 2014 by Dirkitect Link to comment Share on other sites More sharing options...
David Marshall Posted September 10, 2014 Share I doubt that it is your hub. More likely to be tire or rim related. Take it to some one who knows wheels to check it out before you spend money on a hub. BogusOne and The MTBer 2 Link to comment Share on other sites More sharing options...
Dirkitech Posted September 10, 2014 Share Ah, totally forgot to mention that. I've had to replace a spoke on the rear tire about 1.5 months ago. If I remember correct they also made a reference to the hub as opposed to the rim being bent/dented somewhere. I will have my lbs take a look at it as soon as I can to confirm if its the hub (a thanks is in order David, you may or may not have saved me from unnecessarily buying a new hub). For the purposed of this topic though, lets assume the hub axle was bent on a curb snakebite and that it needs replacing- how do I go about diagnosing what hub specs I have? Link to comment Share on other sites More sharing options...
Raydek Posted September 10, 2014 Share Have you got sludge/sealant in the wheel? Might have hardened in one spot and is now throwing the balance off. Alouette3 1 Link to comment Share on other sites More sharing options...
Vangar Posted September 10, 2014 Share I'm going to go with David as well. To bend a hub.......well sho. You MOST likely, have a 9mm quick release rear hub. If it's got a smallish axle that clamps on the sides then it is QR. Check if the QR is not perhaps bent BogusOne 1 Link to comment Share on other sites More sharing options...
Super_mil Posted September 10, 2014 Share Count the number of spokes (probably 32), measure the width of the hub (very likely to be 135 if it is an xc bike) & take note of the axle (quick release, 10mm thru...). These will determine your hub specs. It is very unlikely that you have trashed the hub. Wheel could be out of true or even sometimes too much sealant can make a wheel feel like it has a hop. Edited September 10, 2014 by Super_mil Link to comment Share on other sites More sharing options...
Wyatt Earp Posted September 10, 2014 Share Hi all, As the title states I have no idea how to determine what my rear hub specifications are. My rear hub bearings still spin like new, but there is an off-balance somewhere with the rear wheel area. When I lift the back and step the pedal, the wheel spins well, but the bike rocks up an down slightly when holding it in the air. I tried searching the forum for hub and rear hub but to no avail. Could someone please advice me how to determine my current hub specifications and which of these are important to keep in mind when buying a new hub. I know the hub has the extra part for the disc brake rotor.It says "American Classic" on the hubI haven't counted the spoke-holes as I'm unsure if there are special things that needs to be taken note of. Happens to almost 90 % of bikes you do this with. floatfox 1 Link to comment Share on other sites More sharing options...
Pieterg Posted September 10, 2014 Share Sealant can be the problem Link to comment Share on other sites More sharing options...
ChUkKy Posted September 10, 2014 Share Hi all, As the title states I have no idea how to determine what my rear hub specifications are. My rear hub bearings still spin like new, but there is an off-balance somewhere with the rear wheel area. When I lift the back and step the pedal, the wheel spins well, but the bike rocks up an down slightly when holding it in the air. I tried searching the forum for hub and rear hub but to no avail. Could someone please advice me how to determine my current hub specifications and which of these are important to keep in mind when buying a new hub. I know the hub has the extra part for the disc brake rotor.It says "American Classic" on the hubI haven't counted the spoke-holes as I'm unsure if there are special things that needs to be taken note of. You probably have a ball of sealant in the wheel making it off balance. Happens often.Sometimes you get lucky and it doesnt happen. of the 6 wheels in our garage, 3 are perfect with no imbalance. Saying that, the sealant is a bit old in those 3 particular wheels. Link to comment Share on other sites More sharing options...
NotSoBigBen Posted September 10, 2014 Share Happens to almost 90 % of bikes you do this with. Could be the grease has accumulated in one spot of the bearings? Link to comment Share on other sites More sharing options...
Wyatt Earp Posted September 10, 2014 Share Could be the grease has accumulated in one spot of the bearings? I just base it on the fact the we are dealing with so many variables and inconsistent little faults along the way, but yes I can see how grease bearings could cause that, it's a human application after all :clap: Link to comment Share on other sites More sharing options...
droo Posted September 10, 2014 Share Bike wheels are always slightly out of balance , mainly because of the valve. Spin a wheel with a properly set bearing and the valve will land at top or bottom dead centre every time. JXV 1 Link to comment Share on other sites More sharing options...
Beast Tech Posted September 10, 2014 Share If you have a MTB wheel that is completely true are not riding it correctly 2bliss and droo 2 Link to comment Share on other sites More sharing options...
Dirkitech Posted September 10, 2014 Share Hi all =) I skim read through some of the replies and see some interesting things. As for the sludge part, its a new tube and new tyre. A spoke was replaced about a month ago and that included a truing of the wheel. On Saturday I heard a same clank I heard in PE before a spoke broke (although extensive inspection still doesn't reveal any spoke even remotely coming close to another object). Tonight I will take a short videoclip of the rocking so that people can decide for themselves whether it is severe or common. Point remains, I have no clue as to what to call my hub's technical features and don't know what technical specifications would be important in replacing my current hub and when shopping for a new hub in general. Link to comment Share on other sites More sharing options...
JXV Posted September 10, 2014 Share It seems, from your description, that your wheel is out of balance. This could be due to sealant accumulating in one part of the wheel or a poorly moulded tyre/tube or the valve or any combination of these. Sealant dries out over time and then cannot flow and distribute itself around the inside of the tyre. This is the most likely problem if you are running tubeless or with slime tubes. Apparently, the CO2 in gas bombs will react with some types of sealant and harden it.....maybe you used a bomb recently to inflate a tyre? If the axle is bent this is more likely to make your wheel rotate out-of-true than out-of-balance.....but maybe I'm wrong. Many aftermarket hubs today come with adapters so that they can be changed from old style QR skewer to the newer style 12mm QR and 135mm or 142mm widths. You may also have a choice of centre-lock or bolt-on disc mountng with some brands. Your bike shop will be able to assist. Before committing to a new hub, remove the tyre and spin the tyreless rim up your bike (i.e. without a tyre). If it still jumps or wobbles then the hub or wheel truing job is suspect. If smooth then the problem is in the tyre/tube/sealant combo. Edited September 10, 2014 by JXV Link to comment Share on other sites More sharing options...
Raydek Posted September 10, 2014 Share Are you looking for something like this? Maybe there are better ones out there, but I believe hub bodies are usually just replaced, so not sure if you find an exploded diagram for them. Link to comment Share on other sites More sharing options...
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