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Old 07-11-12, 02:14 AM   #1
Wreck.
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New Gear Hub or New Bike?

Hi all,

I have a bike with a quick release at the rear wheel, the problem is:
the rear wheel is never tight, i tried a couple of shorter axles, it was much better but the disc brake rotor tends to rub at the chain stay and the smallest cog was very close to the dropout ; which means that no enough room is there for the hub width if I want my rear wheel tighter.

so, In order to get the rear wheel narrower i thought about getting rid of the disc brake rotor but the frame is not designed to have a v brake attached to it. I also thought about replacing the 7 speed cassette with something narrower but I found that 7 speed is the least number out there. I'm thinking about buying a rear gear hub to fix the the problem and i think it will be nicer at shifting and maintainance free.

well, the bike is cheap, i got it for 190$ 3 years ago at a discount, and since then I abused it commuting with almost no maintainance. now I'm using it for learning bike mechanics, I did overhaul the front and the rear hub, adjusted the derailleur and now I'm overhauling the bottom bracket. I think buying a gear hub would be expensive compared to the value of the bike, but on the other hand it will make it usable instead of throwing it in the garbage.

2 questions are there for you guys and thanx in advance.

1- what options do I have if I want to fix the bike at the minimal cost?
2- if you're having a bad time financially, and there's a chance to buy a new entry level MTB for 450$, would you still go for the "gear hub idea"? or would you throw the old bike and go for the new one?
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Old 07-11-12, 02:39 AM   #2
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..I have a bike with a quick release at the rear wheel, the problem is:
the rear wheel is never tight, ...
1- what options do I have if I want to fix the bike at the minimal cost?
Fix the problem. There's endless number of threads on this forum about wheels sliding in dropouts. Highlights are as follows:
1) Make sure axle does not protrude outside the outer face of the dropout
2) Make sure that the centering springs on the skewer are positioned point facing in - or remove them
3) Get a good enclosed cam q/r with a steel skewer. You'll recognize them on being boringly silver, or black in color. None of that anodized-in-whatever-hue-of-the-rainbow. Make sure the faces that goes against the outside face of the dropout are serrated. Say a $10-$30 fix
4) Make sure that your locknuts on your axle are serrated too. Maybe a $5 fix. At a pinch, you can take a Dremel to cut grooves in them. I've used a centering punch on one occassion as well.
5) Clean up your dropouts. Scrape away any paint, file down any big burrs or ridges.
6) If all else fails, replace q/r axle with solid axle and track nuts. If you manage to pull loose a track nut /serrated locknut secured wheel - you're Olympic material. I'd guess cost would be $10-$30 range.

And just to make things clear - Making the wheel narrower is not the answer to your problem. But it could certainly create a bunch of new ones - as I guess you discovered with the brake rotor rubbing. You really need to stay within the OLD (over-locknut-distance) that your bike is designed for. A safe guess ist that yours should be 135 mm.

IT's possible to change the rear spacing, but you need to have a fair grasp of what youre doing to pull it off.

Last edited by dabac; 07-11-12 at 02:44 AM.
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Old 07-11-12, 02:40 AM   #3
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I D K, all your issues etc... but I ride my IGH rig more than others..with derailleurs
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Old 07-11-12, 03:32 AM   #4
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IGH hubs may create different problems: many have 1/8" cogs (which fit a 1/8" ssp chain), and 1/8" chains are stiffer on side movement, so the chainline should be pretty much straight. (and adjusting the chainline means moving the cog a bit (if possible) moving the chainring with different spacers on the spider, or moving the crank itself with different length for BB spindle, or fiddling with the OLD distance by moving spacers from the left to the right or the other way around.

And the fact that IGH's have a wide variety of OLD's like 115, 120, 126, 130, 135 - the 130-135 ones are made to fit these frames, but it's mainly a stretched version, because a 115mm OLD is enough for one cog. So beware what is the OLD of the IGH hub you'd desire, you'd want the same OLD, or next smaller one to have room to adjust with spacers (but it's tedious and require a different longer axle, which is a PITA to find for a IGH becuse of the complex mechanism.

So IGH may rise a number of small problems and some of them may be hard to overcome.
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Old 07-11-12, 03:33 AM   #5
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The dropouts need to be squeezed more in order to get it tight, and that achieved only when using a shorter axle, I've proven that in practice, but as I mentioned, the rotor rubs cause it got too close to the chain stay and the smallest cog tends to be very close to the dropout, to the degree that made me saw a slice of the bolt that fixes the derailleur into the frame, in order to prevent the cog from rubbing.

@dabac
I've tried before all of what you've suggested. the bike is cheap and I think that some of such bikes have non standard pieces. but I'm not sure

@Asi
that makes sense, I think It's better to forget about the IGH, thanx

I would be grateful if anyone has further suggestions.

Last edited by Wreck.; 07-11-12 at 03:37 AM.
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Old 07-11-12, 03:43 AM   #6
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Restore your hub spacing and get a new closed cam quick release, if need be pick up a few lock washers and mount those the the outside of the dropout.
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Old 07-11-12, 03:52 AM   #7
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you need to check that the distance across the inner dropouts matches the distance across the hub nuts. they should match up, if the hub distance is less than the dropouts then you lost a spacer somewhere when servicing the hub.
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Old 07-11-12, 05:05 AM   #8
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Thank you all for your suggestions,

I've tried a solid axle with nuts to bypass any problems stemmed from the quick release, still have the same problem, the wheel is loose, and when I fasten the nuts more, the wheel is tight but it doesn't spin because of disc brake rotor rub with chain stay and on the other side, the smallest cog is stuck at the dropout.

does anybody have a clue?
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Old 07-11-12, 05:37 AM   #9
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does anybody have a clue?
Yes, as several posters have mentioned, narrowing your hub was the wrong approach. Restore it's original spacing to get the disc and cog clear of the dropouts. Then if needed add spacers to assure the axle stubs don't protrude past the outer dropout faces and use a good enclosed cam qr skewer. A Shimano or Campy skewer can be bought at any LBS, usually cheap, as they will have a bunch from trashed wheels. It is not necessary to squeeze the dropouts narrower to get the wheel to remain in position and, in fact, doing so is counterproductive.
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Old 07-11-12, 06:00 AM   #10
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It is essential to check that the distance across the inner dropouts matches. And the hub nuts should be match up, if the hub distance is less than the dropouts then you lost a spacer somewhere when servicing the hub.
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Old 07-11-12, 08:02 AM   #11
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Restore your hub spacing and get a new closed cam quick release, if need be pick up a few lock washers and mount those the the outside of the dropout.
This is your clue.

The problem stems from a lack of traction from the stock quick release.
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Old 07-11-12, 08:49 AM   #12
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The dropouts need to be squeezed more in order to get it tight,
Well, sure.
But left dropout is squeezed between left locknut and q/r lever, and the right dropout is squeezed between right locknut and q/r nut. You don't secure by squeezing the left dropout towards the right dropout.

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...., and that achieved only when using a shorter axle.
Ony if you're using a q/r, and the axle is protruding beyond the outside face(s) of the dropouts. Or the centering spring on the skewer is getting jammed in there.
If that's the case, switching to a shorter axle, but keeping the OLD, should do the trick.
And if you keep the OLD, you'll avoid the clearance issues you are reporting with sprocket and rotor.
Axle length, or rather hub OLD in your case, shouldn't have anything to do with how hard you can squeeze each dropout between locknut and whatever retaining device you're using. If it has, it's accidental.
Whatever the OLD, the mechanically operative interface is each dropout being pinched between locknut and retaining device - not dropout towards dropout.

Real cheap bikes sometimes have quite nasty dropouts, made from thin, shiny steel that's somehow slicker than decent frame materials. But properly serrated hub hardware should sort that out anyhow.
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Old 07-11-12, 03:39 PM   #13
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As far as I understand, you problem is the axle spacing. Like on the brake rotor side you removed a washer or something, put it back! You need that nut on that side to be far enough so the chainstay/seatstay clears the brake rotor/gears. The frame (dropout/chainstay/seatstay) will be positione against that nut, you want more space? move that nut farther (by putting washers or another nut)

securing a wheel consists in 2 things: the part that goes trough the dropout (the solid axle, or the stub of a hollow axle for QR), and the part that goes against the inner face of the dropout (which in all cases are some serrated locknuts on either side). Whatever locks that axle in place is squeezing the dropout itself between inner face and outer face (each with its own job, stretching/squeezing the frame spacing it's not related to this matter) - that thing that locks is either a nut threaded on the solid axle, or the QR (the QR tightens both dropouts in the same action, but it is not pulling the frame spacing, only the dropout against that locknut.


Again, you say you have to squeeze the frame? put some more washers behind the locknut, especially on the side you have clearance issues. You should not squeeze the frame when you install the wheel, and this is very easy to do by adding required amount of washers on either side (and will provide more clearance on that side)

This is the same thing when I was fitting 7sp FW on hubs with 120mm spacing for 5speed. - by adding spacers on the FW side and removing washers from the NDS side, this moves the whole hub in the frame and enough clearance was made to fit 7sp FW on 120mm OLD (but now the NDS was very close to the frame, but it worked very well nonetheless). For you, your NDS is too close now and it rubs on the brake rotor, add spacers there.. no need to subtract on the other side as your OLD of the hub is smaller than your OLD for the frame. Get it match!


And as a side note.. you know.. OLD=Over Locknut Distance - because the length of the axle does not matter* for the frame.
*it matters for QR's as that axle must not protrude over the dropout as the tightening will be made against that hollow axle instead of locknuts/dropouts. For solid axle can be as long as you want as long you have enough space to fully thread a nut on either side.

Last edited by Asi; 07-11-12 at 03:46 PM.
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Old 07-16-12, 04:26 PM   #14
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Thank you guys for all the replies,

the spacing issue makes sense. I thought that q/r works by squeezing from the outside without something pushing at the inner sides of the dropouts. is the q/r really designed to work that way? or is it just a trick to solve my problem? I just don't know cause I'm new to that stuff.

-------
beside fiddling with my bike I just needed another bike to rely on, so I've just ordered a single speed bicycle of a decent quality which is also not expensive. less maintenance, more riding, a bit challenging maybe, I had one as a teenager & I remember it was always a great ride.
can't wait to receive the package.
-------
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