Singlespeed & Fixed Gear - rear dropout spacing 120mm hub in a 130mm?
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01-14-06, 03:49 PM
Just a quick question. I'm building up a few conversion fixed gear bikes and was wondering about all the hubs and wheelsets that I've been finding are spaced 120mm a few at 126mm. Most are formula hubs and are 120mm. Will these work in a 130mm older road bike frame? Most of the road bike frames from the 1980's or so are 130mm and I was wondering if anyone else has run into this issue. Any help would be appreciated. Thanks.
01-14-06, 03:51 PM
no, they wont fit without bending the frame a little bit on each side or finding a longer axle to fit the hubs.
01-14-06, 04:00 PM
120mm over locknut dimension (you'll see it written as OLD) is standard track spacing. If it's a steel frame, you can respace the rear triangle to 120mm and be just fine.
If you don't want to do that, you should probably still have enough length on the stock axles. You'll just need some spacers. Any shop that deals with track or singlespeed stuff for the street (as opposed to a top dollar track specialty shop for trackies only) should be albe to set you up. Just put them between the cone and locknut, 5mm worth on each side, and you'll end up with a 130mm hub just like that. Voila!
Generally speaking, you can use a longer track axle with a few spacers. The Bicycle Research chromoly or stainless axles are excellent (and about $11-15 apiece) and most bike shops or www.biketoolsetc.com will have axle spacers in all kinds of widths. Your existing cones, locknuts, etc. by and large swap over without a problem. (Occasionally I can add spacers to an existing axle, but too often, especially with better hubs, there just isn't a lot of surplus length -- and weight -- left there.) With some current fixed gear hubs, the axles are nonstandard funky, either with ledges to support sealed bearings or with slightly different diameters (e.g., the cheap Suzue's). Note that you may need to put most of your spacers on the left side of the hub (and won't be able to flip a double-sided wheel at that point) because otherwise you'll bring the chainline inwards too far on the drive side.
Usually it's easier simply to reset your rear ends to 120 mm. Before you do so check your chain alignment again -- it may work a lot better or worse with one method or the other.
01-14-06, 04:55 PM
With some current fixed gear hubs, the axles are nonstandard funky, either with ledges to support sealed bearings or with slightly different diameters (e.g., the cheap Suzue's). Note that you may need to put most of your spacers on the left side of the hub (and won't be able to flip a double-sided wheel at that point) because otherwise you'll bring the chainline inwards too far on the drive side.
This is not true. Different-sized bearings have no effect on the axle, it remains a consistent diameter. Even if that weren't true, the spacer simply slides on between the locknut and cone, so it's not really important. Those hubs that feature a sleeved axle like the Formula have the sleeve on the inside and spacing has no effect on their functionality. For those, such as the Pro Max, which have a sleeve that threads down from the outside, this acts just like an ordinary cone. Again, adding spacers has no impact.
Respacing should be uniform on both sides unless your frame is out of alignment or features a non-standard chainline. The chainline is measured from the center line of the bike. A road bike with a 130mm spaced rear triangle will have the same 42/43mm chainline as a 120mm spaced track bike. Respacing one side more than the other will shift the hub and thus chainline to one side or the other and screw things up for you.
01-14-06, 05:17 PM
Regarding replacing the axle with a new/longer one.
Is there any quick/easy/basic way to determine what specs your current axle has?
When I went to Bike Tools, they have 3 different(yet very similar) standards.
9M,10M and 3/8'...along with 24 and 26tpi.
I am not sure which one I need...and since there is not a drastic difference in size my cheap calipers do not instill confidence that I would get the right one.
unscrew one of the bolts on your hub.. buy the axle it fits on , in the right lenght.. et voila..
01-14-06, 05:34 PM
Go to the shop and have them thread on a nut. Or, if your hub is known, ask them what the threading is on your hub.
Ain't standards wonderful? There are so many to choose from!
01-14-06, 05:47 PM
Thanks for the help guys.
I was hoping there was some killer key to figure it out.
I would rather order online then try to run between shops trying to find someone who carries the axle.
My closest LBS are nice guys but have not stocked a SINGLE fixed/track item that I was interested in..and my other LBS is Performance..who of course will not have any of this cool stuff.
I know there are killer LBS' in SF, but I do not have the opportunity to get up there.
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