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setting up horizontal dropouts(5 posts)

setting up horizontal dropoutsDaveG
Jan 19, 2002 12:49 PM
I hate to sound like a dummy here but I am a bit confused on getting these adjusted. I just picked up a frame on ebay that uses horizontal dropouts w/adjusters. Believe it or not, none of my previous 6 bikes used them. So my questions are:
How do you ensure proper wheel alignment?
What are the ground rules for adjusting fore/aft? What's the benefit of moving the wheel forward or backward?
Its a singlespeed/fixed gear carryover ...Humma Hah
Jan 16, 2002 3:09 PM
... back when "ten-speed" bikes were newfangled, most frames still had horizontal dropouts. For the most part, they're not needed with derailleurs, and vertical dropouts rule the roost today. They're still seen on occasion -- my 1999 Diamondback 3x7 has short horizontal dropouts.

Forward-opening horizontal dropouts are typical of American singlespeeds, like my venerable cruiser.

Rear-opening dropouts are a feature of fixed-gear track frames. These usually have adjusters.

The rule for adjusting singlespeeds and track bikes are generally to visually line up the wheel so it centers in the frame, with tension set to allow just a slight amount of slack in the chain. A full rotation of the crank should be done to assure that there is still a trace of slack at the tightest position. If the chainring eccentricity is too severe, some wrenching is needed to correct it so that chain tension is reasonably uniform thru the crank rotation.

With derailleurs, the rear derailleur's tensioner generally can take out all needed slack if the chain length is correct, and you simply put the axel to the stops of the dropout slots.
re: setting up horizontal dropoutsNessism
Jan 19, 2002 6:40 PM
Adjust the screws so the rear wheel is centered between the chainstays. Adjusting the screws back will lenghten the chainstays which will slow handling slightly. Not really enough to matter so don't fret about this. Most people leave the screws centered.
Good advice above, Dave.guido
Jan 19, 2002 9:12 PM
You can check to see if the rear wheel is centered with a straight edge or string, pressed along both rims. If the edge touches both rims in two spots, you know they're in the same track.

Also, make sure the brake pads are still lined up on the rear wheel rim, and also centered.
One more thing.Sintesi at home
Jan 20, 2002 6:36 AM
It's easier to torque a wheel out of alignment in horizontal dropouts. So make sure you tighten the quick release extra hard.