Bicycle Mechanics - Horizontal dropouts - wheel for and aft.
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What does it mean in overall bike performance to have the wheel placed at different points on dropouts???
I know that since dropouts are a little slented, when it's more to the front, the rear part of the bike gets a bit lifted.
What are some other characteristics of having the wheel forward or all the way to the back?
It's mostly about wheel base. Rear wheel farther back improves chain wrap a bit which is helpful on the smaller sprockets, especially as they wear. Also, the rear wheel moved back will improve hill climbing stability a bit, while moving it forward makes overall handling more sporty.
Back when these were common on race bikes shorter riders tended to move the wheel forward to choke up the wheelbase, and taller riders who were farther back because of the angle of the seat tube pushed them back to improve weight distribution. I ride a 56cm frame put the wheel about midway when I first set the bike up in 1967 and left it in the same place until I finally (semi) retired it in the nineties.
06-11-10, 11:59 AM
FB, overall we're discussing the effect of less than in inch of overall change. Was this more of an intellectual "feel good" trick or was the effect of such a small shift actually effective in real world ways?
I'm curioius because part of me wants to say that it's such a small thing that it's like a drop in a bucket. But I've always found that bikes that felt more sporty to me turned out to have a shorter overall wheelbase than the "truck" like handling bikes. But I just always chalked it up to all the other differences adding up to produce that sort of effect. I never thought to try it on a bike where the wheel can be shifted.
Moving the wheel back in the dropout is the same as having a longer chainstay. Given the amount of debate about ideal chain length, it's difficult to say what the actual impact is. The general rule was that taller bikes or those with shallower seat tubes should have longer chainstays to improve weight distribution, especially for hill climbing. At least that's how we did things back in the bronze age.
BTW- like so much of what's debated endlessly about bikes it doesn't make an earthshaking difference, and there's certainly a psychological effect, otherwise there probably wouldn't be so much debate.
When I set my bike up I started in the middle figuring I might adjust it later, but was happy with it's overall handling so I never bothered trying other positions, but I knew others who'd go crazy, not only moving the wheel but replacing frames following whatever was trendy. Every Sunday you'd see the members of the Bike-of-the-month-club with their latest and "greatest" rides.
Also remember that what was considered outlandishly short, stiff or steep ("it'll ride so badly your fillings will shake loose") is crazy long, soft and shallow today. Depending on the vintage of the OPs frame, even with the wheel all the way forward, I'd be surprised if the effective chainstay length was as short as a more modern vertical dropout machine.
06-11-10, 12:54 PM
Sounds like you're sort of in agreement with my placebo theory... :D
Did any of all that help the "Bike of the Month" clan? I suspect it didn't.
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