Bicycle Mechanics - Bike Fitting Question
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I just bought an '07 Specialized Sequoia and am trying to set up the fitting better. I started with the height of saddle, then I moved to fore-aft adjustment. I'm doing this my self so I cant do the plumb line check.
I was reading that you should not be able to see the front hub when you look down. I have the sadlle pushed all the way forward and I can see the hub. Is there something else that I need to do? Maybe adjust the handlebars or something.
07-12-09, 12:50 PM
You are supposed to be in the drops for that hub fit thing. It's really just a "ballpark" thing anyway. You need to put on some miles to get a real feeling for your fit. BTW the stem length will affect your view of the front hub, more than seat fore/aft.
07-12-09, 01:17 PM
07-12-09, 02:41 PM
don't worry about what you're supposed to do. go for a 30 mile "tweaking" ride and adjust along the way until you get the sweet spot.
07-12-09, 04:21 PM
I'm with illwafer on this. My bikes evolve into a fit over the first several rides. One of my favorite bikes is perfectly set up for the open road. I can tell because it feels stretched out when I first get on, but 45 minutes later it's all compact and comfortable. Make the bike suit you and your riding.
The looking for the hub thing is no more accurate that putting your elbow up against the nose of the saddle and seeing if your finger tips reach the bar. You adjust that by changing the stem, not by moving the saddle. Move the saddle to get the knee over pedal thing right. Which, BTW is just another guideline, not a law. Then change stems to get the cockpit length dialed in.
Adjust the saddle for height (use whatever formula or experience has taught you about that) move the saddle way forward and back with a quick test ride in between to feel for the difference so you know what you're looking for. Then go on the long test rides and dial it in.
Myself, I'd suggest not committing to a real long ride until you're semi dialed in. Sometimes it's easy to get confused and frustrated about a set up and it's nice to not be far from home when you start wondering if maybe it wouldn't be better to just drop the saddle, throw away the pedals and shoes and just Fred Flinstone your way back home.
07-13-09, 08:08 AM
It sometimes takes me a couple months to find the best fit on a new bike. There are a lot of factors involved, and the only way I've found to get it right is to ride a lot and see what works. Unfortunately, you should probably be prepared to buy a stem or two along the way. It might be worthwhile to buy an adjustable stem to use until you find the height and reach you want.
07-13-09, 01:02 PM
The plumb bob thing can be done alone. As long as the bike is sitting on a level surface, drop the plumb bob from the front of the knee to the front of the crankarm, wiht the crank at the 3 O'clock position - that's what expert Andy Pruitt does. It's still just a rough starting point. I prefer to be 10-20mm further back for better weight balance with less weight on my hands.
As for the bars obscuring your view of the hub, that is when viewed with the hands on the brake hoods, not in the drops. In the drops it's common to be sighting over the front of the bars and see the hub. Adjustments are made with the stem length, not saddle fore/aft position. This test has NO meaningful value. I use a functional test, where I insure that I have some knee to arm clearance when I'm pedaling with my hands in the hooks, my upper back is almost horizontal and my fingers can reach the brake levers.
Those who use Shimano brake/shift levers will have a longer reach to the brake hoods than SRAM or Campy users. Reports are that the new 7900 brake hoods are even longer. The 2009 Campy hoods also have 3-5mm more reach than previous models.
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