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Need forward-leaning seat post(11 posts)

Need forward-leaning seat postChuck
Aug 27, 2001 5:16 PM
I just bought a 56cm Trek 5200, which is the right size for me (5' 10"), but my body geometry is such that I cannot get the seat forward enough to center my knees over the pedals. I need a seatpost that will allow me to do that by either having some kind of angle built into it or some other means, and was wondering if anyone could recommend a seatpost and source for it.

I guess the other option would be to turn the existing seatpost around 180 degrees, but I think that would look funny and might not be as secure. Any ideas?

Chuck
Recheck your measurement...C-40
Aug 27, 2001 5:51 PM
Are you checking the KOP using a plumb bob, with the bike on a level surface and the cranks positioned horizontally? Are you measuring from the front of the knee to the pedal spindle? See coloradocyclist.com for pictures of the proper method. Also remember the setting the knee directly over the pedal spindle is just a starting point. A great many riders, including myself, find this position to be too far forward. I keep my KOP about 1cm behind the pedal spindle even though I'm a fairly high cadence spinner.

It would be unusual to need a special post with the Trek's 73.5 degree STA, unless you're using a MTB saddle like an SDG. These saddles have rail positioning that is made for a more rearward position than most road saddles.

A straight-up post like the Thomson will move the saddle forward by almost 2cm (nominally). I can't imagine needing more forward positioning than this. The Thomson post is available from Excel Sports. Remember that moving the saddle forward will also require a longer stem.
Recheck your measurement...Chuck
Aug 27, 2001 6:55 PM
I am measuring from the knee cap with a plumb bob as you described. Today while riding, I experimented by sitting briefly on the forward edge of the saddle, and I felt much more comfortable pedaling from that position. When I first got it, I had to place a shorter stem on the bike because the handlebar reach seemed too far out, but now I'm thinking that the problem had more to do with the seat position not being forward enough I'm using a Selle Italia X0 saddle on the bike. Is it workable to rotate the seat post to gain more forward positioning?

Chuck
Recheck your measurement...Spoke Wrench
Aug 27, 2001 7:20 PM
If you turn your seatpost around, the angle of the clamp will be wrong and you won't be able to get your seat level.

I've never met you and I haven't seen your bike, but what you are saying sounds strange to me. I'd recommend getting a professional fit or at least having someone familiar with bike fit check your measurements before spending fairly big money on an unusual seat post.

How does the rest of your bike fit?
Recheck your measurement...Chuck
Aug 28, 2001 4:10 AM
I have checked my measurements and by all counts, the seat is too far back. Because of that the reach is a stretch to the handlebar drops even with a shorter, higher-angled stem, and as I said, I cannot sit with my knee caps directly over the center of the pedals. That is why I think a more forward-leaning seatpost will allow me to move the seat further forward, reducing the handlebar reach and allowing me to be centered over the pedals. My problem with fit is that most of the LBS's here are more focused on selling new bikes than in fitting, and since I bought this bike used I'm not having much luck getting good fit advice from them. I've been using the on-line calculators and fit guides like Zimmerman's and coloradocycling.com for guidance as well as my experience in riding the bike...

Chuck
Recheck your measurement...jtolleson
Aug 28, 2001 6:35 AM
Chuck, please go to an LBS that offers a good fitting. Unless you are totally and completely disproportionate (which you'd probably know from, say, clothes shopping) what you are describing makes no sense if the frame is otherwise the right size for you.

If you tell where you live, maybe one of us can give a good suggestion on bike shops.

And if you are absolutely right and we're all absolutely wrong, my humblest apologies, and yes there are seatposts that will bring your saddle forward; they are popular on Tri bikes.
reach shouldn't be a problem....C-40
Aug 28, 2001 9:17 AM
If you're 5'-10" tall, with the saddle pushed all the way forward, the reach to the bars shouldn't be a problem. You may be suffering from beginners lack of flexibility.

One functional test of stem length is to check the clearance between the knee and elbow, when you're pedaling with the hands in the drops and fingers within reach of the brake levers. The knees and elbows shouldn't overlap. Any small amount of clearance is OK. Lots of clearance is not necessary. Overlapping, particularly is you have short femurs(upper leg)would be a clear indication that your stem is on the short side.

Post the actual length and angle of your stem, and the type of post you are using.

I'm only 5'-7" tall with a 32-5/8" inseam. If I rode a Trek, it would be a 56cm, because Trek's frame measurement method makes it similar to a 54cm frame, measured center to top. The Trek does have a long top tube, so I'd probably use a 100mm stem. If I was your height, I'd probably need a 110 or 120 stem.
reach shouldn't be a problem....Chuck
Aug 28, 2001 12:04 PM
Thanks for all of the suggestions and responses. I ordered a Profile-Design Fast Forward seatpost and I'm hoping that will solve my problem. Part of my problem is that I am not accustomed to the forward riding position of a road bike since I've been riding a hybrid for many years, but my body geometry (short inseam) combined with the longer top tube and seatpost angle of the Trek 5200 to make it difficult to center my knees over the pedals and to comfortably reach the handlebar drops. I'm hoping that the new seatpost will solve that for me. Again, thanks for all of the input and responses...

Chuck
Murphy's LawSpoke Wrench
Aug 28, 2001 3:33 PM
A few year's back, NASA had a series of sayings called Murphy's Laws. One of them was: "Once something is screwed up, anything you do to make it better only makes it worse."

How does the rest of your bike fit?

It sounds to me like you have a major underlying fit problem, maybe a bike frame that is just plain too big. If that's the case, there's no adequate retro-fit. You're just going to trade one problem for another.
Murphy's LawChuck
Aug 28, 2001 5:52 PM
You may be right--I guess the new seat tube will tell the tale and that a 54cm frame would be a better fit. But two different bike shops measured me and both recommended 56 or 58cm, so I'm guessing that the seat tube will do the trick. The bike is ride-able even now, with no severe symptoms after riding it hard for a few hours at a time. What I'm looking for is ideal fit, and I'm hoping that the extra inch or so will allow that for me.

Chuck
Try Corimagreyghost
Aug 31, 2001 11:43 AM
Corima makes an excellent reversible seatpost. http//:www.corima.com You can buy it http//:www.bullteksports.com it pricey but if it works, it is worth it.