Expert steerer/fork advice needed
 

Here is the set up:

49 cm 1989 Schwinn Prelude frame built up for a run around bike, 9 speed etc. Everything on the bike is new including the frame but that is another story. 700Cc wheels. Might also add this frame has a short headtube, only 3 ¼ inches and was sold as Schwinn's mid-entry level racing frame in 1989.
Fork is an Edge carbon 45 rake 1” steerer with a threaded headset.

Here is the problem:

Took it out for a first ride. The thing steers like a tank. I have never encountered this on any bike I have built. It did not matter what speed, just sluggish to steer. The headset is properly installed and when the bike is not moving the front fork/wheel turns right to left smoothly with no issues. The wheels are true and no hops or anything. I did not even want to grab a water bottle for fear of setting the thing down is how bad it rode. Is difficult to steer in both directions(right or left).

Honestly if someone was following me on the ride they would have thought I was on my way home from the pub or something. I need to find a solution to this problem. Any ideas? Right now the only redeeming factor is that my ride included an upper body workout.

Several ideas come to mind: Wrong fork rake for this frame? Fork is just a POS? Headset not really installed correctly? It appears to be in correctly. Thanks.

Do you have the original fork, so that you could measure the original rake? It sounds like the new fork has messed up the steering geometry to me, but it's hard to say for sure.

Here's the '89 Prelude catalog page:
http://www.trfindley.com/flschwinn_1...9_Ltwt_08.html

Should have added that the frame had no fork when purchased and since this was a pre bankruptcy Schwinn I have not been able to get any real info about the original rake, etc. Thanks.

Also thanks for the Schwinn catalog link. Great stuff.

The thanks should really go to BF member Scooper, he scanned all of the 1980-1990 catalogs on that site.:)

Here's another page from 1989, the specs page. But unfortunately, it doesn't list the amount of fork rake.

http://www.trfindley.com/flschwinn_1...9_Ltwt_16.html

Did you do all the assembly work? ie. installed the headset cups, fork race, bearings.
Is this the GT Aero Edge CF fork? The steel steerer interfaces into carbon. Can't hammer a race on.
Sounds like there's binding once weighted. I'd recheck the bearings, some use different dia. balls (ie. Campy), fork crown for cracking, then reassemble and fine tune and try again.
There is a chance given such a small frame that the shallow head tube angle is creating so much trail with this fork that it's causing your condition.
Any profile pics of the assembled bike?

On the road right now so when I get home I will put up what pix I have. Not sure of the exact model of the fork. Says Edge on the side, not the straight bladed style.

So if too much trail is the solution, which should be used a fork with less or more rake. From the catalog postings I have found according to the paint scheme the bike is a 1988 not 89. Also they list a wheelbase for the 23 inch frame at 39.75 inches. This wheelbase measures at 39.25 right now.

I did all the assembly and have built up at least a dozen bikes, in other words, not my first project.

Would the 49cm frame use a 650c wheel and fork?

More rake equals less trail, which means faster handling characteristics. Less rake equals more trail, which slows the handling down.

Also, the wheelbase will vary depending on frame size. And it's quite possible that the amount of fork rake also varied some depending on frame size.

I'm not sure what the bike's steering characteristics are from your description. You said "steers like a tank" which, to me, meant it was extremely stable in a straight line but reluctant to turn. Then your later description made it sound like you couldn't keep it in a straight line as it continually wanted to wander. Can you clarify?

The first behavior can come from too little rake and too much trail which makes for great straight line stability but poor turning responsiveness. The second behavior is characteristic of too much rake and too little trail which makes for extreme responsiveness and poor stability.

Hmm.. I scanned the catalog photo of the 1989 Prelude and used a Gerber Variable Scale to derive dimensions using the wheel bead diameter (622mm) as a fixed dimension. All of the '88 and '89 Preludes, including the small frame sizes, were equipped with 700C wheels.

The catalog photo is of a 23" (58cm) frame, and the head tube angle for the 23" frame is listed in the specifications as 73°. I'm not sure whether the 19" (48.5cm) frame had a different head tube angle or not. I know the 1988 19" road Paramount frames had a 72° head tube angle, while the 1988 23" road Paramount frames had a 73° head tube angle, but am unsure of whether or not Schwinn had the more relaxed geometry on the Prelude smaller frames.

It looks like the 1989 Prelude frame I scanned has ~45mm fork rake which, with 700C wheels and a 73° head tube angle, gives it ~50mm of trail, which should provide great handling.

If the OP could provide a profile picture of his bike taken at some distance and using a telephoto lens to minimize distortion, we might be able to see something amiss. Based on conversations with many late eighties Prelude riders, I can say with certainty there's something wrong with the OP's bike; it should handle like a dream.

http://i32.photobucket.com/albums/d7...keandTrail.jpg

Excellent response from Scooper!
I agree that 50 mm of trail should be good though I prefer more, closer to 60. I don't think the bike in question should handle like a tank unless there is something wrong with the headset or frame.

Here is a link to a bicycle steering trail calculator, best to insert metric values:

http://www.kreuzotter.de/english/elenk.htm

I very much agree but I'd still like a clear definition of what "handle like a tank" means to the OP.

I'm very suspicious of the head set bearings, especially the lower one.

Just got back from all day travel and this appears to be the issue. Disassembled the thing and the bearings tumbled out of the holder. I hate the expression, my bad, but this appears to be the case.

My tank steering description maybe should have been modified that it was just hard to steer. Would track ok but was just hard to turn while riding but with no load on stem(no rider) it acted like a normal fork should.

Will report back once either replacement bearings are found or a new headset is installed.

Thanks to all who replied and Happy Holidays and good riding to all.

Good point, I understand that an M1 Abhrams handles very well.