Scary Merckx AMX handling issue - help needed

[phcollard]

Howdy folks!

A friend of mine wants an alloy Merckx and since I'm in Belgium I looked in the local classifieds and purchased a barely used AMX-1 yesterday. We are exactly the same size, same contact points, so I though I could take it for a spin.

As soon as I hit the road I could feel the handling was a bit twitchy but still manageable. The bike felt like it was caught in crosswind although there was no wind at all. I though that was a geometry feature or something.

That's when I started descending that things looked worse : when braking - either front or rear but especially rear - the bike starts to wobble badly. It's not shimmy but rather a slow "S" motion, or weaving. The bike wants to go left, then right, then left every second or so. You can definitely feel the pressure in your hands and if you don't take care that bike will go sideways without notice.

That's downright scary and I don't think that's a feature now! The bike is unmanageable at slow speeds especially when braking. It's like brand new. I was told it was ridden for 100km then stored and I would believe it. There is no sign of crash. Everything looks aligned. Headset is tight enough...

I'm a bit lost. Any idea?

[nighthawk]

Sounds like:

1) loose headset
2) cracked tube (near bottom bracket or tube junction)
3) possessed by demons

[oldpotatoe]

Howdy folks!

A friend of mine wants an alloy Merckx and since I'm in Belgium I looked in the local classifieds and purchased a barely used AMX-1 yesterday. We are exactly the same size, same contact points, so I though I could take it for a spin.

As soon as I hit the road I could feel the handling was a bit twitchy but still manageable. The bike felt like it was caught in crosswind although there was no wind at all. I though that was a geometry feature or something.

That's when I started descending that things looked worse : when braking - either front or rear but especially rear - the bike starts to wobble badly. It's not shimmy but rather a slow "S" motion, or weaving. The bike wants to go left, then right, then left every second or so. You can definitely feel the pressure in your hands and if you don't take care that bike will go sideways without notice.

That's downright scary and I don't think that's a feature now! The bike is unmanageable at slow speeds especially when braking. It's like brand new. I was told it was ridden for 100km then stored and I would believe it. There is no sign of crash. Everything looks aligned. Headset is tight enough...

I'm a bit lost. Any idea?

Puts some stress here and there, like grab the rear wheel and pull left/right//look at BB..sounds like perhaps something is cracked..or maybe a wheel/hub problem..

[phcollard]

Thanks to both of you,

I inspected every square inch of the frame and there is absolutely no sign of crack in any tube.

I also switched the wheels with my other bike I have here but still the same.

The headset is a cheap FSA integrated. There is no play in it when I rock the bike front to back holding the front brake tight - that's how you check it right? But I noticed the top "dust" cap is touching the headtube edge even if the headset is barely tightened. Could it be the issue? Like in this case the bearings are not preloaded enough?

[Cicli]

Thanks to both of you,

I inspected every square inch of the frame and there is absolutely no sign of crack in any tube.

I also switched the wheels with my other bike I have here but still the same.

The headset is a cheap FSA integrated. There is no play in it when I rock the bike front to back holding the front brake tight - that's how you check it right? But I noticed the top "dust" cap is touching the headtube edge even if the headset is barely tightened. Could it be the issue? Like in this case the bearings are not preloaded enough?

That dust cap touching could be an issue. Pull the dust cap off and just use another spacer in place of the cap temporarly.

[oldpotatoe]

Thanks to both of you,

I inspected every square inch of the frame and there is absolutely no sign of crack in any tube.

I also switched the wheels with my other bike I have here but still the same.

The headset is a cheap FSA integrated. There is no play in it when I rock the bike front to back holding the front brake tight - that's how you check it right? But I noticed the top "dust" cap is touching the headtube edge even if the headset is barely tightened. Could it be the issue? Like in this case the bearings are not preloaded enough?

Check to make sure the top of the fork, by the crown, isn't rubbing on the bottom of the head tube or the top cap isn't rubbing the head tube, like you mentioned. We had a Scott frame do this..made handling wonky.Acts like a steering dampener.

[phcollard]

Check to make sure the top of the fork, by the crown, isn't rubbing on the bottom of the head tube or the top cap isn't rubbing the head tube, like you mentioned. We had a Scott frame do this..made handling wonky.Acts like a steering dampener.

The top cap is indeed rubbing the top of the head tube. I am wandering if this prevents the bearings to be properly preloaded?

Is there any quick and dirty way to solve this? I'm lost here with no tool except a cheap Park multitool :)

[CNY rider]

I would get that headset out of there.
I've felt that scary feeling before and it was from a set of headset bearings not seating properly.

[nighthawk]

Might be worth unwrapping the bars and inspecting them, too.

[oldpotatoe]

The top cap is indeed rubbing the top of the head tube. I am wandering if this prevents the bearings to be properly preloaded?

Is there any quick and dirty way to solve this? I'm lost here with no tool except a cheap Park multitool :)

Not easy..you need some spacers under the top cap, to raise the top cap off th headtube..then adjust the HS properly...I would also ensure the bearings are lubed, seated..and again, the fork crown not rubbing on the head tube.

[phcollard]

Not easy..you need some spacers under the top cap, to raise the top cap off th headtube..then adjust the HS properly...I would also ensure the bearings are lubed, seated..and again, the fork crown not rubbing on the head tube.

Thanks very much OP. Mmmm... Sounds like too much work and trouble for me such a long way from home. I'm going to think about it. Either I pack it and bring it back to Montreal as planned and fix it there or I'm going to drop it on the local classifieds where it comes from.

[oldpotatoe]

Thanks very much OP. Mmmm... Sounds like too much work and trouble for me such a long way from home. I'm going to think about it. Either I pack it and bring it back to Montreal as planned and fix it there or I'm going to drop it on the local classifieds where it comes from.

Had the Scott and also a VeloVie have the same thing..fork crown rubbing on head tube..both were warranty fixes..unable to space the lower bearing or FCR...cuz there wasn't one, a 'race'.

[phcollard]

Had the Scott and also a VeloVie have the same thing..fork crown rubbing on head tube..both were warranty fixes..unable to space the lower bearing or FCR...cuz there wasn't one, a 'race'.

Another proof that technology is a great thing. That was the first bike I purchased with an integrated headset. Probably the last. And I don't even mention new BB "standards" :mad:

[ultraman6970]

IMo you can find better than that since you are in belgium/holland area, specially if the bike has issues.

Probably the guy put the wrong bearings in the headset or something?

[chrisroph]

I had an aluminum merckx race that had a headset that either was loose or binding. The handling was horribly poor. I had the lbs work it over--the headtube had to be refaced top and bottom--and install a new headset and the bike has been rock solid under a friend who has ridden the piss out of it for the last 5 years.

[phcollard]

I was able to bypass the issue of top cap rubbing the top of the head tube by putting a spacer between the top cap and the bearing.

That is definitely a headset issue because it's much better now. Only problem I have left is I can't preload the bearings enough because the damn cheapo steerer tube insert keeps popping up as soon as I tighten the headset cap.

Also that must be a cheap headset as well. There is a visible gap between the side of the bearing and the head tube as you can see in the pictures. Is this normal? Any recommendation for a better headset? I know nothing about those integrated thingies.

http://dl.dropboxusercontent.com/u/3032014/paceline/headset-2.jpg

http://dl.dropboxusercontent.com/u/3032014/paceline/headset-1.jpg

[merckx]

Merckx carbon forks of that vintage were made by Advance. Many had steerer tubes with eccentric ID's. This caused the internal bung to loosen that resulted in a perpetually loose headset. You may want to check the steerer spec.

[soulspinner]

I had an aluminum merckx race that had a headset that either was loose or binding. The handling was horribly poor. I had the lbs work it over--the headtube had to be refaced top and bottom--and install a new headset and the bike has been rock solid under a friend who has ridden the piss out of it for the last 5 years.

seen this before, could be...........