matt0ne

I finally took the Gios down to Tacoma Bike to dial in the RD - turns out the Chorus/Syncro group from this era is crap. The mechanic was awesome, gave me a mini-tune up and waive the fee! Cannot recommend this place more (apart from them making fun of my frame and gruppo!!)

During the tuneup the Mechanic identified a bit of movement in the headset. We made sure I had put the bearings in the right way (and much to my relief we had) and then he made the appropriate adjustments. I got some bar-tape on this morning and took it out for my first test-ride - the thing is a joy to ride! Super-light, stiff and rides like a dream! (at least compared to the heavy Battaglin)

Anyways, any time I hit the front brakes the front end shudders like nobodies business. When I was putting the thing together I was curious that the only thing beneath the bottom bearings was a small plastic seal. Am I missing something? The mechanic didn't seem to have any concerns about the assembly of the headset. I was really hoping to ride this thing to work today, but now I'm not so sure.

cudak888 

Any play in the monoplaner arms?

-Kurt

matt0ne

Nada, all the play seems to be at the base of the headtube/bottom-cup of the headset. The brake-pads are jagwire if that provides any more info.

cudak888 

Is the crown race sitting loose on the fork crown?

-Kurt

matt0ne

The brake pads don't seat 100% on the rims - could that cause the shudder?

And, no it doesn't seem like the crown race is loose.

TheOtherGuy

I'd also take a look at the front wheel. Hub bearings, spoke tension... If all else fails, replace the headset or parts of it, and test again.
Though not as pretty as the Record headset, you may try replacing it with a Stronglight Delta or A9 (or other roller-bearing type).

Bianchigirll 

I am not sure you can have play in those brakes.

how di you install the plastic seal? it 'snaps' on the crown race from the bottom before install ing the crown. you can fiddle with it and get it around an already installed crown. it looks like yours is on the top

you need a bit of patience with the early Synchro systems. the insert, chain, RD and freewheel all need to match. also the Chorus RD is set on A+A ot B+B for a wider FW?

for example (accordng to the Campi book from '91) if your running a cose ratio Shimano DA 7spd FW, the RD is in A+A and you need a green 7spd insert, a Regina chain would be best and Shim 600UG next,

matt0ne

BG, I think you may be right about the plastic seal. I did not snap it on, it is in fact on the top. Good call. As to the rest of the stuff you talked about, I barely understand what you're talking about. Can you elaborate on the A+A info?

Bianchigirll 

if you look at a Chorus RD it has little marks A or B on the upper pivot and the cage where they mount to the central body. A has to be aligned witht he little hash mark on the body at both ends for a narrow ratio FW and B for a wide FW.

this is used to change the agngle of the RD so the jockey pulley tracks closer to the cogs. if it is set in A on one end and B on the other it would seem like it is twisted.

you do have an early Chorus RD yes?

nwbikeman

I am looking at the copper color portion of the crown race, is the crown race on upside down? If you like send me a message and I would be happy to look at it for you.

matt0ne

Thanks to nwbikeman for giving me a call and talking through some troubleshooting! BF continues to surprise me. It was also odd speaking about and referring to Bianchigirll and actually having someone know who the hell I'm talking about! Thanks again.

We thought we might have dialled the issue down to the brake pad not hitting the rim parallel so I got some new pads, but the issue appears to continue. On one side at the front one pad doesn't still sit entirely parallel. I can tell you the mechanic at Tacoma Bike was right - these Chorus levers are C-R-A-P!

On a lighter note, I rode it to and back from work and it was an absolute delight! Even though it's got a tiny freewheel, I climbed the one serious hill with almost no effort at all. I LOVE this bike - now if i can just get the shudder and RD/Freewheel issues dialled in! Any good suggestions on a good replacement FW?

Bianchigirll 

so HS is installed correctly? I am not sure we have seen this bike just yet.

when you say the pad does not hit parallel do you mean either the front or rear is hitting first? what kind of new pads are you using? I am not sure if this will cause a shudder but I do feel, and I think others will agree, that if your new pads are not close to the demension of the original the brake will not function as well as it should.

what condition are your rims in? actually what are they? are they annodized? how are you testing the HS? just grabbing the front brake and rocking? the Trackie trick and place the front wheel against a wall and push forward from the drops.

**I can tell you the mechanic at Tacoma Bike was right - these Chorus levers are C-R-A-P!***

just what does he mean by this? I think hte brake levers from this era are some of the nicest on the road. which lever do you have? are you missing the inserts that make the aero?


One thing about the brakes, dispite the massive and strong look of them they were never intended to stop on dime. I 'l have to look around and see if I can find some old advertising but the brakes were designed to modulate speed. in all the miles I have on a Chorus brake equipped bike I don't recall ever locking up a wheel under heavy braking. actually alot of my bikes have some model of the Monoplanor brake.

you were talking about me????

miamijim

It doesnt lok the lower part of the headset is installed correctly, from the pic it doesnt seem like the fork race is up into the cup far enough...although it could be the lback seal thats out of place.

Clean your rims with rubbing alcohol or aceteone and lightly resurface the brake pads with a file or sand paper.

matt0ne

yes - I referred to you a couple of times!

Bianchigirll 

but what about the HS????

matt0ne

Looks like the headset is on tight.

jan nikolajsen 

Stick another caliper on there for a quick test to rule out brake issues. I have had funky, incurable vibration problems w Monoplanars in the past.

matt0ne

So, I replaced the front wheel and it worked great. So, is that the fix? replace the rims? That seems a bit extreme..

MrEss

Sounds like your brake, fork, brake pads, rims, and maybe even tires don't like each other.

I'd be willing to bet a dollar that replacing any one of those things would make the problem go away... that it's the whole system working together to shudder and tweaking it even a little would break the cycle.

DRietz

Check your hub bearings for play.

dbakl

Squeeze the front brake and rock the bike forward and back. If you feel movement its a loose headset or loose caliper arms.

Drillium Dude 

Since you changed out the wheel and all is well, I would say there is play in the hub bearings in the removed wheel.

I get the exact same issue with my Sparrow; headset is good - perhaps just a tad too tight, but I like 'em like that - but there is a little bit of play with the front Phil Wood hub. Lock the front brake and rock: no issues. Pick up the front and lightly drop: rattle. Hub bearings are more than likely your culprit, too.

I'm not at all suprised at your assessment of the climbing ability of that rig - my Compact was the stiffest, best-climbing bike I ever owned.

DD

matt0ne

So.... rebuilt the front hub, adjusted the cups and still! That damned shudder! - I'm riding a dura ace wheel on the front right now and that's working. I'm not going to worry too much about it, since I'll be upgrading to an 8-speed wheelset soonish. _ I'll just keep switching the front between the bikes!