Help With Fork

[santambrogio]

The no. 1 bike uses a 1" Ouzo Pro fork 1" carbon steerer, 1cm spacers, with Cinelli Solido bars and 110 stem the steerer just flexex too much when climbing or off the saddle. What is worst is that there is a great deal of vague mumb steering feel while descending especially while braking into a turn. Afew days ago the no. 2 bike was used because no.1 needs cable replacements, no. 2 a '85 Pinalrello Montello SLX frame & fork with Cinelly threaded stem & bar just descends better. I think because of the more rigid steerer. A dispapontmnet that the modern cistom Foco bike does not handle as well as the 22 yo bike.

Should I try 36 spoke wheels like the old bike insteand of the 32's on the new?

How about the Serotta F series forks in its most rigid version?

Asking the same question on a framebuilder forum a builder compared cf steeres to a cf fishin pole, the same person suggested a Alpha Q fork that ha a metal sleeve at the stem and steerer.

[barry1021]

The no. 1 bike uses a 1" Ouzo Pro fork 1" carbon steerer, 1cm spacers, with Cinelli Solido bars and 110 stem the steerer just flexex too much when climbing or off the saddle. What is worst is that there is a great deal of vague mumb steering feel while descending especially while braking into a turn. Afew days ago the no. 2 bike was used because no.1 needs cable replacements, no. 2 a '85 Pinalrello Montello SLX frame & fork with Cinelly threaded stem & bar just descends better. I think because of the more rigid steerer. A dispapontmnet that the modern cistom Foco bike does not handle as well as the 22 yo bike.

Should I try 36 spoke wheels like the old bike insteand of the 32's on the new?

How about the Serotta F series forks in its most rigid version?

Asking the same question on a framebuilder forum a builder compared cf steeres to a cf fishin pole, the same person suggested a Alpha Q fork that ha a metal sleeve at the stem and steerer.

but some people find them flexy especially on larger frames. I use carbon forks with alloy steerers, I don't need to save the weight.

[labratmatt]

I have a 1 1/8 Ouzo Pro fork on my race bike and it's stiff as can be. Fantastic ride.

For a front wheel, I don't think going to 36 spokes is going to do anything for you. I guess you've tried a different front wheel (just to make sure your issues aren't being caused by a using a low tension wheel)?

What type of stem are you using. I've noticed that my Ritchey WCS stem flexes a lot more than my Thomson Elite X2.

[Peter P.]

No; the only thing to solve your problem is a fork with a STEEL steerer. Neither carbon or aluminum steerers in 1" diameter are stiff enough for the application, which is one reason why road bikes quickly gravitated towards the 1.125" standard; to take advantage of those materials' lightweight properties yet retain the rigidity of the standard bearer-steel.

I'd be curious to know if anyone currently manufactures a 1" steel steerer carbon fork.

[santambrogio]

The bike is 54 cm Mondonico Foco, me is 165 170 lbs.

when spinting or climbing I can see more tha 1/4" movement at the hoods. the stem (cinelli solida & cinelli solida bar) does moove suggesting that the steerer flexex, I've loweres the spacers to 1 cm.

The handling just is not crisp as revealed by the old bike comparo.

I like the F3 fork that comes in 3 levels of stiffness, any experinence anyone?

On this forums there are several complaints on the CF 1" forks. Roding motorcycles in the canyons has been good practice for pedal bike cornering.

I did buy a chromed matching steel fork but am reluctant to use it as I like the old school frame and modern components on the bike.

[michael white]

personally I'd at least try the steel fork.
that's probably the answer, and it wouldn't cost much to find out.

[Ken Robb]

if you need a 1" fork a Serotta F1 sounds like just what you seek.

[vaxn8r]

I'm a lot bigger than you and I have a 1" CF Ouzo Pro on my Legend. It handles like a dream on descents and curves. I wonder if it isn't the fork as much as the frame build. Is Foco an ultra light tubeset?

[santambrogio]

The Foco tubeset is now 3 yars old and replaced by another set (life?)

No, it's not ultralight, the bike is fine and confortable, but it just does not handle as well as the '85 slx Montello. The problem is entering turns braking on turns or even straight descents, if there is a bit of wind the bike feels reallly vaugue, on a long straight descent I had wobbles to the point that I had to stop.

Lowering the spacers from 2cm to 1cm helped and changing to a 2 cross 32 whell to a 3 cross 32 also helped but we still got a bike that is vaugue.

Is the F3 available in a 1" steerer?

And I agree with the previous poster that suggested just using the steel fork, this will confim if the problem is realy the 1" carbon steerer.

[soulspinner]

Are you sure its all steerer flex? A change to a beefier stem like a Deda Newton or Thomson may take out some flex. It made a huge difference even to steering feel on my foco tubed bike. I would try this before changing forks.

[Peter P.]

I did find one manufacturer of 1" steel steerer carbon forks, Wound Up. Very highly regarded.

http://www.advancedcomposites.com/woundup.htm

Your "vague" steering could be due to the wrong fork rake. You will have to find out what the rake of your current fork is, along with your frame's head tube angle, then either consult a framebuilder or post your findings here for very good opinions on whether it is appropriate for your bike.

[cpg]

I've never experienced this in regards to bike handling. What are people talking about? I've heard people claim changing to a stiffer stem or fork made the difference but I don't really buy that. I mean if I turn the bars the wheel turns. There's no delay in the turning due to the flex of any component(s). Even at speed the force it takes to turn the bars and subsequently turn the front wheel is not enough to deflect even the most flexible stem or steerer. Perhaps this vagueness has to do with geometry? That makes sense to me sort of. I've commented before about how we as cyclists have a lingo but not all of it is understood. This is a sincere attempt to understand the notion of vagueness.

Curt

[soulspinner]

Its not a delay I feel turning. Its a less than direct feel in the corner at speed on anything but perfect pavement. It may not be more or less safe, but it feels that way.

[Peter P.]

CPG, I agree that "vagueness" is a "vague" term. I interpret it to mean the feeling I've experienced on bikes with low trail figures, that's why I suggested he look into the fork rake as the culprit.

[santambrogio]

Rode the old steel fork bike again Saturday down a rwisty canyon and it prooved gain that the 1" carbon Ouzo Pro is just too flexibble.

The 1st step is get the head angle and see if the fork has the right offeset.

Thanks for the good advice, i've found here numbers for each head angle and its corresponding offset.

By wathching the stem moove I can see that the flex occurs above and inside the headtube. To minimise this I've reduced spacers from 2 cm to 1 cm.

[djg]

Something seems wrong. I have an ouzo pro fork with a 1" steer tube on my CSi and I don't see how you can get 1/4" of lateral movement out of the length of tube you have above the headset, which is what should be subject to whatever load you're applying -- one cm plus the height of the stem clamp? I've not used that stem and bar set, which could be part of the problem, and I don't know that the fork is right for you or your frame (although it works for me), but there's no way that length of CF tubing should be bending that much.

[gt6267a]

I've never experienced this in regards to bike handling. What are people talking about? I've heard people claim changing to a stiffer stem or fork made the difference but I don't really buy that. I mean if I turn the bars the wheel turns. There's no delay in the turning due to the flex of any component(s). Even at speed the force it takes to turn the bars and subsequently turn the front wheel is not enough to deflect even the most flexible stem or steerer. Perhaps this vagueness has to do with geometry? That makes sense to me sort of. I've commented before about how we as cyclists have a lingo but not all of it is understood. This is a sincere attempt to understand the notion of vagueness.

Curt

fantastico! i don't have nearly the experience of cpg, but i really enjoy your posts of this nature!

[RPS]

Something seems wrong. I have an ouzo pro fork with a 1" steer tube on my CSi and I don't see how you can get 1/4" of lateral movement out of the length of tube you have above the headset, which is what should be subject to whatever load you're applying -- one cm plus the height of the stem clamp? ....snipped......Clarification is needed on where the ¼-inch of “lateral movement” is being observed. I’d guess that he means at the bar end of the 11-cm stem, not at the steerer-end.

While riding I can feel flex easier than see it because the stem moves along with the front wheel, making it impossible for me to see relative movement between the two with any accuracy. Having said that, when I clamp the forks of most bikes I own in a rigid mount and twist the bars GENTLY as if I were steering the bike, the bar end of the stem can pivot ¼-inch side-to-side (much easier on some than others).

We must keep in mind that steerer tube flex even when inside the head tube allows the stem to rotate in all directions – it’s just a matter of magnitude.

[santambrogio]

Clarification is needed on where the ¼-inch of “lateral movement” is being observed. I’d guess that he means at the bar end of the 11-cm stem, not at the steerer-end.

While riding I can feel flex easier than see it because the stem moves along with the front wheel, making it impossible for me to see relative movement between the two with any accuracy. Having said that, when I clamp the forks of most bikes I own in a rigid mount and twist the bars GENTLY as if I were steering the bike, the bar end of the stem can pivot ¼-inch side-to-side (much easier on some than others).

We must keep in mind that steerer tube flex even when inside the head tube allows the stem to rotate in all directions – it’s just a matter of magnitude.

That is exactly what I see happening the cf steerer flexes in between the HS bearings. The 1/4" deflection os athe top front of the hoods sprinting or climbing.

[RPS]

That is exactly what I see happening the cf steerer flexes in between the HS bearings. The 1/4" deflection os athe top front of the hoods sprinting or climbing.I figured that was probably what you were describing, although I can't personally see it while riding.

IMO flex like you describe is cumulative, not just due to flex in the steerer tube. The blades can contribute a significant amount.

[Steve Hampsten]

1/4" of flex? really? can you see it?

and our head isn't moving, right? at all?

you may need a new bike.

[santambrogio]

1/4" of flex? really? can you see it?

and our head isn't moving, right? at all?

you may need a new bike.

Yes I can see 1/4" at the top of the hoods, on the rollers I can look directly at the handlebar and If I push up and down while standing there is that amount of deflection. I understand that not all of it is the steerer, an amount is in the handlebars, cinelli solida not oversize at the stem (not Max).

If the problem did not exist why is there this fix for sale:

http://www.cornercycle.com/custom_carbon_fork_insert.htm

This insert is thicker than the Alpha Q equivalent and seems to address the problem of the CF tube bending and deformning or crushing at the stem's clamp.

Here is a history of what done to this fork:

1. 1st install: 2.5 cm (max allowed by Reynolds) spacers with 110 mm stem inevrted. Steerer 2mm below top of stem. Serius wobbles, very vaque feel while braking into turns. Had to stop one on a descent as the wobbles would not stop. Ordered a steel fork from the builder and not installed it.

2. Thinking that this might be the front wheel changed from a 2 cross 32 to a 3 cross 32 This after a few spokes ripped off a flange out of the campy record hub on a bumpy turn. This improved things a little.

2. Cut steerer tube shorter to limit deflection above the upper HS bearing to obtain this: 10mm of spacers below the stem and 5mm of spacers above the stem, this was not not for future adjustability, but to keep the top of the steerer from being deformed by the stem's clamp and avoid the stem being 2mm above the streerer to allow for the top cap. The stem was also flipped to its right side up position to reduce lever to the steerer.

This improved things the most but it is still not at the level of precision that the steel fork has.

The insert above is the next simple check, on this forum I've learned that there is a neutral fork rake that correponds to a head tube angle, maybe the CF fork is the wring rake, maybe or not the steel fork is right, this might take care if the vegueness but not the deflection.

The last resort is to have a fork built if the CF and the steel ones are of the wrong offset.

I was on the rollers yeasterday on the steel forked bike and it feels more precise more responsive to the small quick corrections on the rollers. On the CF fork bike if can see the front wheel mooving longitudinally if I push up & down while standing. I do not seel the fork blades bending but I do see the forks mooving. The steel forks do this too, but much less.