EGreen

I was looking at a beautifully restored and upgraded Cologno bike, guy said the frame was from the 60's. among other alterations It had a a carbon fork. Got me to wondering about my Motobecane (early eighties), similarly upgraded in components (but not as pretty) and the feasibility of putting a carbon fork on it. Consideration, as always, is that it is a French bike, as far as new forks go is sizing going to be an issue?

I ask this here, because I've sworn off dashing to lbs with every idea I have. I'm going to do this, if possible, on my own.

Thanks!

late

Hi,
the purists will be horrified. Sounds great to me. You'll
need a one inch fork, if you want you can also go threadless, but that's means more parts and money. I'd call around to the bike shops in your area ( or try ebay ) looking for something good, but not too expensive.

https://www.bikemannetwork.com/biking...FKRDPRO/FK1639

EGreen

There's good reason why I didn't post this in C&V Thanks for the link. I might consider going threadless if I can find good instructions on how to do this. I'm seeing some fairly inexpensive forks at Performance that I might go for.

late

Hi,
that's a 1 1/8 inch fork, won't fit. Nashbar used to have tons
of leftover one inchers cheap, guess they're gone. You might call their tech help and see if they have one; and check their returns
section. It's a long shot but worth trying. Keep an eye on the rake,
older bikes had a lot of rake, I'd go with 43 or 45mm, but avoid 40mm.

I like bar end shifters. That's one of my favorite upgrades on an old bike, behind new wheels. Wheels nowadays are so much better than they used to be.

EGreen

Thanks for pointing that out, I thought they were 1'' I'll look around. The forks you linked me to are not bad at all and will be my back up.

Everything has been upgraded on this thing, the only original thing remaining is the frame and as you can see, I'm edging towards changing that too.

I'm sure I'm the antichrist to some of the purest of the purists out there.

stickydpaul

check https://www.chucksbikes.com, I believe they have a one inch threaded carbon aero fork for sale in the fork section. I believe its in the 40-50 dollar range.

EGreen

Turns out Nashbar does have a 1 -incher! However, it is threadless. Can anyone give me a clue about converting to threadless, the additional parts I need to get?

LóFarkas

Headset and stem. Both have to be "1 inch threadless" (surprise, surprise) and the stem needs to have the right clamp size for your handlebar as well. You can use a more accessible 1 1/8 stem with a shim as well, but a 1 inch threadless hs is definitely needed. The two in decent quality will cost $40 or so.

EGreen

Sometimes it helps to actually look at the bike itself prior to posting

LóFarkas

Huh? You posted no pic of that thing and it wouldn't help if you had.

alanbikehouston

Today's generic carbon forks are generally inferior in safety and reliability to the best steel forks of the 1980's. And, their reduced clearance can make the use of wider tires and fenders impossible. Recently, there was a report of a crash caused by road debris getting wedged between a carbon fork and the front tire...there is just not enough clearance.

And, no fork absorbs road shock better than a good steel fork. The classic steel forks were shaped like a "J" near the hub, and had a built-in flex that worked like a shock absorber. Today's straight leg forks send the shock directly into the rider.

Why would anyone want to remove a great fork, and replace it with an inferior fork? Newer ain' always better, but it is often worse.

LóFarkas

Weight? Aesthetics? No corrosion? Any number of reasons.

But probably it's not worth buying a generic carbon fork, agreed. Carbon is a tricky tecnology and many say only the big companies who have the money to do the proper research and then pay skilled people to build their stuff get it right.

TallRider

+2. If I were to upgrade a nice older steel road bike to a Carbon fork, I'd only do it if I got a more expensive carbon fork. Because of the weave aspect of carbon fiber, there's a lot more possible variability in durability and ride quality between cheap and good carbon forks.
Also, where handling is concerned, you might think about what sort of fork-rake you're getting, compared to your current fork.

cs1

Actually, it might be a good move. The headtube I.D. is the same on French and other bikes of the day. See https://www.sheldonbrown.com/velos.html
That means replacing the fork with a standard english fork would mean you can use standard headset, stem and handlebars. Nashbar has carnon forks on sale for $79 for a 1" version. Good luck

Tim

EGreen

The Nashbar fork is what I was looking at. Would this come under the catagory of cheap, generic, piece of junk?

juicemouse

Cheap and generic? Yeah. Piece of junk? Probably not.

EGreen

Done. Bought the Nashbar fork just now. Hopefully this will be yet another alteration to this bike that brings me more pleasure than regret. As always I'll hold on to the old parts.

Not over yet, I still have to get it and install it, I'll have loads of inane questions to post then.

Thanks all for your input!

EGreen

First flat (Impact/front) in a very long time and on my maiden journey with the carbon fork I'd just installed. Coincidence?

Though it has a good rake it is straighter than the steel fork it replaced. Obviously it is lighter. Do these factors, paired with the fact that it is a heavier bike, put more stress on the front tire making flats more likely?

Not stressing though (at least not yet) as the difference in handling is dramatic as the difference between boat and a Porsche. As this is my commuter and I often find myself navigating through heavy mid-town Manhattan traffic, this is not an insignificant improvement.

TallRider

I'd have to say that it is coincidence, or at least there's no mechanism I can think of by which riding with a carbon fork (assuming that it has the same rake, etc.) could lead to a flat. It's possible that some part of mechanically rebuilding the bike could have contributed to the flat - but again I can't think of how.

I'm glad that the handling is improved. However, if I'd known that you were upgrading a steel to a carbon fork for commuting in Manhatten, I'd probably have recommended against it generally. Just that, if you have enough pothole impacts, I'd trust steel more than carbon to not have some invisible damage that could fail catastrophically. Also depends on how heavy you are though, and how often you actually hit bad spots in the road while commuting.

EGreen

For now, I'll trust that it's likely a matter of coincidence.

On the matter of safety, I've been well advised and warned, I do know there is the increased risk of failure with the carbon, but if I concerned myself with the possibility of sudden catastrophes, I'd likely not mount my bike at all, perhaps not leave the house in the morning.

That said, early maddening experience of an insane amount of flats (with 700c's) has made me acutely aware of the surface ahead. I can almost smell a pothole.

cuda2k

We'll find you anyways! Muahahahahaa!

Basically, you'll need a 1" fork, new headset, spacers and stem. Make sure your bike uses 700c wheels not 27" but beyond that you should be alright.

EGreen

Oh it's ancient history now ... I've succeeded in altering this old French tank to the point where all that remains is the frame. It does not stop here Muahahahahaa, next goes the frame itself then all that will remain of this humble yet noble old bike is...well, nothing nothing at all. Muahahahahaa! I'll post its obit in C&V with pics, perhaps eliciting a few tears from those inclined towards Gallic nostalgia. I say, bon débarras!

EGreen

OK so maybe there was a physics lesson I slept through. One of many, no doubt. Why exactly is it that since installing the lighter carbon fork, I lose far more air pressure in the front tire than in the rear when time was the rate of pressure loss would be roughly the same. After a normal length ride I could count on both tires being about ten psi short of what I started out with, now the front tire is always about 20 psi less.

My other (aluminum build) rb with carbon fork has no such issues, but the weight is distributed evenly - no difference felt between front and rear.

So I guess it's just that the front wheel is just bouncing off the pavement more than it used to, huh?

The practical reason this concerns me is that I'd always had a problem with impact flats - which were eradicated when I started being vigilant in keeping the pressure high. Now I'm concerned with the return of routine flats.

Is there anything I can do to compensate? Stronger, slightly heavier tire in the front, maybe?

juicemouse

This can't have anything to do with the fork, the tire, or any weight distribution changes. I'll conjecture that it's simply an old innertube. A 10psi loss after just one ride seems like a lot to me too. What pressures are you running?

EGreen

In the course of the day, I'd say I travel about an average of 40 Miles (often longer) on this bike through city streets. A ten psi loss (from 125 to 115) by the next day when I pump up is pretty typical in my experience. (Further, I'm 185 lbs - which is why I'm so vigilant about tire pressure.)

Ya know, come to think, when I changed that last flat my first choice tube was blown by getting caught between the tire bead and the rim, the second one was questionable to me - though it was in the box it lacked a certain stiffness. Simple enough, I'll get a new tube. Glad to hear on good authority that it's not more complicated than that. Thanks.