Colnago fork upgrade

[123GO]

Afternoon all. I'm thinking of replacing the fork on my Colnago epq with either an ENVE or working with a dealer to obtain a c60 fork. Regardless of the rim I'm only able to fit 23mm tires and would like 28mm tires. Another bike isn't in the cards now and I love my Colnago! Has anyone done this?

[mrd]

I've got an Extreme Power and an Extreme C and can squeeze Gp4000S2 25mm on Zipp 202 NSW's or 25mm Vittoria's much more comfortably on Fulcrum Zero 15mm internal, no problem at all, not even close to frame rub. Star Carbon/Carbon 75 fork on both. Not all 25mm tyre and wheel combinations are equal. I also have a spare Star Carbon fork.

[AJS914]

I have a later C59 (same clearance as C60 I think) and a 25mm GP4000 on a wider (18mm internal) rim fits. Actual width is about 27mm. That said, they barely fit.

The main issue on my C59 is the height of the tire. And the GP4000 is a tall tire. Reports indicated that for example the GP5000 is 1mm smaller in height. BRR measures height and width on all the tires they test.

https://www.bicyclerollingresistance.com

I don't think you are ever going to fit a 28mm tire no matter what you do.

[pdlpsher1]

Colnago forks have a short CTA (crown to axle) distance. This means the front brake is mounted closer to the axle and hence limited tire height clearance. A tall tire will not clear the brake but this not a brake issue which many people who don't understand CTA are lead to believe. Enve forks may have a lightly longer CTA but it won't satisfactoryly clear a 28mm tire. When I had my custom bike built I found one fork with a long CTA and that is the Trek Domane fork. The good news is that there are no markings or logo of any kind so it will go well with your Colnago (they come in many colors and I got the black). The bad news is that the fork is direct mount brake only. The fork is light and well built, and came with an integrated crown which saved me a lot of weight by not having to use the crown from my CK headset. The cost is $300 and you can order one from any Trek dealer. This fork clears a Panaracer GravelKing 32mm tire (actual measured width 30.5mm on 17C rims) with 2.5mm of clearance on each side.

ps this is a tapered fork and I don't know if it will fit on your C60.

[123GO]

Guy's, thanks so much for the answers! I'll reach out too a few shops in three area and see how to put this together. Really appreciate the help!

[Calnago]

If you can get a C60 fork, I think that would be the way to go on that bike, to maintain the overall look and handling characteristics. It’s got the same offset (43mm) and same axle to crown length as the C59 and EPQ. A longer axle to crown length does not however mean that you automatically have more tire clearance. That will depend on how much material is used in the fork crown and how it’s laid up and ultimately where the hole is drilled for the brake bolt. But on a Colnago it will be the underside of the fork crown more than the brake bolt that becomes your limiting factor. And the C60 fork has more clearance than either the C59 or the EPQ. But you will still likely struggle with getting a 28mm clincher in there with ample clearance, especially on a wider rim, if it would even be possible depending on the tire/rim combo. And then you have the issue that your rear brake bridge will be limiting your tire size in the back. I run 25mm tubulars and am happy.
The measurement you’re really after is the distance from the axle to the underside of the fork crown, which is not axle to crown. The crown is the very top of the fork where the steertube extends from. For example, on the C64 they increased the axle to crown length from 368mm to 379mm (11mm) but the clearance from the axle to the underside of the fork crown only increased ~5mm. But ultimately I think if you want to use that frame you should limit yourself to 25mm tires.

[123GO]

Hi Cal, thanks for the reply. Whay would you say about an enve fork? Id like to stay colnago but the price is almost double. Also, do you think the new continental gp5000 in25 mm would fit on my current fork work enve rims. The internal rim measurement is 18.5mm

[Calnago]

I’m sorry, for some reason I thought you had broken your existing fork and you were looking for a replacement. Since your fork isn’t broken I wouldn’t replace it. I presume you’re running clinchers. A 25mm clincher on a rim that wide is going to end up much bigger than the 25mm tubulars I like to run, so I doubt that would work, quite frankly. And again, you’re going to run into clearance issues in the rear as well.
My suggestion would be to try the Specialized Turbo Cotton in the 24mm, but I have no experience how high it will sit on that rim. But the combo of the 24mm clincher on an 18mm internal width clincher rim is going to provide you with some pretty good volume. Certainly would be more than enough for me. But to each their own. At some point you have to start considering a different kind of bike I think. If that isn’t an option now I’d just make do with what you have rather than spend a bunch of money on something the frame wasn’t designed for.
I don’t know anything about the ENVE fork, but if you went that way I’d want it to match up dimension wise with the stock fork (368mm axle to crown with 43mm offset) and I’d want to know what the transition from the fork to the headtube looked like to ensure it doesn’t look like a complete mismatch.

[123GO]

Cal, thanks so much! Too bad you're not in the Washington, DC area. I'd certainly pay you to work on my bike. You've all yours set up beautifully!

[pdlpsher1]

Here’s an example of a fork with a long CTA. The tire is the Conti GP5K 28mm which measures 30mm wide on 21C rim. You can see in the second pic the location of the brake pad- close to the bottom of the brake arm. You can see if another Colnago fork that has a taller CTA than your existing fork. Good luck with your upgrade.






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