cloozoe

Thinking about replacing the stock fork on my Quick 5 with a carbon fork. Why? Truth be told, just for the heck of it.

Pondering a Kinesis Pure CX, as it is affordable and by most accounts does not seem to be rubbish.

Seems as though it would work on the bike, with being set up for 700c tires, V-brakes, correct rake, steerer tube diameter, steerer tube length. Then I get to this:

"...blades with high clearance alloy crown, designed for use with high profile tubs" (Crown height: 405mm)

What does that mean in practice? What in the world are "high profile tubs"? What else do I need to consider in terms of fit?

Thanks

dsaul

It means there is clearance for large CX(cyclocross) tires. "high profile tubs" basically means tubular cyclocross tires, which have knobby tread and are wider and taller than road tires.

cloozoe

Got it, thanks. Does that mean, in effect, that the front of my bike would be higher than it is now? Is the crown height measurement the distance from the axle to the top of the crown? If so, I could measure existing fork and answer my own question.

I've been looking at cx forks as they seem to be the road forks with the bosses for v-brakes. Will the (presumably wider as well as higher) clearance position the brake bosses too far from my rim?

Again, thanks.

fietsbob

If you increase the Crown race seat to Fork tip distance , you alter the head tube angle, + if the rake is different that too can alter the trail .

cloozoe

"If you increase the Crown race seat to Fork tip distance , you alter the head tube angle..."

Yep, roger that. The question was whether the aforementioned, fork manufacturer spec'd "crown height measurement" was, in fact, the "Crown race seat to Fork tip distance". Apparently it is.

Thanks.

FastJake

The front end of your bike may be marginally higher, but CX forks are not tall and it will be a negligible difference you do not need to worry about. This is not like putting a 100mm suspension fork on a previously rigid MTB. Even then it's often not an issue.

The brake bosses will not be too far from your rim. CX bikes are meant for bigger tires but road bikes and CX bikes both use the same width-range of rims. So, no issue there. You may have to flip around the spacers on your brake pads if you want the arms to be an optimal distance from the rims.

I won't question the merits of upgrading to a carbon fork but if you're going through the hassle and expense I would recommend taking the time to weigh your current fork and make sure you look at listed weights of carbon forks before you buy one. Some carbon forks are heavy! And if you don't lose any weight, what's the point?

cloozoe

Thanks, FJ!; answers all my questions. In the meantime, by the way, I measured fork, axle to to top of crown and came up with --depending on precisely whereto-to-whereto I measure-- either 406 mm (fork in question is 405) or 419 mm (a whopping .47" difference). In addition to your assurance, I don't feel the need to dust off my trig skills to figger the changes in head tube angle, etc; obviously they'd be minute and inconsequential. Anyway, since one of my methods came within a mm of published spec on new fork, seems most likely that it's a standard length and the lenths are, in fact, identical.

Glad brake spacing not an issue; tires I have now --32-- may well be as wide as cx tires anyway for all I know. Real road riders consider them balloons.

Nah, I don't want to debate the merits of one fork vs. the other either. Thanks for sparing me the lecture The new one is listed at 480gm and I reckon the alloy fork that's on now probably weighs give or take twice that; so a hair over a pound lighter.

I also was curious if carbon fork feels any different/better/worser in terms of feel in hands and/or in any other ways.

But as I said earlier; I'm just pondering doing it for the heck of it. I like to mess around with stuff and I like to experience things for myself. Don't care much about the pound or the vibration; I ride around town and on bike paths and up and down hills in the countryside and don't set any land speed records or aspire to. If I notice a difference it would merely be a bonus. Basically, it's just something to monkey with and keep me out of trouble.

FastJake

I didn't have a lecture in mind. It's your bike, your preference!

One more thing I forgot. With all the tapered head tube/integrated headset non-sense these days, make sure you get a fork that will work with your current headset design. Looks like your bike uses a standard 1 1/8" steerer tube. That's good. The Kenesis fork is probably 1 1/8" also but check to make sure. If so the fork crown race should swap over ok.

cloozoe

Thanks again. You've been a big help. Meant no offense with my little lecture joke. Had in mind all the responses I've read that go like this: "You don't need a carbon fork, you moron; take a couple of lbs of air outcher tires and you'll achieve 973% more shock absorbtion than any damn fork, you snivelling little poseur"

Yeah, ran into 1.5" steerer tubes; tapered 1.5" to 1 1/8" steerer tubes; integrated headsets...understood just enough to know that it wasn't what I needed. My steerer tube is 1/18" top to bottom; same for the kinesis. Standard headset on my bike and I assume --since all I see in the picture is a cylindrical tube sticking up from the crown-- the Kinesis is intended to be used with a standard headset too.

I'll just forget I heard the term "fork crown race" and assume all will be ok.

FastJake

Well, you'll need to know what that is That's the very bottom piece of the headset that press-fits on to the fork. Check this out: Servicing Bicycle Headsets

You will have to remove it from your current fork and install it on your new one. With some care and a little luck this can be done with a hammer and flat head screw-driver but a competent bike shop should be able to take care of it with less fuss.

cloozoe

Ah! Got it. I'll probably go banging and prying at it myself until I've destroyed it and then bring it to the bike shop. It's The Cloozoe Way!

SlowJoeCrow

If your headset uses drop in bearings the path of least resistance is to just buy another crown race and install on the new fork. I've done that on 2 bikes with Aheadset branded headsets (Asian licensed Cane Creek design) and the hassle is minimal compared with trying to remove the old one and reinstall.

cloozoe

Hmmmm. You mean I don't get to break anything? Headset is Cane Creek, so should work(?)

OK, now please explain to me "drop in bearings" as opposed to, um, non-drop in bearings and why you could just put a new crown race on the fork in the first instance but not in the second.

SlowJoeCrow

Drop in bearings are the sealed units found in higher end headsets like Cane Creek 40 series, Chris King etc. in these designs the "crown race" is actually just a base for the sealed unit so there are no bearing fit issues. Now that i think of it, at least one of my bikes had conventinal caged ball bearings and worked fine with a new crown race so go for it, as long as the part is for the same headset.

FastJake

Caged bearings are also called loose ball, while the more correct term for "sealed" bearings is cartridge. SlowJoeCrow makes a good point. You'd have a much easier time just installing a new crown race on your new fork rather than hammering the old one off. Assuming you can find one. Which I think you should be able to do.

cloozoe

Thanks, guys. It's all clear to me. Much appreciated.