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New fork question... need help!(12 posts)

New fork question... need help!YoungRcR
Nov 13, 2001 4:36 PM
Im wanting a new threadless fork. I have the new headset for threadless and stem, now i need the fork. I am confused with "rake" what is it? I run 700x19-23C anywhere in that range (racing/training tires) Please help. I was looking at a Reynolds Ouzo Pro or Look HSC3. Lightness/stiffness main priorities.
re: New fork question... need help!Akirasho
Nov 13, 2001 5:22 PM
... from Anvil bikes...

http://www.anvilbikes.com/

Rake or Offset is the distance the axle center is from the steerer tube centerline measured perpendicular to the steerer tube. For a given trail dimension, less rake causes increases steering response, shortens wheelbase (moves CG forward), and lessens shock absorption. More rake causes steering response to slow, lengthens wheelbase (moves CG rearward), and offers more shock absorption.

Trail is the principle component of steering traits and handling. More trail causes a tendency toward more stability at higher speeds. Less trail causes a tendency toward more stability at lower speeds. It is the product of tire radius, head tube angle, and rake. If you use MS Excel and want to set up a spreadsheet to calculate trail, then the formula will look like this:

Trail =(tire radius*COS(headtube angle*PI()/180)-rake)/SIN(head tube angle *PI()/180)

Substitute tire radius, headtube angle, and rake with the cell references you enter those numbers into or just enter your values into the formula. For example if your bike has a tire radius of 336mm, a headtube angle of 73 degrees and a rake of 45mm the calculation should result in a trail of 55.7mm. The actual formula would look like this:

=(336*COS(73*PI()/180)-45)/SIN(73*PI()/180) = 55.7mm

Or if you want to take my word for it, you can send me an email and I'll send you a spreadsheet with all this already done and will also figure rake for you and it has lots of pretty colors too. If you don't have a computer (and just how are you reading this) or don't have Excel, then you can use this formula:

Trail = tire radius x cosine of the HTA - rake/Sine of the HTA

Can't give you any direct feedback on the two forks you mentioned, but I use the Ouzo Pro Aero on my TT bikes and they're like butta...

We abide.

Remain In Light.
Now this is useful.Leisure
Nov 13, 2001 10:53 PM
It finally helps to clear up some of the confusion I've been having regarding assorted explanations about rake's affect on handling, particularly trail between high and low speeds.
RakeKerry Irons
Nov 13, 2001 5:25 PM
is a term often used for the offset of the fork dropouts from a straight extension of the steerer tube. IOW, if the dropout center is 45mm ahead of a straight edge laid on the center line of the steerer tube, the fork has a 45mm "rake." Unless you want to change the handling of your bike, you should stick to the same offset you have now. A couple of mm either way won't make much difference.
Big Picturegrzy
Nov 13, 2001 5:48 PM
Try to match what you're running now as far as the rake spec goes, unless you have a good reason for doing otherwise and are sure of what you're doing. What frame are you running and what is the spec?

You really can't go wrong with an Ouzo Pro.
Big PictureYoungRcR
Nov 14, 2001 3:30 AM
My current setup is a (97'?) Trek 5200 with the trek branded OCLV fork. Its threaded and for a size 58cm bike.
Forkzelig
Nov 14, 2001 4:22 AM
You'll probably look for a 40mm rake in that frame size. Some forks only come in 43mm which should be okay. Another fork to consider is the Columbus Muscle, now also available with a carbon steerer, ITM and Mizuno. The latter two are both made by Presenti.

Aside from the rake question, you'll need to consider steerer material which are generally steel, aluminum or carbon (Ti in only a few) and curved or straight.

Have fun. FWIW I have a Look HSC-2, Presenti straight blade with Al steerer, and an older Time Criterium with steel steerer. If i bought another fork I get either the ITM Millenium or the Columbus Muscle, both with carbon steerers.
ForkTony
Nov 14, 2001 7:05 AM
I've been looking at a 1" carbon threadless fork as well, but haven't been able to find much info regarding either the Columbus Muscle or ITM Millenium. What features make these forks desirable, over Look HSC3 or Reynold Ouzo Pro? Which model of Pesenti fork is the ITM Millenium a rebadge of?
Forkzelig1
Nov 14, 2001 10:51 AM
The ITM Millenium resembles the Mizuno Fiandre. I'm told that the carbon steerer tube wall thickness is greater than either the Look or the Reynolds. I'm not sure that the Millenium is a rebadge of an existing Presenti model.

As for the Columbus Muscle, I've been looking at them for the last couple of years but they were not available with a carbon steerer until recently. There are a fair number of bikes in the UK using the Muscle, various Mizuno's and the Presenti's. The guys at Condor cycles particularly like the Muscle. I like the way they look, resembling a HSC3 on steroids in cross section view and when viewed head on, are very narrow at the crown end and then spreading out at the fork ends. BTW, the carbon fork I've rarely seen, if ever in the UK, is the Reynolds. Somewhat ironic.

When I first went from steel forks to the HSC2, I found the fork leg flexing to be visually disconcerting. After riding the HSC2 for about 12,000+ miles, it no longer bothers me and I like the ride quality although something stiffer would be a nice change of pace. Hence the interest in the Muscle/ITM forks.
just remember:Rusty McNasty
Nov 14, 2001 5:06 AM
If you do fiddle around with the trail on your bike, you'll find out about it on the first really fast hill you go down, and not before. Be careful, or else you could end up spending $200 on a fork for a $1000 bike, and have it hadle like a $25 salvation army special.
Trek 5200 rake and forkJon
Nov 14, 2001 11:51 AM
I have a '97 LeMond Chambery, which is the same frameset as the Trek 5200. Last year I swapped
out the Icon Air Rail fork for a Reynolds Ouzo Pro. Result? Better handling at high speed and
better ride quality.
Oh Yeahgrzy
Nov 14, 2001 12:31 PM
My '96 OCLV came with the skinny "Air Noodle". Never liked the way it handled, but it was plush on the longer rides. Upgraded to the Air Rail fork and liked the improvement in handling. The slightly stiffer fork made the bike a lot more precise and less vague on high speed descents. No doubt in my mind that the Reynolds would've booted up the performance to a new level - but I sold the bike before I did that. Replaced the Time POS on my Serotta with the Ouzo Pro - huge improvement in weight, performance and look (no pun intended).

I guess I come away from the whole fork thing with the realization that no one has said anything bad about the Reynolds (on the contrary) and no one has come up with anything that is significatnly better. the Serotta F-1 and F-1 Ti is supposed to be sweet, but the weight and price are a bit harsh. There may be some styling choices, but in terms of performance the Reynolds is rock solid and everything else falls into the "not exactly" bin. So why even mess with the obscure and the "almost as good" stuff? There's no way that the Reynolds unit is going to let you down unless you pick the wrong spec or cut the steerer too short, but that falls into the category of "operator error."