John Clay has announced he is starting a new fork raking service. You can find his flicker page on re-raking HERE

He has a new account here, so he will not be able to reply to PM's for a while

His user name here is Jmclay https://www.bikeforums.net/members/jmclay-341272.html

Cool pics, but I really wanted to see his raking apparatus.

I used to race a sailboat with adjustable rake. But it was a single-tined "mast" not a twin-tined "fork".

Suppose you had adjustable rake on your bike. Wouldn't be C & V but you could dial in the trail and fall asleep riding no-hands or go to criterium-quick handling.

Edit: (and on topic) I never saw the raking devices of either Peter Mooney or TiCycles. I'll have to ask at TiCycles next time I am there. Peter built me two forks. (I crashed the first and didn't really like the too stiff characteristcs; better for the touring I did little of.) Second go-'round, I had him make the forks from lower in the taper. Also started the bend considerably higher. He had recently (1984) acquired a device to do more complex bends. To this day I love that second fork; both how it looks and how it rides.

Ben

I was wondering why a raking service was offered in the spring!

I talked about this with a non-BF-member friend one time. He had an idea to build a fork with custom dropouts with three vertical slots that would let you mount the wheel in three different places. It would be fun. Ugly, but fun.

Not with those smooth curves!

Legend has it that Grant Peterson did that to explore different designs.

Seems like a rear style horizontal dropout would be more useful that large steps.

Cool. And you could adjust the rake on the fly. Just need Peter Sagan skills. Pop a wheelie, reach down, flip that release, move the wheel, re-tighten and you are good to go.

A new meaning to "fork rake". (Don't the three slots form the working end of a very small garden rake with four teeth?)

Ben

if you search for variable rake forks, I think people have done both vertically slotted and horizontally slotted dropouts. If you really wanted to do it on the fly, you could re-purpose some cambio corsa rear drops and the adjustment mechanism. Making a fork that allows different rakes is on my list, but it has been on my list for quite some time.

I posted this because it seems like people regularly ask for recommendations for re-raking forks. John's price is more than reasonable, $20 plus shipping.

Oh man, now I really want to see a Cambio Corsa variable-rake fork in action.

it would be a crime to use it that way though. I have considered making a clone, because the actual thing seems out of reach

Check with John to see if that's for re-raking. Raking individual fork blades for production use (which I think is what the $20 gets you) is a lot easier than reraking an existing fork. But even at $10-20 more, it's still pretty reasonable vs buying a new fork, or entirely new bike.

Mark G is correct (thank you Mark!). This raking service is for new, un-raked blades for use by your frame or fork builder.

Shortly after the initial posting I got inquiries about re-raking and aligning existing forks. I'm happy to provide that service but its more involved both in terms of the actual craft work and changes to overall front-end geometry. A low and tight re-rake of an existing fork will lower the front end more than a longer, more gradual rake. Low and tight generally won't be the way to go in those circumstances; that said the particulars are open for discussion. One might have a replacement fork thats a bit longer and a suitable candidate, so that sort of thing can offer possibilities. Generally I recommend a new fork because it allows one to hit all of the numbers you want to hit. Re-raking is nearly always a larger compromise than I'd want on the frames in my own stable. But drop me an email if you want to discuss your situation & needs wrt a re-rake or alignment.

John Clay
Tallahassee, Florida
USA

+1

Tom Matchak has a white paper about the effect of re-raking on frame attitude and hence head angle. He shows how the rake-added fork needs to be somewhat longer to maintain the original front ride height and head angle.

I think this is one of the most misunderstood aspects of reraking.

Trail calculators you can find online do not work for reraking, because they do not account for head angle change - nor can they. A careful read of Tom's paper will tell you that you need to know the effect on the distance between fork crown and dropout when using a particular mandrel - the curved shape that you're using to add rake to a fork. If you do, there's an iterative method to calculate and predict the change in trail. I built a model using several fork rerake data points to use for this.

The short of it is that you don't need to add as much rake to hit a target trail number as a trail calculator will tell you, since increased head tube angle decreases trail, all other things equal.

The other thing to consider is he reduced clearance between tire and fork crown. I have talked some people out of reraking a particular fork for this reason - typically because they wanted to use fenders; reraking would decrease the fender-tire clearance too much.

As far as the "dropped front end" of the bike, this is a non-significant issue. The most I've seen is about a 4mm drop from a big rerake job. Hold your fingers 4mm apart, and tell me you can see what was once a horizontal top tube is now downward sloping. On the vintage Raleighs that I often do framework on, that would be considered manufacturing tolerance.

yes, I did misunderstand what John was offering

In the early 90's, GT did this with a couple of their high end mountain bikes.

All,

My original intent was to offer low-trail raking services only but so many folks immediately wanted re-rakes/alignments I thought , on the fly, "why not". Having considered the additional liability exposure of altering the work of others I must limit myself to raking new blades for use by your framebuilder, only. So, if you seek a new fork with the type of bend that's shown on the flickr pages linked in my OP I am able to help. You can have your supplier or fork builder send the blades to me with the desired rake indicated. Rather than replying to this message please email me at jmedclay followed by that little @ sign, to the yahoo.com world.

Thanks much,
John Clay
Tallahassee, Florida
USA

If I were going to alter the rake of one of my forks, the first thing I would do is draw it and the bike with CAD. Then it would be easy to see what the new bend will do to tire clearance, trail and toeclip overlap. (Doesn't hurt that all my bikes are pre-drawn, though without detailed fork info. I draw them to see what stem I need to get a good fit. When I am looking at a new potential, I show up with clipboard and tape measure, draw it up that evening and see if the needed stem will be reasonable.)

With an accurate drawing of the stem, with it's centerline shown as a "polyline", the new bend can be made on the drawing, Then it is a simple matter to check that the new centerline length is the same as the old. (The fork will probably get a little longer through the bending, but hardly enough to matter and probably not enough to even measure.

Gugie, if you ever want me to do this, holler. You know where to find me.

Ben

You gotta CAD, I gotta CAD, everybody gotta CAD!


I can do all that with a couple of measurements. The only measurements I need are:

1. Current rake
2. Head tube angle - NOT from the specifications, and NOT measured from the top tube. I don't know any better way to do this than with a digital angle finder.



...and it has to be done on a flat surface, with wheels on it, and either a headset or headset spacers:



3. Current tire clearance.

I like to measure this all myself. Once I have that information, I can calculate the trail. Knowing the target trail, I can back calculate the new rake needed, new tire clearance and new head tube angle, if I use my jig, which I have characterize.

Gugie - Your 650b conversions are mighty nice! Talk about re-doing a bicycle such that it's functionally far better, more useful than new! It's quite fantastic.

All,

I've had some inquiries about the visual results of using the same fork blade curvature but at reduced rake. The 650B x 42 fork that was initially shown has 65mm rake. The one at the first two links, below, is 55mm on a 700C x 33 CX bike:

https://www.flickr.com/photos/216244...7690862863394/
and
https://www.flickr.com/photos/216244...7690862863394/

The one on the left, here is 50mm:

https://lh3.googleusercontent.com/-p...0/IMG_3051.JPG

I think they look nice even at a somewhat reduced rake.

John