rake, trail, boredom

[Dr. Doofus]

"Ok. Our client is bored, because he has no shoes with which to ride his bikes, and he is sore, because he is now King Of The Stupid EFX at the gym, having explored the mind-numbing joys of doing 90-120 minutes on that thing. One has to do something.

Given the idle time, the boredom, and the lack of riding with which to fill client's leisure time -- which, though not altogether unpleasant, has become increasingly discomforting with the sudden and unanticipated substitution of Milly Theale and the unfortunate Herr Von Paulus for threshold intervals and racing -- he borrowed a digital level and set about to measure, once and for all, the seat tube angle and setback of the Giordana. They are as they should be -- 72.1, and 18cm. Moreover, he has been able to draw the conclusion that the discrepancies in setting up an identical position to the Gunnar have been due to the perils of plumb bobs (chainstays...the chainstays), and not due to the possible indulgence of red wine at the Billato factory sometime in the mid-nineties.

It is fortunate that the frame was never sold.

Now, the fork is not original -- Gita, after encountering several moderately troublesome incidents involving some bent and broken forks, sold the remaining frames, apparently, with some forsaken 50mm rake items that bear a suspicious resemblance to Tange work.

The head angle is 73 degrees -- and a 50mm rake works out to a very quick 5cm of trail (whereas he prefers the feel of 5.5). Now that the bike has been forgiven, and will be dutifully ridden before any other as soon as our client has shoes again, his restless, limited, and misled mind has set about wondering what the proper rake and trail for such a frame might be. There is no other recourse than the unnavigable and oft-troublesome waters of this forum (insert <urp> here...influence of wine).

c-c 59cm
setback 18 cm
STA 72.1
TT -- 57.8cm
HA -- 73

not unlike an MX in a 59....

Now, what might be the rake on an MX?

For those of you who pray our client never comes knocking upon your door with a deposit cheque, what rake might you think appropriate for such a frame? For those of you who regard this post, and others of its nature, turgid and indicative of a middling mind in need of better diversion, please type something appropriately witty, dismissive, or simply rude."

Yeah

What they

Said

[weisan]

I dunno, go ask Drunk-pal or seek peer-group support from alcoholics anonymous (http://www.alcoholics-anonymous.org/). :crap:

[Peter]

I had the exact combination 73/50 that you describe, on a bike I used daily. Actually, it was a bike bent as a result of a car accident, and I spec'd those numbers when it was repaired for I wanted a little less trail than the original 72.5/47.

I didn't work well and I returned to the repair man/framebuilder fully expecting a new fork to be built or at least the blades to be replaced. I wanted the new fork to have 45mm of rake. Instead, he told me it's perfectly fine to tweak the rake by bending the blades, but the limit is 5mm. Any changes beyond that would necessitate a new fork.

So he bent the blades while I waited and charged me a paltry twenty bucks. The new, 73/45 setup stabilized the front end remarkably.

Find a framebuilder who is willing to do the deed or do it yourself; you won't be disappointed.

[weisan]

Peter-pal, you are so kind to help out a lost soul like DOofUs. Here's a safer method: MindBenders (http://www.elmwoodmagic.com/?nd=full&key=1233)!!!
http://www.elmwoodmagic.com/ama/med/mindbender.jpg

[Dr. Doofus]

interesting

frame geo is almost identical to MX

59 c-c
57.8 TT
72.1 STA
73HA
41cm stays
8cm BB drop

MX has 43mm rake for 6.0 trail (hmmm...what Kirk likes)

would it screw up this bike to have a 45 or 43mm rake fork made?

if a 45 or 43 would not screw up the bike, who, serottans, shall make for the doofus a threaded fork?

[weisan]

...who, serottans, shall make for the doofus a threaded fork?

You said it yourself, who else but Captain Kirk (http://www.kirkframeworks.com/How%20to%20Order.htm) of the StarShip Enterprise??! :confused: ;)

http://www.geocities.com/phineasbg/nexbanner4.jpg

[Big Dan]

Doctor, for a nice steel fork you should check with Mr David Kirk or Mr Curt Goodrich(cpg)...both can produce the fork you are looking for at a good price... :beer:
I'm using a 43 rake fork on my Corsa 01 (stock 56 racing geo) and handles like a dream..... :banana:

[Dave]

One problem you may encounter in having a fork built is figuring out the axle to crown race length that was used by the frame builder. a fork that is too long or too short will alter the head tube angle and not produce the amount of trail that is desired.

Folks who buy CF forks rarely consider the fork length, but the length varies from 365 to 374mm depending on the brand. This much length difference can change the HTA by about .5 degree.

[Dr. Doofus]

word

dave

its a threaded fork

if its replaced

it will be

a forum member's

work

(no, not sandy)

[Big Dan]

http://www.sheldonbrown.com/rinard/forklengths.htm

This is what Dave is talking about. The fork height varies between forks. The problem is that the Doctor can't be sure what was the original intended height, unless Gita replaced it with one of the same height.

[saab2000]

I once had DWF of Anvil cycles make me a fork for a bike with incorrect rake for the HT angle. Works nicely. That is- the new one works nicely. The old one looked good, but did not handle properly. I am still debating on whether my decision to get a straght bladed fork was appropriate though. Curved probably would look better. The bike in question can be found somewhere in the custom gallery under "Croll".

I am sure that Dave Kirk could do equally well.

That said, send the whole frame into whomever you have do it. That way all the lengths, etc. will be right. I am convinced that my bike with the new fork is now better for having sent DWF the whole frame. Among other things, he aligned it too.

I would be interested in your bike. But it is too big for me, but about 1-2 cm.

Threaded is the way to go with that bike BTW. At least if you can get a proper Cinelli 1A stem in 14 length. The only threadless stem that looks good on a lugged steel bike with small diameter tubes is the Cinelli Grammo threadless. Or some of the lugged Nitto stems would prolly look alright too.

LONG LIVE STEEL FORKS!!! My next bike will have a steel fork!

[saab2000]

http://www.sheldonbrown.com/rinard/forklengths.htm

This is what Dave is talking about. The fork height varies between forks. The problem is that the Doctor can't be sure what was the original intended height, unless Gita replaced it with one of the same height.

This is why it is important to send the frame as well to the builder who will create a new fork. You posted at the same time I did about my Croll. I touch on this in my post.

[Dr. Doofus]

not much variance in threaded steel forks

(more of an issue with after-market carbon)

but

have that info from Gita

now....

dk or cpg???

(box crown and some solid blades....mmmmm)

[Big Dan]

1 vote for Richie's flat crown....got 2 of those........... :D
Runner up...Henry James flat crown(like waterfords)....nice too...... :p

Straight blade??? Also nice.....decisions , decisions...........

[Brian Smith]

not much variance in threaded steel forks

(more of an issue with after-market carbon)




this length difference might be MORE of an issue for "aftermarket" carbon forks, but it's certainly not right that there is not much variance in threaded steel fork lengths. Unicrown vs. lugged is the bulk of it, but even among those of the same style construction there is significant variance.

[e-RICHIE]

this length difference might be MORE of an issue for "aftermarket" carbon forks, but it's certainly not right that there is not much variance in threaded steel fork lengths. Unicrown vs. lugged is the bulk of it, but even among those of the same style construction there is significant variance.


that's no bs, bs!
if there is even a 1mm discrepency 'tween the design
that the frame was spec-ed for and the fork length that
is 'tween the hub axle and the lower ht end, it will
affect the blueprinted dimensions. oh yeah - you're
lucky if it's "only" a 1mm difference to boot.

if you're here agonizing about the angles on your
frame, one way to change them is to insert a too
long or too short fork into it.

hey - thanks for reading.
goin' out to do intervels.

e-RICHIE

[Dr. Doofus]

gettin schooled every day here

the frame will be going to some dude with a torch where Hrbek used to play

new lugged fork, new paint

makeover by two cats who get it

ahhhhhhhh

one question

what do you "lose" if you don't go for the clear coat?

never paid much attention to paint before...if doof goes with the no clear coat JB option, is that molto stupido???

[saab2000]

Hey Doof!

Hrbek used to play in Minneapolis. Are you sending it to Kvale? There are one or two others in Minneapolis, but he is the best known.

Just curious. I used to live there and still call that the closest thing to a "home" I have in the US. I would move to the Twin Cities tomorrow if I could. Forget Philly and DC. If I could go to Minny I would.

[Dr. Doofus]

its a g thang

come to think of it

doof don't need no stinkin clear coats

this is an old-school race bike that will be raced

not an art object

anyway, deep clear coats are for those bikes like M3s and XKEs

doof is more of a hot-rod el camino kind of guy

no clear coat

and the g2 will be ridden to a money finish this year

time off from shoe crisis be damned