Tuesday, September 26, 2006

Golden

Trina and myself visited family Bacon recently. A short hop on a plane and a skip on a train led us to the deep south of England and a beautiful day to sit with Ruth, Biff and the boys (William and Thomas) in their fantastic garden.

A major effort by W, T and me saw a successful ambush of the rest as they collected sloe berries for gin manufacture. Next we had a chance to sample some of Ruth's cookery. It's hard to describe, but when someone can cook, and I mean *cook*, it is a wonderful transcendence from simply eating. A passion for flavour, an innate sense of timing and texture with dish after dish. Truly inspiring.

We yabbered into the wee hours.

Next day saw a visit from a cross star and a man with a sheep with a mission. As the airports are still somewhat stuffed up following the seemingly forgotten chaos of a few weeks ago, I had not brought my own bike. Fortunately, Biff is both well endowed and generous in that department and as such I had a chance to spend some time riding a VooDoo Dambala using Pace RC31 forks and Biff's Jones One. I also had a small but informative time on an On One 29"er (ta Jenn).

I am going to return to Biff's Jones as it deserves an entry solely concentrating on its construction, finishing and ride characteristics. However, I shall refer to it in passing here.

When I started considering a new bike (which in fact was several months *before* purchasing the Kelly RoShamBo) a lot of effort was put into understanding steering geometry of bicycles. Not in an mtbr/Cloxxki style. In a scientific, known facts and proven builders' opinion sort-of-way.

One of the best things I read was the Zinn Bicycle Primer, where he discusses the stability of different geometries which yield the same trail. Previously, my misconception was that trail=trail=trail, and that it was 'god' when it came to working out how a bike would handle. This of course ignores the fact that a bike with a shallow head angle and high rake can have the same trail as one with the opposite. The handling will be different: one *must* be holistic.

If I had any complaints of the Kelly, it was that the front wheel had a tendency to 'tuck' when steering in steep (down) technical situations, usually in soft terrain. One can mimic this by holding the rear wheel up so the bike rests on the front, and tilting to the side. If the bike moves quickly to rotate the front wheel 'under' the imaginary rider, it will be quick/nervous in handling. If it moves more slowly, perhaps more stable, and if it doesn't really move, well, it will prolly feel that way on the trail. Knowwhatimean?

I was after 'the perfect balance': a nice trail number in the 70-80mm bracket (which seems to be about right for 29"ers, for me - the Kelly being 80.7mm) and stability not negating responsiveness in technical riding. A complex project, and one I am indebted to the internet postings of Mike Curiak for germinating.

The end result for me was a 71 degree head angle and 42 mm rake on the pace fork (yielding a trail of 79.9mm) and a rake of 45mm on the Black Sheep Ti fork (yielding a trail of 76.7mm). This will give me something to play with once the IF is built.

Rewind a little. I rode an On One 29"er and a VooDoo Dambala recently, as well as Biff's Jones One. Remember? what do you mean zzzzzzzz? right!

The On One felt stable but well mannered, long of limb and heavy (truth be told, but then it was a 'sensible' build) but settled and supportive (head angle 71 degree, trail 74.6mm as rake is 47mm, note the 18" frame has a 1 degree steeper head angle, making trail 67.9mm, the fork being 470mm length).

The Dambala actually required a good deal of bodily adaptation to ride through the twisting, buff singletrack adorning the South Downs. Both up and down, it required a great deal of weight over the bars for it to steer with the authority needed. It didn't seem to like leaning into turns as much as my Kelly for example. All this despite a head angle a mere 0.5 degree shallower(trail 79.9mm). All this shows the trail is but one thing. The front centre, ride height, bb height and chainstays must all be figured in...

The Jones? well, it rocked really. I haven't enjoyed riding a 26" wheel bike since I tried 29"ers, until now. A very, very special bike. It managed to be instantly familiar, without feeling too easy. It demanded work and speed, whilst rewarding calm, deliberate (and occasionally consequential) moves. In short it acted as a mirror for ones desires and skills. As such, it also acted as a natural foil to the others, in order to compare characteristics.

Some people maintain that you cannot tell the difference between 0.5 degrees here, a millimeter there. I disagree. I would say one can *adapt to these changes easily*, but should one? Depends if you have the time, inclination and admittedly money to throw at the issue.

For me, I just have my fingers crossed about the new one...


first pic is by singlespeedwidow, my beautiful wife.
second I nabbed from Simon Barnes, who has been taking truly epic shots this year...

12 comments:

Nick said...

I'm not a numbers man myself. I set my bikes up by feel not tape measure, and with one, deliberate, exception I have exactly the same saddle-bar length.

Even so I know that I can feel such tiny differences as two extra chain links and consequently different wheelbases between two otherwise identical bikes.

Should one adapt? I don't know. Sometimes the ride calls for the plush and stability that the longer wheelbase gives. Sometimes a harsher rear end and quicker handling is required.

It's good to see an enquiring mind putting some proper measurement, experimentation, comparison and thinking into their approach rather than loudly speaking an uninformed opinion.

Alex said...

"a lot of effort was put into understanding steering geometry of bicycles. Not in an mtbr/Cloxxki style"

LOL, you nailed that one!

"an enquiring mind putting some proper measurement, experimentation, comparison and thinking into their approach rather than loudly speaking an uninformed opinion"

Way too little of that going on...all over the industry and the forums!

Alex

Anonymous said...

Can't help this - cos you keep doing it - 'Trina and I' - myself is a reflexive pronoun - ie I helped myself to a cake, or I said to myself, anything else is I or me - so Trina and I went to visit, or it was me who wrote this horrid comment on your blog!!!

manchester trev said...

hey fella, interesting thoughts(or facts!)you have posted, was working out if running a 440mm pace fork on my new frame carver 96er when it arrives was viable, but as it runs a 70 head angle around 470mm imagine it will be too sketchy, me thinks ,as biffs voodoo runs 72 i think so if it was twitchy then it could be too much on the carver..... and also have taken on your thoughts for crank length...

Chreestoffel said...

hmm...
I probably knowwhatyoumean, but you're gonna have to draw me a picture for it to sink in.

You bring the knowledge, I'll bring the crayons...

Random thought... if you made a bike using the geometry of the bike shape on road signs - how would it ride?

I'm off to dig out my Ladybird Book of Grammer to find out what a reflexive pro-noun is...

dRjON said...

nah! its all about referring to yourself in the third party or soemthing...myself is a person thats not me, see? otherwise i wouldnt refer to myself...cos id be self conscious like...so myself is the person who resembles me *a lot* who does things just like me....ok?

singlespeedwidow said...

odd to correct grammar while using the word "cos"

Deano said...

Not to mention three exclamation marks.

dRjON said...

ive never had so many comments!

!!


it makes myself feel so special...

giggle

Tom said...

Manchester Trev.
You want to run 420mm Pace forks.

Trust me :0)

Nick said...

cos is a lettuce.

lettuce is hardly a reason to do anything.

Wanderin'Gav said...

A visit to chez Biff is always an experience! :o)