c'mon dude, mud getting under your top tube with a 60cm seat tube!? pull the other one it plays jingle bells!

Under the toptube, is where vb wants to shoulder the bike. Under the downtube is where mud get. Over the downtube is where the bottle cage goes. Over the toptube is where the cables go.
do I need to google an image of a geared bike for you? :-P

as if dave will pick it up, thats why he has servants :p

I wish. Can't afford them. The money that used to go on servants goes on bikes. Isn't that what we all do?

Clearance for knobbly tyres too ;)

Hehe! I think you may regret that - VB said he is gonna start charging (you) for commercial use of this site.. :-O ;-)

To avoid scratches to the pain you can get a thin cable outer for where the cables are exposed. It offers protection but minmal cable drag compired to having a fully enclosed cable run.


This bike sound like it will be a good alrounder vb and with a nice versitile set up of swap this bit swap that bit to make it useful for lotts of diffrent situations.

Sounds good, but I've got a few questions:

Is BB drop going to be chosen for cross or for long rides? Usually cross bikes have quite high BBs whereas longer distance bikes have lower ones for stability.

How close are the numbers to your Serotta? I'd expect a cross bike to have a shorter top tube and maybe a slightly higher headtube so that you can sit up on the bike more. I'm guessing the fork is going to have a much higher axle-crown measurement than on the serottaa and more rake as well because of the high volume tyres.

Are you going to be racing cross at Herne Hill this winter?

By the way, I have the largest cross check which must be close to your size if you want to try a cross geometry bike or an Avid bb7 road disc

why not in the top tube?

this bike sounds sweet VB, how much longer you waiting?

internal cable routing = slick looks but increased friction.

It's been selected for road racing as that is the BB height I'm most used to. The extra clearance comes from a smaller single chain ring and the additional height from knobbly tyres.

The numbers are pretty close to the Serotta. Some minor changes include raising the handlbars 1cm for position, and taking into account stock forks so that it is possible to change forks based on use. I'm already quite upright on the Serotta as my position aims for neutral spine over race aggresiveness, this is due to a back injury 5 years ago that I'm trying to avoid aggravating.

If I race anything it's going to be cross. I want the fun of it :) And yes, I would *love* to try both the cross geometry (though it won't now affect the Mather geometry) and definitely the disc brake (which I have no experience of yet).

I can't channel cables internally as I will need to unscrew the cable (as the cable is coupled to be able to de-couple the frame). S&S Couplers you see. So the cable needs to be accessible.

I'm using cable disc brakes because of the brake levers and desire to have cross interrupters on the bars.

And I think I've got another 4 or 5 months to wait. Not sure, I'll find out soon.

And here is roughly what it looks like in BikeCAD. Roughly... because BikeCAD free doesn't allow every minute detail to be tweaked, just 95% of them. So it's 0.3mm out ;)

74 seat tube? (text is a bit weird at the bottom) looks nice, but bike cad is not allways 100%,things tend to look a bit different when its in front of you.

It's mainly because it makes shouldering the bike more comfortable, which is why all cross bikes route cables like this....

Sounds good to me - i'd be twempted to use a slightly extended head tube to get the bars up without


I'm looking forward to some cross this winter too! Mud is a lot softer when you fall off as well... Happy for you to have a spin on my bike at some point and try the brake. I've only had one on the front for a few weeks and it seems good so far - it feels progressive but develops more power than the canti I had on before and is much better in the wet. I'll be trying it in the mud this weekend and am hoping for noticeable improvements.

And they'd fill with mud as soon as you went off road - not cool.

I'm not totally sure this is a good idea. I have found, so far, that when the disc is set so it doesn't rub that full power is about 2/3 of the way through the lever stroke. I'd be worried that cross top levers would add some slack into the system and make it hard to get full power from the normal levers. I'd be tempted to use a shallower drop bar or raise the stem a bit higher so that you can use the drops and hoods more and forget the interrupter levers.

Hi VB, I'm interested in the process behind coming up with this design: recap for me! Is this simply tweakery of something you already have (The Serotta)? Or have you made significant changes to that geometry that will obviously alter handling, say move the BB up or altering HT/ST angles?

That's one of the subtle changes ;)

CycleFit fitting to determine optimum position based on my body and the style of riding I want. This fitting started with my prior configuration, but it needn't... you can start afresh.

The fitting takes into account feet (pronation, twist), knees (whether they move like a hinge or a ball socket - should be hinge with no side to side movement), lower back, back angle, neutral spine (your arms and shoulders should not be carrying your weight), elbow angle... and then things like the optimum position for getting the most power out of you, as well as ensuring that all muscles that could be helping are (such as the glutes which too many riders neglect). Whether the power is evenly distributed across both legs. And lots of stuff that either goes over my head or that I'm hesitant to write down in case I get a term wrong and get called on it (quite likely... I'm bad with physiology terms and muscle groups, etc).

The person doing the fit will ask how you intend to ride, what you do ride, may want to see you riding your bike on a turbo trainer, and video that.

And basically they aim to get a SizeCycle set of numbers that describe where the BB should be in relation to saddle and handlebars... your contact points.

The next step is to take that knowledge and start designing a frame. They have templates for types of ride and sizes of frames... so a 60cm road frame isn't just a upsized 56cm frame. They pick the template that best matches your use and then tweak according to what you tell them. Want more control on descents? Want a tighter turning angle? Want more stability? Want a traditional or sloping top tube? And what about forks? Do you want the geometry to accomodate off-the-shelf parts in the future or fully custom?

Anyhow, my fit for the cyclocross bike only varies from the Serotta in terms of height of the bars. The seat setback from bottom bracket and height from bottom bracket remains the same... which is why the Serotta still fits.

What has changed for the cyclocross bike is everything aside from how it fits me... the front fork to give more control, and the rear triangle to give more control, and the main triangle to accomodate a traditional top tube for shouldering it easily.

So it's not the fit that has changed, it's the bike. And it's changed because the use is different and the way I want to ride it is different.

Bit of an update on the disc now that I've been using it a bit longer and tweaked it further. The main thing is that it is VERY powerful but still with extremely good modulation. Very easy to dab the brake just a little, but when I've tried hard braking I've been amazed by how strong it is. I can feel the rear wheel start to lift under heavy braking even though I'm firmly in the saddle and pushing back on the bars in anticipation. Now that I've dialled in the adjustment knobs the brake bites much sooner in the lever stroke which has given me more confidence in it.

Went out on the singletrack near Dorking last weekend and there was a lot of mud and water. The disc still performed very well although made a little bit more noise. The difference from cantis was unbelieveable (in that I could actually stop rather than just slow down).

All of this is with a 160mm disc - I can't wait to try out my new 200mm BB7s on my new mountain bike! The discs look like dinner plates on the wheels!

By the way, you might want to consider getting the rear spaced at 132.5 or 135 mm if you plan on using a disc on the back as it's very hard to get 130mm spaced disc hubs. I'd go for 135 since you can get some really nice, light mountain bike hubs. Only a problem if you want to use Campag at some point in the future.

You crumbled then and bought a mbt as well.

Certainly did - was enjoying the riding so much and realised that the Cross Check is pretty limited in what it can do on singletrack without scaring the shit out of me (although it's a lot of fun). I bought the Singular that was advertised on STW recently so hopefully it should be arriving early next week. Still SS and rigid but with fatter tyres and big discs!

Found out... my build starts in December-ish time... with delivery early 2009, probably late February given the time to paint it.

It's going to be a long wait... might as well ride the hell out of the Bob Jackson in the meantime.

Kill it. Kill it good.

I thought this might be the best place for some gratuitous shots of my new Mather before it gets covered up with paint:

Well we're moving toward completion - apparently the frame will head off to the paintshop this week, which means I have a tough decision to make regarding colour!
It started like this:

Lugged goodness:

Whole frame:

Underside of the top tube, showing dynamo cable routing and braze-on cable adjusters:

Stem (braze-ons for a bell, cable hanger and my front dynamo light):

Wow.

The work on that is incredible. Absolutely awesome.

Makes me even more excited about mine. Which is nothing like yours, but I love the details he's put on yours.

Very nice bikes he makes.

i bet you shed a tear when he posted those pics. i feel somewhat releived that i'm not the only one waiting for a frame to be built :(

Made. According to his website he's taking no new orders, spending the next 20 months clearing the backlog, then having a break. Bastard. But he has just saved me about three grand.

Mine's not even due to be started until Christmas. In my over-excitement I imagined the time shortening, it didn't... in reality it's slipped a little, but ah well.

I love the lug work he's done above. The small details are wonderful.

I'm still going to go for his fillet brazing though, he's an absolute master at that.

wow, his work is superb.

I love the braze-on for the Gear levers on the stem, at least, i'm guessing that's what they are.
That looks lovely, the curve in the seat stays is beautiful.

I'm a jealous man.

chris

i wish i could afford a totally nuts bicycle.

i still plan to have a custom bob jackson road bike built before i leave this country.