Kirk Frameworks

[baldbones]

Dave
I have a question for you,

Did you design the road bike you ride is Bozeman differently to the one you might have designed for riding in Rome?

Thanks for sharing all your knowledge and skill

[David Kirk]

Originally Posted by baldbones

Dave
I have a question for you,

Did you design the road bike you ride is Bozeman differently to the one you might have designed for riding in Rome?

Thanks for sharing all your knowledge and skill

That my friend is a stellar question. I would change one thing on my personal bike design if I was riding in Rome again - I'd give the frame less BB drop.

I tend to favor low BB's and don't mind having to skip a pedal stroke every now and again on a corner for the benefit of having the BB low the other 99.8% of the time. In Montana I can run a really low BB even with my longish 180mm cranks but in Rome I'd raise the BB as there are so many twisty fun downhills that can be pedaled through. Here in Bozeman the hills can go for many miles but they have very long sweeping curves but in Rome the turns are tight and fast.

Good question. Where do you ride?


Dave

[parris]

Dave you know that next summer isn't THAT far away... Maybe a trip back this way to where the terrain is variable and the trees are green is something to consider.

[baldbones]

Originally Posted by David Kirk

That my friend is a stellar question. I would change one thing on my personal bike design if I was riding in Rome again - I'd give the frame less BB drop.

I tend to favor low BB's and don't mind having to skip a pedal stroke every now and again on a corner for the benefit of having the BB low the other 99.8% of the time. In Montana I can run a really low BB even with my longish 180mm cranks but in Rome I'd raise the BB as there are so many twisty fun downhills that can be pedaled through. Here in Bozeman the hills can go for many miles but they have very long sweeping curves but in Rome the turns are tight and fast.

Good question. Where do you ride?


Dave

Ah you see through my question!
I live in the UK, very near where the Olympics and last stage of the Tour of Britain have just been, which is very very similar to Rome. When I heard you on the Outspoken cyclist when you described Rome it was just like the Surrey Hills on the NorthDowns just south of London.

I'm a big fan of your work from across the hall.
You very kindly gave me some advice a while back re builder choice
Glad to find you still here
Thanks again

[David Kirk]

Originally Posted by baldbones

Ah you see through my question!
I live in the UK, very near where the Olympics and last stage of the Tour of Britain have just been, which is very very similar to Rome. When I heard you on the Outspoken cyclist when you described Rome it was just like the Surrey Hills on the NorthDowns just south of London.

I'm a big fan of your work from across the hall.
You very kindly gave me some advice a while back re builder choice
Glad to find you still here
Thanks again

Cool - I know embarrassingly little about your part of the world and would not have guessed that your roads were like the roads where I grew up.

Cool that you heard the 'Outspoken' interview - that was fun to do. Thanks for listening and of course the question.

Dave

[FlashUNC]

So to broaden out baldbones question:

How important is BB drop to overall frame design? How much does it vary on bikes you're designing for clients? Do you see your bikes as having a "sweet spot" range?

[David Kirk]

Originally Posted by FlashUNC

So to broaden out baldbones question:

How important is BB drop to overall frame design? How much does it vary on bikes you're designing for clients? Do you see your bikes as having a "sweet spot" range?

I hope it goes without saying that no one number will tell how the bike will ride and/or handle but instead it's how everything works together.

That said small changes in BB drop have a bigger effect than most would think. For road bikes on 'normal' tires I'd say the least drop I would use would be 70mm and the most would be 82mm. Lots of stuff factor in to picking this number (type of riding done, crank length, pedal type...etc). I would say that most of my bikes fall between 75 and 80 mm. Small changes are most noticed when climbing out of the saddle (big tends to feel like it pivots during the rocking motion with a lower BB) and in at the limit cornering where the bike is more calm and settled feeling.

Outside of straight up road bikes you find that loaded touring bikes can be very low and track bikes (to be used on a track - not fixed roadies) need to be pretty darn high.

Fun stuff - thanks for asking.

Dave

[mnoble485]

Dave, this may be off topic but you brought up pedals. I have read before about your choice of pedals but many may not have. Can you run it by us again.

Thanks,
Mike

[David Kirk]

Originally Posted by mnoble485

Dave, this may be off topic but you brought up pedals. I have read before about your choice of pedals but many may not have. Can you run it by us again.

Thanks,
Mike

Hey Mike,

I do use a rather unusual pedal on my personal road bike. It's a Vista brand pedal that is a drop-axle design.........I suppose not altogether different than the very old Shimano DD design.

The way the pedal is designed allows the bottom of the foot to be at the center of rotation. This gives this pedal system a 'stack' of 0 mm. Normally a pedal has a certain stack height - say about 12 mm or so. This has gotten much shorter over the years in most brands - the older Looks had a stack of nearly 25 mm.

Anyway this stack height acts as a lever that you need to overcome. It's easier to picture if you think of a very exaggerated stack of say 6". Pushing down on this while trying to keep your foot from pivoting fore/aft would be very difficult and you would have to use a lot of fine motor muscle movements to keep the foot balanced and on top of the spindle. The muscle effort of course can fatigue the ankle and calf muscles over time.

The Vista pedal, with its zero stack, does not require that the ankle muscles do anything other than push down on the pedal - no balance required. This is why every pedal maker brags about it's low stack - it's just that Vista has done them all one better and lowered it to zero.

They feel different, and to me, very good. My foot feels cradled for lack of a better term. My ankle and calf relaxed. I like them very much. One very nice side benefit of them is that they allow you to drop your saddle 10-12 mm compared to most 'normal' pedals. This is a big deal - dropping your entire mass by that much - everything feels better and more stable. The pedals can also be used to effectively raise your bars by 10-12 mm as you can lower the seat.

There are downsides to the pedal. They can't be used with all cranks. If you have a carbon crank where the pedal boss is recessed the Vista will not work as it needs a flat surface. The pedals also tend to increase the Q factor. For me this is good as a narrow Q bothers my hip but it might not be a good thing for others.

At this point I'm not sure who imports or sells them in the USA. At one point they asked me to be the US distributor and even though I love the product I declined the offer - too much shipping and invoicing and it would take too much time away from the work I enjoy.

More than you wanted to know I would guess - thanks for asking.

Dave

[William]

Very cool. I like the concept but it looks like it takes a Look style cleat.







William

[David Kirk]

Originally Posted by William

Very cool. I like the concept but it looks like it takes a Look style cleat.







William

A Look style cleat? It uses its own cleat but it does have a 3 hole Look style bolt pattern if that's what you mean.

Another thing I like about them is the business parts of the cleat and pedal are both heat treated steel. They don't flex around or make noise ever. I HATE noisy cleats.

dave

[basilic]

Vista pedals can be found at
vista-bikes.com

They seem to have changed ownership a couple of years ago. Their distribution network is virtually nonexistent but they ship directly (ask them to remove the VAT if they ship outside the EC).

I like their pedals too, have been using them for years. They improve the feel of my pedal stroke, smoother circles.

They fit just fine on a Kirk - I just posted some pics on the weight-weenies forum yesterday

[Lionel]

Cool, another DK smoked out....

On the JKS-X, I understand you had Fizik do some special run of the correct 30.6 diameter for OOS tubes. Are these now readily available or still in very short supply ?

Thanks

[David Kirk]

Originally Posted by Lionel

Cool, another DK smoked out....

On the JKS-X, I understand you had Fizik do some special run of the correct 30.6 diameter for OOS tubes. Are these now readily available or still in very short supply ?

Thanks

Yep - a few other builders (Darrell Llewellyn and Dario Pegoretti) and I recognized that there was a need of a 30.6 post to work with XL sized, thin wall seat tubes. There were precious few out there and none that any of us were excited about putting on our bikes.

So I approached Fizik and asked to have a 30.6 version of their wonderful Cyrano post made. They were very helpful and interested but frankly very slow in acting. Then Dazza and Dario joined the mission and with Dario being able to actually go and sit with them and explain our needs and we got a batch of posts made.

So Fizik made our posts for us and they work beautifully. Fizik did not however, to the best of my knowledge, make a stock for themselves to sell through their normal channels. So it seems that the 3 D's are the only source of the Fizik Cyrano carbon 30.6 post.

So they are readily available from one of the 3 of us but I don't think you can find them anywhere else. That might change at some point but for now I think this is the case.

Dave

[Lionel]

thanks Dave. They look good. Got the regular version and this is a good post. I had a custom Bold made for my Zank as these were not yet there at the time.