nice shop bike

nice shop bike
Boulder Bicycle Lugged

Wednesday, July 29, 2009

War on the Framebuilders List

Have folks been following the discussion on the framebuilders list (at Boy it is heating up. Seems like a certain framebuilder from Connecticut (Not the one who builds wonderful rando and brevet bikes) is having a fit over the claim that the choice of frame tubing can make a discernable impact on the ride of a bike. Seems like that builder and some others are having difficulties admitting that sometimes, and for some riders, more flexible frames are the better widget.
In fact, the very idea that tube diameter and tube gauge can affect the way a bicycle rides is being challenged! This is rubbish!
During my college days, when I was known to watch metal melt and make a few frames, I was firmly in the camp of stiffer is better. I remember going to the NY bike show and I puchased some Ishiwata tubes that featured chainstays that flared out after exiting the bb shell. Boy were the frames I built with this tubing stiff! For a crit bike, I suppose it was at least entertaining, and at the time I loved it. Those chainstays really did make a difference!
But I kept riding bikes such as Colnago Supers, that were just built from regular Columbus SL. I kept wondering why those bikes were not as stiff, yet they rode wonderfully and seemed so fast.
Fast forward to when I owned Bicycle Classics Inc. around 2001 and 2002. We were selling Waterford bikes, and for some reason the standard Waterford 2200 wasn't completely firing me up in my size. So we ordered one with a heavier downtube. Well we only went up by a smidge, and just on one tube, and frankly I couldn't feel the difference. But then we ordered yet another one (all these had the same geometry), and this time specified heavier downtube AND heavier chainstays. And boy was that bike different! I'm not sure it was different in a good way, but the change in feel was immediate. It felt stiffer, but also less alive and went thud more it seemed over the bumps. The bike lost a bit of its balance. Other riders didn't mind it, though, but I don't recall anyone who rode it and the stock example who couldn't tell the difference.
I think, perhaps, we had to be the only bike shop that had identical bikes with different tube sets on hand for riders to experience!
And interestingly, we also sold the 531 version of Waterfords 853 bike, and that bike had much heavier tubing in the sizes I was familar with. And gosh did those bikes ride different. For folks who wanted stiff, the less expensive thick-walled 531 bike was a radically different ride than its siblings in thinner walled 853.
Why did we go through this effort comparing bikes and tubing? Because riders have different prefferences. Some riders like stiff, while others like flexy. Now some riders also are sensitive to the differences and really care which they ride. Other riders can tell the difference, but are able to tweak their riding style to get in sync with most any bike. I'm in the later category, but up to a limit.
So to say that tubing choice doesn't matter is absurd in my opionion. It may not matter to a particluar rider, but it matters greatly so a great number of riders.
Now many riders have come to realize that the light gauge tube sets with lots of flex work wonderfully with their pedaling style. This is not true for everyone. But nobody is saying that flexy is good for everyone. What is being said is that folks need to find the right flex for their riding style and preferences.
At Rene Herse Bicycles / Boulder Bicycle we spend lots of time learning what works for us, and how that translates to making bikes that are enjoyable for our customers. It is a royal pain, we would save lots of prototype dollars if we didn't do it. But we have to do it. And most of the top builders we know do it as well.

Wednesday, July 22, 2009

Front End Shimmy, headsets, and more

I'm waiting for some images of this past weekends riding - some mildly epic paved and moderate unpaved. But my mind is wondering this morning to the techical.

Front end shimmy is an issue that rando bike builders must deal with. As a basic rule, it seems that front end loads coupled with light tube sets can lead to the problem. Interestingly, a change of headset can make a radical difference.

In the latest issue of Bicycle Quarterly, a Toei was reviewed, and it had a real shimmy problem. I can't imagine that it is the bikes fault. The tube set is not terribly light, and they've been working on geometry for decades. But unlike most bikes in Japan I suspect along with the reviewer, that the "trouble maker" on the bike the Chris King headset. Now the Chris King headset should not be considered a "bad" headset. If anyting, it might be too good! Let me explain.

(Now I'm not sure I have this all straight, but here is my understanding of this topic)

If you spin a wheel in your hand, it wants to "wander" - it goes into a bit of side to side ocillation. Now when the wheel is on the bike, and your moving along, it does the same thing and it rotates the handlebars along with it. Now a bike frame has a natural frequency for its own movement (others can explain this better). If the wheel's frequency of ocillation is in sync with the frame's frequency, together they build, and a shimmy in the frame develops. And all this is related to frame geometry and forkrake as well. I'm sure glosses over something, but it captures the core idea.

For a frame that has a shimmy, anything that is done to change the frequency of either the wheel/fork or the frame, to get them out of sync, can reduce the problem. So a much heavier or much lighter frame can fix things - so a frame may even be "not light enough" to avoid a shimmy. Of course, going super light can have other problems.

One easy fix to imagine is to change the dampening of the headset. A Chris King headset rotates very easily, so with many tube sets and geometries that are otherwise favorable to randonneur riders, it seems to have a tendancy to get systems in sync so they shimmy.

But why to needlebearing headsets, such as the Stronglight A9, or the Miche shown above seem to reduce the problem? Well these headsets have natural dampning! A wise friend who hadn't thought too much about this opened my eyes to the probable reason. With a needlebearing headset, especially one that is not made with tappered rollers, the needles are only in true rotation with the races at one spot on the needle. This is because the race has variable diameter - so where the needle is contacting the race part with a larger diameter, the needle would need to be rotating faster than along the area with the smaller diameter. So with the needlebearing headsets, the actual rotation contact area is small, and there is "sliding" along nearly all the remainder of the surface! On the plus side, there is an increadible amount of contact area, so the headset itself wears out very slowly, but it doesn't move as freely. So a needlbearing headset is a headset with natural dampening.

Now one could even play with grease viscosity to fine tune the system. Of course, the handling of the bike then becomes susceptible to temperature change, but this happens anyway.

Now of course, some bikes might "avoid a shimmy" if dampeining is bad (casuses a frequency match-up). So maybe some race bike shimmy less if a Chris King headset is used. Interesting question. But for us on the rando side, the needlebearing headset is a help.

Is there a downside to the needlebearing headset? For one, I think that at low speeds I can sometimes feel a headset with a lot of dampening as it is harder to correct in sharp turns. But I'm not quite sure about that. Certainly, with hands on the bars, using a needlebearing headset is rather impossible to detect.

Now I have some more thoughts on this too - but those will follow in a few days. It would be great to get some comments on this!

Mike K

Thursday, July 16, 2009

Well we've been busy here - filling orders and trying to clean up the shop a bit.

This morning we picked up a small run of spacers to fit TA cranks from the local machine shop. These spacers are narrower than those typically supplied by TA. Some of the TA spacers are as much as 3.6mm, and with narrow 9 and 10sp chains, folks often have issues with the chain dropping between the rings.

So we had some custom spacers made, with a thickness of 3.15mm. In reality, the spacers float in width between about 3.08 and 3.24mm. We then sorted them, and bagged them in groups of 6, with spacers of fairly close dimension. Note that we were really splitting hairs here - but we want things as close as possible.

So these will work with double or triple TA Cyclotourist Cranks (Pro Vis). We didn't get too many of these sets, as we don't know what the demand will be. We can always get more made, and if we do a bigger batch the cost will come down for sure next time.

On other fronts, we're still waiting on the final twin plate forkcrown parts from the machinist. This is a batch of plates like those on the 650b Herse on our website. The crown uses Continental Oval blades, which we really like. But for those who want Imperial oval (like the old forks of years ago), it looks like a new crown will be forthcoming to accept those blades (such as those still made by Kasai and Reynolds).

We will be adding lots more stuff to our website soon - there is only so much time in a day. Also, this weekend may involve some serious dirt miles on the shop 650b Boulder Bicycle. Stay tuned for photos of this bike with the latest iteration of lighting for the Boulder Bicycle.

Monday, July 13, 2009

Well this weekend I was able to go on a couple of rides. The photo above shows my friend Ted with his cross bike next to the 2008 Herse I rode. This is a great area in the foothills outside Boulder. The stone edifice is part of a gold processing facility that was used I believe briefly in the late 1800's. One can actually find old portions of the gold rail cars that used to run from the mine to the nearby train (I think I have this right). The town's name is Wall Street, and there is even a restored Assay office museum nearby as well.
This is the kind of ride with extensive dirt sections begs for a wide 700c or a 650b tire. My friend Ted used his cross bike, which performed very well. But with the knobby tires stiff Carbon fork and aluminum frame, it was not nearly as comfortable as the 700c Herse with the Challenge tires at low pressure. And on pavement with steep downhill turns, the cross bike was quickly dropped.
Compliance in a bike very important. Discussing this with another friend, a key point we came up with is that Carbon forks are great at dampining vibration, but they don't have much ability to flex over bigger hits. The reason is that the forks must be very stoutly built to avoid failure, while a steel fork can be built that will flex quite a bit without worry of failure. And of course, a resiliant steel frame really "moves with the bumps" instead of getting thrown by them.
I'm kinda surprised cross bikes evolved quite the way they did. Many folks in Boulder, who have not discovered the joy of 650b or wide 700c, are trying to use a stiff cross bike as an all purpose machine. In reality, a new or old steel machine with appropriate tires will give a much more comfortable ride.

Friday, July 10, 2009

Do you even need a Randonneur Bike? Cinelli fun

For most riding, I do prefer a rando style machine. But many of my rides are shorter, just one to three hours. In Colorado, it is rare to get rained on (in general), so fenders are less critical. So for a change of pace (and to enjoy my vintage steed), I've set up my old Cinelli with a Berthoud 192 bag and Challenge Paris Roubaix tires. Now I'm still amazed at the speed and comfort of 650b, but the Cinelli is not going away anytime soon. You can see it is well loved.

Recently, my wife and I did a wonderful day of riding on the Katy trail in Missouri. The trail's website describe this ride as comfortable on wider road tires, or a mountain bike. The Katy trail is amazingly pleasant, with relatively luxurious restrooms and stops all along the way. We stayed in Boonville and did day rides from the area, and it was perfect. Now the trail is not challenging in terms of dirt or pitch; unlike the steep dirt roads outside Boulder.

The Berthoud 192 bag, though was a blessing. We didn't have too much stuff to carry, but did have a camera, extra water (not needed with the amenities), and some food and tools. Another shot of the Berthoud bag is shown below.

What is nifty about this bag is how nicely it attaches with the quick fix. It really comes off in just a moment.

So how does the vintage Cinelli do? Quite nicely. Since it has more trail then a machine designed for a front load, there is a bit of wheel flop. But the rake on some of these older race bikes is often quite generous for a given headangle, so all in all the handling is quite acceptable.

Now what about going "all out" in the rando conversion? The two things the bike lacks are lighting and fenders. Lighting actually can be easy. At some point, I may set up a B&M Cyo or a Schmidt Edelux on a Nitto skewer light attachment (and also use the B&M handlebar diameter adapter) with a Schmidt hub and I'll be grooving at night, at least up front.

For fenders, though, all is not well. It is really important to keep your foot from getting caught in the front fender and unleasing a catastrophe. For a size 8.5 or 9 shoe, a front center close to around 615mm is really needed. A few mm shy may be fine (and often Rene Herse built right to the edge we've found). But the Cinelli is about 590mm. That is an invitation for dissaster. So no fenders on this machine. Plus this one does not have eyelets.

Interestingly, some early Cinelli frames from the early 70's and before were made with fenders in mind. They had threaded points on the chainstay and brake bridges to accomodate fenders, as well as eyelets. I don't know the geometry on them, but memory indicates that they were more laid back with greater clearances so they would be fender safe.

So what is with the horrid handlebar tape (and electrical tape) on the Cinelli pictured? The bike had to spend some time in the roof rack, and sometimes gets locked up around town. So I figure the shabby tape makes the bike look like a beater bike and is a bit of theft insurance. Rather intentionally, I've waited to see how bad the tape can look (and how dirty the bike can get). But something inside me is saying its time to build a real beater bike and get this one spiffed up again.
So if one doesn't need fenders, and can also deal with a lack of "integration", it is quite possible to enjoy many machines in the "rando" style. Unfortunately, many modern bikes simply lack the clearance for wider tires, and have such high trail that a handlebar bag up front is somewhat dangerous.
So maybe the reason I've always loved the vintage steel bikes such as the Cinelli is that in many ways they are extreamely friendly to the style of riding many of us have adopted. I'll have on Cinelli in later posts - they were not just racing bikes!

Time to Blog!

Well its time to get into the new century and start blogging. Some folks want us to "tweet", others say we should join facebook, but one thing at a time. There really is so much to talk about and share. There is the bicycles, the riding, and cool handmade items that are not bicycles that many of our customers and friends also share interests in.

So here it goes - my goal is to add a post 3 or 4 times a week. But maybe some days it will be multiple times per day.

For now, we'll let the comments go "unmoderated". Constructive comments are always welcome, but nastiness to us or anyone else is not OK. So let the blogging begin...

Mike Kone in Boulder CO
Rene Herse Bicycles Inc. / Boulder Bicycle