Rando Tweaking…

27 04 2012

650B All Road from Boulder Bicycle...

My freakishly fun Boulder Bicycle All Road randonneur machine.

Downtube barrel adjuster for rear derailleur...

I had some sudden shifting issues last brevet which I solved [mostly] on the bike by using the downtube barrel adjuster. It’s conveniently located within easy reach while riding.

Shimano XT rando derailleur - fixed now...

As I was going over my rando bike this week [as should be done regularly] I noticed the barrel adjuster at the rear derailleur had come completely unscrewed and was sort of hanging there askew. That explains the sudden shifting issues! Doh!

Fizik Mircotex bar tape...

I’ve been meaning to put some white tape on the Boulder for a while, but haven’t been motivated enough to do it. We’ve had a few rainy days this week so I got my butt in gear and got it installed. It looks pretty spiffy and supposedly it’s tape you can clean so it should stay white a while.

Miche needle bearing headset...

When I first got my Boulder I had a fairly serious shimmy problem. As it turned out I had the headset installed incorrectly! Doh! This type of low trail bike with supple wide tires and a very flexible frame is a candidate for developing a shimmy. The whole topic of shimmying is very complicated and not fully understood. Bicycle Quarterly has published several articles related to this topic if it interests you.  My bike has a needle bearing headset as opposed to the more common ball bearing headset. The needle bearings provide more resistance to turning than a ball bearing which prevents or reduces the development of a shimmy. My bike is pushing the envelope of using very skinny ultralight tubing for a large frame [59cm TT] and a reasonably heavy guy 175lbs. It has taken some playing around with the headset adjustment to find the sweet spot for me and my bike. I can’t recall the last time I noticed any tendency to shimmy and the extra resistance in the bearings isn’t something you can feel when you are steering.

Update: I lowered my tire pressure for the Crouching Rat 300K and was able to get the bike to shimmy if I tried. So the shimmy is not totally gone. It doesn’t happen when I am riding normally, but if I try to ride no hands I can’t pedal or it will shimmy. I’ll play with the setup some more. It’s not a problem I’m going to do much about since it’s not causing a problem in practice. However, if you need a large frame I’d consider the oversized ultralight tubing for a somewhat stiffer frame. If I was independently wealthy I’d build up a 2nd Boulder with the oversized tubing so I could compare them back to back. Sadly I am not!…=-)

Grand Bois Hetres = 650B smiles...

I understand increased tire pressure also helps reduce shimmying, but I like my tires soft so they do their job of absorbing road shock and keeping themselves glued to the road. The standard Boulder Bicycle All Road uses ultralight oversized tubing which would stiffen the frame a bit. I have wondered if I was to order a new rando bike if I would want to go for a stiffer frame or not. I really like how efficient my bike is to climb on and how it responds to hard efforts. I wouldn’t want to give that up by getting a stiffer frame, but without a side by side test it’s impossible to know how much difference there would be.

Gravel country riding = 650B terrain...

Just to be clear I feel like the performance, comfort and versatility of an ultralight skinny tubed 650B bike like mine is well worth the setup hassles of dealing with a shimmy. I’d also point out that Boulder Bicycle can build you a 650B rando bike with zero shimmy issues. I purposely pushed the limits of what is practical to find out what would happen. If  I set my bike up poorly it can shimmy pretty seriously. If I set my bike up properly I have no shimmy even when I am tired and mashing the pedals without full concentration on steering my bike.

Food to go...

My last 200K demonstrated the benefit of staying on the bike between controls. One element of that is being able to eat on the go. So I’ve restocked my bar bag with a bunch of energy food I like that I can munch and pedal. I will still pack a sandwich or two on a ride for those times when I do stop at a control so I can switch it up with some real food.

Mostly wool bike clothes...

Having bike clothes that cover a wide range of conditions is also key to avoiding frequent stops between controls. Our rides in BC start on cool to cold mornings, but often see warm to hot afternoons with cool evenings and cold nights. I’ve been enjoying wool cycling clothes lately. For my next ride I’ll start with a SS wool jersey + wool arm warmers + a wind vest + ear warmers. On the bottom I’ll have a set of 3/4 length wool tights with wool leg warmers underneath [puts two layers over my knees]. At each control I’ll evaluate how I am doing and shed layers as needed. The key is not to sweat so much I soak my clothes which will be uncomfortable even with wool. In spring here often just taking off the ear warmers and wind vest is enough to transition from cool morning to warm day.

If it rains and/or temperatures get crazy cold I have a rain jacket, rain chaps, rain gloves and rain booties to put on that serve as some extra climate control options.

Selle Anatomica saddle...

Of course you can only stay on the bike for hours if you are comfortable. My saddle and my feet are totally happy these days even for 10hrs+ of nearly non-stop riding. My hands are comfy if I wear bike gloves as opposed to unpadded fleece gloves and I move them around the bars a bit. So I can start the ride in warm fleece gloves, but I should switch to bike gloves after a few hours. This also means I have a spare set of gloves on board if one set get wet/damaged/lost. My main comfort issue at the moment is tension in the area between my shoulder blades. This is due to poor bike posture and letting my neck/back tense up. I can avoid it by sitting on the bike in a more ergonomic position [sort of like not slouching in your office chair] and also consciously relaxing my upper back as I ride. I also stretch that area out every time I stop at a control.



7 responses

27 04 2012
Chris Cullum

See you at the 300 tomorrow! BTW how do you keep those Hetres so clean, mine look like grey walls.

27 04 2012

@Chris – it’s amazing how clean your bike stays when you don’t ride it…;-)

See you tomorrow!

27 04 2012
Chris Cullum

Well, the forecast is dry for tomorrow so they should stay clean for another day!

27 04 2012
Bill Russell

Vik, are you able to ride this bike no-handed? I have one with a nearly identical set-up and it heads for the ditch as soon as I let go.

29 04 2012

@Bill – I tried on the recent 300K and I get a shimmy again if I ride no handed and pedal. I can ride no handed and coast down a gradual hill. I thought I had the shimmy licked, but I lowered my tire pressure for rough pavement/gravel and that seems to have brought it back.

I don’t get it when I have at least one hand on the bars and I don’t ride no handed frequently on a brevet simply due to the fact I am tired and not 100% so it’s not worth the risk even without any shimmy issues.

In my normal riding the shimmy problem doesn’t surface so it’s a minor issue.I suspect if I had used oversized thin walled tubing it wouldn’t be an issue at all. If I ever get another rando bike I’ll have to try that.

3 05 2012
Bill Russell

Shimmy’s never been an issue with my All-Road, even with skinny thin tubes and a Miche headset. It’s the no-handed thing I’m currently chasing. It was one of my stated goals in purchasing/building up this bike and has so far proven elusive.

3 05 2012

@Bill – the shimmy potential of a frame depends on a lot of things so your frame/rider combo may be outside the high risk shimmy zone.

OTOH – on way I can get rid of the shimmy for sure is to overtighten the headset. That results in making it impossible to ride no handed since once the bars turn the bike dives for the ditch as there is too much resistance in the headset to allow the normal body weight shift corrections to work.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )


Connecting to %s

%d bloggers like this: