Shimmy cured

[dougP]

My Atlantis has always had an odd, annoying and somewhat unpredictable shimmy.  This topic has been discussed ad nauseum, with the suggestion that a roller bearing headset MAY increase the friction enough to damp out shimmy.  Since my problem was limited to certain load conditions (heavy rear & little to no front load) that were easily adjusted (more weight up front), it was not a Red Alert.  I always thought it would be a nice thing to try but never put much effort into finding one for the Atlantis.  With Rivendell now handling the IRD and Grant specifically mentioning the goodness of a bit of extra stickiness, I had to give it a try.  The original Ultegra was nearing 10 years old & way past 40,000 miles, so it had earned it's keep.  In fact, it was still smooth & I wouldn't have been thinking about it absent the shimmy. 

After a few hundred miles & a variety of loading experiments, I'm pleased to report a complete absence of shimmy.  Even with 15 lbs in each rear bag, shoved as far back as possible on a Nitto big back rack, and nothing, not even my trusty Acorn, on the front, the bike is rock while sitting up-right, coasting a 20 MPH downhill.  Previously, a load this squirrely would get things rocking about 12-14 MPH and be overly exciting by 18.  All that drama is gone. 

For anyone who's got a recurring problem on this issue, give one of the IRD headsets a shot.  It's a relatively quick, simple experiment and the headset looks quite nice as well.  The bike otherwise handles the same so there is no downside. 

dougP

[Peter Morgano]

Hmm, will be picking one up for my bombadil rebuild when it comes back from paint. Looks like the perfect setup at almost half the cost of Chris King.

--
You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group.
To view this discussion on the web visit https://groups.google.com/d/msg/rbw-owners-bunch/-/NDnWRSFdzScJ.
To post to this group, send email to rbw-owne...@googlegroups.com.
To unsubscribe from this group, send email to rbw-owners-bun...@googlegroups.com.
For more options, visit this group at http://groups.google.com/group/rbw-owners-bunch?hl=en.

[BSWP]

Hmmm... I have been wondering what I could do for shimmies on both the QuickBeam and the LongLow, will have to give this a try.

When is the next raffle?... I need a new black woolie zip-tee, too!

- Andrew, Berkeley

[Mike]

Thanks for the info Doug. I have experienced a bit of shimmy on my Hilsen. I didn't notice the RBW was now selling the IRD headset. Here's a link to it.

http://www.rivbike.com/product-p/hsrd.htm

--mike

[mikel...@juno.com]

has anybody tried overtightening their headset to replicate 'roller bearing drag' which seems to cure shimmy?

mike goldman

warwick,r.i.

____________________________________________________________
Woman is 53 But Looks 25
Mom reveals 1 simple wrinkle trick that has angered doctors...
ConsumerLifestyleMag.com

[Peter Morgano]

I tried that but then I just got "notchiness" which was aggravating for the whole trip.

--

You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group.

[allenmichael]

After reading this post, I stopped at my local bike shop to inquire about the price for installing a new headset, $30. Might be a Feb., pre-summer tour, purchase. I've experienced a shimmy at times with my 56 Atlantis, and I'm sure the headset is aged at this point. Probably too much to hope for that it will also quiet the front-wheel dive at low speeds going uphill with a front load (which was much better on second tour with less weight placed lower in the front), but i'm still wanting to try it out.

[Steve Palincsar]

On Fri, 2013-01-04 at 20:51 -0800, allenmichael wrote:
> Probably too much to hope for that it will also quiet the front-wheel
> dive at low speeds going uphill with a front load (which was much
> better on second tour with less weight placed lower in the front), but
> i'm still wanting to try it out.

What is "front wheel dive"? Are you perhaps talking about the effect of
wheel flop?

[BSWP]

I note that the RBW Tange/IRD setup has needle bearings at bottom, and ball bearings at top. Most of us considering switching to roller bearings for added damping, I would suppose, already have ball bearings both top and bottom. So why not replace just the bottom bearing? It must be industry practice to sell only "sets" of upper and lower headset bearings, not individual uppers or lowers.

Also, can anyone comment on Tange/IRD quality vs. no-name manufacturers who supply resellers such as Velo-Orange? VO's roller bearing set (rollers upstairs and down) is half the price of the Tange/IRD set.

- Andrew, Berkeley

[William]

For folks considering 1" threaded roller bearing headsets in general, there is also a Miche offering that QBP sells, meaning any LBS can order for you.  That has rollers top and bottom. 

[Scot Brooks]

Great timing for this topic since I've noticed my Sam/Surly Rack/Saddlesack Large combo makes for a bike that has pretty extreme shimmy at nearly all speeds. With the bike stripped I can ride as long as I please no-handed but its a hairy proposition with the rack and bag, even without a load.

[PATRICK MOORE]

"at all speeds." This is very strange. Can you describe the "feeling" of the shimmy you experience? Usually shimmy occurs at very distinct speed ranges; for example, I once experienced it on my '95 custom at just under 20 mph. I had ridden the bike for Ks of miles and never had shimmy, until the shimmy showed up for a couple of weeks. After a couple of weeks, it disappeared. The cause could have been something as simple as a slightly different f/r weight distribution or f/r tire pressure, but it was a very particular phenomenon that lasted for only a very short time.

On my current '03 Curt road, I've had it occur on a couple of rides at very particular speeds, only to disappear entirely on subsequent rides.

Thus, to have shimmy on a bike over a wide range of speeds and for a long period is, to my experience, very odd.

Note too that Rivendell bicycles, in my experience (3 customs, one Sam) are not the best for more than minimal (over 5 lb) front loads -- tho' of course, this too depends on how and where the front loads are attached to the bike. My Sam would not keep a straight line with heavy loads in a bar bag or in front low rider panniers.

On Sat, Jan 5, 2013 at 12:54 PM, Scot Brooks <scothi...@gmail.com> wrote:

Great timing for this topic since I've noticed my Sam/Surly Rack/Saddlesack Large combo makes for a bike that has pretty extreme shimmy at nearly all speeds. With the bike stripped I can ride as long as I please no-handed but its a hairy proposition with the rack and bag, even without a load.

--
You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group.

To view this discussion on the web visit https://groups.google.com/d/msg/rbw-owners-bunch/-/kdGLTkKQLuwJ.

To post to this group, send email to rbw-owne...@googlegroups.com.
To unsubscribe from this group, send email to rbw-owners-bun...@googlegroups.com.
For more options, visit this group at http://groups.google.com/group/rbw-owners-bunch?hl=en.

--

-------------------------
Patrick Moore, Albuquerque, NM, USA
For professional resumes, contact Patrick Moore, ACRW
http://resumespecialties.com/index.html
-------------------------

[Scot Brooks]

Patrick,
In my case "all speeds" is really all speeds I ride at which is probably between 12mph and 20mph or thereabouts. It happens with and without front load. For instance, my grocery run last weekend was all loaded into my saddlesack, but this weekend I split it up between the saddlesack and the front basket. Same result, same shimmy. It DOESN'T happen at all when I have no racks/bags/baskets on the bike.Having said that, it's not any major inconvenience but I might have a look at the prescribed headset cure before too long.

[Scot Brooks]

Forgot to describe it; it's a back and forth wobble of maybe 4 or 5 inches total side-to-side movement. Maybe more. It doesn't get any more or less pronounced at different speeds that I can tell but the frequency gets a little scary when I'm going quickly.

[Steve Palincsar]

On Sat, 2013-01-05 at 12:52 -0800, Scot Brooks wrote:
> Patrick,
> In my case "all speeds" is really all speeds I ride at which is probably between 12mph and 20mph or thereabouts. It happens with and without front load. For instance, my grocery run last weekend was all loaded into my saddlesack, but this weekend I split it up between the saddlesack and the front basket. Same result, same shimmy. It DOESN'T happen at all when I have no racks/bags/baskets on the bike.Having said that, it's not any major inconvenience but I might have a look at the prescribed headset cure before too long.

I'm with Patrick. That doesn't sound like a classic "shimmy" at all. I
think you may be having issues with your load or your racks.

[Kelly]

When it shimmies at all speeds and doesn't dissipate when touching the top tube it is usually from what I've seen .. a:] Headset (either adjustment or worn out)  b:] alignment (check forks  

If it was when loaded then moving loads etc would usually fix it.     

My experience with front loads is different than Patricks.   My wife's Atlantis and my Bombadil handle 30 to 40 lbs with low riders beautifully ... My quickbeam does well with 5 to 10 lbs even on high speed down hills. 

We've both been very happy as well with the handling fully loaded going up hill at slow speeds.. slow cadence in 24x36 one handed while drinking coffee on a long climb.   

My point being there is something wrong that in my opinion can be fixed with some repair in your case if it happens loaded unloaded etc.   It's not something to just accept.   

The only shimmy I would put up with would be a free handed shimmy that goes away instantly when touching the top tube at certain speeds only or when induced.  

Kelly

[Anne Paulson]

My Atlantis handles 50 or 60 pounds, with maybe 25 up front on
lowriders, with aplomb. The only time I get shimmy is when putting a
lot of weight in my handlebar bag; then I get shimmy on the downhills.
It is alleviated at once if I remove a couple of heavy things from the
handlebar bag. I use an Ortlieb front handlebar bag with no decaleur.
I don't want to use a decaleur, but if I did I'm sure it would remove
the shimmy.

>
> My experience with front loads is different than Patricks. My wife's
> Atlantis and my Bombadil handle 30 to 40 lbs with low riders beautifully ...

--
-- Anne Paulson

My hovercraft is full of eels