Author Topic: wobbly front wheel  (Read 7878 times)

lovefo#

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wobbly front wheel
« on: June 29, 2013, 05:53:00 PM »
Hi. Ive had a wobbly front wheel on my Thorn Sherpa from day 1. It seems to get worse at high speed going downhill. Fine up the hill. Ive tightened everything up including the front panniers and some of the bolts around the stem. This morning I took off the front panniers and it seemed ok. Ive got a laptop in one and food in the other. Ive also got a handlebar bag. Im guessing the weight of the panniers is causing the wheel to wobble. Any suggestions on how I cna improve this? Has anyone had similar experiences?

JimK

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Re: wobbly front wheel
« Reply #1 on: June 29, 2013, 06:29:44 PM »
A front wheel really shouldn't wobble!

1) is it the wheel bearings? When you pick the bike up from the handlebars, and grab the front tire, can you move it side to side?

2) or the headset bearings? Standing next to the bike with the front brake fully engaged, can you push the bike back and forth at all - is there any kind of clicking sound or play especially at the bottom of the head tube? I put a finger down there to feel for play as I am squeezing the front brake with the other and pushing the bike backwards and forwards.

3) is the wheel true? When you pick the bike up from the handlebars and spin the front wheel, does it wiggle from side to side as it spins?

When you are zooming downhill with loaded front panniers etc. and the front wheel wobbles, do the handlebars wobble along with the front wheel?

The more precise you can be in characterizing your wobble, the more likely it can be for anybody to figure out what's going on!

Rockymountain

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Re: wobbly front wheel
« Reply #2 on: June 29, 2013, 07:38:55 PM »
Or is it simply that your tyre is not on straight? That's easily fixed by letting out all the air, wiping a small amount of washing up liquid round the inside of the rim, squeezing the tyre and trying to re-seat it and then pumping it up again.

Fraser

JimK

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Re: wobbly front wheel
« Reply #3 on: June 29, 2013, 07:43:33 PM »
Or is it simply that your tyre is not on straight?

Yeah and Dan has observed that the tread on his Schwalbe Marathon Duremes is not straight relative to the bead so even though the tire is mounted correctly the tread pattern has a wobble.

rualexander

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Re: wobbly front wheel
« Reply #4 on: June 29, 2013, 08:16:47 PM »
I suspect that this is what we normally call shimmy?
My Sherpa shimmies a bit at a certain speed range (around 30 - 36 km/h if I remember correctly) when I have my front panniers on.
Does it only happen when you have panniers on the front?
You can try moving the contents of the panniers around to see if it helps, otherwise just hold one of your knees against the top tube when it happens and that should damp out the shimmy.

Danneaux

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Re: wobbly front wheel
« Reply #5 on: June 29, 2013, 09:42:26 PM »
Hi Fearghal!

I've been following your blog and enjoying your entries and accompanying tour photos very much; they're really outstanding and a pleasure to see. For those who may have overlooked the link in your other posts, your blog is here: http://loveforourworld.wordpress.com/

After such a terribly wet night in Nancy (France), I hope you'll find drier weather ahead, with the rest of your trip being both scenic and pleasant. I'm not sure where you're headed next, but if it is Belgium, you're in for a real treat. I found the Walloons and Flemish to both be really warm and pleasant folks, with Wallonia, especially full of wonderful food stops and great hospitality. I can't wait to return someday.

I'm sorry you've developed a wobble of sorts on your Sherpa. If you can be more specific and provide all details as you go forward and try things, we might be able to offer something more in the way of specific suggestions. Sometimes, a compression strap will help stabilize the load within the bags and tie the bags more firmly to the rack, minimizing second-order vibrations that can cause problems. A weight shift can sometimes help as well. When I had a shimmy problem with my Sherpa, I tried a number of things and received many kind suggestions in trying to address it. Though my problem was an isolated one in my use -- the bike did well for AndyB in his trials of it later -- some of the suggestions in that thread might be helpful for you to try: http://www.thorncycles.co.uk/forums/index.php?topic=4320.0

One thing I would suggest is to try fitting the HB bag to a Thorn Accessory T-bar to get the weight down and a bit closer to center; that should help overall handling. Yours is a lovely bike, and looks "class" (as jags would say) with the red-and-black bags.

Do take care, and know good wishes go with you. Please keep us updated!

Best,

Dan. (...who wonders what brand/model laptop you're carrying and about the battery life)
« Last Edit: June 29, 2013, 10:03:54 PM by Danneaux »

JimK

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Re: wobbly front wheel
« Reply #6 on: June 29, 2013, 10:06:10 PM »
Its a new bike so Im surprised.

If it's really a shimmy then it can certainly happen on a new bike. Dan did all sorts of experiments with his Sherpa to figure out the conditions that caused it to shimmy. I don't think anybody ever figured out the logic. But a lot of times redistributing weight will make it go away. A shimmy is pretty much a whole bike system thing, some kind of resonance where the tracking correction of the steering is part of the action. As I recall, Dan found that moving the weight around on the *back* of the bike could make the shimmy come and go. So you might want to try moving things around a bit even if the connection to the shimmy is not at all obvious. It is in general not obvious what makes a shimmy come and go.

Danneaux

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Re: wobbly front wheel
« Reply #7 on: June 29, 2013, 10:23:12 PM »
Quote
As I recall, Dan found that moving the weight around on the *back* of the bike could make the shimmy come and go.
Spot-on, Jim; the bike generally did well weight with up front -- no problem there at all for me. Adding weight atop the rear rack or in the rear panniers made a difference, and weight in both put things awry quickly for me. Julian (JulK) made a similar observation about rack-top loads vs groceries in his rear panniers.

Jim, Fearghal's bike is shown very nicely here: http://loveforourworld.files.wordpress.com/2013/05/946429_10152896546250277_717374038_n.jpg

I see he has a Mk3 Sherpa, and mine was a Mk2. The Mk3 does have lower weight limits than my Mk2, thanks to tubing diameters proportionate to frame size. I think that may make load distribution even more important.

Fearghal, I'd surely try re-arranging things at the back...maybe try swapping positions for the read and black sacks on the rear rack...and see what happens as a result. Maybe move the front lock to the seatpost as well, getting it away from the steerer. A bit less convenient, but I fear it could contribute to a shimmy/wobble, as it is not rigidly mounted and can move with the steering.

Best,

Dan.
« Last Edit: June 29, 2013, 11:57:59 PM by Danneaux »

mickeg

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Re: wobbly front wheel
« Reply #8 on: July 03, 2013, 03:50:02 PM »
I use the word shimmy if it is a resonance where there is a certain frequency of movement that is predictable, like a spring moving back and forth.

And I use the word wobble if it is an unpredictable shaking movement.

I had a bad shimmy on my LHT but found from shifting weight around that my front panniers needed to be shifted forward.  The shimmy went away when I got the front pannier center of gravity centered at (or slightly above) the hub.  It was worst when the center of gravity of the front panniers was too far to the rear.  

The rear rack design also can contribute to shimmy if it allows too much flex.  For example my Tubus Logo EVO rack is extremely stiff, less noticable shimmy than with my Surly rear rack that weighs twice as much.  The Surly rack has twice as much steel so you would expect it to have less flex but its design allows more flex to occur.

I had a wobble with 26X2.0 tires that I put tire liners in.  As the bike rolled, the bike felt like it wanted to shift side to side with an unpredictable movement.  I removed the liners, the wobble went away.  The liners prevented the tires from taking normal shape upon inflation, the tires had a slightly deformed shape from the liners.
« Last Edit: July 03, 2013, 03:53:02 PM by mickeg »

Danneaux

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Re: wobbly front wheel
« Reply #9 on: July 03, 2013, 04:00:15 PM »
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Any more tips on wobble, or sores would be appreciated :-)
Fearghal, it sounds as if you're closing in on the wobble with adjustments in weight distribution. Next chance you get to lay things out, I'd try to put the heavier things as far as possible *in* the panniers and toward the bottom and nearest the wheel if possible to get weight low and close to center. If you could tie the bags solidly to the rack with some webbing compression straps, I think it would help. I am often a lone voice in the wilderness on this, but I have found compressing the load and bags limpetlike to the rack helps on-tour handling with every bike I've owned. It makes for a quieter ride, a neater internal load, and longer rack life 'cos the load and bags move with the bike instead of independently.

I'll go out on a limb here and say that unlike a majority of tourers, I long ago gave up on elasticated bungee cords. They're fine at first, but over time, I found the elastic broke down and they were no longer secure, wobbling instead. I now use Arno straps -- webbing with a quick-release buckle -- and have had no problems. My last set of Arnos were made in Ireland, so you know they're good! Arno are here (in Swedish): http://www.arnostrap.com/ Google-translated to English here: http://translate.google.com/translate?sl=sv&tl=en&js=n&prev=_t&hl=en&ie=UTF-8&u=http%3A%2F%2Fwww.arnostrap.com%2F&act=url Arno straps allow one to cinch the load down *tight* so no wobbles from luggage. I love the things. For my cinch straps, I went with some I made myself, using even quicker-release Fastex buckles.

My experience with Surly Nice Rack Rear vs Tubus Logo Evo rear racks mirrors Mickeg's exactly. I've found my Thorn Expedition rear rack to be stiff beyond what I ever would have imagined. It has worked out very well also.

Ooh! I can weigh-in on saddle sores, having once had one the size of a Eurocoin that had to be lanced -- ouch! It did feel much better After.

Fearghal, I can feel for you on this, I really can! Saddle sores seem to be caused by a breakdown of tissues and friction aggravated by a locally humid environment. They aren't too unlike a bedsore or blistered feet.

A number of things can help, starting with a change in saddle position. Too much weight on the saddle, the wrong angle, or squirming on it can all start or aggravate the condition, as can a hair that has flexed and allowed bacteria to enter the root follicle.

Riding in damp, wet, or sweat-soaked shorts can be a problem, too. I am often in the position of having to use the same riding shorts for a week at a time while on-tour (desert touring with no available water source for laundry). Eew, I know, but this is the reality. Whenever I stop for the day and make camp, the first thing off is my riding shorts, with a change to casual shorts or even -- if it is truly remote -- letting the nether regions go al fresco for 15 minutes or so to air out and dry. I rotate between two pair of shorts, turning the "old" pair wrongside-out to air in the sunshine atop my racktop load, which does wonders and -- Of course! First chance! -- laundering them at the nearest opportunity or dunking them in a stream when I find it (soap used a hundred meters away from the running water to prevent the fish from blowing bubbles). I also go without underwear on my day rides from home, but will usually take a liner underpant or three while on extended tour (get some that don't have seams where you'll be sitting. The old SpinSkinz brand were good). These can be rinsed out under a water bottle (water and soap, whenever possible), allowing me to extend the life of the shorts.

It is really important to also keep the skin clean as possible. Sometimes on-tour, I will use a dab of waterless, gel-alcohol hand sanitizer in a spot under each of my sit-bones. It does help.

Vitamin E capsules rubbed into the skin under the ischial tuberosities (sit bones) has helped me in the past, as does Desitin or other brands of baby diaper rash cream or a broad-spectrum antibiotic ointment. In the "olden days" when chamois liners were real, I used chamois creme to keep the leather soft and pliable and to reduce the bacteria count (most of the cremes contained vitamin E and some sort of mild disinfectant). Synthetic chamois are so much more comfortable and convenient and require essentially no care. Still, the principle of reducing friction through lubrication can help. I've used a product called "BodyGlide" to good effect. The now make a relabeled version for use when riding in cycling shorts. See: http://www.bodyglide.com/ Amazon also carry it: http://www.amazon.com/BodyGlide-BGCB-Bodyglide-Original-Anti-Chafe/dp/B005L8YVRO ...as do REI: http://www.rei.com/product/745879/bodyglide-anti-chafe-formula-13-oz If you're near Rotterdam, BeverSports have carried it in the past (they have everything and are a great store for the cyclo-camper to visit): http://www.bever.nl/

Once started, the real problem with saddle sores comes with infection. These areas often start with what looks (and feels!) like a pimple and soon staph causes an infection. At that point (before, really) it is wise to visit a physician for a look-see and professional treatment, as home remedies will no longer work. An infection -- especially in that area -- is serious stuff, so please don't delay seeking help if it is already nearing that point or there. Doctors have seen everything and are usually eager to help with such things, especially in places where lots of people cycle and even moreso if you're touring. It seems to be a point of pride to get one back on the road and cycling pain-free quickly.

I sure hope this helps, Feraghal. You're doing well, and all encouragement your way. Thanks for the netbook info; I'm going much the same route myself. Do take care, and let us know how you are doing with these issues as you can.

Best,

Dan.
« Last Edit: July 03, 2013, 04:02:03 PM by Danneaux »

Danneaux

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Re: wobbly front wheel
« Reply #10 on: July 04, 2013, 09:10:12 PM »
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Dan hopefully I will bump into you along the way...
An always welcome thought, Fearghal; I'd enjoy meeting and riding a ways with you if you make it to the NW corner of the States.

Though things aren't fully sorted, I feel even the recent worsening of the shimmy indicates you're on-track to homing in on a solution, else it would have remained the same. I concur with your Dutch friend -- even loads side-to-side really help. On my last tour through the NL and BE, I could really feel when I had the load "off"; it made my back ache, vaguely at first and then gnawingly. Stopping to transfer a couple Kgs from side to side really made a difference and no more back pain. Yes, compressing this bags against the rack will accomplish two things: The load within the bag will be stabilized *and* the bags will become one with the rack/bike. Amazing what it can do.

Please keep us posted as to how things are going. So very much enjoying your trip from afar, and your photos are top-notch!

Meanwhile, all good thoughts your way!

Best,

Dan.

lovefo#

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Re: wobbly front wheel
« Reply #11 on: July 10, 2013, 06:42:49 PM »
Hi Dana and all

Well at the risk of coming across as a bit of a dork, Id like to update you all. I popped into a bike shop where the mechanic adding air to my tyres and tightened up the headset. Problem just about solved. Very little movement today. :-) But think I will stil check out those straps anyway Danneaux.

JimK

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Re: wobbly front wheel
« Reply #12 on: July 10, 2013, 07:30:34 PM »
Thanks for the update! These sorts of things are notoriously difficult to diagnose! It's a big help to hear the experiences we all have, so then it gets that bit easier to figure it out the next time around.

I have a little clicking now, down in the bottom bracket area. I think it's my right pedal. Or maybe not! Those sounds can travel in funny ways!

Danneaux

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Re: wobbly front wheel
« Reply #13 on: July 10, 2013, 09:10:40 PM »
Fearghal!

This is the best news ever! So glad the headset and tire pressure adjustments seem to have caught the majority of the problem -- yay!

Here's hoping all goes smoothly from here on out. Thanks so much for the followup/update.

Best,

Dan.

JimK

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Re: wobbly front wheel
« Reply #14 on: July 15, 2013, 09:40:21 PM »
I have a little clicking now, down in the bottom bracket area. I think it's my right pedal. Or maybe not! Those sounds can travel in funny ways!

Ha! I think I figured this out. First I noticed that the sound only happened with a decent amount of torque. I was thinking, maybe my cranks bolts are a little loose. Then I thought, ah, a good test would be to really push the torque to the max. So I pushed the gearing up a couple steps, stood up, and really mashed for a few strokes. No sound at all!

That clicking is some kind of creaking from my Brooks Flyer!