Parlee RZ7

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FactoryMatt
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by FactoryMatt

^good points. Knees on top tube..

RDY
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by RDY

Try balancing the wheels. If the bike's handling normally at low to moderate speed, but wobbling at high speed, that's a potential and often overlooked culprit.

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Multirider
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by Multirider

Edited
Last edited by Multirider on Mon Oct 11, 2021 11:30 pm, edited 4 times in total.

kode54
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by kode54

Best to balance wheels on a truing stand. You can add weights accordingly...but you'll see the inbalance on the stand. Should be weightless and not weighted...and you'll see that. Heaviest part will 'bottom' out.
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FactoryMatt
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by FactoryMatt

Multirider wrote:
Wed Mar 17, 2021 5:01 pm
How tall are you and what do you weigh? Just curious since you like the 110mm stem.
I'm 6'1'' 78KG on a Large. I like it alot.
Multirider wrote:
Wed Mar 17, 2021 5:01 pm
What headset bearings do you recommend? I would happily replace them as part of the bar swap/stem lowering that I'm about to have done.
like i mentioned, it's almost certainly not the bearings if theyre in good shape, but i'm not a fan of the stock ones regardless. Parlee selected some fairly oddball bearing sizes TBH and frankly, the bearing-to-headtube fit leaves alot to be desired, meaning it's even more important to make sure the headset is tight, as you're solely relying on the taper to keep the bearings in place and not the fit between the frame and the bearings.

https://cannondaleexperts.com/products/ ... et-bearing

https://www.amazon.com/FSA-Orbit-Tapere ... B019CEOEQ0

I'm running a different, taller split ring now from a Syncros headset and a relieved top cap, but that's a whole nother story.

Multirider wrote:
Wed Mar 17, 2021 5:01 pm
I'd love to hear about what techniques might reduce the occurence or severity. I've seen conflicting advice on whether to move forward or back, sounds like you are in the "move forward" camp. I kind of hate that,but am willing to do it if it gets the desired result.
As someone said above, headshake is an enigmatic thing. i don't know for sure. i got a concussion on a motocross bike growing up from headshake, so i know what it's like. i'm of the opinion keeping weight forward (and low) helps to PREVENT the headshake, but once it starts, getting your weight BACK helps to ameliorate it. IOW picking up the front wheel will help the bike to self-center again. I could be wrong. i'm sure others will let me know if so.
Multirider wrote:
Wed Mar 17, 2021 5:01 pm
I watched the Chloe Dygart crash at TT worlds and that's my worst nightmare. Massive speed wobble and over the guardrail. If you watch it in slo mo, it looks like she hit a bump that induced the wobble, it got worse, then better, then MUCH worse and over the guardrail. SCARY!!! I watched it too many times. Can't un-see it. That really freaked me out. I was trying to ignore speed wobble, now I am determined to resolve it or get a different bike.
that was definitely scary and very very odd. That bike runs really poor geometry IIRC. wayy too much fork offset and too steep of a headangle which produces too little Trail. and it's probably pretty flexy around teh headtube. and then you add in that super high aerobar setup and some environmental factors and you get terminal tankslap
Multirider wrote:
Wed Mar 17, 2021 5:01 pm
The "marginal gains" web site isn't coming up for me. Says it is offline at this time, try again later. Argh.
try getting to it from a podcast app like Stitcher on your phone.

Multirider
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by Multirider

Edited
Last edited by Multirider on Mon Oct 11, 2021 11:31 pm, edited 2 times in total.

FactoryMatt
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Joined: Tue Apr 14, 2015 4:35 am

by FactoryMatt

yeah, all good stuff. glad the wheels are dished. i'd still try some other wheels if possible. Josh Poertner probably doesn't know what causes it definitively and it's probably like Epstein-Barr, it can be caused by a number of things in various combinations.

these are decent reads, and is probably the foundation of what Josh was saying around resonance and frequency.

https://www.sheldonbrown.com/shimmy.html

https://ipfs.io/ipfs/QmdA5WkDNALetBn4iF ... himmy.html (Jobst Brandt's responses)

AMGRoadster
Posts: 274
Joined: Sat Nov 08, 2014 3:57 am

by AMGRoadster

Awesome looking bike. The Parlee was at the top of my list for a new bike....Until I saw the weight and the proprietary parts. For me it simply weighs too much for the price. But you can't argue with the looks. Those of you that have purchased the bike. Enjoy the ride and hey, at least not everyone else is riding the same thing.

AMGRoadster
Posts: 274
Joined: Sat Nov 08, 2014 3:57 am

by AMGRoadster

Awesome looking bike. The Parlee was at the top of my list for a new bike....Until I saw the weight and the proprietary parts. For me it simply weighs too much for the price. But you can't argue with the looks. Those of you that have purchased the bike. Enjoy the ride and hey, at least not everyone else is riding the same thing.

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Mr.Gib
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by Mr.Gib

Multirider wrote:
Thu Mar 18, 2021 12:47 am
He says the most effective way to stop it during an incident is to get your butt off the seat. I'm having a hard time imagining standing up a little bit while in the drops at 45mph, but maybe.
Were straying off topic a bit but perhaps this is relevant in your situation. I have never and would never attempt a high speed descent with my ass on the saddle. All my weight is carried by my flexed legs (cranks at 3 and 9 o'clock) and my hands in the drops. I may cradle some part of the saddle between my upper thighs or hover just above it, but that is secondary - that saddle is free to bounce up and down if the road is uneven. With any significant weight on the saddle you are in great peril if you should hit a bump or an undulation in the road. You could easily be launched and lose control. The legs and arms can work as a very effective suspension system as long as the ass is not involved. In fact I won't even take a high speed curve or corner with my ass on the saddle. One bump and you have sudden loading followed by unloading and a loss of traction. A tire can only handle so much road imperfection. You might want to re-think your approach to descending. Again it should all be irrelevant to bike shimmy - that's an bike problem not a rider problem.
wheelsONfire wrote: When we ride disc brakes the whole deal of braking is just like a leaving a fart. It happens and then it's over. Nothing planned and nothing to get nervous for.

kode54
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Joined: Tue May 23, 2006 9:39 pm

by kode54

Multirider wrote:
Thu Mar 18, 2021 12:47 am
I took my bike into the shop. They checked the dish on the wheelsets and said they are perfect. I left it with them to lower the stem and swap the bars.

The Marginal Gains podcast came up on Apple podcasts for me and I listened to it. For others who might be interested, the content on speed wobble starts at about 39 minutes into it. He wanders around quite a bit and talks in 1/2 to 3/4 thoughts instead of complete thoughts. He depends on his audience to already know what he is talking about in order to understand what he is talking about. That was a bit frustrating. But it is clear that he is a subject matter expert with both theoretical knowledge and deep experience. Overall, he says a lot of interesting things about the factors that contribute, but doesn't give a clear answer to how to prevent speed shimmy. At one point, he says that larger tires (i.e. mountain bike tires) eliminate speed shimmy because they absorb the energy, but he also says larger road bike tires have a shorter/fatter contact patch which reduces the leverage of the tire to prevent speed shimmy. Those are contradictory statements - larger tires are both better and worse. I'm not clear on the guidance for my situation. He was pretty clear that heavy wheels and tires reduce shimmy. That is some unattractive guidance for a competitve rider/racer like myself.

He never mentions lowering the stem or widening the bars, but those still seem like they would help, so I'm committed to that path now. I'm thinking more weight on the front, slower steering, and more leverage to keep the wheel straight -- those must all be steps in the right direction.

He says the most effective way to stop it during an incident is to get your butt off the seat. I'm having a hard time imagining standing up a little bit while in the drops at 45mph, but maybe. His points about the resonance frequency of speed shimmy being very close to the resonance of the human body when shivering or tense is entirely consistent with my experience. I've done multiple cold descents where the onset of speed shimmy was more like 30mph and I'm sure it was due to shivering. Similarly, I used to have a death grip when it occurred and in retrospect, that made it worse, relaxing my grip reduces the shimmy.

I'll know more soon(ish)! Just need my bike back and clear roads to give'er a test run. As always, feedback is welcome!
Alot of the Tri guys use both knees and 'pinch' the top tube between their knees/legs to keep the shimmy down to a minimum. I use that technique to be more aero. LOL
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Multirider
Posts: 23
Joined: Thu Feb 19, 2015 10:34 pm

by Multirider

Edited
Last edited by Multirider on Mon Oct 11, 2021 11:32 pm, edited 2 times in total.

Multirider
Posts: 23
Joined: Thu Feb 19, 2015 10:34 pm

by Multirider

Edited
Last edited by Multirider on Mon Oct 11, 2021 11:33 pm, edited 2 times in total.

kode54
Posts: 3749
Joined: Tue May 23, 2006 9:39 pm

by kode54

Ask SAFA for any tips! Fearless.
- Factor Ostro VAM Disc
- Factor LS Disc
- Specialized Aethos Disc
- Sturdy Ti Allroad Disc
- Guru Praemio R Disc

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Mr.Gib
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by Mr.Gib

Multirider wrote:
Thu Mar 18, 2021 7:25 pm
Mr.Gib wrote:
Thu Mar 18, 2021 3:32 am
Multirider wrote:
Thu Mar 18, 2021 12:47 am
He says the most effective way to stop it during an incident is to get your butt off the seat. I'm having a hard time imagining standing up a little bit while in the drops at 45mph, but maybe.
Were straying off topic a bit but perhaps this is relevant in your situation. I have never and would never attempt a high speed descent with my ass on the saddle. All my weight is carried by my flexed legs (cranks at 3 and 9 o'clock) and my hands in the drops. I may cradle some part of the saddle between my upper thighs or hover just above it, but that is secondary - that saddle is free to bounce up and down if the road is uneven. With any significant weight on the saddle you are in great peril if you should hit a bump or an undulation in the road. You could easily be launched and lose control. The legs and arms can work as a very effective suspension system as long as the ass is not involved. In fact I won't even take a high speed curve or corner with my ass on the saddle. One bump and you have sudden loading followed by unloading and a loss of traction. A tire can only handle so much road imperfection. You might want to re-think your approach to descending. Again it should all be irrelevant to bike shimmy - that's an bike problem not a rider problem.
That is totally relevant and totally astounding to me. As an avid mountain biker, I would never descend in the saddle for all the reasons you mentioned. But as a road rider, it never occurred to me to get of the saddle. Just envisioning it at 40+ mph causes butterflies in my stomach. I'm planning to try this at lower speeds and work up to it. Very hopeful that it will increase control and confidence. But right now, just envisioning it causes anxiety.

Do you try to put weight on the bars? or no weight? Or? In mtbing, I keep a pretty light touch on the bars wtih elbows and knees bent and hips hinged. But that is at mtb speeds with mtb tires and terrain and suspension. Very different than road. I only get out of the saddle on the road bike when pedaling and trying to give my sit surfaces a break.

I'm very interesting in hearing from others -- do you get off the seat at high speed? Both turns and straight?

And then I read an article by a guy who tried various bar widths and decided the 42cm felt like dragging a parachute compared to 40s or 38s. And I'm paying a shop to swap the 42s for 44s! Ugh.
I took some mental notes while straight line descending yesterday:
  • Saddle nose gripped gently with inner thigh
    Ass just slightly off the back of the saddle
    Weight concentrated on feet,
    Pressure on hands relaltively light with "soft hands"
Of course you're not actually standing up with straight legs. On the contrary you are very low and compressed - everything flexed and poised for action. You can extend your arms a bit and get your shoulders really low if you want. Your ass can touch the saddle, just don't use it to support all your body weight - that is the job of your legs and to a lesser extent arms.

As for cornering, much the same but with extreme focus on driving the outside pedal down hard to the 6 o'clock position. I really reach for full extension with my outside leg (don't lock the knee) - I want to feel the tire/road contact to with the bottom of my outside foot. Think about carving a turn on skis.

And when you master cornering without weight on the saddle the results are astounding. The sense of grip and ability to control your line are next level. Ever watch pro cycling and wonder why most are such good descenders and a few at times seem lost? This is all it is. And it's not that difficult.

As for 2cm wider bars, don't worry about it. Tighter clothing and a better helmet will have three times more impact on aero.
wheelsONfire wrote: When we ride disc brakes the whole deal of braking is just like a leaving a fart. It happens and then it's over. Nothing planned and nothing to get nervous for.

by Weenie


Visit starbike.com Online Retailer for HighEnd cycling components
Great Prices ✓    Broad Selection ✓    Worldwide Delivery ✓

www.starbike.com



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