Hello, I wanted to see if you know of a racer my size that might be able to help me out to regarding minimizing or eliminating “high speed wobble” when descending.
I had 2 yesterday at the Patterson Pass RR…pretty much scared the you know what out of me.
I’m 6’3" - 220lbs and bought my 2019 Propel Advanced Disc so I could run 28’s and slow better than my 2014 Propel Advanced (rim brake). The 2014 wobbles like crazy when descending (especially down the cork screw at sea otter).
What research and bike setup review have you done to this point?
There are a number of potential causes and cures. I’ve done a bit of research for a larger friend with an issue on his tri bike recently.
Details like pedaling vs not, braking vs not, position on the bars & saddle, head set pre-load and others can all be clues. I can link some existing guides worth review overall, if that is helpful.
UHHHHH! I hate speed wobbles. I have dealt with them before and they are no fun. It may not be your case but for me it was a confidence issue. My body responded to my brain’s fear and tensed up and after that I kept riding locked up because I was terrified. Slowly I started to relax as I worked up my confidence slowly again in moving at high speeds downhill.
That being said, I would definitely take my bike to a mechanic for a tune up. My order of operations as follows:
I’ve only experienced speed wobbles twice (flying down a hill at speed) and on both occasions it was a deeply unpleasant and terrifying experience. A couple of weeks prior to the first time it happened, as luck would have it I’d read an article about what to do if and when it happens. The advice was to relax and squeeze the top tube between your knees. Without my realising it, the advice must have planted itself deep within my brain because when the wobbles struck, I instinctively clenched the top tube with my knees. Amazingly, this killed the wobbles within a matter of seconds and I was safely able to pull over. Scared the life out of me though.
I’d never experienced the wobbles before so was perplexed as to why, all of a sudden within the space of a couple of weeks, I’d had two occurrences. I’ve no idea how or why but it turns out the problem was caused by some cheap inner tubes I’d bought at a cycle sale ( something silly like 10 for £10). Almost immediately after fitting these cheap nasty tubes I was experiencing lots of slow punctures (overnight and while at work, etc.) and the handling of my bike became just ever so slightly sloppy - not quite so sharp or self-assured as it usually was. It slowly dawned on me that all my recent bad luck coincided with fitting these nasty tubes. I swapped them for my preferred tried and trusty tubes (Schwalbe, since you ask) and everything returned to normal. Never had the wobbles since - and that was about 10 years ago.
my 2017 specialized diverge elite wobbles like crazy on descents but I haven’t let it slow me down. Biggest things for me is getting low in the drops and bringing my knees in close to the top tube. Also having a relaxed yet firm grasp on the bars, sort of like how jonathon suggests people ride mountain bikes. Last thing I do on descents that might help with the wobbles but is more for protecting my jewels is getting my butt slightly off the saddle and gripping the nose with my inner thighs. That way all the bumps and ruts in the road don’t hit me and make me sing soprano. Though since @mcneese.chad mentioned headset preload I’m totally going to ask my LBS about that. I’ve been dealing with a twitchy front end ever since I bought the bike and if I can get rid of speed wobbles I’ll be one contented camper. But good luck with yours wobbles! Be bold but wary!
I’ve had a few wobbles in the past myself and it can be rather scary.
I have noticed that it only ever happens when I have a deep section front rim. If I use a shallower rim then I never have any issues.
I experienced wobbles recently on my 2019 Specialized Venge Pro. Had the bike for a couple months and had no issues. Plenty of decents over 40mph. All of a sudden, little gust of wind off a passing dump truck while going about 35 and I’m changing my bibs. Happened 2 more times on windy decents over 30mph.
I thought about what i changed on the bike recently. The only change was new tires, bargain GP 4000 28s from Amazon (karma right) with old latex tubes. Ditched those and put on 25mil Vittoria Pro set up tubeless. I also decided to swap out the 100 mil stem to a 120 mil stem. This matched my old Tarmac geometry better and during my bike fit my LBS recommend a longer stem. The bike feels less twitchy now.
Since then I have been easing into it and upping the speed. I had a breakthrough the other day following some teammates downhill and am getting some confidence back. I do want to try a lower profile rim to totally knock out the fear.
Thanks for asking the question RJ and the thoughtful responses from everyone and links from Chad. This forum is awesome!
My Tarmac was very twitchy at high speed. To the point I considered selling it. I sat down and carefully considered what to do. I slowed it down with a 20mm longer stem. Made an absolute world of difference. I’m not the greatest descender, but I actually enjoy it now😊
Speed wobble comes from several factors. The #1 way to stop it is to relax! 99% the rider makes it worse.
Make sure your bike or components are not compromised. Something broken of flexing will start the death wobble.
Balance your wheels. Some people debate this but it helps and at high speed is where you need it.
Make sure your bars are perfectly straight. Small misalignment will cause an imbalance in weight left to right.
Body position needs to be balanced and relaxed. Clamping down on the bars or top tube will make things worse. Weight needs to be on the pedals. This keeps your weight below the axle line and makes the bike stable. Tring to weight the bars adds energy to the oscillation and makes things worse.
Recovering from a speed wobble:
Breath!
Don’t hit the brakes
Center your weight over the pedals. This is the key!
Don’t let go, but reduce your grip on the bars so they can self stabilize. Also keep light weight on the saddle.
Same here. Had 2 high speed downhill wobbles within a two week period like 10 years ago. Didn’t crash either time, but just couldn’t trust that bike on high speed descents again. Sold the bike and got a new one and have never had one again.
Never knew these were a thing. It’s been a while since I’ve descended long climbs, top speed I’d reach would only be ~65kph. One thing I’ve always done during descents though is getting in the drops and as others have said, relax. This was learnt when I did a motorcycle course and the instructor said any tense grip on the bars just magnifies any bumps ten-fold, the best thing to do, especially when you have no choice but to ride over an obstacle is NOT brake, relax and let the forward momentum of the bike straighten itself out.
Having designed a bunch of bikes on the market and having welded a bunch of my own I’m not convinced that speed wobble is the result of 1 thing but the product of multiple things gone slightly wrong. I’m pretty sure that small changes to the system will provide a resolution.
Wheels/Tires (imbalance on a 1100g set of wheels has more impact than on a 1800g set of wheels)
Static Position ie contact points
Dynamic Position ie where’s your CoG when you descend or sprint or whatever.
Fork offset (rake)
Weight (the bike’s or yours)
Of course, addressing these things should be done only after you triple check your bike for loose or compromised components.
My gut feeling is that if your bikes are in perfect working order then you need to look at you. What are you doing to contribute to this? Can you make position adjustments? If not, you need new bikes.
I remember Zinn talking about this a few years ago - he thinks it is a design issue (or more correctly a system issue, where the system is the frame, components, and rider), and is more likely for taller and heavier riders:
Read the link in there back to the original article.
In my experience you should do the opposite. Slowing down will help, so definitely brake, and the wobbles have always resolved when I clamp the top tube between by knees / thighs.