Safe Speed Forums

Yesterday on my way back from work I came close to an accident which frightened me so much I'm getting rid of my new bike.

I got up to 30 mph down a hill, which shouldn't be unstable, when it went into a huge front wheel wobble. For about 200 yards I thought I was going to come off. In fact, at one point I seriously thought of jumping/falling off on to the road rather than head for the curb. For the motor-bikers out there, it was the equivalent of a tank slapper, but without the tank obviously. I stayed with it, fighting it all the way, using the back brake until eventually I came to a halt.

I haven't been so shaken up in all my life! I honestly thought the front tyre had deflated or something, but it hadn't. When I got home I checked everything; the tyres, the wheels and headstock for excessive play - everything, but nothing was wrong.

I had a bad feeling about the stability of this bike from day one but put it down to the fact that I'm just not used to a road bike. It could be that a change of tyres would help but in all honesty it s**t me up so much I can't face trying it again.

I'm going to call the shop to ask if they will take it back off me, for which I expect to loose gobs of money but it'll be worth it never to see it again. If they won't have it back then I'll post somewhere here, if okay?

It's in new showroom condition of course, with just 50 miles under the wheels. If they wont have it back then I'll put it up, a Specialized Comp Tricross, for the same price as the Sport Tricross so it will be a £1200 bike for the price of a £750 one. I'm not mad, or rich, but it's worth it for my sanity. I just hope whoever gets it after me doesn't have the same, or worse, happen.

When I think of what could have happened it still scares me. It really was that bad! When I got home I gulped down half a bottle of wine just to steady my nerves. When my girl friend got in just after me she said I looked ashen and my eyes were as big as saucers. I was actually quite close to tears, although I didn't let on. I always knew cycling is the most dangerous thing I do but only because of the other road users. I never imagined in my life the bike alone would be the cause of such grief.

I'll post what the shop says about it and what they're prepared to do. Cheers for now.

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The views expressed in this post are personal opinions and do not necessarily represent the views of Safe Speed.
You will be branded a threat to society by going over a speed limit where it is safe to do so, and suffer the consequences of your actions in a way criminals do not, more so than someone who is a real threat to our society.

What shape are the front forks? Are they streight or j shaped. If j shape how far infront of the streight bit is the wheel nut?

Also what angle of rake is the steering tube (if any) It might be 90 deg. to the ground or sloping at 85 degrees.

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Speed limit sign radio interview. TV Snap Unhappy
“It has never been the rule in this country – I hope it never will be - that suspected criminal offences must automatically be the subject of prosecution” He added that there should be a prosecution: “wherever it appears that the offence or the circumstances of its commission is or are of such a character that a prosecution in respect thereof is required in the public interest”
This approach has been endorsed by Attorney General ever since 1951. CPS Code

I've never heard of someone having a tankslapper on a pushbike, I've never noticed instability and I've done a lot of fast/aggressive riding.
I would have thought someone could simply hold the handle bar solid due to the relatively low energy available.

Take it back to the store and get them to check it to make sure nothing is loose (including both axles)

Anyway, I'm glad you are OK.

Not sure how to describe the angles etc. but a quick search on the net will show pictures and info.

I checked everything. I'm an engineer, trained in electronics and mechanics, and I can say without a doubt that nothing is loose or set-up incorrectly. I desperately hoped I could find something simple to explain it but I can't.

I'd be happy to let someone test ride it but with a 58cm frame you'd have to be about six foot tall I think and I wouldn't like anyone else to be at risk. I would feel terrible if someone fell off it, but if the shop will take it back then as I see it, it's back at source and out of my hands.

My friend thinks the geometry of the bike and myself may have something to do with it. I'm quite gangly.

The only thing I can think of is the tyres which are a cross between road and off-road. Thinking back, the wobble started as I was going over a slight hill and bending very gently to the right so I would have been banking over but by no more than a few degrees but maybe enough to be on the tread as opposed to the bald middle part.

I shouldn't really have used the expression tank slapper but calling it a wobble almost understates what it looked like - and felt like.

I was holding the lower part of the bar, in the racing position, which makes the brakes harder to grab in a panic situation.

My old cronk feels like a Rolls Royce by comparison and I'll be happy to go back to it after some overhauling.

Thanks for the best wishes, I feel very lucky to be in work today.

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The views expressed in this post are personal opinions and do not necessarily represent the views of Safe Speed.
You will be branded a threat to society by going over a speed limit where it is safe to do so, and suffer the consequences of your actions in a way criminals do not, more so than someone who is a real threat to our society.

There's quite a lot of info on the Specialized site about the frame geometry etc. I can't imagine they wouldn't have worked out what works well for it to be a good road bike but I'm not an expert on cycles; I just like to ride them - well I think I still do.

The worst accident of my life was on a cycle and I thought history was going to repeat itself.

http://www.specialized.com/bc/SBCBkModel.jsp?spid=22302

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The views expressed in this post are personal opinions and do not necessarily represent the views of Safe Speed.
You will be branded a threat to society by going over a speed limit where it is safe to do so, and suffer the consequences of your actions in a way criminals do not, more so than someone who is a real threat to our society.

That bike appears to have a minimalistic, funky looking front hub, I wonder if that design could be part of the problem?
I can only assume the spokes are nicely taut.

sorry to hear that B.T.

please don't give up !

sounds like you encountered a bit of a speed wobble or shimmy.

for a road bike the tricross looks to have a fairly relaxed geometry, more competition targetted bikes would be more aggressive.

even so road geometry tends to be alot more responsive and perhaps 'twitchy', especially if you are used to more forgiving hybrids & MTBs.

were you in the saddle or out of it ?

typical advice to deal with this can be counter intuitive, if you tense up it tends to get worse....... you should relax your grip & arms. lift off the saddly a little and pull your knees in can also help.

http://www.sheldonbrown.com/brandt/shimmy.html
http://www.pro-am.com.au/speed_wobble_on_a_bicycle.htm
http://www.jimlangley.net/crank/bikingskills.html
http://www.slowtwitch.com/mainheadings/ ... chor-14210

take heart... and take it easy.
if you're not confident, keep the speed down until you are.




i've had a few wobbles before now, most recently on a 40mph+ descent in south wales where i really should have stopped at the top to put my jacket on... i was freezing on the way down and couldn't stop shivering!

That's incredible Ed!

The second link you posted absolutely describes what happened to me - the feelings - everything - right down to looking over every atom of the bike afterwards and thinking I was going to be catapulted into oblivion.

I was on the seat at the time, tucked-in ready to get to my top speed, which was only 31 mph, according to my top speed function. That's when it happened.

If I'd known it was a phenomenon associated with road bikes I would probably have bought another mountain bike instead. There's still no way I will get back on it. I'll have to see what I can do...

Very interesting links Ed thanks

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The views expressed in this post are personal opinions and do not necessarily represent the views of Safe Speed.
You will be branded a threat to society by going over a speed limit where it is safe to do so, and suffer the consequences of your actions in a way criminals do not, more so than someone who is a real threat to our society.

I have had a reply from Mark Haylett of the Customer Services Manager
Specialized UK Limited.


With kind permission, and of great interest to me, I am pleased to print it here...



"Hannah, from the Specialized Concept Store Fort Dunlop has sent me your email.

Firstly, I'm sorry to hear about your Tricross problems, and I will do my best to explain the reason for this. The ratio of cable pull between the Tricross STI shift/brake lever and the cantilevers, causes the brakes to have a very positive feel...almost an ON-OFF feel rather than a linear gradual feel of most brake set ups. This braking action has an adverse effect on the forks, causing them to flex backwards, this flex is limited to the point where the carbon fork blades spring back into the forward position, and this is where the juddering or wheel wobble is coming from. Brake pad adjustment has been known to greatly reduce this judder, although it's not 100% effective in all cases.

The solution could be to fit a stiffer beefed up fork, but this is at the expense of the Tricross bikes handling characteristics and overall light weight. The solution that does work, is fitting mini V brakes, these brakes have a much smoother progressive action which prevents the forks flexing; the only downside to these brakes, is that they take away the true Cross Bike feel and design that Tricross has. Specialized is working on a permanent solution for this, although it's worth mentioning that for every Tricross with fork judder, there is 10 without.

The Fort Dunlop Specialized store will fit these V brakes to your Tricross free of charge, so please contact Hannah to arrange a suitable time to have the conversion carried out. As a gesture of goodwill, I would like to offer you any Specialized product to the value of £100, this can again be arrange through Concept Store Fort Dunlop.

Hopefully this offers you a reasonable explanation of this incident.

Once again, please except my apologies for any inconvenience caused.

Kindest regards,

Mark.

Mark Haylett
Customer Services Manager
Specialized UK Limited"


I think it's very kind of them and couldn't have asked for more, so good for them I say I'm still thinking of swapping for a mountain bike though...

_________________
The views expressed in this post are personal opinions and do not necessarily represent the views of Safe Speed.
You will be branded a threat to society by going over a speed limit where it is safe to do so, and suffer the consequences of your actions in a way criminals do not, more so than someone who is a real threat to our society.

can't hurt to try a free fix !

i'm amazed they accept it as being a design flaw/compromise given the potential to get sued!

plus you can nab yourself some lycra

PS there's a speccy store at the fort ?

That thought did cross my mind actually. I'm certain it could still be proved that I have a dangerous design problem affecting my particular bike, but I'm not 'that' sort of person. I think Specialized should take note however.

Big companies with a good reputation usually recall dangerous or defective things and I would certainly put that model in one of those two categories if it cannot consistently be made safe or if there is any doubt. If I had actually come off and hurt or even killed myself, the ramifications for them would be very bad indeed. I'm not exaggerating about the terror I felt, and I'm no wossy.

There is absolutely no doubt in my mind that if I, or anyone else of my stature, rode down the very same road at the same speed as I did, they would get exactly the same results - or worse! I don't think 31.3 mph is excessive by any means, as recorded on my clock. When I put road tyres on my 16 year old Stumpjumper, weighing in at 30lbs, I once got up to 45 mph down a hill without any problems.

Maybe if it's only about one in every ten then they should road test them somehow before sending them out on the public. I'm referring to Specialized the global company here. I say again, the place I purchased it from have been (are) great and I would recommend them to anyone.

I'm actually not bothered about saving every gram off the bike but I thought I would be getting better and lighter, since I gather things have moved on a bit since my old Stumpjumper. I've never really seen the point in shaving every molecule off the bike when I've got a spare tyre around my waist. So it seems to me that in the bike war of boasting the lightest they have compromised on safety this time.



Yep, that's where I got it from. Nice place, nice people

_________________
The views expressed in this post are personal opinions and do not necessarily represent the views of Safe Speed.
You will be branded a threat to society by going over a speed limit where it is safe to do so, and suffer the consequences of your actions in a way criminals do not, more so than someone who is a real threat to our society.

probably best i forget you mentioned it

Naughty you And I thought you said you like or own a Specialized? I'm not put off them, I'm just put off that model. My dear ole' Stumpjumper has served me very well indeed.

It's not uncommon for a manufacturer to come up with a duffer. Peugeot recently recalled certain models because of a break scare and as for the Rover K-series engine? I feel an internet search for manufacturing clangers coming on

As for the store, go on bud, have a look. You may be tempted to get yer wallet out

Gratuitous link posting: http://birmingham.specializedconceptsto ... ingham.asp

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The views expressed in this post are personal opinions and do not necessarily represent the views of Safe Speed.
You will be branded a threat to society by going over a speed limit where it is safe to do so, and suffer the consequences of your actions in a way criminals do not, more so than someone who is a real threat to our society.

Err, excuse me, but you weren't braking were you? So this ain't it...

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Paul Smith
Our scrap speed cameras petition got over 28,000 sigs
The Safe Speed campaign demands a return to intelligent road safety

You're right Paul! I just took it at face value but now that you mention it, the instability actually started before I even touched the brake.

I was seated down in the aerodynamic position with my hands just holding the lower bar. The wobble started as I went around the bend and down a hill. It was then I started to brake so maybe at that point my braking made a bad situation violently worse.

I don't think he's wrong about where the problem or weakness is - it's the forks and perhaps both braking or the bend could start the oscillation. Maybe if I'd reacted differently, as Ed suggested, it wouldn't have escalated as it did but when something starts to wobble like that your immediate reaction is to slow things down. I really don't want to try it again to be honest.

What I do know is I could get up to the same speed on my old mountain bike down the same road and feel like I'm on rails. This one being more of a road bike than my other, I would have expected it to be better, not worse. I will take safety over lightness or performance any day but I know full road bikes, which are lighter still, can go faster and bank over far greater than I did so there is definitely a dangerous handling problem with that model.

Ed - if you're not far from where I live perhaps you would like to try it? I'm based in Bournville, chocolate land. I'm climbing Snowdon this weekend but maybe some time next week? I'll bung ya for your trouble. Wear an American footballers suit though. I'm absolutely convinced you would agree with my findings.

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The views expressed in this post are personal opinions and do not necessarily represent the views of Safe Speed.
You will be branded a threat to society by going over a speed limit where it is safe to do so, and suffer the consequences of your actions in a way criminals do not, more so than someone who is a real threat to our society.

that one ?

*zoooom*

i did note that also.
speed wobble can happen on any bike, causes are a little hard to pinpoint but many have been suggested, including fork flexing which they admit to.

if the fork flex makes the bike more prone to wobble there are probably a number of disturbance inputs you could induce it with, steering, road surface/camber/potholes etc and braking..... unfortunately it seems their choice of brakes makes a disturbance more likely.

i guess BT's disturbance was something other than braking, the result however being the same!

unless he happened to be carrying a datalogger and riding a spectacularly instrumented bike i suspect this discussion is slightly academic.

My friend Vistaed has offered to try it. He does more miles in a month than I do in a year and has both mountain and road bikes.

If he comes off can he sue me for letting him ride a knowingly iffy bike which I own? Hmmm, I wouldn't be able to take it back to the shop either

I can't see the make Ed, it looks more like a Cannondale to me

Nice leg development by the way Looks like you're at the front wining - or did you doctor the picture with software

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The views expressed in this post are personal opinions and do not necessarily represent the views of Safe Speed.
You will be branded a threat to society by going over a speed limit where it is safe to do so, and suffer the consequences of your actions in a way criminals do not, more so than someone who is a real threat to our society.

Very slightly related....

I once had a very disturbing front end wobble on my VFR800. Not a bike renowned for tank-slappers. This was only once in 80k miles and never before and never since has the bike shown any tendency to do the same.

I was riding fairly enthusiastically down a long, straight hill with a very light grip on the bars, and no braking. I can only conclude it was an unlikely set of conditions that set it all in motion – but it was very unpleasant.

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It's tricky doing nothing - you never know when you're finished

I did too, on my Kawasaki Z750 L1, but I discovered the reason was a recent change of tyre which was out of balance. I'm going back a long time now, (I'm very old), before the norm was to take your bike in to get your tyres changed.

In the old days you did it yourself and aligned a mark on the tyre with the valve, or was it opposite the valve? I can't remember now it's so long ago.

Well hang on a minute! I've just had a thought. Isn't it important to balance them on a push bike too? If I turn my Tricross upside down is it normal for the wheel to rotate and a heavy spot sink to the bottom. I haven't said it yet but the bike actually handles very well at low speeds, below about 20 mph. Hmmm AND the magnet for the clock attached to the spoke will make it worse too. More Hmmm

Something like that may have been the cause of the initial instability before I grabbed the brake? I could be on to something here methinks.

_________________
The views expressed in this post are personal opinions and do not necessarily represent the views of Safe Speed.
You will be branded a threat to society by going over a speed limit where it is safe to do so, and suffer the consequences of your actions in a way criminals do not, more so than someone who is a real threat to our society.