emem

Hello
hope I'm in the right forum: couldn't see one specifically for trikes ...

I've just got a Catrike Speed ... it's good, but ...

there's a lot of vibration in the front end when hands free riding, or riding with one (or sometimes even two) hand(s) lightly on the steering arms ... say I'm going slowly along a smooth road and hit a twig or small ridge, then there's lots of shimmy at the front, if I'm on a slightly undulating road then this shimmy can be enough to shake my foot from the clips ...

if I keep my hands on the levers, then there's enough damping from my arms that the shimmy doesn't happen, altho' I can sometimes still feel it ...

I don't think this should be happening, it feels like crude engineering/design, yet reviews of the Speed don't suggest this is the case ...

I've checked toe-in, headsets on the kingpins, all bolts (including the tie-rod), the roundness and seating of the tyres, the straightness of the rims, everything I can think of, but still nothing; I pedal at a cadence of 90-100 ...

any thoughts?

thanks

emem

Ric

Sounds like you've done everything right, the other thing you might want too check would be the brake rotors. If they're out of wack they can cause a lot of vibration in the front end. Check on the Catrike board / forum https://p216.ezboard.com/bcatrike Some of the guys there may have a solution for you.

mchell

Ditto. Sounds like the rotors, since you've checked everything else out. Wouldn't take much to set off a tiny yet annoying vibration. Keep this forum posted as to how you make out please. There are a lot of Cat owners here.

Mike
Catrike "Road" #589

Dr.Deltron

WOW! You've checked everything I thought of. I'm stumped.
Only thing I can come up with is; are the wheels somehow out-of-balance? I've had a couple of bikes in my life that required balancing the wheels. I used skinny soldering wire wrapped around a spoke for weights.

Do let us know the outcome!

Shaman

Did you check for cracks in the welds?
Did you adjust the toe-in with your weight on the trike?
Are the axles tight? Is there excessive axle bearings clearance? Rear wheel spokes tight?

It shouldn't do this, or even want to do this if all the tires are tracking correctly.

theschwartz

Emem,
Recheck the headsets. I suspect that they are too loose.
Steve

emem

Hello,
I have fixed the shimmy ... yes, but how?, you ask

: I checked and rechecked everything x 5.

Headsets, wheels, all bolts, toe in, tyres &c ...

I spoke to FlyingFurniture, now back from holidays ... very helpful, suggested that I recheck headsets and perhaps tighten right down to damp vibration ... so I rechecked the headsets ... every thing was tight, but I thought I should redo everything, so I (again) loosened the bolts holding the steering arm to the headstem, and rechecked the tighteness of the compression bolt; it felt completely tight but I thought what the hell and tried a little more torque, there was a distinct, loud, and strongly felt, "crack", and the bolt moved again : I thought at first I had broken the thread on the bolt, but then it turned another 1/4-1/2 turn quite easily and tightened ... I retightened the steering arm and found the vibration had lessened considerably, so I redid the process until I had eliminated the vibration ...

so, it was a loose headset, but what was interesting was that I had checked these numerous times and tightened the compression bolts up to what I thought were there absolute tightest (using a ratchet and Allen key, not just a small Allen key) ... what I think happened is that either the compression ring or the upper bearing cup were not quite seated properly and that tightening the bolt to what I thought was beyond its maximum torque popped one or the other into place (with a "crack") ... I have since rechecked the seating of the headset and surrounding area and everything looks fine ...

so thanks to all who were mystified and offered suggestions; I will report if anything further goes amiss, but for now it all feels solid and vibration free ...

sch

Starfangled nuts are known to shift in position in the tube, you may have moved one into a more stable position allowing higher torque.

25hz

I have a Speed, have ridden 2 others beside mine, and they all do EXACTLY the same thing. The reason? Too much weight on the front end - the weight bias is front end heavy, especially if you are about 6' tall or over. It seems to work fien for shorter riders. I've adjusted, tweaked, tightened, lubricated, trued and shifted, and all to no avail. It's a design issue. For a taller person, the wheelbase needs to be longer so the seat can be moved back which will move more weight onto the rear wheel and behind the crossmember. One solution would be to run fatter tires on the front end while keeping the Stelvio on the rear, which would rise the front end, give more caster and shift a few more ounces rearward.

To be honest, I too was pretty disappointed when I first encountered this effect. Once, while riding hard on a warm day (I usually don't wear gloves unless it's cold), on a fast, downhill, easy sweeper that had a few ripples in the ashpalt, the ripples caused the shimmy in the front end, and it escalated so fast, and became so violent, that the bars pulled out of my hands and the front wheels went to full lock and I slid into the shoulder. The only thing that saved me was problem number 2 on the Speed - massive understeer, so it didn't roll. The weight bias issue is also to be watched if you are going fast or on a downhill and need to brake, as not much pressure will spin the rear end around on bare pavement.

Dr.Deltron

That sounds like FUN!

But only if you do it on purpose!

Ric

Again Check on the Catrike board / forum https://p216.ezboard.com/bcatrike and talk to some of those guys, You can also drop Paulo himself at the Catrike factory a message there, he is the designer and manufacturer of the trike and he can tell you the solution for your problem. and he will make it right.
To say that all Speeds do the samething is bull, THEY DO NOT. I purchased my speed in 2005 and and put well over a thousand miles a year and never had the issue with vibration you've encountered, and I'm 5'11 and 194lbs. Too change or run fatter tires on the front end would be changing the design of the Speed and the purpose for which it was designed, anyone who does that purchased the wrong trike to begin with, that's why Catrike makes six different Trikes.

25hz

You're jumping to conclusions and NOT reading what I posted. Of the three Speeds I've ridden, they ALL exibit the same behaviour (2 are 2006, one 2005) - pay attention. My friend, who is 5'11'', and weighs about 185, has no problem with steering issues except a steep hill when he rides mine and the other 2006 Speed. Another friend who is 6'1" has the same problems with front end shimmy that I do, but not as pronounced. My brother who is 6'4", has major shimmy issues on both trikes. So, surprise me, and read the post AGAIN, like I said, the shimmy issue seems to be related to riders OVER SIX FEET TALL! The fact that a shorter rider, on a steep downhill where the weight shift is FORWARD starts to exhibit the same shimmy issues is obviously an issue of weight bias with too much on the front end.

You being a supposed "expert" on yet ANOTHER bent, maybe you can point out where on the Catrike website it says the Speed is the wrong trike for tall riders? That also being the case, maybe you can explain why the extended boom has room for even more adjustment, probably cloce to a 6'6" rider???

As for tire changes, the results it would provide, if any, are minimal except increasing caster, and providing more ground clearance. Again though, apparently you have inside info on what the "purpose" of the trike is and how the 1/2" extra of ground clearance would radically change that?? If the shimmy issue doesn't affect you, then good, be quiet about it. I know two other Speed owners that are over 6' tall and they have the same issues. Your comments are typically worthless, especially in the technical end on this matter. I can (and have) actually built trikes, rather than wander into a shop with a blank look and drop a wad of cash. The same shimmy issues that happen on the Speed have happened on other trikes I've modified and repaired, and the solution is the one I mentioned, twice now. The solution has already been submitted too, move more weight aft on the frame by lengthening the wheelbase and shortening the boom. You, again being the "expert"m maybe you can give paulo some technical help on the solution. Not . . .

"The only truly stupid people are the ones who refuse to learn . . . "

Dr.Deltron

Flamed ol' Ric on that one, didntcha?

emem

Sheeesh!
For what it's worth - trikes are objects made of metal and rubber, not the godhead ... in a few decades or maybe even less, they will be thrown on some scrapheap or seen as quaint ... hardly worth getting excited about.

Perhaps some perspective would be useful here: 99.9999% of the world's population cannot, and will not ever be able to, afford one of these machines. I feel - and am - privileged to have one. As for investing my identity in whether I am right or wrong about what is or is not going on with it ... well, I've got a life. And that's not meant to be a put down.

I have fixed the shimmy, I weigh 91kg, am 179cm tall, and experimented with all sorts of sitting positions on the Speed as well as tightening various bolts &c before getting the headset or starfangle bolt to sit properly and thus eliminate the shimmy ... doesn't make me right, doesn't make me wrong, doesn't make me think I will get it right in a different situation, made me feel slightly stupid for not tightening the bolt further in the first place, and added it all to the experience bank.

25hz

Glad you found out the solution to your problem, emem. For many of us with the steering shimmy, frame mods are the only fix. I've since recieved replies from 6 other Speed owners who are over 6' tall, or who are close to 6' tall and have extra weight over the front end in the form of fairings, etc. They all have the same shimmy I have experienced. Maybe the Catrike gang will consider a long frame version for taller riders instead of a boom extension. While extra backbone and seat frame sections will cost more, the elimination of the handling and accompanying braking issues will be worth it.