Slow speed steering wobble with 2008 Suzuki Trike

[OntarioLes]

With my 08 Suzuki Boulevard Trike I experience a lot of steering wobble, especially at slow speeds over rough surfaces. I had read some info about rake and trail for the front forks - would like to know more. Also I wonder if anyone has ever installed a steering damper on the front assembly. If so where would I get one - I am located in Ontario, Canada. Perhaps Lee - Mann will see this and have some suggestions.

[Lee H. Mann]

Unless and until you rake the front end, you are going to experience headshake.

The cause is the short wheelbase and light weight of the C-50 Tramp.

Check rear tire pressure (20psi hot) and front tire pressure (38psi hot).

Over-inflation will really play a part in a lightweight trike on uneven surfaces.

Lehman had a steering damper upgrade but there are none available now unless you build your own.

A damper will reduce the headshake but at the same time increase the effort needed to steer.

Kinda like a catch 22 !!!!

[Papa Zook]

What Jim said. Also, torque your steering stem to 40 ft lbs and see if that helps. With or without a rake kit, if the steering stem bearings are not torqued to proper spec, you will experience head shake. But with a rake kit AND proper steering stem torque, you will not.

[OntarioLes]

Great feed back! I suspected it might become a DIY project. Will look into the rake and trail aspect with a local Suzuki service depot.

Many thanks for the speedy replies!!

[Gorilla]

william if you decide to get a rake kit contact papa zook for the best deal

[OntarioLes]

Gorilla - thanks. I am considering doing the rake - may be a trick to find someone in my area Eastern Ontario familiar with the job.

[Gorilla]

william if you can turn a wrench its not very hard on a trike without a fairing. something to consider doing yourself if you can.

[OntarioLes]

I like the idea of doing a rake kit transformation myself. Next step is to find a rake kit. Lehman (Champion Sidecars) has no record of kits for Suzukis so no help for a source. Any tips to find a supplier are appreciated.

Thanks,

William

[Gorilla]

I like the idea of doing a rake kit transformation myself. Next step is to find a rake kit. Lehman (Champion Sidecars) has no record of kits for Suzukis so no help for a source. Any tips to find a supplier are appreciated.

Thanks,

William

William go to our page that has the ads (bottom of FORUM main page). Look for CUT-N-SHOOT CUSTOMS. Call the number talk to Randy the owner. He is also the owner of this forum. He will sell you a rake kit at a darn good price if one is available for your ride. Randy is PAPA ZOOK on the forum.

[OntarioLes]

William go to our page that has the ads (bottom of FORUM main page). Look for CUT-N-SHOOT CUSTOMS. Call the number talk to Randy the owner. He is also the owner of this forum. He will sell you a rake kit at a darn good price if one is available for your ride. Randy is PAPA ZOOK on the forum.

Gorilla - I sent an email to Papa Zook at Cut-N-Shoot Customs to see if a rake kit is available and how to get it to Canada.

Thanks,

[Lee H. Mann]

William, If Randy can't help, try this guy.

https://www.customtripletrees.com/

[dougv]

Jim I was going to mention the rear tire pressure but you mentioned 20 pounds on the rears and 38 pounds on the front, hot. What would be the cold temperature pressure, I have the Avon trike tire for the front and everywhere I see, it should be set to 41 pounds cold. I have set my rears to as low as 20 pounds cold.

I have an older CSC sport on a 97 Goldwing with a straight axle and did notice the shake over rough roads but it is better with the lower rear tire pressures. I ran into a guy in Florida that was running over 40 pounds in his rear with an independent suspension and was complaining of a rough ride.....no doubt it was....

[Lee H. Mann]

Jim I was going to mention the rear tire pressure but you mentioned 20 pounds on the rears and 38 pounds on the front, hot. What would be the cold temperature pressure, I have the Avon trike tire for the front and everywhere I see, it should be set to 41 pounds cold. I have set my rears to as low as 20 pounds cold.

I have an older CSC sport on a 97 Goldwing with a straight axle and did notice the shake over rough roads but it is better with the lower rear tire pressures. I ran into a guy in Florida that was running over 40 pounds in his rear with an independent suspension and was complaining of a rough ride.....no doubt it was....

Optimum tire pressure should variate between 3 and 4 pounds from hot to cold. And I don't mean cold at below freezing temps. Cold temperatures of 55-75 degrees.

Get a cheap pyrometer to check tire temperatures cold and then hot after normal riding at highway speeds. I would Never exceed 170 F on the front tire. Increasing the air pressure 1 or 2 pounds will decrease the temperatures significantly.

Most people don't pay that much attention to their air pressures and allow them to run low creating rapid wear and overheated temperatures.

Keeping the air pressure a little higher kinda solves this problem.

If you are the rider that keeps his eye on tire pressures, the recommended pressure is on the side of the tire.

If you are a spirited rider, up the recommended pressure 1 or 2 pounds.

If you carry a combined rider/passenger weight, do the same as above.

Rear tire pressures for a Trike should be the same rule, except for manufacturers pressure recommendations.

Start at 20 pounds and see what the pressure differentials are (3 to 4 pounds) and the temperatures are.

[OntarioLes]

Hi Lee H. Mann,

Thanks for the tip! Also I did adjust the air pressures with some improvement in the head shake. Checking with Randy and will look into Custom Triple Trees.

This forum is amazing - great ideas and feedback!

[dougv]

Lee, I'll have to try that. I was concerned about lower pressure in the front tire and rolling off the rim since the front sees a lot more side pressure than a normal bike. I think our shop may have a temp sensor I can borrow, if not will look for one. I did have the front down lower than what I would normally have it set at and noticed the steering force was a lot higher. At 41 pounds the front end is pretty rough over bumps.....thanks for the info

[ProudTexson]

The only place I can find a rake kit for a Lehman Tramp was this place Quoted me a price of 925.00 push shipping. To high for my blood.

I sent and email and that what I got back

https://www.customtripletrees.com/

[SmartAceWoLf]

I have no doubt the measure of importance of this to many riders of trikes. However, with that said, in terms of wobble of the front end at any speed there is one cause of that and one only. Specifically that would be that the plane of the rear axle is not in a directional plane exactly 90 degrees to the front wheel. While there can be little doubt that rake and trail may mitigate the occurrence of this wobble, it is important not to lose sight of the forest for the trees.

Having setup several trikes with and also without HD FXR rubber-mounted type frames, in my experience, no trike minus the isometric properties of the rubber mount frame should exhibit wobble of any significance at the front forks when properly aligned. To give the best possible representation of this, I will use what is available on the keyboard to illustrate. _|_. Here the vertical line represents your front wheel in its straight ahead position and the two horizontal lines represent the plane of your rear axle. The only thing that will make that front end wobble is when those two alignments are skewed. While turning the handlebars does change this relationship somewhat, it still does not induce wobble, it simply steers the vehicle in a relatively expected fashion. When traveling straight ahead the front end should have an equally applied lateral force on the front wheel. If the 90 degree angle of relationship between these two planes is not properly enforced, the wobble is the immediate effect of the whole geometry of your chassis perpetually attempting to right itself as it struggles to deal with two differing lateral forces applied to the front end from one side as opposed to the other by the rear wheels.

Further I will note that the amount of distance outward to either side of the center point of the front wheel also has no wobble-inducing exertion of force on the front end. Example, ___|_, where the end of each horizontal line would represent the distance of the tire when measured from the plane of the front wheel, even this will not induce excessive front end wobble. Even sidecars must be setup to observe this rule of physics. Furthermore, wobble (when it exists at all) just as "Critical Speed of rotating mass" will be accentuated or more or less prominent at certain RPMs or speed, it still exists solely due to forces of physics which are diametrically opposed and at odds with each other.

The absolute best example of this I can point to for a true real-world example is in a true Positive Traction rear end or actual live axle attached to a 3 wheeler. In such cases, a 3 wheeled vehicle is virtually next to impossible to move setting at complete rest with the front wheel cocked at an angle! Until the front end is used to remove the characteristic opposing force of the 2 rear wheels trying to move forward at differing rates of rotation by righting the whole structure back into a perfect right angle to one another, the structure is fighting itself. This opposing force does not correct itself with speed, it usually only serves to get further pronounced with more speed. Wobble however is not a thing we as trike riders must accept as a reality. More on this further down in this post.

There was at one point in time a significant number of live axle trikes on the road as most trikes (other than the servi-cars) were being built by custom creators at one time. And to be clear, any trike configuration of this nature had to be seriously manhandled and also would have inherent wobble at times in maneuvering, not to mention violent instances of flipping over. Even with the isometric setup there is a nominal amount of wobble due to the fact that the perfect relationship of 90 degrees is not set as a result of the rubber giving way at some points even if for very brief moments. Rake and trail adjustments on a trike will indeed serve to make the vehicle easier to steer under certain conditions, but it should never be the first avenue of correction in stopping wobble.

Given that one has the typical adjustment inherent in chains and sprockets or belts and pulleys, it is very easy to use the immediately discernible forces in opposition here in order to adjust this relationship of the rear end to the front end. This can be done by loosening both sides of the binding force of each side of the axle where they are attached to the rear end. With both sides loose, simply grab the handlebars and turn them even a little bit side to side and observe how the sliders move within whatever means they are normally attached to the vehicle. Even the slightest of movement of the front end will be easily visible in the sliding areas of pivot where one would adjust the chain or belt. Now, armed with this knowledge, move the rear wheel closest to the actual drive-line (chain or belt) very near to the tension you desire your chain or belt to be when properly adjusted. This should be done with the front wheel as straight as possible. Bind that side down tight. With the one side clamped down tight, now go to the handlebars and give them a good left to right tug. Moving the front end even just a little will force the other side to come to rest at the point of least resistance. Allow the front end to come to rest at center or the straight ahead steering position. Hold it there and bind the other side down and then recheck the tension of your belt or chain. If the tension is within specs now roll the bike forward just a few inches and observe the force on the front wheel as you attempt to roll both rear wheels straight ahead at the same rate. If the front end rolls even a few inches before falling to one side or the other violently or rapidly, then you have probably achieved very close to the perfect relationship in terms of true.

Hope this helps someone having the wobble experience with their trikes. Let no one convince you however that wobble is something all trikes do. This just is not so if everything is properly aligned. And again, while it is a factor of very minimal consequence with a rubber-mounted frame, it should absolutely not be a factor with typical chassis alignment outside of this one exception. And in closing, I apologize for what seems like an exceptionally wordy post here, I was simply trying to cover all of the many various scenarios of the equipment and methods utilized by each in order to accomplish the desired objective.

[OntarioLes]

Thank you for this detailed explanation of the geometry that is involved with the steering of a trike. Combine this with an understanding of tire air pressure as well as rake and trail I feel better prepared to really enjoy my trike. Some trike riders I have talked with have very little insight to their three-wheeled ride.

SmartAceWolf - thank you for taking the time to post this. I am sure other trike riders will be grateful!

[Trail Blazer]

I still get a wobble on some ruff roads at slow speeds. but only happens on ruff roads, I did get a low speed ( 23 or 30 mph) when showing down after looking at everything we could think of it turned out the front tire was cupped just a little I changed it out and no more descending slow speed wobble