110515-T10-misconceptions-suspension-f

All motorcycles come with suspension, and some of those components have settings that the riders themselves can adjust. That’s great if you know what you’re doing. Some bikes have a wide variety of settings for the rider to fiddle with. Again, if you know what you’re doing, the extra adjustments are a huge benefit. However, with the increase in adjustments available, the number of wrong combinations of settings also increases.

Now, suppose you add misinformation into the mix, and you’ve got a recipe for a foul-tasting suspension stew. In search of clarity, we turned to Ed Sorbo, owner and chief bottle washer of Lindemann Engineering – and the person who single-handedly saved MO’s 24 hour Grom race effort – to determine the biggest misconceptions concerning the suspenders on our favorite two-wheeled vehicles. So, let us take a look at, according to the vast knowledge base of Ed Sorbo, the Top 10 Misconceptions about Motorcycle Suspension.

  • Ed Sorbo

    I love the picture of the Pike Place Market gum wall. Gross but a lot of stiction.

  • Alexander Pityuk

    Can someone re explain #8 for me, please?

    • Simon Evans

      Sure. Even a race bike has to pass through the same compliance region as a normal street bike – You can’t get to 200 mph from 10 without passing through 50, 70, 100, 150 etc… As most corners on most tracks are not flat out the same suspension rules apply to a racebike as a street bike. What they take away in terms of bump compliance requirement (although some race tracks have notoriously bumpy corners) they add back in terms of rapid transition, harder braking, more acceleration.

      At least for the most part. The differences tend to be because the rider knows he wants a `feel`. And that’s very different from a `requirement`.

      I’ve spent a lot more time teaching a rider to better understand his feedback loop than I ever have adjusting the suspension to suit the rider. Mostly it’s hooey and bullcrap the rider has been inundated with by `egg-spurts`.

      • Mahatma

        I don’t pretend to understand suspension stuff,but an IoM rider said that one has to compromise the set-up to suit the mountain part (stiff) with the low land part (soft).It seems to me that if set up for track use,it is too stiff for ordinary use…But agree with most here.

      • Ed Sorbo

        Great explanation but you lost me at hooey and please tell what “egg-spurts” are.

  • Douglas

    Some useful info here. In the vein of suspension, handling, et al, there are a couple silly things certain individuals do to bikes that really screw up the steering geometry, likewise safety/stability factors that the engineers who designed them, put there. (And after years of riding, I have to believe that they know what they’re doing).

    First is the “apehanger” bar that rises up to and even above the rider’s shoulder,causing both inability to properly corner, at the same time cutting down on visual perifery (and invariably these are the types who are “back brake only” in a panic stop).

    Second, the extended swingarms usually seen on the Ninja/Hayabusa type bikes,
    along with a 240 or so rear tire. Supposedly added to reduce wheelies (due to the badass power delivered) but more to attempt to impress, I think. This seems to be nearly the exclusive province of a certain “culture”…..

  • Vrooom

    Perhaps if you’re bike comes with Ohlins it won’t benefit from aftermarket suspension. I have to say I’ve always found it an improvement. Typically on Sport Tourers and Dual Sports though. Or perhaps I’m deceiving myself?.

    • Speedwayrn@yahoo.com

      Even most OEM Ohlins is not the same Ohlins you buy aftermarket. Most OEM branded suspension is built to a price point by using plastic where possible or ways to cut corners on cost.

      • Ed Sorbo

        Never seen plastic used to reduce cost.

        • Speedwayrn@yahoo.com

          You have never seen plastic shims to reduce costs?
          And fork and shock oil never needs replacing.
          Is this April Fools day???

          • Ed Sorbo

            A shim is a thin washer that flexes, it’s used to control oil flow. I’ve never seen a plastic shim used in motorcycle suspension. Plastic is used as a spacer in many cases. Plastic can be used as a seal/bushing between a damper rod and the inside of a fork tube and in other places but being plastic/inexpensive does not mean it does a poor job. Today is Nov. 9th, modern suspension fluid does not get thinner, stick to stuff less or in any other way stop doing it’s job. It can get dirty. You can replace it anytime you like but new oil will do the same job as clean old oil.

    • Ed Sorbo

      See number 12.

  • Ian Parkes

    Great information and great explanations. But re no 3, if add preload doesn’t ‘stiffen’ a spring, what’s it for? Seems to me all it can do is prevent the shock working at all until you get past 100 pounds of load. Why would you do that?

    • azi

      Preload changes ride height on a loaded bike. That’s all.

    • Ed Sorbo

      Pre-load adjusters are the lowest cost adjuster you can add to suspension. People pay more for bikes with adjusters. Pre-load adjusters help sell bikes.

  • Old MOron

    This is great. Thanks, Ed and Evans. Very informative.

  • Speedwayrn@yahoo.com

    Tell me more about how I don’t need to ever change the oil in my forks or rear shock unless there is a compromised seal.

    • Ed Sorbo

      The oil won’t wear out so you don’t need to replace it. Fork and shock oil has an easy job. When the seals leak then dirt can get into the oil and the dirt will cause wear.

      • Michael Barrientos

        I changed my fork oil at 10k miles and it was black from all the metal shavings. Showa oil is clear to start with so i would have to say even if the oil has not broke down those metal shavings are causing friction.

        • Ed Sorbo

          I think it was black from oxidation not metal shavings. Where would the metal come from? The bushings are Teflon. It does not hurt to replace the oil, you just don’t need to do it as often as some people claim.

          • Robs

            What causes that funky smell?!!! =D
            In 2009, I bought an 06 Ducati Monster. As I weigh considerably more than your average Italian teen-ager, I installed springs with a higher rate front and rear. When I poured out the “old” fork oil, it filled the garage with a truly heinous funk! Smelled like rotten fish!! Is this because the Eye-ties used olive oil as a damping medium? Enquiring minds want to know!

          • Ed Sorbo

            Maybe some kind of organic compound in the oil that broke down. Maybe the air in the forks, as in the smell of air that comes out of tires. Maybe some crazy mix of factors. I like the idea of someone asking to have their oil changed because it stinks, that is a reason I can agree with.

          • Iconyms

            My guess is the black is from tiny particles of exhaust and or brake pad dust that got on the fork tube and stayed there as the fork compressed (getting past the seals) then mixing in with the oil. There’s a lot of black dust stuff like that near freeways and in cities with a lot of cars just look at any white window sill in LA.

  • 123db

    Agree with most of this, but got to add something to the point about race suspension and road suspension. While the point made is true, what is forgotten is that the track tends to be smooth, while the road isn’t, so you run out of race tolerances quickly – making for an uncomfortable ride.

    Put it another way, you don’t get pot holes on the track, so your suspension doesn’t need to be set up to deal with them – but your road bike does!

    But totally agree with the placebo effect – it was even meant to work on some legend racers too! :-)

    • Ed Sorbo

      Streets of Willow and Mid Ohio are just two bumpy tracks I can name.

  • azi

    I agree with most of what Evans has said, but I think there’s more to #2 (aftermarket). Whilst most stock suspension can be revalved and resprung to meet/exceed the performance of aftermarket components, sometimes it’s more economical to just start from scratch. This is especially true for rear twin shocks on retro bikes such as Bonnevilles, W800s, and Sportsters which are so cheap and nasty in design and material choices that rebuilding them for the right spring/damping curve isn’t worth it.

  • Josh

    #9 is very wrong. I stopped reading after this bit.

    “When you crank preload into your bike, you’re storing energy in the spring. If you preload a 100-lb spring one inch, then placing less than 100 lb on top of the spring will not compress the spring more. So, it doesn’t move anymore until you add more than 100 lb of load to it. Placing 200 lb on it will compress the spring an additional inch.”

  • Eyam TheZombie

    I’m wondering about the “bonus misconception”. If I stand next to my bike and rev it, the back end squats.

    • Evans Brasfield

      Put it in gear squeeze, the front brake, and start releasing the clutch what is the back end now.

      • Eyam TheZombie

        I’m going to pay more attention next time I do a burnout.