Unsettled across roadway seams?

[Rallyfan]

Hello,

I've noticed odd handling on a 2006 GS500F US CA model.

Front: Bridgestone Battlax BT45f 110/80/17 33 PSI

Rear: Kenda Cruiser s/t 140/70/17 36 PSI

Stock forks; stock rear shock set at 6. Rider is ~100 kg.

Sometimes freeways are widened, leaving a "joint" that is usually a narrow strip of asphalt where the interface between the old roadway and the added width is covered and smoothed. The bike travels parallel to this narrow strip within its lane; sometimes the strip is crossed within the lane by the bike at a shallow angle.

I've noticed an odd, "loose" or squirmy feeling both through the bars and through the seat when going across these seams in the lane. The angle is always very shallow, meaning the bike travels on the seam a bit before crossing over.

I've not noticed this on other bikes before. Any advice? Normal? Should I increase pressures?

Thanks!

[fetor56]

Normal,don't sweat it.

[Rallyfan]

Ok great thanks! I appreciate it.

[BockinBboy]

Yep, normal. Don't try to manhandle it over them or try to 'correct' or force a path over them. But rather keep on the throttle, continue looking where you want to go, and let the bike steer through them on its own.

- Bboy

[RossLH]

Be light on the controls. A death grip will only end badly.

[Rallyfan]

Thanks. Light is right ends up being the strategy. At least it's normal.

[adidasguy]

Anytime you ride with a break in the pavement that is uneven, you get that. Same happens in a car if you pay attention. The more the un-level-ness, the more you notice it.

Don't ride the seam. Get to one side or the other.

If you want something that gives you the willies, ride over a draw bridge with a steel grated surface. You feel the bike go all over the place. Just go with it and all is fine.

When you try to fight things, you get in trouble. The geometry/engineering/mechanics of a bike will make it want to stay upright and go straight. Weird grooved pavement? Just go with it. Let the bike do its thing. You will be OK if  you don't fight it. Spooky at first. After a while, you get used to it and feel like you're floating.

[prmas]

Same applies when riding on gravel. Let it stay loose and shake it's head a bit. As long as you don't snap the throttle shut in a panic you should be OK.  I have surprised a few friends with "Adventure Bikes" with how quickly I can go on unmade roads. The sharp ones can leave me behind but the more timid ones are left in my dust and I am still on the original BT45 tyres.

Macka

[Rallyfan]

Yes gravel can be a bit disconcerting but it's not unfamiliar to me. I wonder if there's something about the combination of rake, rubber, suspension, mass with rider, and wheelbase of the GS that's "ideal" to bring about the float effect, as I've not noticed it nearly as severely on other bikes.

Thanks again to all.

[mimikeni]

If you aren't ready for it, those asphalt snakes on 90+ degree days can sneak up and bite you in the ass.

[gsJack]

You don't mention what previous other bikes you are referring to but if your experience is anything like mine was none of them had as steep a rake as your GS has.  The GSs have a 25* rake which is near sportbike territory in quickness compared to the 4 old standard Hondas I had before my first GS.  I traded a 85 CB650SC Nighthawk in on my first GS back in 99 and riding it home it felt like an all out sportbike compared to the NH which was actually one of Hondas sportier standard type bikes of the 80's.  It launched me into my second childhood riding.   

Just hit all those irregularities in the road running lengthwise at a good angle and it will soon become automatic to do so.  The tar strips, construction grooves, differences in lane height while paving, etc.

[bombsquad83]

I think the GS is a bit more sensitive then many bikes to these kind of things because of a few different factors.

1. Sportbike style rake = quicker steering
2. 17 inch wheels (instead of a big 21" front like a dual sport)
3. Skinny tires (for a sportbike) = smaller contact patch

[Old Mechanic]

I like to check alignment of every bike I buy, to see if anything is tweaked as far as both wheels being exactly parallel to each other. I use a string wrapped around both tires with a bent washer to maintain tension on the string. With a little experience it will tell me if the front or rear wheel is not properly aligned by checking the gap in the rear of the front wheel which should be equal when things are right (front tire narrower than the rear tire), with the same distance from each handlebar end to a single point on the center of the bike.

regards
Mech