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Losing a little confidence

M

MASHMAN

Joined Jun 2007
70 Posts | 0+
NZ
I was out for a wee blast today and had a re-occurence of a problem that i'd just put down to tyre pressure. When gettin on the gas i've started to suffer a lot of speed wobble (nope, i've actually lost a few kg's) and as such have started going into corners with a more defensive state of mind . When i first went to a 43T rear I was having lots of corner exit sag at the rear and a little wobble. Pumped the rear up and that seemed to cure the problem. That was about 5-6000 K's ago. I pumped the tyres up to pressure today and then headed out for an hour or so, but soon realised that I was getting the above mentioned problem. I'm reluctant to fiddle with the suspension as it's served me well thus far and I was wondering if it's just the change in the profile of the tyre, change in ride height due to less rubber or something entirely different that may well be rear shock age related.

Any thoughts, as it's starting to piss me off after 2 weeks?

Cheers

Mash
 
You might have to start playing with suspension.

Rear shock and forks don't perform the same as they age (rather, as the fluid ages). The rear shock might not have as much nitrogen pressure in it as it used to and thefluid is starting to foam a bit affecting performance, the fluid might not have the same viscosity as it used to.

The fork oil might be contaminated and not working like it used to as well.

Got a steering damper? Same issues.

Then, there is wearing tyres like you mentioned too. I've not had a set of tyres last me 5-6000km, so I can't eally comment on that, although I do notice the difference between an old and new set, mainly the turn in effort not so much a steering stability issue.

(I check my pressures before every ride)
 
Bugga. I assume that the heat from the engine is playing a part in the rear shock degredation too as it's spot on for the first 10 minutes or so and then starts entering into lounge lizard mode. Can the Sachs be refilled etc??? I'll wack on another couple of preload clicks and see how that helps.

I know what you mean by the profile of the tyres and the amount of turn in effort required (has 11000k's on my first set of Mich Pilot Sport), when i got these things (conti-attack road) 4 months ago i spent the first day or two just trying not to fall off the bloody thing.

Unfortunately i'm technically challeneged and as the bike is still under warranty i ain't gonna start messing with any fork oils etc... I'll wait until i put the Prila in for a full service next month.

I ride in a straight line 95% of the time and i'm sure that doesn't help when winding on and rolling the tyre across the squared edge.

Cheers for the help, i'm off to fiddle...
 
Cheers Steve. I've read those articles a few times before and they've never really made too much sense, preloading, damping, rebounding and sagging WTF are they talkin about. I guess now I have a problem to solve they make a little more sense. Lack of Compression damping apparantly. I assume that this should be done whilst the bike is warm, i.e. under running conditions? I'm off to remove the preload clicks.
 
On reflection. which way do i turn the bloody screw to add more compression damping? Or is it less compression damping, erm... yeah, add less
 
Meh, as dumb as i feel I fear there may be something amiss. I've had a check of static sag both front and rear, unladen, and that seems to be about right. Front springs back quite happily and the rear tops out without too much effort. I had a go with the compression damping rear yesterday and noticed that i had 1.5 turns, as per the book on, so moved that to 1 turn, then .5 turns and now have nowhere else to go and the bike still dives at the rear when exiting corners and really doesn't feel nice to ride at all, even in a straight line (although that could just be my head)

Any more thoughts?
 
How old are the tires in age and mileage? What pressure are you running? What are your sag #'s? Old or worn tires can make a huge difference and cause all sorts of weird handling issues.

Is the chain tension correct? Did you have to make any major wheelbase changes when you installed the 43T rear sprocket?

Freshening up the suspension can't hurt either - both the fork and shock oil can be changed:)
 
Tyres are about 4 - 5 months old, 5-6000K's, Conti-Attack Road 37F 42R, unladen sag is about right as is laden sag. Chain is about spot on, no great dramas after changing the wheel base, other than noticing my tyres weren't at pressure. Essentially nothing has changed apart from a little more time and me losing a couple of kilos. Still feels fookin 'orrid in a straight line too. Guess i'll go for a full service and see how things are after that, maybe mention it to the shop as the bike is only 10 months old.

Thanks
 
hmm, you might take just a little preload out of the rear if you lost some weight. Even a 5mm change in sag can make a big difference in how a bike responds. The tires don't sound like the issue, though I suppose they could be getting a big squared, but shouldn't be bad by any means at this point.

If the forks have air bleaders (many don't so don't worry if yours don't) you might try releasing the air pressure:O

best of luck
 
Removing the preload sounds fair, i can do that, although it sounds counter intuitive as that softens the spring? and i'm trying to firm the rear up etc... But i know nothing, i shall try it, just so I don't have to start from scratch...

thanks
 
Last edited:
those tyre pressure seem high to me. I hate running 36F and 42R (which seemed to suit all me prev bikes).Its allover the place with those pressures and i hated how it handled. I now run 33F and 36R on the road with no probs
 
The guys at the stoer made a point of telling me that they were high pressured tyres, something to do with the carcass. Any time they go down 2psi or so you can really feel the difference. You can feel the tyre squat under acceleration it makes the bike handle similarly to the way it does now.
 
You just need to go faster and heat them up more!!! only kidding.
I ran those pressure in both cont attacks and conti sport attack with no probs,(although on UJ bikes I ran the regular pressures) So mebbe its not the tyres??? The only thing I didnt like about those tyres was, as soon as they were part worn they tracked badly over surface irregularities on the road. On a good side they had a nice wide shape to themallowing a nice lean angle.
 
I've noticed the bad tracking over the slightest road imperfection, i'm assuming my suspension isn't helping as it likes to go in different directions at times, just for the sheer hell of it. ******** question time. When fookin around with the rebound damping, is clockwise on the clicker from above or from below? Hopefully it's from above. I had it all back stock settings today, which was basically where the bike was to start with, but i've removed a little rear rebound damping. Primarily as when I sit nuts to tank, don't try this at home kids without wearing a cricket box TRUST ME, and then bounce gently and then a little harder, AGGGGHHHHHHH, I can now get the front and rear to squat bounce together. Whereas before only there was definately more rear bounce than there was at the front. Next dry day i'll give it a push and see how we go. Thanks for the help
 
I'm down in Windy Wellie. You guys are takin a bit of a battering up there by the looks of things. Someday I shall ride north. I've been South and it was absolutely breathtaking once you got over the white stone roads phobia. Only been here for 11 months and it's stunning.
 
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