Handling

The Sprint seems to be far more sensitive to grooves in the surface,
white lines etc. than the Fazer was. It is actually somewhat
disconcerting and is deifinitely reducing my cornering confidence.

The bike has 7k miles and a pair of what would appear to be little-worn
BT010s. Pressures at the moment are 30psi front, 42psi rear.

Any suggestions on what to check?


--

jeremy
'01 Triumph Sprint ST in green
_______________________________________
jeremy0505 at gmail.com

 

Check the Bridgestone website - 30 in the front sounds a little low.

 

I would have thought the front should be more like 36. A flat front
will make the front feel like it's running *in* rails and not wanting
to turn. IMLE though this is only noticable when you have a silly
amount of font tyre pressure like 20psi or less. Might still be worth
looking at.

 

Jeremy wrote

Tyre pressures, the suspension, the rider, the cat, all the usual shit.

I have a feeling though that this pursuit of quick steering and tyres
that only grip on the side and all that stuff has led to a bit of over
radicalisation in profile design. I think there is a good argument for
fitting flatter profile rubber, especially for lardy old tourers.

 

And the rear sounds too high as well.

Have you checked for wheel bearing play?
Swinging arm bearing adjustment?

The big Triumph I had a go on also felt a bit flighty on grooved tarmac,
mebbe it's just the price you pay for a fairly quick handling setup...

 

I should have been clearer - it's the back that feels "wrong".

Bridgestone site doesn't list a rear but for the front it says:

Front IPC :
Front dimensions : 120/70 ZR 17 (58W) TL
Front Profile : BT-010 J
Front Pressure : 25.0

So according to that, it's a little high. The book says 36psi front, 42
rear. So as you say, a little low.

--

jeremy
'01 Triumph Sprint ST in green
_______________________________________
jeremy0505 at gmail.com

 

Well, as others have said, the front is a bit low, so I'd check the
manuel and adjust that. As to whether it would provoke said response,
I wouldn't be at all surprised.

I always found mine to be very sensitive to part-worn or
incorrectly-matched tyres and it would then be very sensitive indeed
to any slight variation in road surface. Going over the tramlines in
Basel was a nightmare. Still, it's one more challenge ;-)

--
_______
..'_/_|_\_'. Ace (brucedotrogers a.t rochedotcom)
\`\ | /`/ GSX-R1000K3
`\\ | //' BOTAFOT#3, SbS#2, UKRMMA#13, DFV#8, SKA#2
`\|/`
`

 

tallbloke says...

Not really. The ZZR1100, which weighs about the same, is 42 front, 42
rear.

 

Wow, surprising.

 

That'll be corrected before next outing.

How did you find its stability and tracking of line through bends when
the tyres and pressures were spot on?

The feeling of unease is definitely limiting me - I was expecting
something actually more poised than the Fazer.

--

jeremy
'01 Triumph Sprint ST in green
_______________________________________
jeremy0505 at gmail.com

 

tallbloke says...

It always struck me as odd, but I never had a any handling problems with
any of my ZZRs when I ran them at those pressures.

 

Have you checked what units the Bridgestone site is using? I don't think
it's psi...

 

Ahh. That'l be a fucked rear shock then. Mine went after about 15000
miles, IIRC, which made for, err, interesting times. I remember
completely fucking up one bend on an early botafot when mine was
offering no damping whatsoever. Just trying to remember who was behind
me at the time...

That's not lb/in**@ though - it'll be kg/cm**@ or whatever that there
other measure is.

36psi is correct for the front, and it may well still be the cause,
even if it feels like it's the rear that's odd.

--
_______
..'_/_|_\_'. Ace (brucedotrogers a.t rochedotcom)
\`\ | /`/ GSX-R1000K3
`\\ | //' BOTAFOT#3, SbS#2, UKRMMA#13, DFV#8, SKA#2
`\|/`
`

 

It had a very slight tendency to weave in very fast sweepers if you
weren't spot on with throttle control. Easing off the gas tended to
induce a bit of a forward/backward wobble on occasion. But that could
be dialed out with suspension settings.

I got so used to it that I didn't feel like it minited me at all,
although my corneringlines were sometimes downright strange when
running on worn boots. But it's never going to handle like a gixxer -
apart from the weight of the thing, the suspension units just aren't
up to the job and have very limited adjustment.

Still, as I say, when it comes right, it can be very good, as I found
by chance when I had to carry AndyB down from Luxembourg to my place
through the Vosges mountains. I just cranked up both the the rear
settings 'a bit' and it seemed to get it just right, so maybe careful
tweaking by SWK could get it just right all the time.

--
_______
..'_/_|_\_'. Ace (brucedotrogers a.t rochedotcom)
\`\ | /`/ GSX-R1000K3
`\\ | //' BOTAFOT#3, SbS#2, UKRMMA#13, DFV#8, SKA#2
`\|/`
`

 

What are these "tyre pressures" of which you speak?

 

I guess it's possible however:
1) we've just 7k on the clock
2) I fear the speeds involved were hardly those that might put much
pressure on the shock (or perhaps this is irrelevant) - we're talking
60-70 mph (yes wuss speed) gentle bends. But with a none-too-great
surface it has to be said.

--

jeremy
'01 Triumph Sprint ST in green
_______________________________________
jeremy0505 at gmail.com

 

Well the above was copied/pasted from the site - it says 25.0 clear as
day (but doesn't specify the units).

--

jeremy
'01 Triumph Sprint ST in green
_______________________________________
jeremy0505 at gmail.com

 

I have a spreadsheet that records the household expenditure and it says,
as clear as day, I have £1,000,000 in the bank account.

It doesn't mean it's right.

 

What's it actually like with 36psi front and 42 rear, as suggested, is it
any better?

 

Too busy posting to usenet to be able to ride it. Also am on a business
trip until late Wednesday and have a really tight schedule Thursday so
can you wait until the end of the week?

--

jeremy
'01 Triumph Sprint ST in green
_______________________________________
jeremy0505 at gmail.com