WaleSWeST: suspension thread

["Keith Tynan" <keith@xxxxxxxxxxxxxxx>]

Apologies all,

A recent non-regional thread at WaleSWeST should have been carried via TSRA
instead. Sorry - unintentional. It covers my suspension article on the
TSRA -> FAQ -> Suspension page.

There are a couple of pictures that go with this, which I'll upload
directly. Note: I believe the damper rod diagram is different in detail from
that used on the ST. My experience of the ST item is that it doesn't have a
'check valve' or 'rebound orifice' - but I haven't seen the stanchion out of
the slider. Does anyone know any different?

BRG

Here's the thread:

************************* BRG
************************* Tue 2001/01/09 14:43
Whoa Keith, this lot's going to take some explaining.....

The short answer is that Mark Hammond is a very approachable and helpful
guy - why not give hime a bell/drop him an 'e' instead?

I wouldn't class my knowledge of suspension as encyclopaedic, though:
- - recent experiences on: '94 Trophy 900, Sprint ST, Speed Triple (old),
Ducati 748/996 (track) and CBR600F (track)
- - discussion with Mark Hammond (and watching the mods to my forks being
done)
- - a fair bit of web browsing
have improved matters a great deal.

I recommend that you read up a bit, then have a good long hard ride (ON THE
PACE) to firm up your diagnostic powers.

STICTION is the static/sticking friction of the forks. Stiction is
undesirable, as it means there is some uncontrolled damping in the forks.
(You can experiencing this by sitting astride the bike and bouncing lightly
on the front with the brake on. You should notice that the forks don't move
straight away. Similarly, they don't bounce back (under their own steam) to
the 'rest' position). This is why the TSRA -> FAQ -> Suspension -> Article
#2 suggests calculating 'mean sag'. To minimise stiction, I had the damper
rod polished, and used Ohlins oil - you would NOT BELIEVE the state of the
oil that came out when the forks were being dismantled (yes the seals were
in good nick!).

I came to MHRacing through personal recommendation. A colleague with track
tendencies put me on to a one-man-band tyre/chain/brake specialist name of
Dave Newport (http://www.tyretech.com/) who also does some track work on a
Kwak 750. Excellent bloke, used him now for 5 years. First tyre change on
the ST, I was bemoaning the handling (re tyres) and he recommended the bloke
he uses for his race suspension: Mark Hammond
(mailto:mhracing@xxxxxxxxxxxxxx). MH is also a one-man-band who does
suspension only. He's been in the trade for more than 10 years, and is
Ohlins-certified.

Mark and I discussed the problem, he inspected the bike, I let him know my
budget, and then we sat back to wait for the bits [this took 16 weeks, as
Ohlins don't make a lot of these units!]. I stood and watched the whole
operation, which took about 3.5-4 hrs. Some of this might have been as a
result of my nattering.

I now run with 5mm pull-through (against 0mm stock) and zero preload
(against 10mm stock/Standard). This makes the turn-in (the tendency to
'fall' into the corner once off the straight and narrow) muck more
pronounced. This is highly desirable in by book. Speaking with the Avon rep
at the NEC show, a different tyre, e.g. Avon AV39, would increase the
turn-in further, as the tyre is more cambered.

The Ohlins rear shock (WaleSWeST seems to digest umlauts and pound signs) is
adjustable for compression, rebound and preload - the last via a remote knob
(mounted near the o/s pillion footrest), which makes it easy to adjust for
riding 2-up.

There are basically two types of fork construction (regardless of whether
the forks are RWU or USD): damper rod and cartridge. The ST forks are
definitely 'bottom-of-the-range' damper rod types. Damping is provided by a
pair of holes in the damper rod, with no valves. This means that compression
and rebound damping is the same. The RaceTech solution, often quoted on the
TSRA pages, involves mounting the 'cartridge emulator' on the top of the
damper rod. The 'cartridge' is a unit that allows separate regulation of the
damping in each direction (compression & rebound) with the use of valves. It
is only an emulator (and not a converter) because unlike a proper cartridge
fork, it can't be adjusted in situ. I'll post a couple of supporting pics.

Have a look at http://www.ohlins.com/ for some informative articles.

Hope this proves helpful.

Regards,

[BRG]

************************* Keith [W. Peters]
************************* Tue 2001/01/09 11:49
Keith T at 09:34 09/01/01 +0000, you wrote:
>I'll continue to post general/technical ST material to the TSRA site, and
>regional stuff to WaleSWeST. (I access this via an ISDN line, so the speed
>is 'acceptable' - KWP: I can post the suspension article to you if that'd
>help.)

I read the article fine, but even in work with ISDN connection trying to
access eGroups to check your email address for clarification was painfully
slow around 21:00 last night.

>My suspension mods were carried out by Mark Hammond (MHRacing) in Corsham
>near Bath.

MHRacing, yup seen their adverts in the press. How long did it take ?

>A very helpful and knowledgeable guy, he came highly recommended.
>mhracing@xxxxxxxxxxxxxx Tel: 01225 811583 Mob: 07970 596206. I haven't got
>the details with me here, but ROM cost was: front: £170, rear £600 covering
>parts, labour (full dismantling) & VAT.

Your article is very good. I'm sure given the explanation of the symptoms
in the detailed way that you did obviously gave Mark Hammond
a good sound base to work on to enable a cure. Being less able to explain
the feelings I have may result in a less sorted result as surely the result
is only as good as the initial input. For example you use the word stiction
(even the spell checker isn't sure about it), I can make a guess as to what
it refers to but would not be sure.

Would Mark (or anybody else) be able to provide a solution purely on
statements like 'the front feels too light' and 'when carrying the wife and
lugage it goes really light' or 'the bike always seems to ride nose up' .
Maybe his experience would enable questions to be asked to find the true
cause of the problems but hey I'm just guessing as to what the bloke can do
or how other companies like his go about finding the cause.

If you have time I'd like to know what actions took place between you first
contacting MHRacing and getting the bike back.

Do the forks still have pre-load only and what functions does the rear
shock now have ?

>I notified my insurers last week, and there was no change in premium (mind
>you, the value
>of the bike had plummeted to compensate for the hike in accessories
value!).

What they missed an opportunity to get more money out of a customer ;-)

[KWP]


************************* BRG
************************* Tue 2001/01/09 09:34
Keith, Mike, all,

Much though I hate the limelight.... I claim the handle 'BRG' (as in British
Racing Green).

The ST is my third bike in BRG, and was custom painted by Dream Machine, as
Triumph hadn't given it as an option when I bought mine in March 2000. (BTW,
DM paint some OE bits on behalf of Triumph.) My car is BRG too.

I'll continue to post general/technical ST material to the TSRA site, and
regional stuff to WaleSWeST. (I access this via an ISDN line, so the speed
is 'acceptable' - KWP: I can post the suspension article to you if that'd
help.)

My suspension mods were carried out by Mark Hammond (MHRacing) in Corsham
near Bath. A very helpful and knowledgeable guy, he came highly recommended.
mhracing@xxxxxxxxxxxxxx Tel: 01225 811583 Mob: 07970 596206. I haven't got
the details with me here, but ROM cost was: front: 170, rear 600 covering
parts, labour (full dismantling) & VAT. Value for money? Well, it's
subjective - it depends how you ride. If it's well within the design
envelope, you shouldn't have much of a problem. But with my
size/shape/riding style, the stock set-up was never going to cope! Certainly
the front is money well spent (by comparison, Racetech in the UK is 115
excl. fitting, springs extra). Regards the rear, for me it was a case of
change the stock strut or change the bike, and there's not much to choose
from in price between the quality alternatives (hlins, Wolsky (WP), Penske,
Maxton), so I went with what I consider to be the best. I notified my
insurers last week, and there was no change in premium (mind you, the value
of the bike had plummeted to compensate for the hike in accessories value!).

Regards,

[BRG]


************************* Keith [W. Peters]
************************* Mon 2001/01/08 21:04
Keith,

Is the BRG that sent the suspension comments on the main ST FAQ section you
?

If so, tell us more, where did you get the work done, how much, what did
the insurance company say, any increase in premium etc.

The statement 'Front feels too light to have sufficient contact - no
confidence in grip' hit a nerve.....

For those that haven't read it:
http://www.triumphnet.com/st/faq/suspension/brg.html

[KWP]


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