TYRES & PRESSURES

TYRES - Owner's Reports

Subject: Tyre choices
Date: Wed, 7 Oct 1998 12:06:46 +1000
From: "Christian D Smith" <cdsmith@ozemail.com.au>

At the moment I'm running Dunlop Arrowmax, courtesy of the previous owner. Front is standard size but the rear is a 120/90 instead of the original 110/90 (only way he could get matching rubber, apparently) - hasn't been too bad, no adverse effects that I've been aware of up until now, when handling has gone right off due to it being almost out of tread and very square due to my Budgie trip. I'd like to throw a few questions into the ring - apologies if this subject has been covered previously, but I've lost all the earlier messages in various "crashes".

Questions : Any feedback on a Metzeler/Michelin Macadam combination? I've been told it's good but is there any formula to it (e.g. Michelin rear/Metzeler front or vice versa?) I can only get the Metzeler rear (locally) in a 120/90 size - any thoughts on this as opposed to the standard size?

All Michelin vs all Metzeler (price excluded) ? Other suggestions/brands?

Subject: RE: Tyre choices
Date: Wed, 7 Oct 1998 12:27:46 +1000
From: BERNIE DWYER <bernie@caloundra.qld.gov.au>

When Dunlop stopped making the K700 in the 110/90 18 size (rear), I switched to a Metzeler - never again. Wet or dry, the K700 NEVER let go, under brakes or sloppy gear changing/engine braking.

Three times now (once during an emergency stop) the Metz started chattering under heavy braking. Lucky it's the rear. I use an Arrowmax on the front, almost as good as a K700, but it wears out VERY fast. I'll switch to an Arrowmax for the rear once I get rid of a bit more tread on this Metz.

I gave Dunlop a serve (via email feedback on their web page) about not making the K700 in my size, but I didn't get a response. Funny that.

Subject: RE: Tyre choices
Date: Wed, 7 Oct 1998 13:00:14 +1000
From: craig.nuttall@dwt.csiro.au

It looks like the lid has come off the can of worms.IMHO, Concerning my LeMans (MK V), and tyres, I've never chosen to outsmart the factory too much. I stick with:

Metzeler ME 33 Front
Metzeler ME 55 Rear

I'm using all the tyre F+R, and doing silly stuff like chasing "Lolly-wrappers" around the GOR, no complaints and they're affordable and give good mileage.

Subject: Re: Tyre choices
Date: Thu, 8 Oct 1998 08:53:52 +1000
From: "Roper" <jkn@dynamite.com.au>

For a while, (For the benefit of newer members.) I ran Shinkos which always performed adequately until I had one where the tread began to separate from the carcass, ARRRRRGH!!!!!!!

I've since swapped to a set of Pirrelli Match's which are confidence inspiring even for a fat, flacid old git like me who rides like a complete wanker. One thing worth remembering is that Pirrelli were actually involved in tyre design to suit our old dungers when they were pretty 'Hot Shit' back in the mid seventies and they still seem to suit. The Pirrellis, both front and rear are a lot narrower than a lot of tyres of the same nominal profile and while it is trendy to have somthing that looks like an enormous liquorice doghnut at each end of yer moterbyke they really don't, I'll say it again, louder, DON'T, work on any of the 18 inch wheel models from the '70's and '80's. All that happens is the steering goes all vague and if you try a bit they try to tuck in and sulk. How many of us really ride that way on the road anyway? Come on be honest.

Subject: Re: Tyre choices
Date: Wed, 07 Oct 1998 23:45:57 +0000
From: Raf Dedal <rafdedal@cia.com.au>

Roper wrote:

> For a while, (For the benefit of newer members.) I ran Shinkos which always
> performed adequately until I had one where the tread began to separate from
> the carcass, ARRRRRGH!!!!!!!

I've been running a Shinko on the front and an Avon on the rear for a year now, over 10,000k's and there is still only half of the tread left on both. No complaints but I can't comment on hi-performance as I don't ride that way anymore....but I still give it a handful whenever I can :)

> One thing worth remembering is that Pirrelli were actually involved
> in tyre design to suit our old dungers when they were pretty 'Hot Shit'
> back in the mid seventies and they still seem to suit.

Phantoms! Phantoms! and how can one forget...the Gordon. Pirelli chose some classic names in those days and won alot of races (not with Gordons though). Australia was a leading test bed for Pirelli till the mid '80's courtesy of our 6-Hour races and Frank Matich's efforts. Guzzi's and most bikes of those 120/70-18 rear days need no better, compound, tread pattern and construction is heaps better today than back then. Choice of tyres for our bikes now are more than capable of handling whatever we and our bikes can dish out. In fact most riders on the current crop of wizzbangs with 180/60-17 $400 radials don't ride their bikes hard enough to even warm up their sidewalls!

TYRE PRESSURES

Subject: Tyre pressures
Date: Tue, 13 Jan 1998 20:34:14 +1100
From: Darrell Rigby <mbi@1earth.net>

O.K. here's the big question. My bike handles OK but I'd like it to be a little softer all round.

The mark IV is 215 kgs and I am about 75 or so ringing wet with a leather jacket on. I have had the rear at 32 psi and the front at 30psi. Just the other day i let the back down to 30 also and it seems to me that it is just a bit more grippy like that.

The rear shocks are already on the lowest setting and of course front is not adjsutable except for dampers which I don't want to muck about with as they were replaced just before I purchased it.

What do you guys recommend?

Oh, tyre profile front and back is 120.

Subject: Re: Tyre pressures
Date: Tue, 13 Jan 1998 21:28:23 +1100
From: "shadow" <shadow@nlc.net.au>

30 psi is far to low you should be running 32 psi front and 36-38 rear if you are running mazzochi shocks they have a spring set far too hard. try some koni shocks the front forks can drop down to 10 weight oil and change the springs to progressive suspension items. that should fix it

Subject: Re: Tyre pressures
Date: Wed, 14 Jan 1998 00:31:16
From: Hendrik Gout <hgout@cobweb.com.au>

liar with Le Mans pressures, but 30 sounds awfully low to me. Even on a light bike like the V50 I run about 34. I say 'about' cos tyre pressure gauges at service stations are + or - 10 per cent according to the RACQ. If you're shooting for 30 that means it could be 27 or 33 psi.

But an even bigger variation is the temperature of the road, the tyres, and whether you're fanging through the hills or crusin' for a coffee. A V50 tyre which we checked (last year) before the ride at 34, was 40 when we got to the Cudllee Creek stop - about 20 kilometres of twisties.

On the other hand, Darrell, if it feels good...

Subject: Re: Tyre pressures
Date: Wed, 14 Jan 1998 09:55:30 +1100
From: "nettleinghann" <jkn@dynamite.com.au>

Back in the UK ten or more years ago I usually ran Avon's on the road with the occasional set of more 'Sporting' rubber when I could afford it or for track days. I always ran them at 28psi front and 30-32 psi rear, solo.

<snip>

With high profile tyres like on '70's bikes it also allows the tyre to deform more under load increasing the contact patch area when leaned over.

My gut feeling is that 30 front and 32 rear is about right as long as the road temperature is not extreme and/or protracted high speed flogging is not being done with a 2 to 4 psi increase in both for load or temperature.

Higher recommended pressures may have more to do with trying to allay owners fears if they talk to mates with more modern machines than the real needs of the tyres, you can imagine the conversation.

" 'Ere, Boris, wot pressure you run in your back tyre?" Asks Colin of the Mk V lemon.

" 'Bout, firty-ate," replies Boris who owns a YZF 750. " Like wot it sez in da book."

" Reckon I'll try that." sez Colin who blows his hoops up to 38 psi cold, rattles off and falls off on the first bend.

I'm quite happy to be told I'm a complete twat who hasn't a clue what he's squalking about but my reasoning seems logical and my experience seems to indicate that this is the way things work.

With the Shinkos I'm runing at present on the PB the rear wore very quickly at 30 psi so I've upped it to 32 and the new one isn't wearing so fast. The front I'm running at about 30ish and wear is acceptable. I've done very little riding in the rain so I can't comment on wet weather performance but in the dry they work well. While there are lots of much more expensive tyres available given that modern, (Read anything under 12 years old worth a cracker.) 'Performance' bikes all have fat, low profile radials I can't honestly see the 'Name' tyre manufacturers putting much money into R&D for tyres with tubes for obsolete rim sizes so the cheapo Shinkos are probably not that much worse than the 'Name' brands. I also can't go past re-tyreing the PB for under $200 cos I'm a terrific tightwad:).

Subject:Re: Tyre pressures
Date: Wed, 14 Jan 1998 10:40:38 +1100
From: Peter Cusack <Peter.Cusack@tip.csiro.au>

nettleinghann wrote:
> With regard to the tyres and tyre pressure question I am a bit confused

And with good reason. The whole question is a mix of physics, know-how and gut feelings, not easy to come to grips with.

Reading Guzziology during the silly season, I happened to read the section on tyres. It didn't all stick in my mind, but there was some advice about setting the tyre pressures by trial and fang and measure.

It went something like this:

Think of a number between 25 and 50 Put that in your tyres and go for a (short) fang Measure the pressure with the tyres hot. If it hasn't risen by 10% (I think, check the book) then drop the pressure by 10% and go for another fang. If it has risen by more than 10% then increase the pressure by 10% and go for another fang.

Repeat until busted for fanging around the shopping centre carpark or tyre pressure changes by 10%.

It made sense at the time...