Triumphrat

Sprocketti · 09-19-2005

.... Ok, this may be the defining post about tire pressure for Speedmasters with fitted with Metzler tires....

I have an '03 Speedy, that I've put 13,500 miles on since purchased in February of '04.....

At @ the 8,000 mile mark I started to notice a slight 'wobble' in the front end at around 47 mph through 52 mph.... The 'wobble' had gotten progressively more intense, to the point that I had the front wheel rebalanced, which did not solve the 'wobble'. This 'wobble' caused the bars to shake vigorously through the frequency range, then settled down at speeds above 60 mph.

At my 12,000 mile service interval it was finally determined that the front tire was developing a 'cupped' profile and the tread had a slight 'wobble' as observed when spinning the wheel while on a stand....

It turned out that the rear tire had developed this 'cupped' profile as well....!

(P.S.- The tires were not worn beyond Metzler warranty specifications...)

"Cupping" on a tire tread is caused by running the tire at too LOW of a pressure.

Recently in the last months I've posted the question about the correct minimum tire pressure for the Speedmaster/Metzler tire combination...

The Triumph Owners Manual states: 36 psi (front), 36 psi (rear)... This is the pressure I've been running since the beginning and this is the pressure the techs that service my Speedy have been using.

Metzler recommends: 42 psi (front), 46 psi (rear).

The CORRECT tire pressure according to Metzler is the numbers that METZLER recommends!!!! NOT TRIUMPH!!... 42 psi / 46 psi.

Triumph WILL NOT !... warranty the tires!

Check your tire pressure ASAP!!

--Sprocketti :wink:

[ This message was edited by: Sprocketti on 2005-09-19 10:45 ]

larryshep · 09-19-2005

Triumph does not warrant tires, that is up to the tire manuf. Talkl to Metzeler, although you have gotten more miles than most. The average is around 12,000 that I have experienced.

dazco · 09-19-2005

Thats up to 10 lbs difference ! I just emailed Metzler and asked them to tell me who is right, WHY, and to contact triumph and get this strightened out because this is a serious issue. Geez. 36 or 46? Someone is sooooo wrong here it's pathetic.

What do most bikes in the 500 lb range with similar size tires use for PSI?

larryshep · 09-19-2005

Hey Daz,
I just looked at the Metzeler website and they list the MAXIMUM PSI as 42 lbs for the ME 33 Laser front and 42 lbs for the ME 880 Marathon rear. I have always run 36/36 and everyone I know stays at that psi with no problems.

PAAS · 09-19-2005

Just to add a bit more confusion (!), page 24 of this document (Metzeler US) on the US Metzeler website gives the MINIMUM tyre pressures as 38psi front and 40psi rear for the Speedmaster. The "correct" tyre pressures will be somewhere between the minimum and maximum recommended according to personal preference, riding style, type of roads used, load, etc...

As an aside, I have a T100 with OEM Metzeler tyres and the Triumph recommended pressures are the same as the ones on Metzeler's German website but different to the ones recommended in the US document given above. Go figure as you chaps would say! To be fair to Triumph, I don't know of a car or bike manufacturer that does warranty tyres.

larryshep · 09-19-2005

I should make clear that I am now riding a T 100 and it has Metzeler MEZ2 rear and Lasertec front. I run 34/38 with this setup, with the original tires MEZ2 and ME 33 laser I ran 33/38.
On the three SM's I had I did run 36/36 with the stock Metzeler tires.

Sprocketti · 09-19-2005

Metzler will warrant the tires....

They were still within warranty specifications.

The problem is this... the oscillation may have precipitated early front wheel bearing failure (which occured)... It may have precipitated early steering head bearing failure (which occured).... I sure it has had an effect on the rear suspension/swingarm and anything else that could be affected by the oscillations.

Metzler is replacing the front tire with a "ME330 Lasertec", a bias ply tire with a tread pattern like the "Roadtec" series... They are replacing the rear with the stock "ME80"

Until both tires are replaced, the 'jury' is still out as to what is precipitating the 'wobble'.

The cupping was difficult to see... The wheel/tire had to be spun next to a flat surface while observing the profile/sillouette as it rotated to see the uneveness...

This tire condition may have been the reason for some degradation of cornering stability.... the front end seemed loose at times.

In the future I'm sticking with the Tire Manufactuers specifications for minimum pressure....

In case you're in doubt.... The MAXIMUM-(Post Scripted) tire pressure is included in the description/ratings information 'stamped' into the sidewall of the tire.

Metzler has a great pamphlet that describes every aspect of their tire designs and application notes, along with correct fitment parameters, load rating, etc..

--Sprocketti :wink:

[ This message was edited by: Sprocketti on 2005-09-19 17:03 ]

larryshep · 09-19-2005

On the tire pressure stamped on the side wall of my Metzeler's, it give a Maximum pressure of 42 lbs at "x" # of pounds load...this is on both the MEZ2 rear and the Lasertec front. I would assurm that the ME 880 has "maximum" stamped on the side wall as well...I will find out and let you know...it seems a bit strange that I would have "maximum" on my tires and you have "minimum on yours.

larryshep · 09-19-2005

I just checked my son's Speedmaster (03) with the ME 880 rear and it too says maximum 42 psi at "x" # of pounds weight.
I wonder if your steering head was not properly tightened from the factory...it could well have been and slowly worked more loose causing the tire to cup..just an idea.

Sprocketti · 09-19-2005

Quote:

On 2005-09-19 14:27, larryshep wrote:
I just checked my son's Speedmaster (03) with the ME 880 rear and it too says maximum 42 psi at "x" # of pounds weight.
I wonder if your steering head was not properly tightened from the factory...it could well have been and slowly worked more loose causing the tire to cup..just an idea.

...I stand corrected.... it is "MAX" pressure.

How coincidental is it that BOTH tires exibit cupping??

The steering head bearing may be another issue.... It has been adjusted about 4 times for loose feel 'clunking' or chatter.... the bearings were replaced last week.

--Sprocketti