Author Topic: I'm Tired of Tyres  (Read 1924 times)

Offline Williamson

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Re: I'm Tired of Tyres
« Reply #25 on: November 07, 2017, 09:03:01 AM »
The PR4 GT rear has let me down.  Only around 15k and it's shot, kaput ..... Running it at 44psi, perhaps I'll try 46psi ........

Or try 42 psi (290 kPa).  Works for me! Front and back.  Never had one fail before it wore to the wear bars.
But then I only weight 74 kg...    :whistle


...... New tyre on now, pressure set at 42psi (cold).  It is interesting (to me) that the dealer in Bairnsdale suggested 38 to 40psi.....

.... 42psi is fine for the bike when you ride it out of the show room as a empty bike ..... 42 PSI is under inflated for a bike once its loaded .... 44 front and 48 rear and now get 20K minimum.....

.... Increase the air pressure is ok ....

I think the factory recommended tyre pressures are set to provide a compromise between wear and road holding and providing a reasonable braking contact patch. The higher presuures will give better wear rate when riding in mainly open country, just be well prepared for that emergency stop to avoid contact with ‘roos, road debri, other vehicles, pedestrians etc.

I am willing to sacrifice good wear for more safety and better cornering in the Alpine country I do most of my riding in.

Yes, I am confused. 

But I agree, safety is more important than wear.
Cheers,  Williamson (AKA Michael)

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Offline Sicman

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Re: I'm Tired of Tyres
« Reply #26 on: November 07, 2017, 09:26:21 AM »
Its my opinion that the right pressure and suspension setting for the weight of a loaded bike is actually safer than a tyre which is underinflated for the weight. Just a gut feel but it would especially apply for riding thru lots of twisties  :thumb
Cheers
Tony
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Offline STroppy

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Re: I'm Tired of Tyres
« Reply #27 on: November 07, 2017, 10:57:28 AM »
Never had a problem but I suspect there is much more at play here, riding style, different makes of tyres, different tyre build types, different loads, different distribution of loads, different suspension builds, heights and settings . . I think the factory settings are a guide and each should try a mixture of front and rear and collect data and ďfeelĒ, tyre wear etc and choice of safety or maximise wear and adjust tyres for each ride . .
Terry, Canberra 0412499625
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Offline Sicman

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Re: I'm Tired of Tyres
« Reply #28 on: November 07, 2017, 11:03:44 AM »
Well said Stroppy  :thumb
Cheers
Tony
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Offline tremarg

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Re: I'm Tired of Tyres
« Reply #29 on: November 10, 2017, 05:40:50 PM »
Saw the photos at the beginning of this post and it looked a familiar picture. I had the same experience in a short distance, so when I replaced it, I finally listened to some sound advice. Tyre pressures are important and critical to tyre wear. I now run run higher pressures for Mich. PR4 GT F&R and as I run a tyre pressure monitoring system was able to confirm that the sound advice was valid. At 42psi cold with 30 degrees ambient temp, the rear pressure would rise to 55-56 psi at 100KPH. At 47psi cold, the pressure would rise to 53-54 under the same conditions, i.e. a lower running pressure. The result of this is less wear due to the lower temperature that the tyre is running at as pressure rise and temperature are directly related. The first PR4 (42 psi cold) lasted just over 8,000 K with most of the wear being the right side edge with lots of 'bearding' and abrasion. The second PR4 (47psi cold) is at the 9000 K point with an estimated 40% life left. My riding habits have not changed, love that flat torque out of corners.
There are other factors that come into tyre wear, one of them being suspension setup. Rear suspension settings affect the performance/handling and front tyre wear. As well as checking tyre pressures on each ride and during the ride, I check the suspension setting, in particular, preload on the rear. I change from solo to 2 up often requiring the suspension to be changed each time (bit of a PITA). Also use tyres that conform to the specs required for this bike, both in sizing and importantly load ratings. Remember that the weight on the tyres is not just the weight of the bike, rider, passenger, load, fuel and in some cases trailer ball weight. Those that undertake flying know that in a 60 degree bank, 2G is applied to the aircraft and it contents. When turning on a bike is no different and effectively starts to increase from 30 degrees upwards. This is taken by the tyres at an angle which produces tyre distortion, further increasing contact pressure/temperature. Also, when accelerating and/or going uphill, the weight on the rear increases. That rear tyre has a lot to put up with.
I was iffy at first in increasing tyres pressures beyond the book value but tyre technologies have improved in the 18+ plus years since the design of the 1300 and 27+ years for the 1100 and monitoring has confirmed that the lower running pressures/temperatures=longer tyre life. BTW ride comfort has not changed significantly and ride handling is better if the suspension setup is correct. I know now if the setup is wrong as it does not feel right.
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Offline STroppy

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Re: I'm Tired of Tyres
« Reply #30 on: November 10, 2017, 07:34:06 PM »
Thanks for the report and data tremarg, something to chew on . .
Terry, Canberra 0412499625
Ulysses #22354, FarRider #761
Current bikes 2013 Triumph Trophy SE, 2008 ST1300
Previous bikes1948 Triumph Tiger 500 Twin - sprung rear hub, 1963 BSA Bantam 175, Yamaha 75cc & DT250, Honda ST1100, 400N & CX500 sports, BMW K100RS & K100 LT, Harley Electra-glid
 

Offline Williamson

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Re: I'm Tired of Tyres
« Reply #31 on: November 10, 2017, 08:14:53 PM »
Thanks for the report and data tremarg, something to chew on . .

Yes very helpful, I hope!

..... I finally listened to some sound advice

..... I run a tyre pressure monitoring system was able to confirm that the sound advice was valid. At 42psi cold with 30 degrees ambient temp, the rear pressure would rise to 55-56 psi at 100KPH

..... At 47psi cold, the pressure would rise to 53-54 under the same conditions, i.e. a lower running pressure.

..... I check the suspension setting, in particular, preload on the rear.

..... I change from solo to 2 up often requiring the suspension to be changed each time (bit of a PITA).

..... trailer ball weight.

..... ride handling is better if the suspension setup is correct.

..... I know now if the setup is wrong as it does not feel right.

I've had lots od sound advice, problem is some if it is opposing.   :think1

Similar readouts on my TPMS, when tyres are hot.

Very interesting.

How do I know when the rear preload is correct for me?

Preload is set, not changed when riding with pillion or with trailer.   Might explain a few things?

When, how do I know?

With my riding style, I can't tell.

Phew!!!!!!
Cheers,  Williamson (AKA Michael)

Motorcycling - the best time you can have with your clothes on ...........

Afterlife - up there for the climate, down there for the company.
 

Offline Sicman

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Re: I'm Tired of Tyres
« Reply #32 on: November 10, 2017, 09:12:17 PM »
I have found when the suspension is set for our bike being fully loaded, it rides, and handles like it does, when its just me on the bike unloaded.  :thumb Before I found the sweet spot when loaded, it felt heavy in the rear and bounced, wallowed and the front was light.
Cheers
Tony
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Offline tremarg

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Re: I'm Tired of Tyres
« Reply #33 on: November 16, 2017, 06:18:38 PM »
'Sweet Spot' is the key to a lot that happens while riding. My riding, as the rider, continually varies from just myself to 2 up to 2up with luggage full. The continual setting of the preload with the manual knob became a pain. I tried an adaptor which slid over the knob to make it easier to turn, particularly at higher settings when the knob becomes harder to grip as it becomes flush with the plastic work. It is one of the items on the list of checks before riding but occasionally is forgotten resulting in 'Something is not right'.
The sweet spot for me is when the rear suspension preload is set at the point where the rake angle of the front fork to the ground is at the bike's design point for correct 'feel' while cornering etc. If it incorrect, the rider has to hold the corner which places a force on the front tyre. Hence my assertion about front tyre wear linked to the suspension setting.
To correct this and maintain correct preload for any given load situation, I converted the rear suspension preload setting to electric. I can now alter the preload on the hop and now have the ability to accurately set the preload to any load condition. This is why the Goldwing and BMW's of this world go to the effort of fitting 'electronic' rear suspension.
2008 Honda ST1300
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"Having a positive mental attitude is asking how something can be done rather than saying it canít be done"
 

Online alans1100

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Re: I'm Tired of Tyres
« Reply #34 on: November 16, 2017, 09:27:06 PM »
When I replaced the OEM rear shock with a Progressive (company name not spring type) one I tried to set the new ride height at a compromise position between 1 and 2 riders. The rebound was advised to be set at 1 for one rider or 2 for the two of us and I tried 3 when I had the trailer as well but after the first two up and trailer trip I decided to leave it at 2 and it seems ok.
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