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Author Topic: Tire pressures and handling  (Read 1171 times)

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Paul_42

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Reply #15 on: August 09, 2018, 05:21:33 pm
Sorry, arvo shift at the hospital is killing me lately. I'm running Bridgestone BT45's. 130/80/18 rear
110/80/18 fronts. Have not had the front wash out ,the rear will give me a gentlish wiggle when lent over too far with too much throttle but it's a fun sort of wiggle where I usually open the throttle more. Oh. Went taller profile too if you didn't pick that up. Tips in faster 8)


gizzo

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Reply #16 on: August 09, 2018, 05:51:24 pm
If RE India has designed a machine for such poor road and use/abuse. Why are we trying to turn a draught horse into a pretend race horse?. Why not just buy a performance bike in the first place.
RE didn't design the chassis. They farmed it out to Harris Performance. This is a company that  knows how to make good handling bikes. And they bought in suspension from Paoli (OK it's not cutting edge stuff, but better than what the Bullets come with). So with the GT you get an actual good handling motorbike. It's just slow, but that's ok.
FWIW I don't have a problem with the Sport Demons. I have one on the front and a BT45 on the back. 'Cause that's what they had when I needed a tyre.
simon from south Australia
Continental GT
Pantah
Monster
DR250
TRX850
DRZ400SM


ace.cafe

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Reply #17 on: August 09, 2018, 09:15:07 pm
IMO, they just reprinted the C5 manuals for the most part.

Again, IMO, this all stems from the original early C5 bikes which had flawed handling due to poor geometry in frame/suspension. The bikes were very twitchy at speed, speed wobbles, etc. Well documented.  The "fix" was to use a low pressure in the front to slow down the response of the front end by a underinflated front tire. Later models has changes to fork and front wheel to correct the matter, but the manual was never corrected. They never admitted that there was any "design error" probably to avoid the cost of a recall.

So, to this day, you see the low pressure spec in the manual.

Sad.

I have been recommending 28/32 for years, and still stand by it.


Donat Santowiak

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Reply #18 on: August 10, 2018, 04:40:40 am
Would be interesting to learn from Pirelli on what optimum pressures/rim width/bike +rider weight the Demons are designed for.
From Victoria Australia
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Guaire

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Reply #19 on: August 10, 2018, 07:56:02 am
Would be interesting to learn from Pirelli on what optimum pressures/rim width/bike +rider weight the Demons are designed for.

I trust the feedback from the experienced riders here more than anyone. I don’t think Pirelli has test drivers experimenting with tires on their own Continental GT.
ACE Motors - sales & administration


Richard230

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Reply #20 on: August 10, 2018, 08:13:22 am
Would be interesting to learn from Pirelli on what optimum pressures/rim width/bike +rider weight the Demons are designed for.

I have been reading tire manufacturer "fitment guides" for years. They list most motorcycles and the tires that they sell that will fit that brand, model and year. They also include recommended tire pressures and would usually provide a pressure for the front and rear tires when riding solo and when fully loaded. Very useful.  Then a few years ago the tire companies, in their customer fitment brochures, stopped providing the solo riding pressure information and are now showing only the maximum tire pressure recommended for each motorcycle. More often than not these pressures tend to be 36 psi front and 42 psi rear.

I am looking at my 2013 Dunlop tire fitment catalog, which has a section covering Royal Enfield models, but not the GT. All of the traditional models are listed, from 1996 through 2012, and all use the same tire, the K70, with a recommended pressure of 24 psi in the front and a 32 psi in the rear tire.  My 2013 Michelin tire guide lists their tires that would fit a lot of strange motorcycles and scooters, but Royal Enfield is not one of them. So I recommend that you visit the various tire manufacturer web sites and get the latest information on tire availability and pressure recommendations from that source.
2011 Royal Enfield B5 500, 2018 16.6 kWh Zero S, 2016 BMW R1200RS, 2009 BMW F650GS, 2005 Triumph Bonneville T-100, 2002 Yamaha FZ1


portisheadric

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Reply #21 on: August 10, 2018, 12:17:08 pm
Avon SM MKII come in at 24 and 29 for the 325x19 and 350x19.
Nothing listed on their site for the 535GT :(



General_Apathy

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Reply #22 on: August 12, 2018, 04:56:07 am
If RE India has designed a machine for such poor road and use/abuse. Why are we trying to turn a draught horse into a pretend race horse?. Why not just buy a performance bike in the first place.
For me that is the charm of the bike. I have had plenty of very fast bikes and they leave me cold. Clinically efficient with easy speed albeit at mph way beyond what is allowed. The GT operates at a speed that matches the roads I ride. As I understand it's been developed to handle but the front feels all wrong when you are pressing on. I already had my doubts about the tyre pressures and these guys have answered my question from experience and that's good enough for me. This bike will be a work in progress, it will grow with me and that's it's appeal :)


ace.cafe

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Reply #23 on: August 12, 2018, 08:38:07 am
For me that is the charm of the bike. I have had plenty of very fast bikes and they leave me cold. Clinically efficient with easy speed albeit at mph way beyond what is allowed. The GT operates at a speed that matches the roads I ride. As I understand it's been developed to handle but the front feels all wrong when you are pressing on. I already had my doubts about the tyre pressures and these guys have answered my question from experience and that's good enough for me. This bike will be a work in progress, it will grow with me and that's it's appeal :)

Our CGT riders who have been road testing our billet head prototypes have easily exceeded 100 mph on the factory bike with more appropriate pressures.


Donat Santowiak

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Reply #24 on: August 12, 2018, 04:16:14 pm
With no formal mechanical or motor engineering qualifications my views on how things work on motorcycles are either seat of the pants or self concluded. And hence may be way off the real science of what actually happens. Given all this, if my bicycle tyres run on 60psi ther ride is tolerable but at 100psi it jumps around like a wild bronco. This is because it has no springs or dampening. So how can a 30psi tyre pressure on my CGT not affect the suspension who's job it is to manage the extra forces. Given that apparently it is designed to work at 20psi (30% less). I rest my case.
From Victoria Australia
Honda cbr 600rr Repsol Edition
Moto Guzzi V7
Excelsior Universal 1947


General_Apathy

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Reply #25 on: August 12, 2018, 04:53:23 pm
With no formal mechanical or motor engineering qualifications my views on how things work on motorcycles are either seat of the pants or self concluded. And hence may be way off the real science of what actually happens. Given all this, if my bicycle tyres run on 60psi ther ride is tolerable but at 100psi it jumps around like a wild bronco. This is because it has no springs or dampening. So how can a 30psi tyre pressure on my CGT not affect the suspension who's job it is to manage the extra forces. Given that apparently it is designed to work at 20psi (30% less). I rest my case.
So are you running 20 front and 30 rear as per the manual then on your GT? How does your bike feel mid corner at speed? Does it feel planted compared to other bikes you have ridden? Wondering if it may be down to riding style maybe? Just to be clear, I am not talking about knee down, pegs scraping speed here. I am talking about out for a ride, flowing bend swinging kind of speed.
« Last Edit: August 12, 2018, 05:02:36 pm by General_Apathy »


Paul_42

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Reply #26 on: August 12, 2018, 05:22:45 pm
With no formal mechanical or motor engineering qualifications my views on how things work on motorcycles are either seat of the pants or self concluded. And hence may be way off the real science of what actually happens. Given all this, if my bicycle tyres run on 60psi ther ride is tolerable but at 100psi it jumps around like a wild bronco. This is because it has no springs or dampening. So how can a 30psi tyre pressure on my CGT not affect the suspension who's job it is to manage the extra forces. Given that apparently it is designed to work at 20psi (30% less). I rest my case.
How does the GT compare to a pushy?? Go off the book then if you are more comfortable to go off information that's designed to cope with 3rd world roads and 10 up on the one machine. As already stated. The book is incorrect and was written to cover up frame shortcomings. There is a wealth of PRACTICAL hands on knowledge. I may have read into your post the wrong way (which i'm hoping i have) .Guys have given first hand experience including myself on setting up the bike to getting it to handle around bends.( Fark, i better not mention ive inverted my rear shocks then. There will be an Indian exorcist knocking at my door) If your not willing to take on board the R&D that's been done real time on real roads by real owners that love our bikes to death then follow the book, stay at your 20 psi and please dont whine about the bike wanting to throw you off mid corner.
Heres a snip from Putty road with the mods apart from fork oil replacement. Running 32/30 chasing down (trying to) a mate on his firestorm.
https://www.youtube.com/watch?v=PtNaqhQHKYc&t=388s


gizzo

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Reply #27 on: August 12, 2018, 06:56:38 pm
First off, the suspension wasn't designed to work with a 20psi tyre.  It was designed to cope with a variety of surfaces with a reasonably diverse range of loads on it.  It's not a clever fork. It just gets the job done.  Even if it were made for a 20psi front, once you went to a different tyre, you're out of spec again, because all the tyre carcasses are not the same.
Second,  what Paul said. ^
simon from south Australia
Continental GT
Pantah
Monster
DR250
TRX850
DRZ400SM


gizzo

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Reply #28 on: August 12, 2018, 07:05:12 pm
Nice ride, Paul. I was under the impression the Nasho is cop and motor home infested. Looks OK on that day 😎
simon from south Australia
Continental GT
Pantah
Monster
DR250
TRX850
DRZ400SM


Paul_42

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Reply #29 on: August 13, 2018, 08:13:05 am
Hi mate. That one was Putty rd chasing stevevtec. 8)