| stuartyboy |
03-03-08 12:12 AM |
Re: New tyres - read this!
Using tyre warmers on new tyres before going on track is hardly the same scenario as scrubbing in new road tyres on normal roads.
Anyway...this below from Bridgestone's UK tyre guru...I've posted the whole article. See secton on scrubbing in for an explanation of why they need bedded in. Dont shoot the messenger.
Quote:
www.bridgestone-eu.com
Bridgestone UK tyre and fitment advice for FZS600 and FZS1000 owners
I've recently been contacted by a couple of visitors to the Fazer Owners Club site. They had been reading the threads concerning tyres and had become confused about which Bridgestone tyres were best for whatever purpose, and also what the difference is between the BT-020U and the BT-020NT for the FZS1000. So I thought I'd send you the full details on Bridgestone UK's tyres for Fazers, along with a couple of other bits of information your visitors may find useful.
As you probably know, there is more rubbish talked about tyres than anyother motorcycle product - I've lost count of the amount of riders I've spoken to who know more about what makes a bike handle than our development riders, some of whom are former GP riders! Some of the threads that I've read on various sites over the years have left me amazed - some of the claims that owners have made for Brand-X tyres in comparison to Brand-Y tyres go completely against all in-house and independent testing that I have the results of. So I thought I'd try and clear a way through the clutter and give you the definitive, official Bridgestone UK line on our motorcycle rubber for Fazers. If you abide by this information you will have no handling problems, if you listen to the bloke down the pub who thinks he knows better, you will have problems. Trust me when I say that if the information the bloke down the pub gives you differs from this information, he does not understand tyres and how they work.
Choose the correct tyre:
I'll start with the one thing that many riders overlook - just because a tyre is available in the sizes to fit your bike it doesn't necessarily mean that it will suit your bike...not all tyres are suitable for all bikes. For details on this see my comment below about the BT-010 and the FZS1000. The BT010 is the UK's, if not the world's, most popular sports tyre, and if we don't approve it's fitment on the FZS1000 there must be a good reason. The same goes for other tyres in our range - the BT-012SS fast road/track day tyre is too "full-on" for the FSZ1000, the new BT-012 gives more than enough grip for this bike, even for track day use. None of the major tyre manufacturers approve the fitting of their entire range of tyres for every bike, and this stands to reason - why should we expect an extreme-performance tyre to offer its best when fitted to a bike that was developed for general all-round riding? It's more important to choose the tyre that best suits your needs and the bike's purpose. E.g. If you're going
on a European jaunt the BT-020 sports touring tyre would be a better choice than the BT-010 or BT-012 sports tyres. If you use your bike for transport as well as fun the BT-020 would again be the best choice. But if all you use your bike for is fun and the occasional track day you should probably choose the BT-010 or BT-012.
Grip:
Don't worry about the grip available from your tyres. This may not be something you're used to hearing, but grip isn't something you should be worrying about - let us do that for you. The grip level available from the latest sports touring tyres, such as our BT-020, is comparable with full-on sports tyres of just five years ago. So don't worry about grip, we've already got that sorted, concentrate more on what type of tyre suits your purposes, and for that information see above. And don't focus too much on the compound - there's a lot more to how a tyre grips the road than just the compound.
If your tyre slips, don't automatically blame the tyre. Think about where it happened - was the road surface contaminated, was it on a greasy roundabout,was the road surface worn out? If the road surface is not contaminated
modern tyres give plenty of warning before they slide and if you've ignored those warning signs you can't really blame the tyres.
Running tyres in:
Running tyres in takes approximately 100 miles and involves more than simply scrubbing-in the tread surface of the tyre. When tyres come out of the mould they have a smooth surface and to obtain optimum grip levels this smooth surface needs to have it's entire surface scrubbed-in and the best way to achieve this is not to rub the surface with emery paper, but to go for a ride. The first few miles should be spent riding upright so that you have a broad band in the centre that has been scrubbed-in. You can then start increasing your angle of lean while always keeping a portion of the scrubbed-in area in contact with road. Scrubbing-in can be achieved by an experienced rider in as few as 10 miles, but this does not mean that your tyres will be fully run-in. Running tyres in also involves seating the tyre on the wheel, and this is not achieved simply by fitting the tyre to the wheel. Running-in also allows all of the components of the tyre to seat in against one another - by overheating a new tyre you can cause lasting damage that means the tyre may not achieve its optimum mileage. While running-in new tyres you should not subject them to hard acceleration or braking forces.
One final point: Contrary to popular opinion BRIDGESTONE DOES NOT USE RELEASING AGENT ON ITS MOTORCYCLE TYRES. New tyres feel slippery because they are very smooth when they come out of the mould - see above. Riders who crash on new tyres often try to blame releasing agent for the accident, but if we don't use releasing agent how can this be? Actually, very few people crash on new tyres, most riders are conscientious when running-in their new tyres, but the vast majority of those who do crash on new tyres usually admit to leaning their bike over at low speeds - junctions and slow roundabouts are the most popular places. Think about it: when travelling at low speed and leaning over there is very little force acting upon a tyre to help it grip the road. Add in a brand new, smooth tread surface and you have a recipe for a sudden slide.
Mixing tyres:
There is absolutely no point in mixing tyres on the same bike. e.g. BT-010 front with BT-020 rear.
In the case of FZS600 owners, many did it because the 110/70ZR17 BT-020 was not available until early 2003 and if they wanted to use a BT-020 sports touring tyre on the rear they had no other choice. The problem with fitting this mixed pair on this particular bike is that stability is not as good as with a matched pair of BT-010s or BT-020s. And this just highlights the possible pitfalls when fitting mixed tyres on any bike - if one type of tyre is designed as a smooth handling, totally neutral sports touring tyre and the other is designed as a rapid steering, ultra responsive tyre, why should we expect them to work together? If a bike doesn't handle when fitting mixed tyres it's not going to be the tyre's fault.
But the main reason why riders fit mixed tyres is to supposedly benefit from having a grippier tyre on the front while getting sensible mileage from the rear tyre. Well...we kinda know this. We are, after all, the biggest tyre manufacturer in the world and we really do know what we're doing. We know that the demands placed on a front tyre are different to the requirements of the rear tyre, and that is why the compound of our front tyres is different to the compounds of our rear tyres. So the front BT-020 compound is different to the rear BT-020 compound and the front BT-010 compound is different to the rear BT-010 compound, etc., etc., all the way through our various ranges of tyres. Now that you have this information you can see that it's pointless mixing tyres, Bridgestone is already giving you what you want when you fit a matched pair of our tyres.
Punctures:
Bridgestone approves the repair of it's motorcycle tyres in conjunction with BS159f, which precludes the repair of punctures in Z-rated radial tyres. Punctures are unfortunate and it doesn't help when the vast majority happen in the more expensive rear tyre. This is usually because the puncturing object, which was lying in the road, is kicked up by the front tyre into the path of the rear tyre. I know that it upsets a few riders that Bridgestone doesn't approve the repair of our tyres, but we have valid reasons for this. As soon as an object penetrates the tyre a steady progression of road contaminants starts to enter the hole. By road contaminants I mean diesel, oil, chemicals dropped by farm vehicle and trucks...all of the bad stuff that can seriously effect the construction of the tyre. If, as is likely, these contaminants settle between the tread strip and the carcass, a process called delamination can start. Delamination is the separation of the tread strip from the carcass and the first visible sign is a bulge in the tread. If this bulge is not noticed the delamination process will continue until a catastrophic failure occurs. Unless you're very skilled or very lucky this usually involves crashing the bike as the tyre disintegrates.
If you notice during your regular tyre checks that the tyre has a penetrating object and you decide to have it repaired, do you know how long the object has been in the tyre? If the delamination process has started, plugging the tyre will not prevent it continuing.
If you get a puncture and the tyre gradually deflates as you are riding, the chances are that the tyre is ruined beyond repair by the time the bikes poor handling alerts you to the situation. An under inflated tyre runs very hot and this can lead to invisible internal damage. If the tyre deflates fast enough so that by the time you bring the bike to a standstill the tyre is flat, the sidewalls will have come under such strain that the heat generated will have ruined the tyre.
But just because Bridgestone doesn't approve the repair of our Z-rated tyres, it does not prevent you having your tyre repaired by your local fitter. If you are satisfied that the repair that they make will be good enough then that is up to you. But I have to make it clear that if the tyre has been repaired, Bridgestone will not guarantee any further claim you may make on the tyre and neither will we guarantee the quality of the repair.
Personally speaking I would never repair any motorcycle tyre...my life is worth more than the cost of a new tyre.
Bridgestone Approved Fitments
FZS1000 Fazer
This is the bike that's causing most confusion at the moment, and that confusion surrounds the BT-020 tyre. Firstly I'll give you all of ourapproved options for the bike then I'll explain more about them.
120/70ZR17 BT-012
180/55ZR17 BT-012
Recommended road pressures for the BT-012 are 36psi front and rear.
or
120/70ZR17 BT-020U
180/55ZR17 BT-020NT (U)
Recommended road pressures for this pair are 36psi front and 42psi rear for general riding, which includes solo commuting, motorway work, pillion and/or luggage. For most solo uses these pressures are absolutely fine, but if you're off to have some sporty solo Sunday fun you can reduce them to 35psi front and 36psi rear.
When we were developing our original equipment (OE) tyres for the FZS1000 we quickly discovered that a steel belt rear tyre construction was the only one that offered the high-speed stability we were looking for - at that time all of our tyres used a Kevlar belt construction. The steel belt rear tyre that we developed for the FZS1000 became known as the BT-020U (same designation for front and rear tyres). Because of the performance advantages the rear BT-020U gave us, we decided to test the tyre on a wide variety of bikes that had "standard" BT-020 approval. In every case the BT-020U outperformed the "standard" tyre. Because of this we took the decision to stop production of the "standard" BT-020 and to make the BT-020U the new "standard" tyre. At the same time a decision was taken to use the new steel belt construction in four other rear BT-020 sizes so that owners of bikes like R1150RS, GSF600 Bandit and VFR750 could also benefit from the performance gains - all of these sizes now carry the suffix letter U to indicate that they are constructed with our new steel belt. Because we now had a range of five
BT-020U steel belt rear tyres we decided to re-name them BT-020NT (New Technology), and this is where the confusion arises. The BT-020U rear and BT-020NT rear are the same tyre - BT-020NT appears on the label and BT-020R Radial U appears on the sidewall. The BT-020NT is the tyre that everyone is currently asking for because it has recently appeared in MCN and the monthly magazines, gaining rave reviews from every journalist who attended the launch on the roads of Sardinia. I know, I know...with a little more forethought we could have made it a little easier to understand, but when we initially developed the BT-020U for the FZS1000 we could never have guessed that it would perform so well on such a wide range of other bikes.
The NT name only applies to the rear tyres, the range of BT-020 front tyres remain unchanged. So the front tyre for the FZS1000 is still called the BT-020U and it differs from the "standard" front BT-020 by being 4mm narrower and having a slightly sharper crown radius that enables the tyre (and so the bike) steer and turn more nimbly.
You will notice that the BT-010 is not approved for use on the FZS1000 and there's a very good reason for this. The BT-010 uses a Kevlar construction and does not give us the high-speed stability we are looking for. I am not saying that the BT-010 gives poor stability when fitted on the FZS1000, it's just that it doesn't give the high level of stability we require. The BT-012 that is approved for the FZS1000 uses a steel belt construction and so gives the stability we require. The BT-012 is our new performance sport road tyre and was launched at the same time as the BT-020NT earlier this year. It runs alongside the BT-010 in our line-up, but is not interchangeable with the BT-010. And neither is it to be confused with the BT-012SS fast road/track day tyre that was launched in 2002. Anyone looking for a high performance
tyre for the FZS1000 and who would normally choose the BT-010 should go for the BT-012. The BT-012 builds on the performance of the BT-010 by having increased high-speed stability in straights and corners as well as having a lighter and quicker steering response.
Thanks for allowing me to take up your time.
Bryn Phillips
Bridgestone Motorcycle Technical
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