Divvy_Rider Posted January 16, 2005 Share Posted January 16, 2005 Hi. I'm a bit confused about what tyre presure i should be using, .. the tyres on my bike are still the original ones that were on the bike from new ( it's only done just over 6k miles, Although i'm the 3rd owner ) .. I don't know what make they are, probably some cheepo make, it doesn't say anything on them as to what presure to use, but in the owners hand book it says 28/32 but i have read on other websites that there is now a general standard of 36/42, Do you use the presure that the owners manual says or go by the brand of tyre, ( or a mix of both) .. What did those of you that have /had a divvy use (pressure wise). Sorry about all of the questions, maybe this is why the bike wobbles when riding over painted lines (lack of presure) ? and cornering feels dodgy.. i should be getting new bt45's when i get time to, .. but i know the psi for them (for a divvy) is 33/40 ... anyway thanks for any help. Link to comment Share on other sites More sharing options...
liquidcooled Posted January 16, 2005 Share Posted January 16, 2005 i always put 28/30 in mine mark Link to comment Share on other sites More sharing options...
plain darren Posted January 16, 2005 Share Posted January 16, 2005 Not meaning to bring the thread off course, but i was just thinking, how often should i check my tyre pressure? Just now it occured to me that i've only done it twice since i got my bike, +the service Link to comment Share on other sites More sharing options...
liquidcooled Posted January 16, 2005 Share Posted January 16, 2005 you cant go wrong checking it once a week darren Link to comment Share on other sites More sharing options...
plain darren Posted January 16, 2005 Share Posted January 16, 2005 you cant go wrong checking it once a week darren Ok, cheers Link to comment Share on other sites More sharing options...
Pete Posted January 16, 2005 Share Posted January 16, 2005 Go with the MANUFACTURER pressures from their website not the handbook. Tyres have changed over the years so if you've got an older bike technology has moved on. Divvy 6 I'd go 36/42.....bear in mind Alan's quoted pressures are for dualsport tyres which are always less than pure road. And use a quality footpump of your own not a forecourt machine. Link to comment Share on other sites More sharing options...
Divvy_Rider Posted January 17, 2005 Author Share Posted January 17, 2005 Thanks for the tips guys, Seeing as i'm already using around 28/30 and it feels a bit weird i think i'll give 36/42 a go, ... and i'll get a foot pump tomorrow on my lunch brake, i've been meaning to get one for ages but keep forgeting The same goes for checking the tyre presure, I do it about once every 2 months .. I know .. i know very bad it's the same every week, get up, ride to work in a rush, get home and its dark, .. then its the weekend which i sleep most of away forget to check tyres / clean bike / go shopping .. then it's monday again! Link to comment Share on other sites More sharing options...
RDly Posted January 17, 2005 Share Posted January 17, 2005 I had a Divvy 600 until I decided to go back to RD's full time. My pressures were 32/38 one up. The wiggles over white lines are the first sign of a worn tyre carcass and time to get new rubber. My GPZ600R was also always stable at practically any pressure within reason, but when the tyres got beneath 2mm tread it would be a real pain and near dangerous ! especially over white lines between traffic. Don't forget tyre pressures are influenced by the weight of the rider as well as the machine, you must find the best (and safest) balance for yourself. Spend a Sunday afternoon and a splash of fuel and experiment, it will be the best spent spare time ever KEEF. Link to comment Share on other sites More sharing options...
Divvy_Rider Posted January 17, 2005 Author Share Posted January 17, 2005 Thanks for the info, I put a bit more air in them today, atm its 30/40 .. and does feel a fair bit better, ( i would have put the extra 2 psi in the front but my lunch brake was running out ) As for the tyre its not all that worn tread wise, .. but i think they are getting knackered because my bike is a R reg and it still has the same tyres on it since new ( previous 2 owners were fair weather riders, and only did 4K miles between them ) so they spent alot of time just standing, am i right in thinking that would screw them up just as much as being used daily? .. now if only the roads would stay dry for 1 day Link to comment Share on other sites More sharing options...
Pete Posted January 17, 2005 Share Posted January 17, 2005 I wouldn't run more than 6psi difference between the two tyres. Link to comment Share on other sites More sharing options...
Divvy_Rider Posted January 18, 2005 Author Share Posted January 18, 2005 I wouldn't run more than 6psi difference between the two tyres. im gonna top it up tomorrow, .. but why is that anyway ? Link to comment Share on other sites More sharing options...
Moderator YamaHead Posted January 18, 2005 Moderator Share Posted January 18, 2005 I think 6psi is a safe gap to keep a balanced feel from each end of the bike. Link to comment Share on other sites More sharing options...
Pete Posted January 18, 2005 Share Posted January 18, 2005 As Scott says it's all about balance. Link to comment Share on other sites More sharing options...
Moderator Beezkneez Posted January 18, 2005 Moderator Share Posted January 18, 2005 i check mine on every ride out and set them @ 36/42 (exup 1000) if its trackday time then i drop them to 30/33psi hth Link to comment Share on other sites More sharing options...
Divvy_Rider Posted January 18, 2005 Author Share Posted January 18, 2005 talking about droping you PSI for a track day reminded me of this i found on another fourum. check it out ) "Some general information on tyre pressures from an Avon tyre representative. TYRE pressures are a crucial factor in determining how your bike handles and how quickly you wear your (not exactly cheap) tyres There are lots of myths and misconceptions about what pressures you should run in the wet, on track days or when you’re loaded with luggage Usually you’ll find someone propping up the bar who knows better than the manufacturers’ recommendations. To find out how close they are to being right we talked to a genuine expert – a man who should know tyres if anyone does Leo Smith spent years as chief development tester at Avon tyres. He is now motorcycle product manager. He said: " We probably get asked more about tyre pressures than about any other aspect of a tyre. " There’s so much bad information kicking about that people can’t separate the truth from fiction. " Smith says that is largely the fault of tyre companies themselves. Several years ago, different tyre companies recommended different pressures for different tyres and different bikes. But around 10 years ago, a decision was reached between the companies to standardise pressures so that most bikes can run on the same no matter what tyres they’re on. That standard is 36psi at the front and 42psi at the rear **** There are some exceptions, like 400cc grey imports which run 29psi at the front and 36psi at the rear. Another notable exception is the Kawasaki ZX-12R – which is meant to run 42 front and rear. But if you’ve got a modern mainstream bike, chances are you should be running the 36/42 standard That 42 figure in particular will have a lot of the gentlemen at the bar shaking their heads. But it is not a figure chosen at random. Pressures determine how your tyres deflect. The lower the pressure, the more the tyre will flex. That may make for a comfortable ride when you’re cruising in a straight line, but the tyre will flex too fast at speed and make your bike unstable. The bike will feel vague going into turns and feel like it’s going to tip into the corner suddenly. This is because the tyre isn’t " strong " enough and it’s literally buckling under you. The bike will also feel wallowy through turns and it’ll weave under acceleration. Conversely, if you over-inflate a tyre, the flex will be slower but that will make your bike more stable at high speeds. The ride comfort and the tyre’s ability to absorb shocks will be lost and your wrists and backside will take the brunt of it. The bike will feel so harsh that many people will think they have a suspension problem. Cornering won’t feel as bad as when pressure is too low, but you will again lose feel and feedback from the tyres. For example, if you ride over a stone, an over-inflated tyre cannot absorb it and the tyre breaks contact with the road. Smith says the classic myth about tyre pressures is that you deflate them for wet-weather riding. He says most grip comes from the tyre’s compound and the contact patch – and the shape of the tyre where it contacts the road is everything. Tread patterns stop water from building up under the tyres – which could caused a bike to aquaplane. Smith says: " A good front chucks enough water out of the way to enable the rear to get the power down. If you reduce the tyre pressure, the tread becomes compressed so it can’t clear as much water. " . If anything, Smith recommends you increase the rear tyre by 2-3psi in the wet but leave the front as it is. Another widely held misconception is that the psi recommendations are the maximum the tyre can take. They’re not. The figure only tells at what pressures the tyres were tested at for all-round use. You could actually safely inflate a tyre up to around 50psi if you really wanted to, although it wouldn’t do you much good. But the biggest area for debate has to be track days. If you’ve ever been to one it’s almost certain someone has told you you’ll be best off reducing your tyre pressures. You get more grip that way, they tell you. Smith has radically different advice. You should leave them alone, he says. " Racing tyres are of a totally different construction and stiffness to road tyres so they need less pressure to maintain the carcass shape. That’s where the rumours and bad advice comes from. " If you drop the psi in road tyres you will get more movement in the tread pattern. They will heat up too much and that will eat into tyre wear. You’ll almost certainly ruin a set in a day without gaining any advantage in grip. ". Smith says he’s known people to drop their rear tyre to just 22psi when heading for the track. His advice is to leave your tyres alone, saying a good tyre at standard pressures will give more grip than you need on a track day because you almost certainly won’t be going as fast or for as long as racers. Track surfaces offer much better grip than the road, too – another reason for leaving your tyre pressures the same for the ride to the track as for the ride around it. Many people also ask the experts at Avon if they should increase psi to take pillion passengers. Again there’s no need. The manufacturers’ agreed pressures of 36/42 were arrived at after testing with pillions, luggage, cold tyres and every other combination you could think of. One of the few cases when Smith does recommend you change your pressures is when your tyres wear. A worn tyre has lost a lot of its strength as the shape and flexibility levels have changed. That means it will handle differently to a new tyre. Try increasing the tyres by 2psi when you’re down to around 40 per cent tread depth. It will only make a marginal difference, but it should improve your bike’s handling a bit. You may not have to keep changing your tyre pressures, but you do have to maintain them. Smith recommends that you check them once a week as an absolute minimum but to be extra safe, you should really check them every day because a tyre can change by as much as 3psi on its own just because of changes in the weather. You should always measure your tyre pressures when they are cold. A few bikes are now coming with tyre pressure gauges in their under-saddle tool kits. If you haven’t got one it’s worth buying one. They only cost a few quid and take up about as much room as a pen. Forecourt gauges are notoriously inaccurate. Link to comment Share on other sites More sharing options...
Admin Alex Posted January 19, 2005 Admin Share Posted January 19, 2005 Interesting read there mark Link to comment Share on other sites More sharing options...
Moderator Beezkneez Posted January 19, 2005 Moderator Share Posted January 19, 2005 Interesting read there mark pity its all bollocks though everyone knows that your tyres get a lot hotter on a track than on the road, so the air inside heats and increases in volume therefore increasing in pressure Link to comment Share on other sites More sharing options...
Pete Posted January 19, 2005 Share Posted January 19, 2005 You want Japanese air in your tyres you do! Link to comment Share on other sites More sharing options...
madandy Posted January 19, 2005 Share Posted January 19, 2005 I never knew what pressure to put in mine so i took a guess went out tried it ,it felt hard to turn and rather vague and slidy round the bends so i put more in and arrived at 32 Front and 36 Rear i did put more in but found it a real pain in the wet so i went back and it seems to work. If its a popular machine just go to local bikeshop and they will normally give you a clue Link to comment Share on other sites More sharing options...
Divvy_Rider Posted January 24, 2005 Author Share Posted January 24, 2005 BTW The day after i put more air in my tyres i got to work and saw that i was missing a bar end, That extra pressure must have been to much for it to take. well that or just the normal divvy vibes nevermind, I have a new set on it now, Its a bit worrying tho because those bar ends have a fair length of thread on them, If that can work its way loose what else can / has Oh and BTW it's snowing Bloody weather. Link to comment Share on other sites More sharing options...
Recommended Posts