TimXX Posted July 5, 2003 Share Posted July 5, 2003 It seems that almost every bike uses 120/70-17 in front and 180/55-17 rears. This includes [because most people on this site are Americans, I will use lbs and psi instead of kg and bar :wink: ] [i did use cc instead of cubic inches,but Americans are gradually understanding metric :cool: ]: 350lb 600cc bikes, our own 500 lb Blackbirds, and even BMW K1200GTs that weigh 635lbs + can carry 2 passengers, saddle bags and a trunk for a total weight of about 1200lbs. It seems that the tire pressure recommendations don’t seem to cover the weight variations. If I ride my Blackbird [+tank bag and 2 saddle bags for a total weight of about 855lbs] with the recommended pressure of 42psi, what do I put in the tires when I ride 2 up and carry a total of 1015lbs? What is the safe weight carrying capacity of the 120fr and 180rr tires and at what pressure? What is the maximum capacity of each of these tires, and what is the max. pressure they will take safely? Also- how fast can you go safely without the tires failing? What happens to handling with these tires and different weights and ptressures? Are there any sites that show testing with these tires? All info [and even a few wise ass remarks] is appreciated. TimXX Quote Link to comment Share on other sites More sharing options...
mickcbr1100 Posted July 5, 2003 Share Posted July 5, 2003 If you read the bikes owners manual it answers your basics questions, thats if one came with your bike- 1. Combined weight of rider/pillion/luggage and all accessories should not exceed 185kg/411 lbs 2. recommended tyre pressures are the same for solo and two up riding at 42 lbs Every tyre made is marked with its properties including its max pressure and speed rating, in our case its a Z rated tyre we need which is good for bikes capable of 180mph (the Z bits right I'm not sure of the exact max speed though) If the tyre is a recommended fitment to the Blackbird then it will be capable of taking up to the maximum load given in the owners manual. That said people experiment to find the ideal tyre pressure for the use of the bike e.g. drop a few PSI for track, put a few in for luggage but some tyres are extremely pressure sensitive and just a couple of pounds either way can alter it tremendously making it an evil handling bitch. You've got to pick your tyre then get suggestions from people with the same choice as to the ideal settings and start from there really as tyres are only part of the equation, whats good for them may not suit you, everyone rides different. Quote Link to comment Share on other sites More sharing options...
mickcbr1100 Posted July 5, 2003 Share Posted July 5, 2003 Here you go, this explains the tyre sidewall codes --------------------------------------------------------------------------------Decoding all that information on the sidewall It's confusing isn't it? All numbers, letters, symbols, mysterious codes. Actually, most of that information is surplus to what you need to know. So here's the important stuff: Key Description A Manufacturers or brand name, and commercial name or identity. B and J Tyre size, construction and speed rating designations. Tubeless designates a tyre which requires no inner tube. See tyre sizes and speed ratings below. C Denotes type of tyre construction. D M&S denotes a tyre designed for mud and snow. Reinforced marking only where applicable. E Load and pressure marking requirement (not applicable in the UK). These go from a load index of 50 (190kg) up to an index of 169 (5800kg). F ECE (not EEC) type approval mark and number. G North American Dept of Transport compliance symbols and identification numbers. H Country of manufacture. -------------------------------------------------------------------------------- Tyre Speed RatingsTyre speed ratings are a safety factor based on the highest speed acceptable for use over sustained periods of that particular tyre design/compound. R - 170km/h S - 180 T - 190 U - 200 H - 210 V - 240 W - 270 Y - 300 Z - over 240km/h, generally a road/racing tyre. Quote Link to comment Share on other sites More sharing options...
Involute Posted July 5, 2003 Share Posted July 5, 2003 Tim ol buddy...............you must be bored. Go find some online porn and relax a bit ya maniac. :boobies: Quote Link to comment Share on other sites More sharing options...
TimXX Posted July 6, 2003 Author Share Posted July 6, 2003 You're right Scot- I must be. However it still amazes me that bikes between 350 and 650lbs use the same tire. Also, if Mick is right that I get a max of 411lbs for rider and gear, what does that mean for the BMW 1200GT- do they get only 261lbs for rider, pillion, saddle bags and trunk? And the GT has 130hp and is supposed to cruise at 130mph with everyone on. Anyway- how much pressure will our tires [or tyres] take safely? TimXX BTW: tomorrow I am racing my car in Solo2. It is easy to set tire pressures here because I set it to 40fr and 38rr, mark the treads with chalk to the sidewall and then check where it wears to after a lap. Then I play with pressures [usually reducing them in stages] and shock damping to get the over/understeer balance I want. In any case, I never have to worry about carrying too much weight for the tires. Quote Link to comment Share on other sites More sharing options...
bbirdxx2000 Posted July 6, 2003 Share Posted July 6, 2003 How much tire pressure can our bikes run safely :?: I may be able to answer this :wink: Met my buddy on his 02 Busa in Pitts Pa on my way to W.V. :cool: , After dinner he pulls into a gas station and put some air in his rear tire, (tire still hot), just held the air nozzle on for a few seconds thinking only a few pounds went In :wink: . After running about 20 miles of twisties we stopped and said lets slab it to the Hotel (In W.V.). we also decided to switch bikes. Looking down on his busa speedo doing 110 thinking I was doing 80 or 90 :grin: :grin: . Now to your question :cool: . the next morning he checked his rear tire pressure it was 50 Lbs :shock: :shock: , I said HOLY SHIT, 50 Lbs at 110 MPH at about 85 degrees surprised it did not blow :???: I hope this helps Harry Quote Link to comment Share on other sites More sharing options...
Pete in PA Posted July 6, 2003 Share Posted July 6, 2003 I agree, this has been bothering me since owning this bike. My last few bikes had a PSI range front and rear for the load. Pass. or no pass. This is my first bike with this speed capability though and I think thats why they want max. PSI. I'm trying to figure the right PSI for tire mileage, torn between keeping the tires cool/high press. and warm but more tire on the road. Quote Link to comment Share on other sites More sharing options...
bbirdxx2000 Posted July 6, 2003 Share Posted July 6, 2003 Pete What I do is go by the outside temp :wink: , If its going to be 70 or higher I run max cause the temp on the ground will keep the tire's warm :cool: , on a cool day I run a few pound less, on a cold day under 50 I may run 35 front and 38 rear :wink: On my trip in W.V. where we were in the mid 90's (way to hot for me but had a great time anyway) had the tires on max (42/42) during one of many water breaks felt the tire's, they were hot and spongie :cool: :cool: , never once broke loose :cool: I have the Avons 45/46, best tire period :shock: Harry Quote Link to comment Share on other sites More sharing options...
Pete in PA Posted July 6, 2003 Share Posted July 6, 2003 Harry, how many miles you got on the 46 rear? I've got 3000 miles and down to2 1/2 32nds. on my 46. Very disapointed with wear. 020 'stone got 5500 miles and no complaints with handleing. Front cupped though. :sad: I'm haveing a hard time understanding this mileage. Avon has the 49/50 for a sport tire, I geuss I would wear it out at 1500 miles. Your hardest tire should REALLY get mileage, especially if you have Supersport, Sport, and sport touring. Michelin HAD the 100X. Some reports gave it 13K miles! :shock: Before I was ready to try it it's updated to the road. Less mileage. I GIVE UP!!! :evil: :evil: :evil: I talked to a guy at swmototires.com and he said put a tire on your roof and let the sun outgas it and it will get better mileage. Heard of this in the 60's am considering doing it. Bake at 95F for three days then turn over. :razz: Quote Link to comment Share on other sites More sharing options...
bbirdxx2000 Posted July 6, 2003 Share Posted July 6, 2003 Pete Just chexked my AV46 at 3800 miles. 3/32 or 2mm :cool: , I am running 42 Lbs :grin: , you may have gotten a bad tire :sad: , It does happen :wink: , DO NOT, repeat DO NOT put your tire on the roof, this could effect the tire structure, or heat cycle front should last over 10,000 miles. :shock: :shock: . I know your pissed based on the Imfo from the Board members :wink: Either you got a bad tire or about 15 guys on this board purposly lied and bullshitted :wink: . I will put my money on the 1st choice Now go order another rear and run 42 lbs and stop doing those wheelies and burnouts :wink: :wink: Cheer-up :cool: Harry Quote Link to comment Share on other sites More sharing options...
Involute Posted July 6, 2003 Share Posted July 6, 2003 Hey Tim, if you get a chance post some pics of your race. You piqued (sp?) my interest in Cody. Quote Link to comment Share on other sites More sharing options...
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