hi,
there were pics posted on here awhile back of 15 inch car tires that exploded when they were being installed, i've seen those pics many times, didn't save them, now i need them to show a dummy that doesn't believe what can happen when you use 100+ lbs. of air pressure to seat them, tried the search function for a hour, can't locate them, if someone can direct me to them, i would appreciate it. thank you
moonlite - 9/19/2010 9:23 AM
hi,
there were pics posted on here awhile back of 15 inch car tires that exploded when they were being installed, i've seen those pics many times, didn't save them, now i need them to show a dummy that doesn't believe what can happen when you use 100+ lbs. of air pressure to seat them, tried the search function for a hour, can't locate them, if someone can direct me to them, i would appreciate it. thank you
I was wondering about that. I noticed on the Darkside site that they speak of very high pressures needed to seat a car tire on a motorcycle rim. I've asked various people and have yet to receive an answer as to why this is necessary.
Does that mean that the tire must be forced onto the bike rim since the designs are different? That would be a consideraton if you were to need a tire somewhere out on the road....I guess you might have a hard time getting the car tire off of the rim.
100 psi is quite a bit.....
I am no expert on this subject as most of the darksiders seem to be. I have taken a lot of slack over the years on this subject. I worked in several motorcycle shops over the years and I one of my personal policies was I will not mount a "car tire" on a motorcycle rim. This is the reason the bead construction on a car tire is different than a motorcycle bead the car rim has a flatter surface on the beaded area the motorcycle bead area is on an angle. Car tires have no real lateral force when corning side wall flex some and downward pressure remains thus a flatter area. When you apply lateral or side force corning a motocycle your angle of the tire changes we have stiffer and shorter sidewalls on the tire, this is why we now need an angle surface to transfer the the force created. I'm sorry I can not put this in more technical terms just think of it this way you can push on a 2 x4 straight up and down all day but turn it on a slight angle and it will kick out easy if you cut it on a sight angle and then try to push it stays put. There was a fellow back in the '70 that had made a tire or rim lathe to fix this problem he could take your rim and turn it down some what making it flatter thus helping it hold a car tire. The pictures you speak of have failed because of this angle you need more pressure to stretch the steel bead of the tire up that angle, in some cases it will fracture the internal steal wires that form the bead (the only thing holding it to the rim) and then the rubber will split failure is not will it but when you are literal forcing the tire depending on the rim manufacture up and 1/8" more than it was made for to get it to seat on the bead lock. Now this is why you need all the pressure to inflate and set the tire. Many have been riding with car tires and never had a failure thank heaven but that is the when part. As a side note you may look at it this way too back in the day some street cars and dragsters tried to run motorcycle tires on the front since they were smaller (I tried running them on my VW) if you remember they were always flat and you had an airtank with you. Why as long as you went straight you were OK but when you turned they would roll off the rim the angled motor cycle tire and the flat car rim there was not enough sealing surface you could use a tube with greater air pressure to keep it on but then you had just as much weight as the car tire you were replacing. Please just go out and look at an old rim of each or look at the bead area of a car tire vs a motorcycle one. Please remember I am no expert I usually don't inject my opinions on others, I am not telling anyone out there to do or not to do this. I should add this I know sidecar bikes don't lean in to corners so the lateral force is not needed to keep the tire on yes the behavior of our sidecars is like that of a car in this instance and car tires should work this is true if it was not still for the fact you have to stretch those little steal-wires in that tire up to or past the breaking point trying to run them up that angled surface. I believe if you want to run a car tire on your hack just use car rims and you will have no problems.
for your consideration:
moose
moose - 9/20/2010 11:11 AM
I am no expert on this subject as most of the darksiders seem to be. I have taken a lot of slack over the years on this subject. I worked in several motorcycle shops over the years and I one of my personal policies was I will not mount a "car tire" on a motorcycle rim. This is the reason the bead construction on a car tire is different than a motorcycle bead the car rim has a flatter surface on the beaded area the motorcycle bead area is on an angle. Car tires have no real lateral force when corning side wall flex some and downward pressure remains thus a flatter area. When you apply lateral or side force corning a motocycle your angle of the tire changes we have stiffer and shorter sidewalls on the tire, this is why we now need an angle surface to transfer the the force created. I'm sorry I can not put this in more technical terms just think of it this way you can push on a 2 x4 straight up and down all day but turn it on a slight angle and it will kick out easy if you cut it on a sight angle and then try to push it stays put. There was a fellow back in the '70 that had made a tire or rim lathe to fix this problem he could take your rim and turn it down some what making it flatter thus helping it hold a car tire. The pictures you speak of have failed because of this angle you need more pressure to stretch the steel bead of the tire up that angle, in some cases it will fracture the internal steal wires that form the bead (the only thing holding it to the rim) and then the rubber will split failure is not will it but when you are literal forcing the tire depending on the rim manufacture up and 1/8" more than it was made for to get it to seat on the bead lock. Now this is why you need all the pressure to inflate and set the tire. Many have been riding with car tires and never had a failure thank heaven but that is the when part. As a side note you may look at it this way too back in the day some street cars and dragsters tried to run motorcycle tires on the front since they were smaller (I tried running them on my VW) if you remember they were always flat and you had an airtank with you. Why as long as you went straight you were OK but when you turned they would roll off the rim the angled motor cycle tire and the flat car rim there was not enough sealing surface you could use a tube with greater air pressure to keep it on but then you had just as much weight as the car tire you were replacing. Please just go out and look at an old rim of each or look at the bead area of a car tire vs a motorcycle one. Please remember I am no expert I usually don't inject my opinions on others, I am not telling anyone out there to do or not to do this. I should add this I know sidecar bikes don't lean in to corners so the lateral force is not needed to keep the tire on yes the behavior of our sidecars is like that of a car in this instance and car tires should work this is true if it was not still for the fact you have to stretch those little steal-wires in that tire up to or past the breaking point trying to run them up that angled surface. I believe if you want to run a car tire on your hack just use car rims and you will have no problems.
for your consideration:
moose
thank you for the reply, first let me apologize for bringing up a subject that has been beaten to death, i will not comment on anything i don't have first hand knowledge of, i did tons of research and experiments on this subject, the rim i am referring to specifically is the gl 1100,gl1200, gl1500 goldwing rim, the problems and situations you described are exactly what i'm talking about, my conclusions are the same as yours, the gl1800 is a different animal, i have personally mounted c/t's on the 1800 rim with no difficulty and have no concerns about running one, if ya look at the bead area of the 1800 rim you will see that it is totally different from the earlier models and accepts a car tire without any problems, i remember the fellow you referred to that use to show up at various meets and machine your rim to accept the car tire, i believe i last saw him in the late '70's or early '80's at laconia n.h.
what brought on the discussion on another forum i visit is that a few members there have tried this new tire they have found that supposedly goes on the stock gl1500 rim, but they all report that mounting it is a real bitch and then it takes 100+ lbs of air pressure to get it to seat, same as before, just trying to explain to them that this is old news in the sidecar world, i run a car tire on my 1500 but it is mounted on a car rim that has been adapted to the 1500 hub, you stated everything so much better than i, would you mind if i post it on a 2wheel forum? still looking for the pics of the tire failures, thanks a lot.
mark stevens, if you read this please tell us your experiance with mounting your new tire, any difficulties? mark is in the land of oz and has just went this route after i told him what i had heard about this new tire size, kinda sorry i told him, especially if it is as hard to mount as i am now being told'
once again moose, a big thanks
gnm109 - 9/19/2010 10:11 PM
moonlite - 9/19/2010 9:23 AM
hi,
there were pics posted on here awhile back of 15 inch car tires that exploded when they were being installed, i've seen those pics many times, didn't save them, now i need them to show a dummy that doesn't believe what can happen when you use 100+ lbs. of air pressure to seat them, tried the search function for a hour, can't locate them, if someone can direct me to them, i would appreciate it. thank youI was wondering about that. I noticed on the Darkside site that they speak of very high pressures needed to seat a car tire on a motorcycle rim. I've asked various people and have yet to receive an answer as to why this is necessary.
Does that mean that the tire must be forced onto the bike rim since the designs are different? That would be a consideraton if you were to need a tire somewhere out on the road....I guess you might have a hard time getting the car tire off of the rim.
100 psi is quite a bit.....
thanks for the reply, i too read various darksider forums, the rim i am talking about is the gl1500 rim, the gl 1800 rim accepts the car tire without any problems and i have no problem with running one, the earlier model g/w rims are a animal of a different color, i' ve read enough of your posts to know you are knowledgeable about h-d and that you probably remember when they came from the factory with car tires on them, i think it was about the time the wheel was invented(LOL), again thanks
I don't know about GW rims, but I can tell you I have run a car tire on the back of my Valkyrie for years. It does not require any more air pressure to seat it than mounting a tire onto a car rim.
I've run it as 2 wheeler and with the sidecar on. No issues at all. Great improvement in traction and tire life. Again, my experience is limited to those 16" Valk rear rims.
On the maintenance side, the extra life means I pull the wheel to do rear drive service before the tire needs replacing. I also suspect that with the extra rubber on the ground (not to mention a sidecar hanging off the bike), the lateral stresses may shorten bearing life and have other consequences, but nothing is really showing that at 35k miles.
Those pics were soem I posted in various places. I think they actually were sent to me by Hal Kendall who had done alot of research on the issues related to cars tires years back. As far as rim sizes go the 15" rims are the bad boy as the 15" car tire bead diameters are smaller than the bike tire bead diameters in 15". The other common size rim diameters are very very close and no issues should present themeselves related to bead diameters....however....the bead design argument is seemingly a valid one although we do not seem to see any issues with car tires becoming unseated on the cycle rims due to lateral loades imposed on them. The exception I am aware of was on a very wide tired HP outfit where the bike tires were switched out due to a concern about rolloing of fhte bead due to th esheer cornering forces that this type of rig can generate and the idea of running less than recomended air pressure....THAT was a different animal that your everyday sidecar outfit.
It is IMPORTANT to realize that if anyone decided to go this route you are still 'outside the box' so to peak and must be willing to accept whatever results you end up with yourself. Of course sidecar folks are pretty much outside the box in many areas aren't they?
In today's world it seems less people are willing to take responsibility for their own actions. You run 'em or you run em not ...your call. All disclaimers apply 🙂
That guy that turned down rims at rallies years ago , at least the one I met, was only making 15" cycle rims smaller to accept 15 car tires. Quite a setup ...lol. Wonder if he ended up getting sued or just made his million and is living in the islands somewhere?
claude #3563 - 9/22/2010 5:11 AM
Those pics were soem I posted in various places. I think they actually were sent to me by Hal Kendall who had done alot of research on the issues related to cars tires years back. As far as rim sizes go the 15" rims are the bad boy as the 15" car tire bead diameters are smaller than the bike tire bead diameters in 15". The other common size rim diameters are very very close and no issues should present themeselves related to bead diameters....however....the bead design argument is seemingly a valid one although we do not seem to see any issues with car tires becoming unseated on the cycle rims due to lateral loades imposed on them. The exception I am aware of was on a very wide tired HP outfit where the bike tires were switched out due to a concern about rolloing of fhte bead due to th esheer cornering forces that this type of rig can generate and the idea of running less than recomended air pressure....THAT was a different animal that your everyday sidecar outfit.
It is IMPORTANT to realize that if anyone decided to go this route you are still 'outside the box' so to peak and must be willing to accept whatever results you end up with yourself. Of course sidecar folks are pretty much outside the box in many areas aren't they?
In today's world it seems less people are willing to take responsibility for their own actions. You run 'em or you run em not ...your call. All disclaimers apply 🙂
That guy that turned down rims at rallies years ago , at least the one I met, was only making 15" cycle rims smaller to accept 15 car tires. Quite a setup ...lol. Wonder if he ended up getting sued or just made his million and is living in the islands somewhere?
Interesting points you make here, Claude. While I sympathize with the motorcyclist's desire to get more mileage, I can also see the design problems with changing to a tire that wasn't designed for a motorcycle bead.
It's one thing to use a car tire on a rim that is close. As far as modifying existing wheels to fit car tires, something like that is beyond the pale. If an accident were later to happen and the investigation showed that the design of the modified rim was in any way responsible, the liability would be limitless.
I'm not against better mileage, it's just that, as you say, whenever you use a car tire on a motorcycle, you should be willing to accept what comes, including the higher mileage.
I mounted a 16" Federal tire on my GL1500 rim last spring with no problem. Took about 60 to 65 PSI to seat the bead which is not much more that a lot of touring tires require to seat them. It is still early and the jury is still out, but so far I have had no problems with the tire.
I was of the impression that the high pressures were only needed to mount a car tire to a 15 inch rim. I have mounted three of them now using only a set of Motion Pro spoons, an Ancra ratchet strap, and a 2 horse compressor. All of mine, however, were on 16 inch Honda rims.
G'Day Moonlite and others
Your correct in saying that you need more pressure to seat the cat tyre on the goldwing rim. The Guy that mounted mine used heaps of soap and seated ok. He used 75-80psi to get it seated.
I am a little concerned about the wires stretching in the beads that I have just read and will keep a close eye on things.
Having said that I love my tyre.
I have never ran a motorcycle tyre on the back as a vintage car tyre was fitted when I purchased it. It was an Excellsior 5.00/ 525/16. The dia was far too large and outfit lugged in every gear. Was a PITA to get the thing moving esspecialy with a trailer. If you were on a hill,forget it. I was always on the lookout for a 15" inch wheel and when Moonlite put me onto 175/60R/16 tyres. Thanks Moonlite I dont regret it. Outfit runs smother better economy, can leave the thing in OD while going up a hill with cruise control on. Dont know how its going to wear but has got to be better than the 8,000klms that I used to get out of the Excellsior.
Your decision if you mount one or not But I love mine and have 6 more in the shed just incase I need them as they are not easy to get here in Aus.
PS any Aussies interested should contact Josh at National Tyre Wholesalers in Canbera as they are getting rid of their stock (175/60R/16 Federal Formoza) $75 and $11 delivery. may be even cheaper now.
Mark
mark stevens2 - 10/2/2010 8:29 AM
G'Day Moonlite and others
Your correct in saying that you need more pressure to seat the cat tyre on the goldwing rim. The Guy that mounted mine used heaps of soap and seated ok. He used 75-80psi to get it seated.
I am a little concerned about the wires stretching in the beads that I have just read and will keep a close eye on things.
Having said that I love my tyre.
I have never ran a motorcycle tyre on the back as a vintage car tyre was fitted when I purchased it. It was an Excellsior 5.00/ 525/16. The dia was far too large and outfit lugged in every gear. Was a PITA to get the thing moving esspecialy with a trailer. If you were on a hill,forget it. I was always on the lookout for a 15" inch wheel and when Moonlite put me onto 175/60R/16 tyres. Thanks Moonlite I dont regret it. Outfit runs smother better economy, can leave the thing in OD while going up a hill with cruise control on. Dont know how its going to wear but has got to be better than the 8,000klms that I used to get out of the Excellsior.
Your decision if you mount one or not But I love mine and have 6 more in the shed just incase I need them as they are not easy to get here in Aus.
PS any Aussies interested should contact Josh at National Tyre Wholesalers in Canbera as they are getting rid of their stock (175/60R/16 Federal Formoza) $75 and $11 delivery. may be even cheaper now.
Mark
good news pal, i hope ya never have any problems and glad i could help, the reason i started this discussion was that on a wing site i visit a few were saying how much problems they were having mounting the tire and the great amount of pressure needed to get it to seat, i stararted having regrets about telling ya about it, glad ya didn't have the same problems, i should have just considered the source, everyone knows the cheapest thing on a wing is the owner(LOL) probably didn't want to spring for the cost of the soap(lol), ride safe
mark stevens2 "I was always on the lookout for a 15" inch wheel and when Moonlite put me onto 175/60R/16 tyres. " What wheel do you use 15" or 16"? I think you have 1500 godwing. 5.00/ 525/16 is correct size for godwing. Standart 160/80-16 is 26" and 5.00/ 525/16 is 26.25" 0.9%bigger so why are you saying "dia was far too large and outfit lugged in every gear" 175/60-16 24.5" - 6% smaller.
G'Day Vlad.
I have the 16" wheel and the new tyre is much smaller in dia than the old Excelsior. I dont know what the Dia of an original motorcycle tyre was because I bought this outfit with the Excelsior on it. I figure the exculsior was a larger dia because the tread wore away the rubber cover on the regulator box thingo or inner guard rubber/ Not really sure what it was. All I know is bike performs much better with the 175/60r/16. At 100klm/hr in OD, tacho used to sit on 2500rpm, now it sits on 2750rpm not a great deal of differance but sure notice it when riding through hills and overtaking. The center stand scrapes on driveways when riding in but it used to do that anyway with old tyre, if I had eaten too much. Rig weighs in at 520kgs with nothing in it or on it. Quite a heavey piece of machinery, maybe that is why I can notice the differance with the reduced dia and lower gearing. Like I said before. I LOVE IT.
Cheers
Mark
