instead of using automotive wheels for the back 2, there are plenty of motorcycles that use a single-sided swing-arm... on those bikes, it's often a 5 hole pattern -- couldn't those wheels/tires be used for conversions ?
a thought/question for trike mfr.'s
- Thread starter JG122
- Start date
It's not cost effective... the tires are smaller, have less side wall for cush'n and cost more to replace... Those are my guesses? :Shrug:
- Thread starter
- #3
yes, they'd be quite a bit more money...
but there'd be a big savings in weight, and the difference in sidewall characteristics would be a positive -- alot of the poor handling traits of conversions would be lessened (if not eliminated).
but there'd be a big savings in weight, and the difference in sidewall characteristics would be a positive -- alot of the poor handling traits of conversions would be lessened (if not eliminated).
not quite sure i get that one..... because it stays flat on the road a car tire is made for a side load and a bike tire is not quite the same as the bike tire is made to lean.... the car tire will certainly have a way bigger contact patch than the bike tire too
The other issue with doing so, a motorcycle tire is not designed for the type of side load a trike exerts on the rear. This causes additional stresses on the side wall of a tire that an automotive tire is designed to handle, but a motorcycle tire is not.
In addition, a motorcycle tire would actually harm the handling because of the extreme reduction in the contact patch on the roadway as well. This would be expecially "tricky" in wet and icy weather given you would only have 1 1/2 to 2" of contact with the roadway on each tire.
The cons of doing such a thing far outweigh any "positives" that one may percieve.
In addition, a motorcycle tire would actually harm the handling because of the extreme reduction in the contact patch on the roadway as well. This would be expecially "tricky" in wet and icy weather given you would only have 1 1/2 to 2" of contact with the roadway on each tire.
The cons of doing such a thing far outweigh any "positives" that one may percieve.
On a side note concerning "trikes poor handling". Take a close look at some of the times on the tail of the dragon.. Some of the fastest times on that road are trikes, not 2 wheelers.. This is testament to the all to common misconception of trikes handling "poorly"
I didn't know we were going to get into the engineering of the whole thing...lol
There is always an Issue of un-sprung weight when you are talking pure performance..not so much when we are talking a trike that is not really designed for race or High performance. the weight saving is negated when you think that there might be two people on the trike, plus all the things you bring with you or even a trailer.
Automobile tires for passenger cars and light trucks have a much great contact patch than the motorcycle tires and unlike a motorcycle tires the roll makes it safer in the trike application as it keeps more tire on the ground while cornering.
My thought is that unless you designed a trike that "leaned" into corners motorcycle tires on the rear would be pointless and less safe the auto tires and there is always the center of gravity advantage with the higher un-sprung weight. :Angel:
There is always an Issue of un-sprung weight when you are talking pure performance..not so much when we are talking a trike that is not really designed for race or High performance. the weight saving is negated when you think that there might be two people on the trike, plus all the things you bring with you or even a trailer.
Automobile tires for passenger cars and light trucks have a much great contact patch than the motorcycle tires and unlike a motorcycle tires the roll makes it safer in the trike application as it keeps more tire on the ground while cornering.
My thought is that unless you designed a trike that "leaned" into corners motorcycle tires on the rear would be pointless and less safe the auto tires and there is always the center of gravity advantage with the higher un-sprung weight. :Angel:
On the plus side, automotive tires increase friction, which helps with acceleration, cornering and braking. On the minus side, they decrease gas mileage. Take your pick...
I like your readers digest "condensed" version... right to the point! ThumbUp
- Thread starter
- #10
those are valid points...
I got my line of thinking after chatting with the builder of this trike :
Harley-Davidson : Custom Trike Harley-Davidson : Custom Trike | eBay
his position --
1. automotive wheels have to support the weight and turning forces of a 4,000 lb. car (i.e. they're very heavy), and the sidewalls on a car tire are also designed to flex with the weight of a car, which obviously won't flex with only the weight of a motorcycle/trike.
JG note: this is why trikers run very low tire pressures in the rears, right ?
2. this added unsprung weight is the worst, because is not dampened by the suspension... case in point -- the original HD ServiCar trikes had spoke motorcycle wheels, and they were mounted with motorcycle tires, for this very reason.
I got my line of thinking after chatting with the builder of this trike :
Harley-Davidson : Custom Trike Harley-Davidson : Custom Trike | eBay
his position --
1. automotive wheels have to support the weight and turning forces of a 4,000 lb. car (i.e. they're very heavy), and the sidewalls on a car tire are also designed to flex with the weight of a car, which obviously won't flex with only the weight of a motorcycle/trike.
JG note: this is why trikers run very low tire pressures in the rears, right ?
2. this added unsprung weight is the worst, because is not dampened by the suspension... case in point -- the original HD ServiCar trikes had spoke motorcycle wheels, and they were mounted with motorcycle tires, for this very reason.
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I suspect that HD used spoke motorcycle wheels BECAUSE they already had them, purely economics.
Jon
I concur.
I don't think at the time that the first "service" HD that Nasa had been to the moon let alone computer aided design or anything like that. They put spoke wheels on because they had them and it worked well enough. I am sort of an buff on old car companies and old cars and engineering. Most things got done through trial and error and lot's of test drives and destructive testing done in open fields and warehouses...
So, someone at HD Said "hey we got some of these spoke wheels left over from WWI" Wanna try them" ...and they did! :Shrug:
To the best of my knowledge tubeless tires were not around then so spokes were in vogue. Also the Servicar wasn't expected to be a sporting or touring machine. I remember it only being used by auto dealers. They would deliver your serviced car to your home by towing the Servicar with your car, drop it off, then disconnect it and ride it back to the dealer.
Agreed. Tires use to be made from almost all rubber with very few compounds. Very few riders used they're motorcycles and servicars for long distance riding. Motorcycle tires didn't evolve much the first 50 yrs
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