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Discussion Starter #1
Has anyone in our wonderful community ever tried 'darksiding', this is fitting a car tyre to the rear of a bike. From what I have found out it is a much practiced and perfectly legal thing to do in America, In the UK it's not legal as such but there are loopholes. The main interest for me is economical, car tyres are the fraction of the price of a motorcycle tyre and they also last a lot longer.
I've read many write ups on the pro's and con's of this practice but would be interested to hear from anyone who has actually tried it?
 

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Has anyone in our wonderful community ever tried 'darksiding', this is fitting a car tyre to the rear of a bike. From what I have found out it is a much practiced and perfectly legal thing to do in America, In the UK it's not legal as such but there are loopholes. The main interest for me is economical, car tyres are the fraction of the price of a motorcycle tyre and they also last a lot longer.
I've read many write ups on the pro's and con's of this practice but would be interested to hear from anyone who has actually tried it?
I really wish people would stop doing this. Motorcycle tires are ROUND. Car tires are FLAT. It is physically impossible to properly corner a motorcycle with a car tire installed. This all started because some redneck somewhere didn't want to spend $200 for a new tire on his Goldwing. So, he went to Wal-Mart and threw a $40 pickup tire on it, and swore to the world you get more mileage for a quarter of ther cost.

Just don't do it. Your bike WILL NOT handle correctly.
 

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You don't say what your bike model is. This practice is usually done with heavy bikes such as what High On Octane posted. Some who own Rocket III use them. There are plenty of Youtube videos on the subject showing how the car tire responds while riding with a camera pointed at the tire. If you use a side car rig all the time, car tires can be used since there is no leaning. But, pose this question in the Rocket forum and you will probably get responses from those who use a car tire.
 

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You don't say what your bike model is. This practice is usually done with heavy bikes such as what High On Octane posted. Some who own Rocket III use them. There are plenty of Youtube videos on the subject showing how the car tire responds while riding with a camera pointed at the tire. If you use a side car rig all the time, car tires can be used since there is no leaning. But, pose this question in the Rocket forum and you will probably get responses from those who use a car tire.
Exactly. This was originally done on trikes and hacks where you actually steer the bike to turn, not lean it over. Keep in mind too, car tires use a much, much harder rubber compound than motorcycle tires. And THIS is the main reason people do it. Because they think they should be able to get 30-40,000 miles out of a motorcycle tire. To each their own. I personally wouldn't even do it on a trike. Your tires are the only thing keeping your bike planted on the road. Are you REALLY wanting to scarifice your safety to save a few bucks?
 

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Discussion Starter #6
Exactly. This was originally done on trikes and hacks where you actually steer the bike to turn, not lean it over. Keep in mind too, car tires use a much, much harder rubber compound than motorcycle tires. And THIS is the main reason people do it. Because they think they should be able to get 30-40,000 miles out of a motorcycle tire. To each their own. I personally wouldn't even do it on a trike. Your tires are the only thing keeping your bike planted on the road. Are you REALLY wanting to scarifice your safety to save a few bucks?
I do quite a lot of miles mainly commuting which usually means a lot of upright riding, I've got a Triumph america which I picked up in june this year with an almost new Bridgestone Exedra on the rear. I've covered around 4000 miles on it so far and it's life is almost up. I put an Avon cobra on the rear of my last bike which gave me good mileage but it set me back £120, you can pick up a car tyre for less than £50 which makes more economical sense to me. One of the reasons I ride bikes is because they are hell of a lot cheaper than running a car, or they used to be anyway.
 

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Discussion Starter #7
You don't say what your bike model is. This practice is usually done with heavy bikes such as what High On Octane posted. Some who own Rocket III use them. There are plenty of Youtube videos on the subject showing how the car tire responds while riding with a camera pointed at the tire. If you use a side car rig all the time, car tires can be used since there is no leaning. But, pose this question in the Rocket forum and you will probably get responses from those who use a car tire.
Thanks for your reply. I ride a Triumph America mainly upright, it's by no means a high powered sports bike so I don't really do any cornering at great speed. When I got involved in the bike scene in the late 80's it was through going to custom bike shows and some people were dabbling with fitting wide car rims to bikes so they could fit wider rear tyres on them, I remember someone telling me that in order to go into a bend he had to 'flick' his bike onto the edge of the tyre. Anyway I'll have a look at some youtube vid's and ask some people in the Rocket rooms.

Cheers, Jerry
 

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well why not go ahead and try it ......
we'll all be waiting for your post saying " my bike handles really badly ... " ...!!!!!!
 

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Discussion Starter #11
well why not go ahead and try it ......
we'll all be waiting for your post saying " my bike handles really badly ... " ...!!!!!!
I'm not feeling much love in the room for this idea. I'm a little confused, why would I make a post about your bike not handling very well BonnieJon?
 

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I did a little over 20K on a car tire on the back end of my Rocket 3. The only issue I ever encountered was some wobble in dipped areas of pavement, ie lanes where big trucks leave ruts in the hot asphalt. Rode many a mountain curve and hung in with the best of them. I went back to an mc tire when several new brands hit the market that were a better value than the crappy Metzler and lasted twice as long.....
 

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Discussion Starter #15
I did a little over 20K on a car tire on the back end of my Rocket 3. The only issue I ever encountered was some wobble in dipped areas of pavement, ie lanes where big trucks leave ruts in the hot asphalt. Rode many a mountain curve and hung in with the best of them. I went back to an mc tire when several new brands hit the market that were a better value than the crappy Metzler and lasted twice as long.....
Brilliant, thank's for your sound advice. I've been talking to some chaps on the Rocket forum and it's definitely something I'm going to give a go. I'm laying my bike up at the end of December for a couple of months until the weather get's a bit warmer, this will give me chance to find someone willing to fit one for me, but this shouldn't be too much of an issue. The only thing that does bother me slightly is wet weather cornering, but I'm sure I'll get used to it. I'll let you know how I get on when I get one fitted.

Cheers, Jerry
 

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Going back well over half a century I somehow came by a "new" 19x3.50 rear tyre, great I'll stick it on the bike of the day, either a ES2 or a model 18, can't remember which, they came and went. Anyway, I fitted it, and damn near killed meself. Dad took one look at it and was quite rude. That, my son, is a sidecar tyre. Square section, you'll fall off the "corners" of it. So very true. The UK is rather small, the roads were laid out to cope with horse drawn traffic, then tarmaced over. Very few straight bits, and loads of corners. I can't speak for the long straights of The USofA, but if you fit a car tyre to a bike over here, you'll want your bumps feeling..And you'll have some!
 

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Discussion Starter #17
Going back well over half a century I somehow came by a "new" 19x3.50 rear tyre, great I'll stick it on the bike of the day, either a ES2 or a model 18, can't remember which, they came and went. Anyway, I fitted it, and damn near killed meself. Dad took one look at it and was quite rude. That, my son, is a sidecar tyre. Square section, you'll fall off the "corners" of it. So very true. The UK is rather small, the roads were laid out to cope with horse drawn traffic, then tarmaced over. Very few straight bits, and loads of corners. I can't speak for the long straights of The USofA, but if you fit a car tyre to a bike over here, you'll want your bumps feeling..And you'll have some!
I remember back in the late 70's Avon did a tyre called a 'Speedmaster'. It was pretty much a square section tyre, a mate of my brothers had a nasty spill on an old RD250 with one fitted, I was still in nappies but I remember people used to call them Avon deathmaster's. In the 90's I had a hardtail CB750 chop fitted with a square section bike tyre on the rear, the tread was reminiscent of an old crossply tyre. I've got no idea what make of tyre it was but I rode on it with no issues. You do have a good point about British roads being designed for horse and carts though, they can get quite windey.
 

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IIRC the profile of a motorcycle wheel is different from the profile of a car wheel, therefore the tyre bead profiles are different, and a car tyre cannot seat correctly on a bike rim.

I don't know about the situation in other countries, but in the UK, that could have both legal and insurance implications.
 

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Discussion Starter #19
IIRC the profile of a motorcycle wheel is different from the profile of a car wheel, therefore the tyre bead profiles are different, and a car tyre cannot seat correctly on a bike rim.

I don't know about the situation in other countries, but in the UK, that could have both legal and insurance implications.
I know that in the UK you are permitted to have a car tyre fitted if you use a sidecar,but I'm not sure how you stand if you should remove the sidecar.
 

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I remember back in the late 70's Avon did a tyre called a 'Speedmaster'. It was pretty much a square section tyre, a mate of my brothers had a nasty spill on an old RD250 with one fitted, I was still in nappies but I remember people used to call them Avon deathmaster's. In the 90's I had a hardtail CB750 chop fitted with a square section bike tyre on the rear, the tread was reminiscent of an old crossply tyre. I've got no idea what make of tyre it was but I rode on it with no issues. You do have a good point about British roads being designed for horse and carts though, they can get quite windey.
I think you'll find the "Speedmaster" of the 60's 70's was a front tyre which was quite "rounded". Popular rears were the "Universal", which was squarish, but became more rounded, then came the Safety mileage, which was quite rounded from the start.

I think! Long time ago.
 
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