Car tyre on a scooter (or motorcycle) why is it called "Dark Side"?

My two pence (nod across the pond) - It is merely a "Granfalloon" and an attempt to make it seem cooler than it would otherwise.

Granfalloon - see "Cat's Cradle" by Kurt Vonnegut for clarity.

What are the advantages of running a car tire on a scooter? Do they wear longer? And what about handling? Robert in Az. Ride Safe.

Cause some people fear it

Tankyuong,

But since the reference is from a fictional drama how is that scary?


Robert,

I think the primary reason is that the car tire does wear longer. Folks are all over the map on the handling and most of the 'evidence' regarding handling is anecdotal, meaning it is feeling and not necessarily evidence.

As I said on the thread that has obviously started this spin off.

I simply don't understand why use a car tyre, (tire).

Is it better for longer distances with little or no turns?
Is it simply for economical reasons?

We in the UK do not use car tyres on our scooters, in fact until I started posting on non UK sites I had never even heard of it.

It is the profile of the tyre that is probably the confusing issue for me. The rounded profile of the Bridgestone Hoop allows the machine to be banked over. Whereas the flat profile of the car tyre would allow superb straight riding but when cornering, especially tight turns, I can only foresee handling issues.

If some of you knowledgeable types could explain I would in all sincerity be grateful and better informed.

Thank you in advance.

Doug

JD....i assume it is called darkside because of all the controversy surrounding the subject...there really is no middle...You have your extreme "Right"(those who oppose) and your extreme left(those who favor). You know like in stars wars....the dark side was the bad.....see the trend?

A car tire does last much longer, i hear. I just installed on my scoot. so far i have had favor experience. Handling is not that much difference. I would not have gravitated to the DARKSIDE if i could get a scooter tire to last more than 5000 miles.....thats highway robbery(in my opinion).

For our comrads located "across the pond", i wouldnt install a car tire on my scooter if it was illegal in my country, but far as i know its not illegal in the USA.

How do you bank hard (lean) when turning at a high rate of speed?
From what I understand, the Sumitomo car tire runs underinflated so that the sidewall "gives" when banking. Is that correct?

BigBird .....Absolutely. I have no problems with the tire....but i dont push it to find out how far it will go....i drive reasonably. If u do a lot of hard leaning, u may not want to get one of those, but i have nothing but good things to say about the tire under normal driving conditions.

I do lean aggressively when travelling at higher speeds. That's why I own a big heavy scooter capable of "ton up" speeds, as our "over the pond" friends say.
My driving style would not lend itself to a car tire on the rear. It would likely scare the bejeezus out of me if I tried a hard bank on a decreasing radius turn while accelerating on a highway on-ramp.

I'm of the same mind as bigbird. A car tire on a two wheeler is fine if you don't corner aggressively. Myself, the only time I don't lean aggressively (or at all for that matter) is when I am on pavement that isn't dry. On dry pavement, I really lean into the turns and curves. So therefore "for me" it wouldn't be a good idea. I too don't like the 5K to 7k limit on scooter tires, but that's scooters that have small wheel sizes. You get one of the bigger ones like a Gold Wing or a cruiser and you can probably get 10K to 15K out of the tire. That's still not as good as a car but what we operate is not a car. It's a motorcycle. Feet forward, automatic transmission notwithstanding they are still motorcycles. It's like comparing apples and oranges. And as I ride in all weather, except ice, a tire designed for the vehicle I'm operating is essential.

I totally understand what u guys are saying about your driving style...i live in dallas, tx and drive highway a lot so the car tire is good for me. when my scoot tires were worn out....the center only would be worn out.

Thanks for all the input fellow Riders, a couple of more questions, what tire brand is best for mileage and handling? also is it possible to install abs on a non abs S/Wing. I've had some close calls having to slam on the binders a few times. Ride Safe...Robert in Az.

im not completely certain about the abs question but i think all u need to do is switch out the brake assembly with an abs version. I made the choice of installing the Sumitomo 165/70-13 on my bike because it has the best dark side track record. as far as scooter tires which would be best...i couldnt say because i never got many miles out of any of them.

Big Bird, You are right about the high cost of trying to add abs, I'm going down to the Honda dealer, see what they will give me on my 08' towards a new 2011, I've also been looking at the Mana Aprilia 850 gt, looks like it would do the job. Ride Safe...Robert in Az.

Car Tire on bike----rather stupid. Basic, rim/beads are different from bike to car.
(see SAE paper)
Some people say they only ride straight. How about exits/emergencies?


Doubt there are many million mile two wheel riders out there on car tires.


Car Tire ok sidecar with special rim (see EML) and bike never ridden solo.


Have some experience car tire on bike----once bought WLA HD 45 with 18" junk yard car tires----off they came in order to ride safely. Also 15" car tire/special rim on MZ ETS sidecar outfit---could not/was illegal to be used solo.


If car tires were so great, why aren't road racers or round the world riders using them? Police?


Has anyone with car tire on scooter mounted the tire themselves or had tire shop do it?

Scooters are handling compromise, no need to make it worse.


Fresh tires for me this week----amazing how just fresh proper tires improve the way the scooter feels. Next time for SilverWing @ 10,000 miles change out matched set as bike is more fun to ride when everything is right. I can and do get 10,000 out of rear, of course front goes longer, but fresh feels better.

IRC front feels better than well worn Bridgestone. Had IRC rear, but tack/nail but it in junk pile. This time Michelin on rear....I know not approved but will see how it works---Dennis Kirk has them @$42 and fresh.


I think the idiots in marketing in both japan and US should have to try to do roadside front wheel removal on SilverWing.... I am making prop to raise front wheel.
Laying bike over on side could cost expensive plastiic. For this front tire change I used only on board tools and no lift---cheated block of wood and floor jack to raise front wheel. 8mm Allen head, 22 mm socket needed. Funny that stuff doesn't come in tool kit.


John Grinsel



European rules on tires/mods are probably better--none approved mod=no insurance if you crash, etc.

I don't necessarily regard a car tire on a bike as stupid (rather judgemental), but I do think it is a risk. Some feel that it is a risk worth taking - especially those who put a lot of miles on their bikes and don't want to change tires 3 to 4 times a year. I can't quibble with that.

I have followed 3 different riders, two on SilverWings and one on a Burgman who were riding with car tires installed on the rear. All of them were able to negotiate "twisty roads" at speeds that were easily (and exuberantly) described as spritied. And not just for short sections - but for sustained runs of 20 - 30 miles of back to back curves.

As for the handling. Almost to a person each individual that has made the switch to a car tire has commented on the need to get used to the tire. That implies that there is a bit of a difference in handling. Based on the comments, I'm deducing that it is a greater difference than just the transition from a worn tire to a new tire.

I have read personal accounts that lead me to believe that the car tire has a tendency to make the bike a bit more inclined to try to right itself to vertical as the rider begins to exit the apex of a curve and get on the throttle. This behaviour characteristic is easily compensated for and an experienced rider should be able to adjust to this idiosyncracy rather quickly.

That said, I still would not put one on either of our bikes as I am not convinced that it is as safe as a tire designed for the purpose. We all have levels of acceptable risk that are widely divergent.

You know....i had a real hard time making the choice to put a car tire on my bike because of all the negative comments from those who DONT have one on their bike therefore i was getting opinions and not FACT. Boy am i glad i gave it a shot. Stupidity also falls under the category of ignorance. For all the non believers.....keep installing those expensive scoot tires. The non believers wouldnt appreciate a good deal any way.

I am not experience at all in the dark side tire discussion. But, I would be more influenced either way if there was any empirical evidence of tire failure for a dark side setup. I read a ton of opinions of both sides. I never hear anyone say, "I had my car tire fail on my two wheeler". Am I missing that bit of evidence? As I said, I don't have a dog in this fight. If there has been any history of tire failure, can some one put a link here please.

The difference in being ignorant and stupid is that ignorance is just not knowing better, stupid is knowing better but doing it anyway. Stupid people don't ride Silverwings.

I did a little googling myself and found this web site. Probably won't change anyones mind, but will maybe get some of you like me out of the ignorant ditch.

http://mcdarksiders.forumotion.com/t3920-riding-on-the-darkside-question


I still have an open mind to any link to a report of CT failure on a two wheeler.

Not wishing to be argumentative but does anyone ever consider the construction of the bike?
Granted a car tyre will last longer and may afford the same or better grip than a motorcycle tyre but what is it doing to the bike?

In my youth, radial tyres became readily available for all cars but it was made very clear in the Motoring Press that in certain cars, namely Morris 1000s in our case, the design of the suspension could not cope with the additional stresses generated by the superior cornering-grip of the radials.

One has only to look at the cars retro-fitted with tall wheels and low-profile tyres (rubber-bands) to see that they are working the suspension far harder than when fitted with standard wheels and tyres, which extra work (shock and stress) is being transmitted to the rest of the car.

The tyre is part of the suspension system of the bike and I would not be happy in fitting my Silverwing with much heavier, more stiffly-constructed car tyres without first having independent engineers' reports on the ability of the bike to withstand the extra loads over the same period of time as it would with the correct motorcycles tyres fitted.

because the sumitomo is a bit taller than the scoot tire i did have to back the rear suspension back one notch....but now it rides like a cadillac. I wouldnt change that tire for a free scoot tire. I didnt get my tire from tire rack ...i bought it from another site a bit cheaper and it arrived to dallas from oregon in three days....blew my mind. If someone wants to know the link PM me....other wise happy scooting on cheap chinese rubber :-)

I cannot find any direct link but the MoT, (Ministry of Transport) site says indirectly you cannot mix car tyres and bike tyres and an examiner will fail your bike therefore making it illegal to ride on public roads.

So for me in the UK that means the tyre debate is no longer an issue as I could never legally fit a 'darkside' tyre anyway!! It was good reading up on the matter. Enjoy your tyre longevity, we Brits will continue to pay mega bucks to throw our 'Wings' around on rounded tyres .

As a side line curiosity question... do yall have trikes in the UK? If so, do they allow CT on the real axles? I will have two CTs on the rear of my trike, but, it will have standard automobile wheels as well. The front will remain MT until the time comes that I decide whether to add CT to the front. I probably won't live long enough to put many more sets of tires on anything. I am not sure how often tires have to changed on wheel chairs in nursing homes.
I may be the first to go Dark Side in the local home. Now that is another forum to get started.....

Hi Gary, yes we have trikes, and most of them do have car tyres fitted, but there again they are purpose made for that fitting. A few sidecar outfits have them fitted as well, some front and rear, others just to the rear depending on the suspension fittings.

Trikes mainly fall into two catagories here in the UK, those built from scratch as trikes by such firms as Boom, Rewarco, Can-am etc. and those built converting (mainly) motorcycles or three wheeler vehicles like Reliants.

The production machines are type tested and registered as such. The 'individualy' built machines are put through a 'Single Vehicle Approval' Test or SVA for short. On completion of the inspection, which can take upto 5 hours, the vehicle is issued with the relevant documentation to make it a 'new' machine - what you don't get is an age related plate unless you can meet some very specific criteria during the build; most refer to the use of new parts or parts from a donor vehicle. If you can't meet those requirements then you get a 'Q' plate which used to be a hinderance for insurance purposes etc. but today isn't a problem so much because the SVA gaurantees a very high minimum standard of engineering work has taken place and the whole vehicle meets those standards!

Fitting car tyres is the riders choice, how it would effect the outcome of court proceedings etc. should it be found that such a fitment contributed to an accident is a differant matter; as always most riders I know tell their insurance company of such modification just to make sure they are covered.

Adjusting the suspension doesn't alter the effect of a heavier tyre on the unsprung parts of the bike.