Car tyres on bike rims

Chat about anything to do with sidecars and outfits. NOT BMW specific - all welcome

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keiththeoutfitter1
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Car tyres on bike rims

Postby keiththeoutfitter1 » Sat Jan 10, 2015 1:26 pm

Hi Sofa,
I can't find the info from Claude yet but this page covers it quite well, including profile details for car and bike rims.
Note that the car 17" tyre is actually 0.1" larger than a 17" bike tyre which is why mine would slip round on the rim so easily and why they have to be overinflated to stay on. Again, could be an insurance problem if incorrect tyres are fitted to rims, not to mention the risk of having an accident in the first place.

http://www.hpsidecars.com/forum/viewtop ... bile+tires

Regards,
Keith
R1200RT
K1100RS + EZS Rally Sidecar
Kawasaki Versys 650

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keiththeoutfitter1
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Re: Car tyres on bike rims

Postby keiththeoutfitter1 » Sat Jan 10, 2015 2:14 pm

There is probably more information than you need on his page and it is primarily concerned with solo motorcycles but it does show cross-sections of m/c tyres fitted to car rims which show the disparity between the two profiles

http://www.goldwingfacts.com/forums/10- ... -tire.html

Cheers,
Keith
R1200RT
K1100RS + EZS Rally Sidecar
Kawasaki Versys 650

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Sofa
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Re: Car tyres on bike rims

Postby Sofa » Sat Jan 10, 2015 8:59 pm

I do understand the situation Keith.
So just to explain a bit further. Rod at Motopodd is fitting the chair, Klicktronic, trail adjusting kit etc. He has fitted many modern outfits with 17" car tyres with no problems and I am going to have to take the risk if only temporarily. Being unable now to ride a solo bike at all and even a sidecar outfit without a klicktronic I have no way of deciding if the bike I am choosing (K1200GT) is going to do the job until it is fitted to the chair I already have. If I was sure then I would go the whole hog, leading links £2,500, subframe £1,000, steel swinging arm £goodness knows, and a wheel £750, plus fitting. But I could spend all that on pretty unique bits with little resale value and ride it a hundred yards to find it isn't right for me. So the current plan is already have the klicktronic on the knackered K100, £1,000 subframe (can't avoid that), £160 trail adjusting kit plus fitting. Ride it until I am sure, then do the back wheel. Ride until I have the compensation for the accident then decide either new or newer bike and do it all again, or stick with the K1200GT and go for respray, steel swinging arm and maybe leading links and possibly a K1200LT gearbox/reversing mechanism.

I have a friend who has had outfits for nearly 40 years and has built 20 himself and I listen to his advice as he not only rides them daily but is constantly adjusting and fettling them (currently he and his wife have two outfits each). His opinion is more along the lines as to whether the bmw wheel is capable of handling the sideforces of an outfit than the tyre staying on it, so I'm not going to be allowed to ride it for long with a car tyre on if he has his way (even though he is a 14" front and rear, leading links, 6 pot billet brakes loony).

We also had a discussion the other day about insurance and he pointed out that the third party cover is why we really have insurance and that cover is not altered by any modifications that may or may not be made to a vehicle, otherwise insurers would never pay out third party claims as there will always be something that isn't standard (and also wouldn't pay out if their customer was breaking the law at the time either). Any modifications only effect the theft and fully comp bit of a policy and if it's stolen they won't know it's modified, if I crash it myself then I take that risk and pay for any repair myself.

I have spent months deciding what bike to use and how to do it this seems the best solution for me at the moment. Having had R80 outfit (both std wheels), R100 outfit (both 15"), K100 (15" rear, std front), K1100 (both 15") and now a K100 (std front, Ford sierra 4x4 wheel with adapter boss and offset) I am hoping the K1200 will be the business and as soon as I am happy it is the one for me will be ordering a rear wheel.
2003 K1200GT Hedingham HUB Sidecar. RSP Top Yoke, RT bars, ABS/Servo removed, Klicktronic. EZS subframe, trail reducing kit and rear wheel. Wheelchair rack. Previous BMWs R80RT mono, R1100GS, R80RT (added a sidecar), R100RT sidecar, K75, K100 sidecar x2, K1100 sidecar, R1150R.

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keiththeoutfitter1
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Re: Car tyres on bike rims

Postby keiththeoutfitter1 » Sat Jan 10, 2015 9:47 pm

Hi Sofa,
you have obviously thought through the issues and reached your conclusion but I stand by my original statement that using a car tyre on a motorcycle rim is risky to the point of being dangerous.

Regarding insurance, with all due respect, I would take issue with your friend's view. Quoting from my documents:

' In arranging your insurance both we and the Insurers will ask a number of questions which you are required to answer. Please take reasonable care to answer all of the questions honestly, to the best of your knowlege and provide full answers and relevant details. If you do not answer the queations honestly or to the best of your knowlege then your policy may be cancelled, treated as if it never existed, your claim rejected or not fully paid'.

One of the questions always asked is 'has the vehicle been modified'. I have just been reading a case of a driver who had an RTC and whose insurance was treated as if it never existed because, although he had declared performance modifications, he had not declared the fitting of bucket seats and other internal modifications. It is true that the law will always take a reasonable view for example the case where an insurance company refused to pay out because the vehicle had been fitted with an undeclared roof rack and had subsequently to meet the claim. However in the case of more technical modifications, the law may not be so accommodating. By not declaring significant changes to a vehicle you are inviting the insurance company to enter into a contract which they may not have entered into on the terms proposed and agreed had they been aware of the modifications. Such misrepresentation can render a contract unenforceable hence the statement that the policy may be treated as never having existed.
It is also worth bearing in mind that even if the insurance company does pay out to a third party, there is nothing to stop them suing you to recover their losses on the basis of the fraud committed by the making of a false declaration.

Having said all that, I hope the outfit works out well for you and hope that we may meet up sometime once you are on the road again and able to get to the club events.
Regards,
Keith
R1200RT
K1100RS + EZS Rally Sidecar
Kawasaki Versys 650


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