Wednesday, February 3, 2010

The Beginning of the front Wheels assembly. for the sake of the lowest possible front profile I want the smallest and narrowest wheel I can find. I also need to take into consideration the tires available for any rim I choose. the tire needs to have a speed rating high enough to handle the speeds I hope the bike will see on the salt. all other things are secondary, however modern sport bike rubber (which will handle the speeds) is usually made in a 130 width tire. Keeping the front tire narrow helps with not only the frontal area and thus air resistance, but also rolling resistance which, with a wider tire, is the greater concern at the speeds I'm shooting for. The other limiting factor is that High performance rubber is only made for sport bikes which these days all have 17 inch front rims. I have decided to make the steering mechanism a hub center type because of the advantages in being able to keep a very low profile with no steering neck or stem. This means that aside for clearances for the riders line of forward sight the height of the front of the bike needs to only be as tall as the front wheel. Luckily for me Honda decided to build their revolutionary CBR900RR with a 16" front wheel from its introduction in the early 90's till they went to a 17" rim in 2001. This means that there are tires that are rated to 175+mph available for 16" rims and with a relatively small profile this saves on the overall height. Also I remember from back in the 90's a neighbor who had a Kawasaki Ninja 250 which had a rather large hollow hub and was also 16". Thanks to EBay and $35+ shipping I had one to mess about with a week later. Here it is and me using a sawzall to cut out the center of the hub. With all that room, it should make bearing selection easier and cheaper, as well as making it easier to design and build the Hub Center mechanism. The Hub is a symmetrical with respect to the centerline of the rim with Disk mounting holes on only one side. This may present a problem but I don't think at this point that it will make the rim useless for my application. FWIW a quick calculation shows that at 200mph with a 110 profile tire this wheel will be spinning at about 2715RPM. This is well within the speed range of most regular bearings.  See Pictures Below and Stay tuned.

Monday, February 1, 2010

The future of the front Hub Center steering. Is there anything a Sawz-all can’t do? A marital aid, and Kitchen utensil, a....

From here it's on to the mill. I don't have the exact Hub dimensions worked out, and the mill is tied up with paying work so I may not get to that for a while, but as soon as I do there will be pics.

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