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Author Topic: Opinions needed: 77 CB550 Frame "Rake/Stance"  (Read 971 times)

Offline paulschell

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Opinions needed: 77 CB550 Frame "Rake/Stance"
« on: Jan 24, 2017, 01:12:47 »
Hey guys,

Just wanted to run an option by you for my first build. I'm pretty far into it, subframe is cut up and I'm about to get a new rim/spokes for the rear wheel. I put a brand new wheel on the front (see picture, 17"), and I have a brand new 150/70-17 tire lined up for the back.

1) My question is, since I want a slightly more aggressive rake/stance towards the bike, do you think it would be beneficial to run an 18" back there, or would sticking with the 17" be conducive, and weld the subframe accordingly to obtain the correct rake (have Cognito led hoop with upsweep). I know it's a bit hard to picture without picture of the frame, I'll try and attach one as soon as I can.

2) Secondly, I made a mistake in ordering a 36 hole hub for the front, and then realizing the rear hub is 40 hole, the mix-match of spokes won't be an eyesore/noticeable will it?

Any/all opinions welcome,

Thanks guys!

Offline Shoeman

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Re: Opinions needed: 77 CB550 Frame "Rake/Stance"
« Reply #1 on: Jan 24, 2017, 07:15:44 »
Oh boy.   I'm guessing you're not talking about rake as defined in relation to the rake and trail designed into the forks.   
I like cilp-ons, clubman's and superbike bars depending on the bike.  And rear-sets.

Offline Tune-A-Fishİ

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Re: Opinions needed: 77 CB550 Frame "Rake/Stance"
« Reply #2 on: Jan 24, 2017, 08:22:21 »
What front fork setup do you plan to run?

If stock you can run an 18, if USD and shorter more vertical rake, you likely need to go 17-17 or the front end will be too steep.

Get a protractor and search "measuring rake and trail" do some research on the subject, this is what will make or break your ability to turn and front stability... you don't want to be surprised with a full on head shake right out of the box.

All of this has been tried and trued on the 550... Ask Devin at Cogneto, he should be able to steer you right, but legally he's not going to send you instructions  :-X

Fishy Fishy
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Offline jpmobius

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Re: Opinions needed: 77 CB550 Frame "Rake/Stance"
« Reply #3 on: Jan 24, 2017, 15:52:32 »
That is a very large (wide) wheel/tire for the front of your 550.  You will be well served to learn a bit about the chassis dynamics of motorcycles (as advised by Mr. Fish) before proceeding too much further.  The rational process is to determine what you want in chassis dimensions first and creating the "look" (or stance) afterward without making any alterations to the chassis.  If you are not going to ride your bike, this is of course irrelevant.  Most people are best served by keeping extremely close to the stock specifications.  If you find that you wish driving characteristics that differ from the stock set up, then make changes that will take you in that direction.  There are quite a few on line calculators for bike chassis.  Plug in all the stock dimensions and then compare to what you are planning.  You may get lucky, but the likelihood is that you will be very unhappy with your changes if you deviate very far from the "known to be good" stock arrangement.  Commonly, people fit way overlarge rims/tires which in general slows handling and overwhelms smaller engines.  Fork swaps with much lower offset along with lowering the front of the bike to make it look cool in general will put much larger loads into the frame, and reduce rake and stability.  A great many great looking bike drive like crap, some are dangerous and potentially un-rideable. all for the sake of aesthetics.  That's not to say that you can't make a lot of changes or even build the whole works from scratch, but it is a lot more complicated than whether you can get all the parts to bolt up.  Modern bikes do not handle well because they have huge sticky tires.  They handle well because the entire vehicle is designed around being able to capitalize on them.  So the big sticky tires are only a good idea if you are going to re-engineer the rest of your bike appropriately or you may find that you have actually down graded the overall function of the bike. 
As far as the spokes go, you can't use a 36 hole rim with a 40 hole hub or vice-versa.  I doubt there would be much of a visual issue with a 40 spoke front and a 36 spoke back though.  Regardless, it is important to get the correct rim for the hub you have and there is more to get right than just the spoke count.  The angle of the holes in the rim must match what is required for the hub - they are not universal.  Your front rim is intended for a hub with a much smaller diameter.   Because if this miss match, you can see how your spoke nipples are aiming toward a smaller diameter base circle causing the spokes to bend - they should be perfectly straight.  I think this unlikely to actually cause a problem (spoke wheels are very tough, flexible and strong).  But, you do not wish to repeat it on your rear wheel.
Mobius


On a long enough timeline, the survival rate for everyone drops to zero.

1973 RD350 Yamaha build  http://www.dotheton.com/forum/index.php?topic=66498.0

Online irk miller

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Re: Opinions needed: 77 CB550 Frame "Rake/Stance"
« Reply #4 on: Jan 24, 2017, 16:43:02 »
You're going huge on front and rear for the tires.  Have you measured up to see if they actually fit the forks and swing arm width (plus clearance for the chain)?  3.25-19 is the stock tire size for the front and 3.75 - 18 on the back.

Offline J-Rod10

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Re: Opinions needed: 77 CB550 Frame "Rake/Stance"
« Reply #5 on: Jan 24, 2017, 19:05:10 »
You're going huge on front and rear for the tires.  Have you measured up to see if they actually fit the forks and swing arm width (plus clearance for the chain)?  3.25-19 is the stock tire size for the front and 3.75 - 18 on the back.
You can squeeze a 160 in the stock swinger. Takes some machine work on the sprocket carrier to make it work, but it'll fit.