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Author Topic: Is this safe?  (Read 788 times)

Offline redrover

  • Posts: 193
Is this safe?
« on: Jun 17, 2018, 13:09:56 »
CB500T

I noticed on this build that the rear shock is not mounted directly to the swing arm mount like its suppose to, but somehow mounted to part of the hub? Or the mounting bolt for the rear brake?

Is this ok to do? (Aside from lowering the bike and potentially bottoming out)

Is this safe to do? If no, why not?


(Added extra photo of another 500T as reference)

Offline crazypj

  • Posts: 13157
  • Split personality, I fake being smart
Re: Is this safe?
« Reply #1 on: Jun 17, 2018, 13:43:52 »
Looks like some kind of lowering blocks are bolted in? They were common in 1970's but were usually only about 2~3" long, those are probably home made and 5"6" long. They work but personally I don't like them mor even the idea of them. There will always be people willing to make and sell stuff with dubious safety
'you can take my word for it or argue until you find out I'm right'
Best thing I ever overheard
"yep, PJ's my boss, he taught me everything I know, just didn't teach me everything he knows"
Brian Morgan, 1982

CB360's,  http://www.dotheton.com/forum/index.php?topic=11736.0
XS650,  http://www.dotheton.com/forum/index.php?topic=11922.0

Offline irk miller

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Re: Is this safe?
« Reply #2 on: Jun 17, 2018, 14:12:48 »
Plus, the angle of the shocks will stiffen up the ride.

Offline redrover

  • Posts: 193
Re: Is this safe?
« Reply #3 on: Jun 17, 2018, 17:00:58 »
Ya here is the actual build post link, it does mention plans of ďremoving lowering kitĒ, seems like it was left in after all.

http://vintage-and-classic-honda-s.456789.n3.nabble.com/1976-Honda-CB500T-Brat-Project-td4062231.html

Why donít you like the idea of them?

And ya the angle of the shock is way different... Would it be better/safer to just install shorter shocks to lower the bike?

Offline irk miller

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Re: Is this safe?
« Reply #4 on: Jun 17, 2018, 17:05:05 »
It would be much better to install shorter shocks, as long as they are sprung for the weight of bike and rider.

Offline farmer92

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Re: Is this safe?
« Reply #5 on: Jun 17, 2018, 20:20:38 »
Plus, the angle of the shocks will stiffen up the ride.

Wonít they make the ride softer?
The Wheel creates force vector (0,10) assuming the SA is level at this moment
But the shocks are at an angle, So they need to produce a force vector (x,-10).
If the shocks are at say 45* then the resulting force vector from the shocks is a (-10,-10) the total magnitude of which is just over 14.1
So those shocks see 41% more load at that angle VS a vertically mounted set.

Offline teazer

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Re: Is this safe?
« Reply #6 on: Jun 17, 2018, 20:30:01 »
In the most simple of terms, it's a bad idea.  It changes overall frame geometry.  May be good may be bad but without measuring, it's a bad idea.  Changes shock loading.  Overall effect can't be good, but how bad is it, who knows.  It's just a dumb idea.

Most importantly, if the struts/extensions/lowering kit is not secured in all planes, it will seriously impact the way the rear suspension works.  All in all, it's a dumb idea and poor way to do things. I would recommend going back to stock suspension and work from there. 

Not sure that a cheap brat style seat is an improvement on the looks of that thing, but back in the day no one loved a CB500T.  They were just butt ugly bikes. So maybe it's an improvement in looks if you like that sort of thing.

Offline irk miller

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Re: Is this safe?
« Reply #7 on: Jun 17, 2018, 21:01:01 »
Wonít they make the ride softer?
The Wheel creates force vector (0,10) assuming the SA is level at this moment
But the shocks are at an angle, So they need to produce a force vector (x,-10).
If the shocks are at say 45* then the resulting force vector from the shocks is a (-10,-10) the total magnitude of which is just over 14.1
So those shocks see 41% more load at that angle VS a vertically mounted set.

Yeah, you're right.  I had it backwards.  As you angle the shock, it essentially moves the load to spring and takes away all the damping.  You would need twice as heavy of a spring for such a change in angle.


Offline redrover

  • Posts: 193
Re: Is this safe?
« Reply #8 on: Jun 18, 2018, 21:28:30 »
Ya it didnít seem right to me either... Which is why I asked here. I reached out to the builder too, but havenít gotten a response. Lower shocks just seem like the way to go.

Either way thank you everyone for chiming in with feedback

And whatís wrong with the 500T looks?? Or do I just have the same taste in bikes as I do in women... Butt ugly with big seats! ;D


Offline irk miller

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Re: Is this safe?
« Reply #9 on: Jun 18, 2018, 22:24:44 »
I think the seat/side cover design is the big issue with the 500t.  Teazer has expressed more than once his disdain for brown seats.  LOL.  The tank is actually really sought after for cafe bikes because of its shape and knee dents.