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Old 04-25-2011, 12:16 PM   #76
Lornce
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Quote:
Originally Posted by Houseoffubar View Post
Good explanations Lornce!
This is one of my favorite topics!

I've got a great old book by Foale, and another fellow. They build several special bikes, to experiment with. They build bikes with zero rake, and find, the less rake, the less trail is required, with no stability loss, if fact it increased at lower speeds, and no offset is used at all. I didn't commit that book to memory, but I thought they discovered trail needed to be maintained while rake was largely unimportant beyond effecting how well the suspension worked. ie: rake effected stiction.

I'm personally of the belief that offset is the worst thing you can put into the front end of a motorcycle, and that the minimum possible should always be used. As I understand it, that's sort of like saying bore and stroke aren't important as long as displacement is maintained. Offset in and of itself is unimportant. It's is only there to achieve a desired trail dimension with a given rake and ride height.

BTW, experimenting with some of the race cars I build, we ran as little as 1/2 degree of castor (rake) with very good stability. What is the automotive equivalent of the trail dimension? I forget the terminology.
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Old 04-25-2011, 12:48 PM   #77
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Hey Lornce, I'm a motorcycle guy, I call it trail, not sure if car terminology is different.

My thought on offset is that it is a side consideration to rake, and trail. What I mean is: you can achieve the trail number you want with rake alone, however when steering lock limitations (fork, bars hit the tank, ETC.) offset is required to clear the problems, however then more rake is required to get the trail number you had before adding offset.
The other limitation is fork rigidity. The more flexy the fork, to more rake is required to avoid excess flex under braking. More rake means more offset is required to avoid excess trail.
If like foal, you build a very rigid fork, without steering limitations, no offset is needed, just a bit of rake, to get the trail numbers you want.
Of course you could have zero rake, and put an inch, or three of negative offset to achieve the trail numbers you want too.
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Old 04-25-2011, 02:01 PM   #78
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Quote:
Originally Posted by Houseoffubar View Post
Of course you could have zero rake, and put an inch, or three of negative offset to achieve the trail numbers you want too.
As I recall that's what Foale and co. did with their test mule R75/5 which brought them to their conclusions about the relative unimportance/purpose of rake.

Rake morphed to straight up and down with 4" or trail. They found that suspension action/quality actually improved at that attitude.

Trail is basically the length of the lever working to keep the wheel pointed straight ahead.

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Old 04-25-2011, 02:08 PM   #79
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Yep, that's the one, They did a BMW, and a Ducati. From 0-15 degree's there was almost no handling difference. I think they went from 4 down to 2 inches of trail, with little ill effect.


Oh, enjoying YOUR thread here SOLO! I'll shut up now
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Old 04-25-2011, 02:12 PM   #80
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Originally Posted by Houseoffubar View Post
I think they went from 4 down to 2 inches of trail, with little ill effect.
Don't remember that part.

I'd imagine 2" of trail might be interesting the moment you applied the brakes and wound up with negative trail.

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Old 04-25-2011, 02:18 PM   #81
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Oh, enjoying YOUR thread here SOLO! I'll shut up now

No worries, this is thread for education, as well as being a repository of my half-assed mechanical antics
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your bike is suitably dirty. Well done.
R65LazaruS
So I sold my GS and went shopping for a G/S!
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Old 04-25-2011, 02:32 PM   #82
datchew
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Originally Posted by SOLO LOBO View Post



[/CENTER]
I didn't catch the bent spoke, but there seems to be a ding in the rim OD at about 230 position
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Old 04-25-2011, 03:11 PM   #83
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I didn't catch the bent spoke, but there seems to be a ding in the rim OD at about 230 position
Check 300-310, just above the round sticker on the lower drawer of the lower tool box...

But that being said, say hello to my new wheel (that I will get in a few weeks)...

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Quote:
Originally Posted by Stagehand
your bike is suitably dirty. Well done.
R65LazaruS
So I sold my GS and went shopping for a G/S!

Solo Lobo screwed with this post 04-25-2011 at 03:36 PM
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Old 04-25-2011, 08:31 PM   #84
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Yes! Looks much nicer!

Quote:
Originally Posted by SOLO LOBO View Post

But that being said, say hello to my new wheel (that I will get in a few weeks)...

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Old 04-27-2011, 12:40 AM   #85
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Got a reply from Gletter regarding an inquiry about their triple clamps for 50mm WP extremes. As part of the email they sent me an image I hadn't seen before and I thought it belonged here.
Nice looking, not so cheap
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Old 05-01-2011, 04:38 PM   #86
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Second verse, same as the first (sort of)

Start


so far so good


and still going fine


still OK


and then this trick didn't work again... that top nut wouldn't come off.


then the stupid's struck... I couldn't get that nut off, and the other side kept loosening (here is where I didn't say to myself, oh, just slip the spacer in from the other side). I made two clamping blocks out of increasing hardness' of wood and they failed, and I tried everything else I could think of. I kept saying to myself "don't clamp it in the vice" and what did I do? I clamped it in the vice

I totally f-upped the damper tube, no problem while they are in short length, but will land in the area of travel when extended again. I need to find a replacement.




Done with the first step in this conversion (still need oil)


From here


to here in 30 minutes


Houston, we have a problem, lower triple hits the stock steering bumper not allowing the clamp to seat the lower bearing fully






Need to go see a machinist, ain't gonna cut that tab


parting shot to ponder... will rotate this one later

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Quote:
Originally Posted by Stagehand
your bike is suitably dirty. Well done.
R65LazaruS
So I sold my GS and went shopping for a G/S!

Solo Lobo screwed with this post 05-01-2011 at 07:57 PM
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Old 05-01-2011, 05:04 PM   #87
Lornce
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Originally Posted by SOLO LOBO View Post
Need to go see a machinist, ain't gonna cut that tab


You got a file? It's what I'd do.

Hey, Solo. Do you know the distance eye to eye on the stock R80G/S shock?

cheers!
Lornce

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Old 05-01-2011, 06:36 PM   #88
Airhead Wrangler
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Quote:
Originally Posted by Lornce View Post
Hey, Solo. Do you know the distance eye to eye on the stock R80G/S shock?

cheers!
Lornce

It's either 360mm or 361mm depending on which source you want to trust. Not a big deal if you choose the wrong one of the two.
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Old 05-01-2011, 07:54 PM   #89
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You got a file? It's what I'd do.
Yeah, that's my fallback. All depends on the cost to have that flange machined off.
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"punk rocks what it's all about" - J. Strummer

Quote:
Originally Posted by Stagehand
your bike is suitably dirty. Well done.
R65LazaruS
So I sold my GS and went shopping for a G/S!
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Old 05-01-2011, 07:54 PM   #90
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Nice update Solo.
Damaging things in the Vice? I'm pretty good at that trick!

So, as we were led to believe, the steering stop is a problem eh?



I too would probably just take to it with a file, after I attacked it with an angle grinder. Of course, first I would clamp it in the vice to do all this!
Looking at this photo it looks like if you turned the triple towards either extremes (left or right) that the steering stop would at some point drop down past the ridge that is blocking it allowing the bearing to seat. Is this the case?
I am trying to imagine the radius of material that would have to be removed from that ridge. How thick/high is this ridge btw?

On the other hand, would packing the lower bearing up with a spacer work? Would depend if you have enough length in the stem I suppose.

Keep up the good work.
P.S. My WP50 ktm front-end seller seems to have disappeared. No reply for a couple of weeks now. I have been hoping for a long holiday on his part, but it might be time to start looking again. Dammit.
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