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Jones truss fork on another bike ?

Posted: Fri Jan 29, 2021 12:35 pm
by ton
can this work? has anyone done it ?

thoughts please.

Re: Jones truss fork on another bike ?

Posted: Fri Jan 29, 2021 2:16 pm
by fatbikephil
Nope. They have 76mm of rake which would wreck the handling of anything but a Jones. Most forks are 45-55 rake. 76mm would reduce the trail to a point where your bars would be flapping around all over the place at low speed and feel decidedly unstable at higher speeds. They are also quite short A-C as Jeff doesn't want people to put suspension forks on their bikes.

Re: Jones truss fork on another bike ?

Posted: Fri Jan 29, 2021 2:39 pm
by ton
thanks for the info mate. every day is a school day. :-bd

Re: Jones truss fork on another bike ?

Posted: Fri Jan 29, 2021 2:47 pm
by Pirahna
I've got two Jones bikes. The way most people fit the Truss fork is using a 10mm spacer on the bottom and a shim on top to tension the fork against the headset. The headset is basically a pair of top bearings, one on the bottom and one on top.

A quick go with a tape measure shows the centre of the axle to the top of the fork crown is 445mm. I've both rigid and carbon Niner forks, these measure up at 470mm. Measuring the head tube on a Jones, including the headset in approx 165mm. My Niner with an external headset is 140mm.

Both measurements have a 25mm difference, so I could fit a truss fork on my Niner using a few spacers to pad it out. If I put the spacers on the bottom of the Niner head tube it should lift the front of the frame sufficiently to retain the handling. I won't be trying it.

Edit: just seen the comment re rake. Another reason not to try.

Re: Jones truss fork on another bike ?

Posted: Fri Jan 29, 2021 3:00 pm
by Bearbonesnorm
just seen the comment re rake.
It's not rake, it's off-set ... rake's something different. Sorry Phil :wink:

Re: Jones truss fork on another bike ?

Posted: Fri Jan 29, 2021 3:05 pm
by jameso
htrider wrote: Fri Jan 29, 2021 2:16 pm Nope. They have 76mm of rake which would wreck the handling of anything but a Jones. Most forks are 45-55 rake. 76mm would reduce the trail to a point where your bars would be flapping around all over the place at low speed and feel decidedly unstable at higher speeds. They are also quite short A-C as Jeff doesn't want people to put suspension forks on their bikes.
Older truss (and I think the SWB fork) has 55mm offset which isn't much past many 29er forks now. A-C would fit some bikes, just not anything designed for a suspension fork longer than a 26" 100mm travel fork. A 445-450mm rigid was slightly shorter than common but still good swap-in for a 26" 80-100mm sus fork.

A Genesis Fortitude could match ; ) Too small for a big guy in the 21" maybe. That was rigid-specific and designed for a 440-445mm fork though it was a 40mm offset on the fork specced - way ahead of that low offset trend eh*

*Nope, just back to 1990s fork offsets

Re: Jones truss fork on another bike ?

Posted: Fri Jan 29, 2021 8:37 pm
by substandard
A mate of mine has fitted a truss fork to his stooge enduro machine, he’s a bit of a slayer and regularly podiums on it with a fully rigid setup!

Not sure what brand the truss fork is though, setup looks slack on his frame and he rides it at warp speed

Re: Jones truss fork on another bike ?

Posted: Fri Jan 29, 2021 9:35 pm
by Hamish
Coastkid managed to fit a truss fork on a Moonlander

http://coastkid.blogspot.com/2013/04/su ... t-and.html

Re: Jones truss fork on another bike ?

Posted: Sat Jan 30, 2021 10:53 am
by psling
substandard wrote: Fri Jan 29, 2021 8:37 pm A mate of mine has fitted a truss fork to his stooge enduro machine, he’s a bit of a slayer and regularly podiums on it with a fully rigid setup!

Not sure what brand the truss fork is though, setup looks slack on his frame and he rides it at warp speed
Possibly a Stooge truss fork, they made one on, I think it was, their Speedball

Re: Jones truss fork on another bike ?

Posted: Sat Jan 30, 2021 11:35 am
by jay91
substandard wrote: Fri Jan 29, 2021 8:37 pm A mate of mine has fitted a truss fork to his stooge enduro machine, he’s a bit of a slayer and regularly podiums on it with a fully rigid setup!

Not sure what brand the truss fork is though, setup looks slack on his frame and he rides it at warp speed
I seen that on the gram(insta) the other day :lol: :oops:

Re: Jones truss fork on another bike ?

Posted: Sat Jan 30, 2021 11:49 am
by fatbikephil
Bearbonesnorm wrote: Fri Jan 29, 2021 3:00 pm
just seen the comment re rake.
It's not rake, it's off-set ... rake's something different. Sorry Phil :wink:
It's not, its the same :mrgreen:
I think the terms use changed in the '70s:-
Image
The chap on the left just added longer forks, the one on the right 'raked out' his head stock so his longer forks didn't jack the front end up. I've heard the term rake used as offset or head angle.....

I'd forgotten that the old truss forks had a more normal 55mm offset, and I did see Bruce Mathieson's Monnie with Jones forks. He said they worked well but sold them due to lack of mud clearance. Moonies had a short A-C though

Re: Jones truss fork on another bike ?

Posted: Sat Jan 30, 2021 11:56 am
by Bearbonesnorm
I've heard the term rake used as offset or head angle.....
So have I, hence my comment :wink: Seems to be something which is prevalent within cycling for some weird reason?

Re: Jones truss fork on another bike ?

Posted: Sat Jan 30, 2021 2:33 pm
by jameso
Bearbonesnorm wrote: Sat Jan 30, 2021 11:56 am
I've heard the term rake used as offset or head angle.....
So have I, hence my comment :wink: Seems to be something which is prevalent within cycling for some weird reason?
There is only (or should only be) Offset, HT Angle and Trail :grin:

Is a curved fork blade raked or offset? :???:

Re: Jones truss fork on another bike ?

Posted: Sat Jan 30, 2021 2:39 pm
by Bearlegged
Shouldn't that be HT angle, offset and axle-ground distance?

Re: Jones truss fork on another bike ?

Posted: Sat Jan 30, 2021 2:44 pm
by Bearbonesnorm
There is only (or should only be) Offset, HT Angle and Trail
Offset, rake and trail :wink:

Re: Jones truss fork on another bike ?

Posted: Sat Jan 30, 2021 2:54 pm
by fatbikephil
jameso wrote: Sat Jan 30, 2021 2:33 pm Is a curved fork blade raked or offset? :???:
dunt matter how you get the offset - curved fork, straight legs set at an angle, leading axle, offset yokes (or crown).
Just had the front end apart of my elderly motorcycle and interestingly as well as the offset in the holes in the yokes, the legs themselves are at an angle to the headstock for more offset.

Re: Jones truss fork on another bike ?

Posted: Sat Jan 30, 2021 2:59 pm
by Bearbonesnorm
dunt matter how you get the offset - curved fork, straight legs set at an angle, leading axle, offset yokes (or crown).
Just had the front end apart of my elderly motorcycle and interestingly as well as the offset in the holes in the yokes, the legs themselves are at an angle to the headstock for more offset.
I was looking at a set of Tolle forks, interestingly (for some) the steering stem is fitted into the bottom yoke at an angle rather than the usual 90 degrees*. Which allows the rake of the fork to be different to the rake of the frame ... see, interesting.


*Yes, I'm aware that 90 degrees is also an angle but it made sense when I wrote it. :wink:

Re: Jones truss fork on another bike ?

Posted: Sat Jan 30, 2021 5:51 pm
by Bedmaker
I don't have much to add to the OP along with what's been said above.

Just came here to add a gratuitous pic of my custom truss fork with 100mm offset, to suit a 63 degree HA. It's more capable on proper trails than a rigid bike has any right to be :grin:
Designed around a 29+ setup, with 150mm spacing giving room for a fat front if required.

Image

I do like a truss fork.

Re: Jones truss fork on another bike ?

Posted: Sat Jan 30, 2021 6:36 pm
by AlasdairMc
I’ve got a XCAD truss on my fat bike. The frame is based on a Stooge, and the fork a 150mm bolt through design. The original owner had a Ti shim made to space out the bottom of the steerer to allow a lower headset race to be used instead of two uppers. Stiff, rides well too.

Re: Jones truss fork on another bike ?

Posted: Sat Jan 30, 2021 6:43 pm
by ScotRoutes

Re: Jones truss fork on another bike ?

Posted: Sat Jan 30, 2021 6:49 pm
by Bearbonesnorm
Ooh I do like that Colin.

Someone I know rides this :wink:
Image

Re: Jones truss fork on another bike ?

Posted: Sat Jan 30, 2021 6:54 pm
by fatbikephil
Two nice machines there, not seen that Van Nic thing before. Hmmm maybe I do want a Ti frame......
Not convinced about the saddle on the moto though :grin:

Re: Jones truss fork on another bike ?

Posted: Sat Jan 30, 2021 6:57 pm
by Bearbonesnorm
Not convinced about the saddle on the moto though
Neither is he anymore Phil - takes a cushion out with him now :wink:

Re: Jones truss fork on another bike ?

Posted: Sat Jan 30, 2021 7:54 pm
by pistonbroke
That Ti fork on the Van Nic Revelstoke is €1300, or the same as a Lauf with change for 100 blindfolds

Re: Jones truss fork on another bike ?

Posted: Sat Jan 30, 2021 10:13 pm
by AlasdairMc
Having cracked a truss fork at a weld, removing half of the legs doesn’t fill me with much confidence.