fzr400 1wg and 3tj frame rake angle geometry question

sev · Post by **sev** » Fri Feb 06, 2015 8:25 am

Hi All,

I have a 1wg 400 frame which I am looking to start a project with.

I was looking through some websites for inspiration and ideas and I was surprised.

I believed that apart from the obvious physical changes, the rake angle and wheel base was the same across all the fzr400's with the 400rrsp maybe having a shorter wheelbase, but otherwise they were all 24 degrees rake and 1400mm wheelbase. iirc the 1wg has a greater ground clearance but I had put that down to the rolling radius of the 18" wheel and tyre.

Would a more learned member be able to help me?

many thanks

RoadDogma · Post by **RoadDogma** » Fri Mar 20, 2015 2:01 pm

1WG:
-Rake: 24 degrees
-Trail: 89mm
-Wheelbase: 1400mm

3TJ:
-Rake: 24 degrees
-Trail: 92mm
-Wheelbase 1365mm

Increased trail on the 3TJ was influenced by 5mm less fork off-set in the tripple clamps and moving to a 120/60-17 front tire. Swingarms are the same length, so wheelbase is due to decreased frame dimensions. My 3TJ 160/60-17 tire mounted on the 4.5 inch rim has the same overall diameter as a 1WG 140/60-18, so I would say any difference in ground clearance would be a result of fork length/spring rate and swingarm angle.

Evilchicken0 · Post by **Evilchicken0** » Fri Apr 17, 2015 6:52 am

The 3TJ is shorter to the headstock than the 1wg. The 3tj SP uses similar forks to the RWU R6, both are 43mm dia, but the R6 forks are taller.

greasemeup · Post by **greasemeup** » Sat Apr 18, 2015 4:47 pm

RoadDogma wrote:1WG:
-Rake: 24 degrees
-Trail: 89mm
-Wheelbase: 1400mm

3TJ:
-Rake: 24 degrees
-Trail: 92mm
-Wheelbase 1365mm

Increased trail on the 3TJ was influenced by 5mm less fork off-set in the tripple clamps and moving to a 120/60-17 front tire..

Could I ask what "5mm less off-set" means, is it distance reduction between centre of fork leg to centre of bearing stem?
Another question was what dice tire did this model move from?

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Evilchicken0 · Post by **Evilchicken0** » Mon Apr 20, 2015 11:45 am

http://www.gearheadcollege.org/knowledg ... w.php?id=2

The 3TJ uses 120/60 R17 front
160/60 R17 Rear

The rear 3TJ wheels doesn't fit the any of the 1wg swingarms

greasemeup · Post by **greasemeup** » Tue Apr 21, 2015 3:49 am

So without looking at "tree rake" I was right, except it would seem that an increase of tree offset would be needed to increase trail, rather than a reduction?

Thanks for the link evil hook

gives a clear insight into the results of making changes, if you take the time to draw it out & do the trig

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greasemeup · Post by **greasemeup** » Tue Apr 21, 2015 4:00 am

What was it you are looking for SEV? Are you trying to pick the " best" base to start your project with?

What is your target?

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RoadDogma · Post by **RoadDogma** » Sun Apr 26, 2015 3:25 pm

Evilchicken0 wrote:The rear 3TJ wheels doesn't fit the any of the 1wg swingarms

Modify the swinger to accept the 3TJ axle, and make up some wheel spacers. It will fit.

greasemeup wrote:So without looking at "tree rake" I was right, except it would seem that an increase of tree offset would be needed to increase trail, rather than a reduction?

Yes, except increasing off-set decreases trail.

More reading here. http://www.sportrider.com/art-science-f ... ry?image=0
Calculator for lazy people, like myself. https://www.rbracing-rsr.com/rakeandtrail.html

greasemeup · Post by **greasemeup** » Tue Apr 28, 2015 7:11 am

RoadDogma wrote:
Evilchicken0 wrote:
greasemeup wrote:So without looking at "tree rake" I was right, except it would seem that an increase of tree offset would be needed to increase trail, rather than a reduction?
Yes, except increasing off-set decreases trail.

More reading here. http://www.sportrider.com/art-science-f ... ry?image=0

Got it now, thanks for sharing your knowledge base.

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Evilchicken0 · Post by **Evilchicken0** » Tue Apr 28, 2015 11:43 am

RoadDogma wrote:
Evilchicken0 wrote:The rear 3TJ wheels doesn't fit the any of the 1wg swingarms
Modify the swinger to accept the 3TJ axle, and make up some wheel spacers. It will fit.

Is that the usa 3GM model ???

RoadDogma · Post by **RoadDogma** » Tue Apr 28, 2015 10:26 pm

U.S. FZR400s (1WG) got the 1WG box-section swingarm (1989), or the 3EN2 Deltabox swing arm (1990) Both offer the same width, but I lied. The rear caliper mount and sprocket carrier will also need machine work to get the 3TJ wheel in. Similar to fitting a TZR250 wheel. I've read of other accounts, but personal experience was limmited to mock up. I decided to swap over the 3TJ swingarm, as well. This allowed better clearance to space the rear sprocket out to align with with the T-Cat motor counter sprocket.

Evilchicken0 · Post by **Evilchicken0** » Wed Apr 29, 2015 7:47 am

Yes I think the later 4JH and 4TV engines might have the sprocket in a slightly different position, possibly to allow for the larger tyre.
There was a rumour the Suzuki rear would fit

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