Slimline frame dimensions needed

timmyC · Jun 26, 2022

I recently purchased a Triton project with a 1966 Atlas frame. Someone has cut the shock and exhaust mounts off the frame. I have searched the forum and the web but can’t find enough information to fab replacement parts. Or is their someone that offers these parts for sale? Thanks for the help!

Fast Eddie · Jun 26, 2022

The slimline frame had those loopy shock mount tubes going on.

The best looking Tritons that Degens used to build used slimline frames with all that hacked off and a ‘normal’ wideline style rear sub frame welded on.

Really made one wonder why the factory didn’t do that, as it had the looks of a Manx frame but was slimmer in the middle.

Made for a very slim and nice looking bike.

You don’t need the exhaust mounts either, alloy footrest plates extended to the rear is the ‘norm’ on a Triton, this way you can design the plates to fit your pipes and forgo unnecessary excess brackets etc.

t ingermanson · Jun 26, 2022

Can't vouch for the accuracy of the numbers, but here's a couple somethings:

I'm with @Fast Eddie on the aesthetics. The rear loops are easier and faster to make than the segmented subframe found on the Wideline if you're the factory and already have the box-section upper shock mounts, and the fabricated exhaust brackets. But, since none of us are so equipped, a wideline style might be easier as well as look better.

Andover Norton sells frame bits more closely resembling Manx frames than either of the standard road going Wideline frames. None of the tubes for AN are mitered though, so it's not an easy solution. The seat loop could probably be massaged to work on a Slimline and they've got a bunch of brackets and gussets that would be helpful.

There's several folks making aftermarket Featherbeds, so unless you've got the know-how and tools for fabrication, it might be easier to send it to one of those outfits. A buddy with a buzzbox MIG welder might do ok, but also might kill you.

Fast Eddie · Jun 26, 2022

t ingermanson said:
Can't vouch for the accuracy of the numbers, but here's a couple somethings:

View attachment 96311 View attachment 96312

I'm with @Fast Eddie on the aesthetics. The rear loops are easier and faster to make than the segmented subframe found on the Wideline if you're the factory and already have the box-section upper shock mounts, and the fabricated exhaust brackets. But, since none of us are so equipped, a wideline style might be easier as well as look better.

Andover Norton sells frame bits more closely resembling Manx frames than either of the standard road going Wideline frames. None of the tubes for AN are mitered though, so it's not an easy solution. The seat loop could probably be massaged to work on a Slimline and they've got a bunch of brackets and gussets that would be helpful.

There's several folks making aftermarket Featherbeds, so unless you've got the know-how and tools for fabrication, it might be easier to send it to one of those outfits. A buddy with a buzzbox MIG welder might do ok, but also might kill you.

Timmyc would be well advised to contact you IMHO !

t ingermanson · Jun 27, 2022

Fast Eddie said:
Timmyc would be well advised to contact you IMHO !

I have replaced rear ends before.

lcrken · Jun 27, 2022

Here's a couple more that I snagged off the web some time back. Like t i above, I can't vouch for their accuracy.

Ken

lcrken · Jun 27, 2022

And just for fun, the featherbed patent info.

Ken

t ingermanson · Jun 27, 2022

lcrken said:
Here's a couple more that I snagged off the web some time back. Like t i above, I can't vouch for their accuracy.

View attachment 96317

View attachment 96318

View attachment 96319

Ken

Head angle give or take 5-6 degrees.

timmyC · Jun 27, 2022

Thanks so much for all the drawings and suggestions. I have seen most of them and was going to start to compare them all to see if I could get a complete and accurate picture. I do like the idea of fabricating the parts to match the wideline design. I like the wideline look better than the slimline. I will post a few pics of what I decided to go with. Thanks again!

t ingermanson · Jun 28, 2022

None of the drawings seem to have the placement of the upper shock mounting holes, just the loops. Do you need those? I can measure if needed.

lcrken · Jun 28, 2022

t ingermanson said:
Head angle give or take 5-6 degrees.

According to Ken Sprayson, all the featherbed frames originally had a 26 degree rake. Having said that, it's not uncommon to find one that is more like 24 degrees due to a crash. The telltale on those frames is usually a slight bend where the down tubes have bent just below the steering head.

Ken

timmyC · Jun 28, 2022

t ingermanson said:
None of the drawings seem to have the placement of the upper shock mounting holes, just the loops. Do you need those? I can measure if needed.

Yes that is my point. All the drawings give you almost enough info to make the parts. Yes any dim that you can provide to locate and replicate the shock mounts would be much appreciated. Thank you!

t ingermanson · Jun 30, 2022

Here's what I measured on a '57 Wideline. I can vouch for this frame only, but the numbers were so startlingly round, that I can only assume they are correct.

I did a rudimentary drawing (length of string as compass, etc) and drew it on 1" sq graph paper. The squares are actually not that square, but it gives the drawing some reference and a rough scale. The numbers are true and accurate (as much as you can get with a pretty thickly painted frame), even if the radii and graph paper are not. The numbers were drawn using a scale and not to the printed squares.

The horizontal reference is the top of the top rails (up to the point where they begin to arc up toward the headstock), and the vertical reference is the back of the seat rails.

If anyone wants to double check my numbers, please add to this!

Since you're building a Triton, maybe get the Slimline seat you'd like to use (if it'll be an off-the-shelf item) and build the profile of the top rails to fit within the seat's confines, to the pertinent dimensions below.

I think that seat loop from Andover would be a good place to start, and the plates, gussets, fender, seat and tank mounts are probably worth buying done and ready to weld together. My 2 cents.

The shock mount plates for the Andover frame more closely resemble the Manx, rather than the shape of the road Widelines' plates, but the holes should be in the same spot.

The oil tank mounts are different between the Manx and the road bikes, but you'll not be able to fit a Manx style tank into the Slimline anyway.

Andover shows the subframe tubes being 3/4", but the later road Wideline bikes (not bolt-up) are definitely 1".

Good luck!

timmyC · Jul 1, 2022

t ingermanson said:
Here's what I measured on a '57 Wideline. I can vouch for this frame only, but the numbers were so startlingly round, that I can only assume they are correct.

I did a rudimentary drawing (length of string as compass, etc) and drew it on 1" sq graph paper. The squares are actually not that square, but it gives the drawing some reference and a rough scale. The numbers are true and accurate (as much as you can get with a pretty thickly painted frame), even if the radii and graph paper are not. The numbers were drawn using a scale and not to the printed squares.

The horizontal reference is the top of the top rails (up to the point where they begin to arc up toward the headstock), and the vertical reference is the back of the seat rails.

If anyone wants to double check my numbers, please add to this!

Since you're building a Triton, maybe get the Slimline seat you'd like to use (if it'll be an off-the-shelf item) and build the profile of the top rails to fit within the seat's confines, to the pertinent dimensions below.

I think that seat loop from Andover would be a good place to start, and the plates, gussets, fender, seat and tank mounts are probably worth buying done and ready to weld together. My 2 cents.

The shock mount plates for the Andover frame more closely resemble the Manx, rather than the shape of the road Widelines' plates, but the holes should be in the same spot.

The oil tank mounts are different between the Manx and the road bikes, but you'll not be able to fit a Manx style tank into the Slimline anyway.

Andover shows the subframe tubes being 3/4", but the later road Wideline bikes (not bolt-up) are definitely 1".

Good luck!

Edit: Just noticed the file got cropped somewhere along the line. I'll get the uncropped version tomorrow at work.

Thank you very much!! That is the info I needed. I truly appreciate all your input. Enjoy your day

t ingermanson · Jul 1, 2022

timmyC said:
Thank you very much!! That is the info I needed. I truly appreciate all your input. Enjoy your day

Just replaced the drawing with the uncropped version in the above post.

No sweat. This forum has been a big help to me, so I'm happy to do what I can to help others.

Let me know if you need any other dimensions.

timmyC · Jul 1, 2022

t ingermanson said:
Just replaced the drawing with the uncropped version in the above post.

No sweat. This forum has been a big help to me, so I'm happy to do what I can to help others.

Let me know if you need any other dimensions.

Thank you, will do!

Fast Eddie · Jul 13, 2022

This is an example of a slimline frame modified with a Manx style rear subframe. Makes a really nice, neat, slim frame. If you have a frame sans rear loops, this is definitely the way to go IMO:

timmyC · Jul 14, 2022

Hi. I do like the look of the wideline rear And think I am go into go that route. I need to check a friends tubing bender to see how thigh of a radius it can bend in a 1” or 3/4” od tube. Any idea on a source for that style of header pipe? I really like the style that crosses over the side of the motor. Thx!

Matt Spencer · Sep 13, 2022

Couple of THINGS with THOSE PIPES ! Only seen out of dozens of makes , ONE that swept IN at the rear lower frame rail . ALL others were WIDE there .
As its the FIRST PLACE to GROUND , its totally unacceptable . If youre going to go on a race track . Picture illustrates how it wants to fit , HIGHER there
increses LEAN ANGLE also , as per picture . When they used the ' Trigonic ' Race Tyres , with the increased lean angle through increased GRIP ,
they went to the HIGH PIPE , so as to avoid GROUNDING the EXHAUST . !

Actually , you can SEE the ' race ' gearbox , non kickstart , outer cover . Recessed to allow the pipe to fit in closer .
An ancient Motorcycle Mechanics mag , stated the TRIUMPH ENGINE fits the NORTON engine plates , IF you
Redrill One Hole ( of three ) but the Cylinder is canted forward . ( Which improoves the look , sit , C G , / weight distribution , And the VIBE's ! as the plane of vibration is angled .

However , the orrible Triumph Chaincase , at the clutch , is WHERE it holds the pipes to LOW & OUT , therefore , if its ' All Triumph ' , if its mounted so as the lower chain run is about
parrallel to the lower frame rail , Canting the whole assembly , You might fit the pipe in against the frame rail , preferably with 45 degree ' Lean cCearance ' .

If youre iting moden sticky tyres , and racing . ? Below Dunstal , likely ' Race spec . ? pipes ?? fit up & in , close . Looking at avg. swept Back pipes , many hang low & out , adversly ! .

Maybe you could get copies of the GENUINE RACE THRUXTON swept back pipes ? see how theyre not going to drag . Parently copies of the glass pack straight through mufflers are around too . Terry Mcdonald might be able to help .

Matt Spencer · Sep 13, 2022

Rear Subframe ! Light weight ( Ex Commando 1 in tube ) frame , with 7/8 ? & aft loop 3/4 , sub frame . Orrible pitcher shows the LINES anyway. at Least . NOTE :

The REAR SECTION , after the top shock mounts , though welded , is REPLACEABLE . 3/4 Dia. 16 G. tube bends easy . The GENERAL IDEA being , as youre
RACING , if the fence hit the rear of the machine , the LIGHTER TUBE is the First to Go , Cut the welds - toss it , & fit another , AND its Lighter . Disposable .

That got dual R H pipes , like a Yankee dirt Tracker . More room , that side . and leaves primary access clear . ' UNDER ' T T pipes angle Out aft,
so would be workable too . fitting Inside the lower tube width & under . The EARLY MANX
had similar rear sub frames , the ' kick down , notably .
When Brazed inside the rear top tube , a lick of gas & it will pull out , no worries . You can just about see the joint .

These are the ' T. T. pipes , redilly available ? thatll let you crank it over without dragging . the Triples archilles heel was theyed drag the CASES leant over , dirt tracking , and
Have you OFF . hence the tirade . Press on rewardless . 2 - 6 .

the i.o.M. regs were 45 degree clearance , rider in seat . they had a ' V ' of plywood to check nothing caught .

Slimline frame dimensions needed

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