Topic: Best Triple Tree for Seeley

[Humble Pie]

I got a tree with this thing but its kinda funky ( lil tweaks here and there ) I have been reading there are a few different rake CB750 trees, which one will give the best steering with the Seeley 28 degree rake ?

Here is all the parts for the dual disc front end, that came with the bike, it was sitting for 30 years the guy said so guessing that kind of dates the parts.

Also are the two threaded posts on the neck for fairing mount ?

[turboguzzi]

you should be aiming to about 4" trail

enter your data here changing offsets till you get the right trail,
enter 0 & 0 in the last two boxes (they are for harley double offset triples only)

https://www.rbracing-rsr.com/rakeandtrail.html

[Humble Pie]

Also what do I need as far as master cylinder ? It has dual stock calipers

[Tim2005]

If you are going with stock forks and wheel (which I bet you will regret as soon as you ride it) then stock triples too, you can't get any triples for 35mm forks with more offset and you wouldn't want less offset.

m/cyl- AP are best, GSXR750 work well with clip-ons, lots of options, depends on fairing choice & clearance too. Radial are really good performers but look too modern imho.

[Retro Rocket]

If you are going with stock forks and wheel (which I bet you will regret as soon as you ride it) then stock triples too, you can't get any triples for 35mm forks with more offset and you wouldn't want less offset.

Less offset is better than more offset Tim, a common misconception, most people get it wrong, less offset will give MORE trail and considering the trail on a 750 is around 3.75 inches stock, a little less offset adds some trail which aids stability, as Turboguzzi said, trail around 4 inches is a good compromise of stability and handling, more offset would be dangerous if not catastrophic.... {most, if not all modern sports bikes have around 4 inches of trail}2 of my 3 750 honda's will have slightly less offset on the triple clamps {slightly more trail}, the 3rd is stock {60mm}, still with custom clamps to suit the 41mm forks i'm using...... The F model 750's had less offset {10mm i think from memory?} and slightly different rake and were known to be more stable than the K's.....

[scottly]

The early K triples had 60mm offset , and the K7/K8 had 50mm offset. I don't know #$%* about F models. In any case, Mr Seeley designed the 750 frame around the original bike, (unlike the Rickman) so the "best triple tree" for a Seeley would probably be a CB unit, at least from a geometry standpoint. 

[Tim2005]

Less offset is better than more offset Tim, a common misconception, most people get it wrong, less offset will give MORE trail and considering the trail on a 750 is around 3.75 inches stock, a little less offset adds some trail which aids stability, as Turboguzzi said, trail around 4 inches is a good compromise of stability and handling, more offset would be dangerous if not catastrophic....

I was of course aware that less offset gives more trail. Having experience of trying different triples on a Seeley, you do not need more trail, less trail improves the turning and stability is still rock solid.   

[Humble Pie]

Perfect, thank you all

[754]

 Ceriani trees, the roadrace type,  may give greater offset, have to check the measurement on mine..

[Humble Pie]

From the look of the parts seems the original owner was going for a CR750 type front end

[Retro Rocket]

Less offset is better than more offset Tim, a common misconception, most people get it wrong, less offset will give MORE trail and considering the trail on a 750 is around 3.75 inches stock, a little less offset adds some trail which aids stability, as Turboguzzi said, trail around 4 inches is a good compromise of stability and handling, more offset would be dangerous if not catastrophic....

I was of course aware that less offset gives more trail. Having experience of trying different triples on a Seeley, you do not need more trail, less trail improves the turning and stability is still rock solid.

That depends on what the numbers are Tim, I was correcting that for the OP as you DO NOT want to have less trail if the bike he has, has stock Honda clamps, as i said, that would be dangerous and tank slappers and instability would be the result of the low trail numbers..
What rake does the Seeley frame have and whats the stock Seeley offset..?

[Humble Pie]

28 degree rake

56.6in wheelbase, 30in seat height. Engine lower by O.5in, seat by 2in than original Honda. Ground clearance 6in, castor angle 62 deg, trail 9 in. Turning cycle 18ft 10in.

[Retro Rocket]

28 degree rake

56.6in wheelbase, 30in seat height. Engine lower by O.5in, seat by 2in than original Honda. Ground clearance 6in, castor angle 62 deg, trail 9 in. Turning cycle 18ft 10in.

Trail can't be 9 inches, it would handle like a long chopper if that was the case, great in a straight line but you'd have to talk it into going round corners... , I think you'll find its around 4 inches... If you can give me the triple clamp offset i can calculate the trail...

[scottly]

Since the stock Honda trees available in '75 had 60mm offset, that's the number I would use, Mick.

[Retro Rocket]

Since the stock Honda trees available in '75 had 60mm offset, that's the number I would use, Mick.

Yeah, somewhere around there Scott, the rake is very similar to the old Honda's as well, 60mm would do fine...   If thats the case there are plenty of people making clamps for the stock sized forks...

[Humble Pie]

Cool thanks and here is where I got the trail info from

http://www.seeley-honda.com/tech.data.htm

[scottly]

That may be a typo? Perhaps it is 9 cm, or 3.543"?

[Retro Rocket]

That may be a typo? Perhaps it is 9 cm, or 3.543"?

 

thats possible but i just calculated that if you have 325mm to the centre of the front wheel spindle {got that measurement from a 19 inch tire shod wheel in my garage}, with 28 degree headstock angle and 60mm of offset, the trail would be around 104.8mm {4 and 1/8th inches}. if you drop down to an 18 inch front wheel its 91.5mm of trail {3.6 inches}, if using an 18 inch front i would use a 50mm triple clamp offset to give 102.8mm of trail {4and 3/64 inches}...

[01Thomas]

I run my Seeley with stock trees and stock wheels, with modified stock forks (changed the spring rate) and Konis in the rear. I also have a dual disc set-up and I use the stock master cylinder (with a small mod). I have several bikes, younger and older, faster and slower than the Seeley and for me it handles nicely. We don't know in which direction you want to take your Seeley (figuratively speaking) but my recommendation is to stay with the stock tripple-trees.

As someone else here said, Colin Seeley designed his frame to work best with stock Honda components - in the 1970s.

[Retro Rocket]

As someone else here said, Colin Seeley designed his frame to work best with stock Honda components - in the 1970s.

Whilst i understand what you are saying,  I also know that suspensions and understanding of suspension geometry has come along way since then and if you know what you are doing you can always improve on what was done way back then, If Colin Seeley was to build that frame today he would definitely use different geometry......

[scottly]

Thomas, were there any geometry changes, ie rake, for the F Seeley frames, or just oil tank mounting tabs? What about the racing frames?

[Retro Rocket]

Thomas, were there any geometry changes, ie rake, for the F Seeley frames, or just oil tank mounting tabs? What about the racing frames?

Thats a good question Scott, as the F model Honda's had different geometry....

[Humble Pie]

Thomas, were there any geometry changes, ie rake, for the F Seeley frames, or just oil tank mounting tabs? What about the racing frames?

Thats a good question Scott, as the F model Honda's had different geometry....

yes ,,and

[Retro Rocket]

Thomas, were there any geometry changes, ie rake, for the F Seeley frames, or just oil tank mounting tabs? What about the racing frames?

Thats a good question Scott, as the F model Honda's had different geometry....

yes ,,and

Slightly different rake and 10mm less offset on the triple clamps.

75/6 F  wheelbase 57.9 inches
            caster angle  28 degrees
            offset 50mm
            trail  4.5 inches
           
76K     wheelbase 57.3 inches
           caster angle 27 degrees
           offset 60mm
           trail  3.7 inches

[Humble Pie]

Thomas, were there any geometry changes, ie rake, for the F Seeley frames, or just oil tank mounting tabs? What about the racing frames?

Thats a good question Scott, as the F model Honda's had different geometry....

yes ,,and

Slightly different rake and 10mm less offset on the triple clamps.

75/6 F  wheelbase 57.9 inches
            caster angle  28 degrees
            offset 50mm
            trail  4.5 inches
           
76K     wheelbase 57.3 inches
           caster angle 27 degrees
           offset 60mm
           trail  3.7 inches

Awesome, thank you