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Thruxton Wheels on SE (Mag Wheel) - Conversion

11K views 28 replies 10 participants last post by  Toad 
#1 ·
While I realize its unlikely that anyone has first hand experience with this, I thought I'd throw the question out there.

Im considering (further) converting an 09 SE (mag wheel) and replacing the wheels with Thruxton rims. Im failry confident I know what is needed (forks (or just lowers) and wheels (thruxton rotor for the front) and rear wheel will bolt right up.

Why ??
Aside from the "aesthetics" of it (wire wheels look better - imo), the added height and larger wheel would serve me better on dirt roads and 2 track.

Why not use Srambler or Bonnie wheels as they are even taller??
Basically because I like the road manners of the SE much better than the T100 or Scrambler (had/have both) and the slightly taller Thruxton wheel seems like a good compromise.

So on the off chance that anyone has actually done this conversion:

1.Has the on road (pavement handling) been adversely effected?

2.Anything im NOT thinking off in terms of parts needed?

Thanks in advance for any helpful or insightful replies :grin2:

-Brian
 
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#2 ·
Actually, Brian, there is something you haven't thought of. A couple of things, actually. The Thruxton uses the same fork tubes as Scrambler, which are about 30mm longer than mag wheel bikes. They also use longer rear shocks, to keep the bike level, and the space between forks is wider on mag bikes, to accommodate the wider cast wheel. The brake rotor from the cast wheel won't fit the 18" Thruxton wheel, and as you mentioned, you need the Thruxton fork lowers to mount the caliper at the right level for the brake rotor. Not sure about speedometer drive. Yours is on the front wheel, right?
 
#5 ·
You'll need fork lowers from the thruxton, the thruxton wheel with rotor, the speedo drive (on the left instead of the right...spins opposite direction), and a front fender (has proper radius for 18" wheel). Don't bother getting the fender mount/fork brace as it is narrower than your mag wheel one and you have to use the existing.

The rear wheel is a direct swap/nothing needed other than the wheel.

You might want to consider longer shocks in back...otherwise it will turn in way, way slower than you're used to...the heavier, larger diameter wheel combined with increase in rake kills the responsiveness.

BTW, I went the other way on my thruxton before going full F3 conversion...its a lot easier putting the spokes on a maggie than the other way around - so count yourself lucky!!

Regards,

--Rich
Thanks guys for the replies.

Only thing I didnt realize was that the Truxton front end is narrower and the speedo drive being on the opposite side.

Which presents 2 issues:

- Spacers would be needed to take up the slack OR swap out the entire front end - triple tree and all ???

- the SE has the mechanical speedo, so I would as mentioned need the Thruxton speedo drive as well - soooo... that would mean I would need the fork tubes and bits from an older (mechanically driven speedo Thruxton).

(I have the longer rear shocks on hand to accommodate for the added height)


thanks again for the info.
-Brian
 
#3 ·
You'll need fork lowers from the thruxton, the thruxton wheel with rotor, the speedo drive (on the left instead of the right...spins opposite direction), and a front fender (has proper radius for 18" wheel). Don't bother getting the fender mount/fork brace as it is narrower than your mag wheel one and you have to use the existing.

The rear wheel is a direct swap/nothing needed other than the wheel.

You might want to consider longer shocks in back...otherwise it will turn in way, way slower than you're used to...the heavier, larger diameter wheel combined with increase in rake kills the responsiveness.

BTW, I went the other way on my thruxton before going full F3 conversion...its a lot easier putting the spokes on a maggie than the other way around - so count yourself lucky!!

Regards,

--Rich
 
#4 ·
You'll need fork lowers from the thruxton, the thruxton wheel with rotor, the speedo drive (on the left instead of the right...spins opposite direction), and a front fender (has proper radius for 18" wheel). Don't bother getting the fender mount/fork brace as it is narrower than your mag wheel one and you have to use the existing.
(snip)
...its a lot easier putting the spokes on a maggie than the other way around - so count yourself lucky!!

Regards,

--Rich
Hey Rich, doesn't he also need a wheel spacer, to take up the slack for the narrower hub?

@Toad ^^^ this guy KNOWS ^^^
 
#9 ·
...and a front fender if the radius on the SE one appears odd once you get the wheel mounted up. It might be fine. You'll use your SE fork brace/fender mount either way.

I'm not 100% positive, but I believe the cush drive was identical...other than it being black of course, whilst the thruxton one is raw alloy. I can email you a pic of the drive side of my thruxton wheel & its cush drive if you want. I've kept the wire wheels around in the event I want to revert my thruxton back into something that has a narrow rear wheel, slow turn in up front, and crappy rubber choices all around. Wait. was that my outside voice? ;)

No worries on the brakes, either....Triumph has used the same tired 2-pot caliper on all models. $$s to donuts that they have the same unit on the water cooled bikes...and putting twins calipers on the T120 allowed them to use up that old speedmaster inventory languishing on the shelf.

Good luck with your conversion.

Regards,

--Rich
 
#10 ·
Wait a minute.... now im confused. The SE has a 3.5" rim width. I thought the Thruxton rear rim is the same @ 3.5"???

FWIW - I do get that the bike will not handle as well on pavement... but since I hit the half century mark my "go fast" days are behind me. I describe my riding style as "tourist" :ride

-Brian
 
#13 ·
just in case anyone is following along and/or is interested in doing the same thing (unlikely)

I recently started this conversion.... not quite sure I would be happy with the change in handling, I took some time to ponder the change and compiled the parts I needed (&thought I needed).

Swapping out the SE forks with Thruxton forks (whole fork or just the lowers) you are in fact left with roughly a 1/4" gap on the right side. The shoulder on the axle does not make up for the difference in the width of the SE hub vs. Thruxton hub.

I was considering making a spacer to fill in this gap when it occoured to me that this will result in the Thruxton wheel being off "center" with the rear by that same amount.

With the speedo drive in place on the left side and caliper bolted to the fork its not possible to "center" the wheel in the forks (and with the rear) using equal spacers on both sides.

Best solution is to swap out the SE yoke/tripe tree with Thruxton yoke/triple tree. Which I do not currently have.

Now you and I know.... :wink2:

Ill update this I make progress. Likely sloooooowly.

-Brian
 
#14 ·
Update

Again, just in case anyone is interested....

I have the 18" Thruxton wheel and forks mounted. I fabbed up a space for the right side.

The wheel is off center (out of line with the rear) by about 1/4" (best guess) but it doesnt appear to effect the handling.

That said, I have to believe that this cant possibly be "O.K." so Im in the process of swapping out the triple tree on the SE with that of a T100 (same spacing as the Thruxton).

Once done, that should line up the front and rear wheels and finish the job.

More to come.

Interestingly this thread makes no mention of the issue with this...

-Brian
 
#15 ·
The wheel is off center (out of line with the rear) by about 1/4" (best guess) but it doesnt appear to effect the handling.

<snip>

Interestingly this thread makes no mention of the issue with this...
But the following post in this very thread does...;)

http://www.triumphrat.net/air-coole...s-on-se-mag-wheel-conversion.html#post8770409

So have you checked the alignment or just assume it is off due to the 1/8" width differential in the triple clamps?

The reason I ask is because the rotors are aligned in the calipers front & back...that hasn't changed. So the only difference in front to rear wheel alignment would be how much offset is built into the laced rim vs. the offset provided in the cast wheel. It might warrant an alignment check before getting all worked up about this perceived issue.

Regards,

--Rich
 
#16 ·
It really is a good ides to run a string line around the back wheel past the front, taking into account tyre size difference, measure it up, will tell at least how in line they are, I like to get this to ~1mm, my mag wheel bike likes the 17x3" wheel and geometry on the mag wheel bike withe 360mm thrux length rear shocks, next favorite is thruxton geometry with 18" front wheel, this is quicker steering than T100 triples trees.

Sent from my SM-T310 using Tapatalk
 
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#17 ·
If you are having problems centering the wheels between the forks/swingarm while maintaining clearance for the rotors, why not just get longer bolts to attach the rotors to the hubs and devise some sort of shim/spacer to take up the slack? If you bring your parts to a machine shop or have measurements or can make a basic drawing, they should be able to whip up a full set of custom spacers for you for like less than $100. Tbh, this whole changing forks/wheels thing sounds like a lot of work for very little improvement. Can you not achieve the same change in rake by manipulating tire sizes?
 
#19 ·
Mike, the idea of using 18" Thruxton rim up front (vs. the 17" cast) came from my experience riding all various forms of Bonneville (T100, Scramblers, SE's, Thruxtons). While the SE definitely handles better on pavement than any of the others, I wanted more ground clearance and more "off-road-ability" than the cast wheels provide without losing (too much) of the SE's road manners. The 18" Thruxton wheel was the compromise.

What I can say is that side by side on pavement the SE - even with the "not centered" 18 Thruxton wheel on front, somehow still has handles better (quicker in turns and feels more nimble) than a Thruxton on pavement..... I realize "handling" can be a bit subjective. Possibly the difference in rake between the SE and the Thruxton accounts for this difference? Maybe the ever so slightly shorter wheelbase on the SE makes the difference??

At some point I plan on swapping the wheels/tires between the bikes (SE has Sinko 705 and Thruxton has OEM Metzler up front) to see how it effects the handling on the different bikes.
 

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#20 ·
dont forget the shorter kickstand, I recently did a similar conversion and ended up with a bike that leaned wayyy to far to be comfortable when it was parked. I ended up swapping the kickstand but also had to swap the left frame rail since they are actually different at the kickstand mount
 
#21 ·
Why would you? ... my Thruxton wheels leaked air like crazy, to the point it was almost unsafe! I have a NewChurch with mag wheels, great!!! I love the wire wheel look and should I need it again, and I will ... the answer will be to purchase good quality aftermarket rims.
 
#23 · (Edited)
Mission Completee (mostly)

For anyone interested and/or playing along at home, I have (mostly) completed the conversion.

Twas indeed alot of work, but now that its completed and I've sorted out all the "what works and what doesn't", I can say that if I had known then, what I know now... it'd be much easier.

Take one SE (mag wheel) and add"

- 1 part T100 (Top and Bottom Yokes)
- 3 parts Scrambler (Header pipes, Right side Hanger, rear Master Cylinder)
- 3 parts Thruxton (Wheels, Speedo drive, Forks)

add a few custom bits, reroute a couple cables, torque to specs and you get one ScrambledBonnieThruxton

Pros:
- Increased Ground Clearance
- Smoother ride (longer travel suspension)
- Better looking (subjective)

Cons:
- Higher COG (slightly noticeable in turns)
- Tubes

Still need to sort out the side stand (figured the Thruxton would be a simple bolt on - hint = it isnt).. so sorting out a proper side stand is next up.

With the addition of tubes, the need for a center stand in case of tire puncture is job two.

Still have to fab up a front fender and likely will go with a Thruxton (bobbed).

Before anyone asks or wonders - the total cost of all the parts was nominal compared to the cost of aftermarket wheels alone.
Most of the time spent was sorting out what will work and being patient and gathering the bits.

In the end I am extremely happy with the results and have the bike "I" want... for now :wink2:


a couple questions remain:

Anyone know if a T100 Side stand will bolt up correctly to an SE frame ????

Anyone know if a T100 center stand will work on an SE frame with Thruxton height suspension ????

-Brian
 

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#26 ·
a couple questions remain:

Anyone know if a T100 Side stand will bolt up correctly to an SE frame ????

Anyone know if a T100 center stand will work on an SE frame with Thruxton height suspension ????

-Brian
Nice bike there......... :smile2:

The frame cradle on the left hand side is different on the SE models (and later Bonnevilles Part # T2075251) compared to the other higher models, including the T100 (Part # T2075241). So I don't think the T100 side stand will fit.

You'll need to mod your old one or you could buy a left hand cradle from another model they do come up on eBay every so often, my guess it's only the side stand area that is different.

Sorry, not sure about your centre stand question, you'd need to bolt one up and see.
 
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