Light bracket for old Thorn racks

[Edocaster]

Hello all - my Thorn Nomad (2001) model comes with Thorn's original 531 rack, which is different from the current EX rack.

It has a bracket for a rear light like this: http://www.sjscycles.co.uk/thorn-rear-rack-fitting-light-bracket-single-for-1-light-for-original-thorn-steel-rear-racks-prod1727/

...the two vertical holes in the middle are for standard reflector brackets, and I've currently got an old school Vistalite there. I'd like to mount one of the many dynamo tail lights available, but they all have 50 or 80mm horizontal mounting holes.

Short of drilling or fabricating an adaptor, is there a product that converts the vertical holes to the standard horizontal ones? Topeak do something promising (http://www.bike24.com/p233374.html and also visible here: http://www.bike24.com/1.php?content=8;navigation=1;menu=1000,5,79;product=33383), but has anyone used it on a normal (i.e. not Topeak) rack with mounting holes like my current bracket?

Any ideas welcome. Thanks!

[Danneaux]

...is there a product that converts the vertical holes to the standard horizontal ones?

Yes, there is! I ran into just this problem when I used a Surly Nice Rack (Rear) on Sherpa; the rack had a single threaded mounting hole, and it was left to the user to come up with a light-mounting solution.

I found the solution in the form of a USD$7 bracket by B&M (BUMM) sold by Peter White cycles (also available elsewhere) called the "Single Hole Mount Adapter", shown 2/3 down the page here: http://www.peterwhitecycles.com/taillights.asp (photo link here to avoid copyright infringement: http://www.peterwhitecycles.com/images/products/Lights/B&M-bracket-singlehole.jpg ).

It has holes spaced at both 50mm and 80mm, so should allow the fitting of any taillight to your rack and should attach simply by placing the threaded stud in the hole and securing it with the included nylock nut. On the Surly Nice Rack (Rear), I had to thread the stud into the rack's mount, then secure it with a jam-nut in-between. You can see it in profile here: http://www.thorncycles.co.uk/forums/index.php?topic=3896.0 in my "Danneaux's Sherpa" gallery here: http://www.thorncycles.co.uk/forums/index.php?topic=3896.0

I do have two examples of the Topeak mount in my spares box, but decided it would be more secure to use the B&M all-steel mount. The Topeak version has the same vertical spacing as any rear reflector and secured using two self-tapping screws.

Best,

Dan.

[Edocaster]

Thanks for the quick reply. I saw the B&M mount, but the way it fixes with one screw... I'd always believe I haven't got it straight and level!

So there's nothing about the Topeak mount to suggest it wouldn't work on the Thorn bracket?

[Danneaux]

So there's nothing about the Topeak mount to suggest it wouldn't work on the Thorn bracket?

Well...if the Thorn mount will accept a standard reflector, it should also accept the Topeak mount, 'cos the spacing is the same.

Not guaranteeing it'll work, but this one falls strongly into the "should work" category. I'd try it myself to see for you, but my Thorn rack uses a different (newer) mounting plate and everything is attached and ready to go.

I saw the B&M mount, but the way it fixes with one screw... I'd always believe I haven't got it straight and level!

If you decide to go with the B&M, leveling is easy: Just sight across the top of it and align it so it matches the plane of the mounting bracket, then tighten down the nut. Done!

Best,

Dan. (...who also likes his bike stuff on the straight and level)

[Edocaster]

Thanks Dan. I'm putting together an order on a German bike shop site, so should be quite easy to just add the Topeak and see how that goes.

[IanW]

Hi

I have the older "531" Thorn rear rack on my RST
I chose to make a custom rear rack light mount as described in my responses to thread http://www.thorncycles.co.uk/forums/index.php?topic=4771.15

I have manufactured a light mounting plate for both my older "531" Thorn rack on my RST
and a different mounting plate for the newer Thorn "expedition" rack on my spouse's RST

You could obviously "source" *some* mounting option for a 50mm-horizontal-separation or 80mm-horizontal-separation mounting lights
as produced by the likes of Busch & Muller et al.

The question is: Do you want to mount *more than one* rear light?
(I.e. a dynamo-powered light *and* another, possibly battery-powered backup light?)

If so, then a custom mounting bracket is probably required.

Regards
Ian W.

[il padrone]

The question is: Do you want to mount *more than one* rear light?
(I.e. a dynamo-powered light *and* another, possibly battery-powered backup light?)

If so, then a custom mounting bracket is probably required.

If you want to run two lights like this another option is to keep your Vistalite mounted on your rack, and use one of the very good mudguard-mounted tail-lights. B&M have the Seculite 1W LED, and the new Secula with the new linear-focused LED that produces a ring of light. We have three bikes that run the very good Seculite mounted on SKS mudguards, with a backup battery flasher on the rack. I have run the light cable up inside the guard taped in place. These lights have been functioning very well for us for the past 4-5 years.

[Edocaster]

Outstanding job on the plate, IanW. I was tempted to do something similar, but more minimal (just the vertical holes, 50 or 80mm horizontal holes, and the 90mm holes to mount to the rack). But I've made the order now, so will see how the Topeak bracket turns out.

Il Padrone - yes, I also considered a mudguard light, but the wiring seemed like a headache! Even though I can see holes in the mudguard, whether taping the wire inside the mudguard or trying to make use of the conductive strips I believe are in there... seemed difficult and involved more cleaning than I wanted...

I have managed to fit a Smart/Planet Bike Superflash clone sideways on the last horizontal tube of the rack, so will have a backup light. But I'll keep the Vistalite to hand - I could use it one day by getting another of the original 531 brackets and mounting it upside down, if I didn't mind it rising higher than the level of the rack.

[Edocaster]

Quick update on this - the Topeak bracket 'kinda' worked. Unfortunately, while the original Thorn bracket did have the two vertical holes in the right place, one is larger than the other. The small hole (5mm) is just large enough to hold the stud on a Vistalite, but the Topeak has two raised, ridged holes ( ), which are about 6mm. The raised ridge won't seat in the 5mm hole, so would prevent the two brackets being flush with one another.

So I just mounted the bracket higher via one hole. And, yes, it needs to be levelled carefully.

This could be solved by either reaming out the Thorn bracket to 6mm, or filing down the raised ridge on one of the Topeak's brackets and using a second self-tapping screw.

[Danneaux]

Hi Edo'!

One one of my Topeak brackets used on a non-Thorn rack, I just sanded the raised rim of one of the bracket mounting holes flush using my vertical/horizontal disc/belt sander. I think the same thing could be accomplished with a craft blade or file.

After my work, the bracket set nice and flush against the rack and I simply used a second self-tapping screw to hold the bracket securely (and vertically).

Best,

Dan.

[il padrone]

Il Padrone - yes, I also considered a mudguard light, but the wiring seemed like a headache! Even though I can see holes in the mudguard, whether taping the wire inside the mudguard or trying to make use of the conductive strips I believe are in there... seemed difficult and involved more cleaning than I wanted...

Late reply to this.

Not really difficult at all. You just need to drop out the wheel, rub the dirt clean and then run the cable and tape in place with gaffer tap. It's a one-off job. I've had no concerns with tape coming off or anything. The SKS mudguards are conductive with the alloy core - my son rigged up his lights with dual-wire and then some time later I've noticed he has a rear light wire broken (a bit sloppy with his wiring technique). I aked him about it and that he has no rear light. He said "Oh yeah, but the lights are still running as the mudguard gives an earth-return". And sure enough that is correct.

 

I prefer a dual-core cable but if you have SKS guards, the tail-light on the mudguard will connect to the mudguard and then various mudguard mounting bolts will give a return via the frame.

[Danneaux]

The SKS mudguards are conductive with the alloy core...

Hi Pete!

...Have been since the very early 1980s when they were ESGE and...some of the ones intended for the European market even came equipped with snap terminals and matching connectors on their wiring.

Also, see...
http://www.thorncycles.co.uk/forums/index.php?topic=2273.msg15762#msg15762
http://www.thorncycles.co.uk/forums/index.php?topic=2273.msg16261#msg16261
http://www.thorncycles.co.uk/forums/index.php?topic=3896.msg17113#msg17113

Best,

Dan. (...whose homegrown foil-core mudguard terminals from the early 1980s are still going strong)

[martinf]

If you want to run two lights like this another option is to keep your Vistalite mounted on your rack, and use one of the very good mudguard-mounted tail-lights. B&M have the Seculite 1W LED, and the new Secula with the new linear-focused LED that produces a ring of light. We have three bikes that run the very good Seculite mounted on SKS mudguards, with a backup battery flasher on the rack. I have run the light cable up inside the guard taped in place. These lights have been functioning very well for us for the past 4-5 years.

I've also got double rear lights on two bikes, both using B&M Line Plus and Seculite. But lazier external wiring zip-tied along the mudguard stay (just visible in the rather poor photo).

No problems with the lights on either bike so far.

[Edocaster]

Hi Edo'!

One one of my Topeak brackets used on a non-Thorn rack, I just sanded the raised rim of one of the bracket mounting holes flush using my vertical/horizontal disc/belt sander. I think the same thing could be accomplished with a craft blade or file.

After my work, the bracket set nice and flush against the rack and I simply used a second self-tapping screw to hold the bracket securely (and vertically).

Best,

Dan.

Yep, just hacksawed the ridge off. Two screws so all sorted now.

Loving all the mudguard lights from everybody. I think I'll keep to one dynamo light and one detachable blinky for now, though.