Nomad S&S 5mm or 6mm lower carrier mounts?

[vik]

Thanks for the previous help I've rec'd with my Nomad questions.  The beast arrived recently [quite fast for an international parcel!] and I've been slowly trowing parts on it as time allows.  It looks like a great bike and I'm impressed with the attention to detail on this frame.

My question relates to fitting a Thorn rear rack to the Nomad.  Based on the Nomad S&S brochure I was expecting the upper and lower mounting points to be 6mm, but it seems only the upper mounts are 6mm and the lower ones are 5mm.  That goes against logic it seems as the lower mounts certainly take most of the abuse and if you were going to make only one set of mounts oversized it seems the bottom ones should be 6mm.

All the mounts on the fork are 6mm as well which adds to the odd choice of only using 5mm on the rear mounts.

I just wanted to make sure I wasn't missing something obvious before I went any further.

safe riding,

Vik

[Dave Whittle Thorn Workshop]

You need a set of these m8 http://www.sjscycles.co.uk/product-Thorn-Thorn-FOR-ROHLOFF-cast-end-2-x-M5-to-1-x-M6-stainless-dropout-adaptors-per-pair-11703.htm

[vik]

You need a set of these m8 http://www.sjscycles.co.uk/product-Thorn-Thorn-FOR-ROHLOFF-cast-end-2-x-M5-to-1-x-M6-stainless-dropout-adaptors-per-pair-11703.htm

Thanks for the explanation...*sigh*...too bad nobody mentioned that when I ordered the Nomad & Thorn carrier.  I imagine the shipping to Canada is as much as the adapters....

cheers,

Vik

[Dave Whittle Thorn Workshop]

The dropouts were cast before we decided to offer the possibility of M6

There are 2 solutions

Redrill one of bosses each size and tap to M6

Call me on +441278441500 and I’ll do a set of those adapters post free just for the cost of the item

[vik]

Thanks Dave I appreciate that.  I've sent an email as I only have a mobile and international calls are uber expensive.

cheers,

Vik

[Dave Whittle Thorn Workshop]

No worries, I'm not in the office until Monday now, someone may get back to you before then if not I will e-mail you then.

[Grumbler]

 Vik I´m happy you brought this up. I´ve been having this issue on my mind  ???since I noticed this boss size discrepancy on my own Nomad after purchasing it on july 2007. I haven´t loaded up enough my bike yet to worry to post the question myself  but I´m equally grateful for your answer Dave. I didn´t know these adapters even existed until now but I don´t quite like the idea of adding any extra components to the bike, no matter how small, unless they are really necessary. Now, can the mounts be safely redrilled up to M6? I mean: a) isn´t there any risk of weakening the bosses? b) No warranty issues with this?
    I will ask my LBS to do this if the answer to both questions is a solid yes. Since I live in Barcelona I can´t even think of taking my Nomad to SJS´s for this procedure . I would have requested to have it done there when I collected my bike if I had noticed this back then. As a matter of fact I think it should be performed routinely on every Nomad (or any other Thorn bike for that matter stated to have "6mm carrier bosses").
    Vik I wish you enjoy your Nomad at least as much as I am enjoying mine. It´s a hell of a good bike!!!  Dave, thanks again for your help (please reassure me about the redrilling being a safe option) and keep up the good work at SJS´s 
    Enrique Rene

[john28july]

Hello,
Having toured with heavy loads on various bikes including some other than Thorn, I can see no reason at all why the difference in size of these mounts is at all important.
John.

[vik]

Hello,
Having toured with heavy loads on various bikes including some other than Thorn, I can see no reason at all why the difference in size of these mounts is at all important.
John.

John,

Have a read of the Thorn Rear Carrier description - particularly the weight capacities based on surface of the road and size of bolt used to support the weight - the difference between a 5mm and 6mm bolt is significant.

http://www.sjscycles.co.uk/product-Thorn-Thorn-Expedition-Steel-Rear-Cycle-Pannier-Rack--Black-Powdercoat-11694.htm

"Max load when used on surfaced roads:- When fitted with 6mm screws = 60Kg…when fitted with 5mm screws = 40kg. These figures should be halved when being used on South American Ripio."

I think for most people touring on paved roads 5mm bolts would be more than adequate - however, the amount of abuse your bike receives on unpaved roads and offroad is many many times more.  That doesn't mean a 5mm bolt would fail on any given tour, but if you want the peace of mind to carry a heavy load and abuse your bike the larger 6mm bolt makes sense - especially given that just about every other part of the Nomad S&S is beefed up.

cheers,

Vik

[vik]

No worries, I'm not in the office until Monday now, someone may get back to you before then if not I will e-mail you then.

No problem Dave - I'm still assembling the bike so next week is fine.

BTW - I went back to look at the Thorn Expedition carrier and the Nomad S&S frame on the SJSC online store and this adapter isn't one of the "matching items" on either product's page.  That might be something to change as well as adding a note to the carrier's product description that to use a 6mm bolt you need the adapter.  Without that note it's unlikely someone who is not intimately familiar with the ins and outs of the Thorn line up would know they needed to order the adapter.

Thanks again for your help,

Vik

[stutho]

Hello,
Having toured with heavy loads on various bikes including some other than Thorn, I can see no reason at all why the difference in size of these mounts is at all important.
John.

I've bent a M5 rear carrier bolt before now.  Possibly I might of bent an M6 if it had being fitted but a bigger bolt can only be a good thing - within reason.

[vik]

Just to close off the loop on this thread - the 6mm rack adapter I need is in the mail to me - thanks to Dave and Rachael at SJSC for looking after me.

cheers,

Vik

[julk]

If anyone is getting the urge to do a spot of retapping to M6, I just drilled and tapped my rear dropout rack fixing points to take M6 bolts.

It was very easy and took me about an hour, going carefully as this was a first for me.

I got the M6 taps, handle and a 5mm drill from Model Fixings as a kit.