Bonneville America Forums Forums Technical Forums Custom Corner BRAKES

G'day,

I want to upgrade my 02 America with twin disc brakes and keep my big spoke wheel. The question is 'HOW'. If possible I want it to be a Triumph factory set-up... ie the brakes off a Tiger ??

I saw a speedmaster in a magazine with a spoke wheel and twin brakes but he had heavily modified the whole bike 'Marlon Brando' style, looked real cool.

See the problem is when I go for rides with my mates that have speedmasters and I'm following them, if they hit the brakes hard I'm afraid I will just keep going and run up the back of them. Not good. But I can not loose my spoke wheel, its way too cool.

Thanks, KG

I've done a lot of chasing up on this subject - one of the reasons I bought the TBA over a SM was the spoked wheels but I'd really like twin disks on the front.

The Triumph Thunderbird Sport has spoked wheels with twin 310mm disks (same as ours), and I'm told the hub's the same as ours, however the rim's smaller than ours - 17" instead of 18". Both bikes also run 36 spokes so you should be able to lace your standard TBA rim onto the TBird's hub. There's no reason you couldn't use it with the smaller rim (maybe with a higher profile tyre to fill out the guard) and if you're into whitewalls there's more options for the 17" one.

Once you've got the wheel sorted you'd also need the right lower leg from an SM, a right hand caliper, and an extra brake line and fittings. I don't much like the way the SM's have the plumbing for the extra caliper running over the top of the front guard, so I'd either use a splitter under the lower yoke (stolen from a virago maybe) or just run a 2nd line from the master cylinder with a dual banjo bolt.

The bad news is that so far I've completely failed to find anyone who's ever wrecked one of these bikes in Brisbane - I'm not even sure if the Sport was imported into Australia as I've only ever seen the standard TBird here. It might end up that it's easier to buy the hub new from Triumph, or maybe purchase a 2nd hand wheel overseas. If that's the case you then have to find out if the America/Speedmaster rotors will bolt to that hub - you may end up having to buy a pair of TBird rotors, or just one TBA rotor to complete the set.

Let me know if you have any more luck or info on this, as it's something I'd really like to do. Don't know why Triumph didn't do it in the first place.

Matt

A bit more info for you - just spoke to my local parts person who tells me there's no part number for just the hub for the TBird sport, but they'll sell an entire wheel assembly (which of course will be without disks). They've got a steel one at AU$1700 or an aluminium one (which I think is a mag) for AU$1000.

They don't have a part number for disks for the sport but they do for the TBird, and it's different to the number for the America so the disks aren't interchangable. This means you'll need to buy two disks. The right hand outer tube for a Speedmaster sells at AU$825 and the RH brake caliper assembly is $1125.

This won't be a cheap exercise at all if you want to buy new.

Matt

I'm buying a T-Bird rim off a guy on Triumphrat.net and it's an 18"... Not a TBS, a single disc TB rim. Does that make sense that the "sport" would have a smaller rim?

The Triumph Thunderbird has an 18" wheel with a single 320mm disk. The Thunderbird Sport has a 17" wheel sith dual 310mm disks.

Matt

Interesting, I wonder why they went smaller? Well in two weeks I'll have that new rim to replace my bent one. So I'll let you guys know if they are in fact interchangable, and we can add it to that list floating around.

The rear hubs are the same between the T-bird, TBS and BA. The Tbird uses a 17" front and 16" rear. The Tbird sport uses a 18" front and a 17" rear. Th rear hubs are the same but the later models '00 and up use 40 spokes instead of the 32 spokes the BA's use.

Fryguy

Actually, Tbird is 18, TBS is 17.... Right? At least that's what I've seen... At any rate, the hubs are the same!