Street Twin Brake Disc

The original Street Twin has a non-floating 310mm front brake disc. The second gen Street Twin comes with a better Brembo caliper and floating brake disc. Does anyone know if the floating brake disc (not the caliper) will fit the earlier ST's?

 

Anyone tried this mod? Or can someone with the 2nd gen Street Twin tell me the diameter of the front disc?

Hmm, done a bit of research on this. The ABS pulser ring on the older model is part no. T2022122 but the newer one is T2022022 and costs significantly more. This suggests that the pulser ring from the older model is not compatible with the newer disc.

 

Still pursuing this search. I'm looking for a floating front disc to replace the non-floater on my 1st gen Street twin.
The floating disc from the 2nd gen Street Twin has a different ABS pulsar ring, so I'm guessing that won't work.

Today I was at the Superbike shop in Macclesfield and noticed a T100 with the same 2-pot caliper as my ST but with a floating disc. I think the 1st gen T100 came with the same brake set up as the 1st gen Street Twin (ie. non-floating disc) but this was later upgraded to the floating disc BUT it kept the same caliper. If this is the case then that floating disc from the T100 should fit the ST and be compatible with the ABS.

Any useful comments or advice appreciated, especially from T100 owners.

I have thought about asking at a Triumph dealer but I know from experience they probably won't have a clue!

 

That is extremely helpful Paul and thanks for going to the trouble of checking part numbers.
So it looks like the floating disc (T2021404) will be straight swop with my non-floater and the pulsar ring should be compatible. Excellent.

The reason I'm thinking of doing this is because I have a Brembo 4-pot caliper that will fit my Street Twin (using a Free Spirits adapter) and work with the standard non-floating disc. I am going to fit it anyway but I thought if I'm going to the trouble of upgrading the caliper I may as well see if I can find a floating disc.
I know EBC make one for the 1st gen ST, so that's an option, but I would prefer to use a Triumph part if possible.


Cheers Paul.

 

I agree, that looks neat. However as I already have the Brembo 4-pot I'm not going to lay out even more squids for a new caliper. Thanks anyway.

 

You're right about the master cylinder, the standard is 11mm. I'm assuming you've not changed yours, or you would have said. I have info that says the 11mm ms. will be fine with the upgraded caliper but if necessary a 12.5mm ms. from other Triumph models can be fitted.

 

Where did you get the 14mm master cylinder? Is it a Triumph part from another model?

 

I've just discovered (via YouTube 'Toni Reviews' 23/9/19) that Triumph made a floating disc upgrade kit for the Street Twin, part no. A9628040.
As far as I can tell it seems to be discontinued . Now why have they done that? It would have made my life so much easier

 

Thanks yet again Paul! I'll order it after I've got the caliper adapter, just in case there are any issues.

 

Yes I do. From day 1 I felt that the Street Twin brakes were underpowered. One twin-pot caliper trying to haul down 300kgs (bike + rider) from 100+mph doesn't sound good on paper and in my opinion doesn't work well enough on the road. My 3 Jap bikes all weigh significantly less and have more than twice the stopping power. Up to a point I've got used to it and ride accordingly, but there are occasions when rapid braking is required and the Street Twin could be better. I've tried the pad swop and maybe that made a slight improvement but a 4-pot caliper on a floating disc has got to make a bigger improvement.
Strange how Triumph came to the same conclusion in 2021 and made exactly that upgrade.

 

Interestingly I've just got off the phone to Youles in Manchester. I made the enquiry about the floating disc upgrade pretty much expecting the answer I got. The sales people don't know, the technicians don't know and Triumph head office won't say one way or the other.

 

You may well be right and I wouldn't bother with just swopping the original disc for a floating one unless I was changing the caliper as well.
Makes you wonder though, why Triumph marketed a floating disc only upgrade kit for the 1st gen Street Twin (up until 2019 at least) if it made no difference. They then pulled it from their accessory list and a few months later the 2nd gen ST was released.