revtothelimit - motorbike forum

Mr. Dazzle wrote: Sat Aug 27, 2022 12:28 pm Silly as it might sound, just changing whereabouts on the lever you pull makes a difference too! And/or moving the mounting left/right and changing the adjustment so you've still got the same span but you're gripping the lever closer/further from the pivot.

S'just GCSE* physics of trigonometry, levers and hydraulics after all.

*O Level.

I'm moving the brake mount clamp around to try out different lengths between pivot point and where I grip the brake lever. Much easier than trying to mentally recalibrate something I've been doing automatically for over 50 years.

Potter wrote: Wed Aug 31, 2022 5:18 am I did a similar long post about ratios on one of the forums, it might have been TRC.
I was trying to work out what works best. I have a single disk with a TZR250 standard caliper on my LC.

I had something very similar on my old Hejira/LC special using a Billet 6 pot caliper using a 14mm Brembo m/cyl off an 851.

Potter wrote: Wed Aug 31, 2022 5:18 am If you feel like being nerdy the calculation is (((Pi x R^2) + (Pi x R^2))x n) / (Pi x R^2).
IIRC the formula came from Brembo, and there is a generally agreed ratio for single disk set-ups as being between 12:1 to 14:1. Can't remember what it was for twin disk.

Yes, seen that formula. It's not so difficult doing the maths, more knowing how to interpret the result. I'm in France at the moment, and the LC is in the UK, but when I get back the 5/8" (15.9 mm) m/cyl is going on in place of the 1/2" one. That should give me a clue which way to go. Hopefully it will be reet...

Yeah, it's all trial and error. 5/8" may be too much - it was OE on the 350LC and the lever feel was really wooden with OE calipers, which was why I swapped it for a 1/2" m/cyl. But I have the 5/8" sitting on the shelf so I'll try it. If that doesn't work then I'll be buying a 14mm TDR m/cyl. There's only so much you can decide with formulas - feel in use is the ultimate judge.

Unless I've read it wrong, you're using an 11mm m/cyl on a single caliper/disc -is that right?

If you need to try a 14mm, I've got a couple of Yamaha floating about which you can 'borrow' for testing purposes.

Can I just say, the mix of metric and imperial in this context actually gives me cancer.

Mr. Dazzle wrote: Fri Sep 02, 2022 9:45 pm Can I just say, the mix of metric and imperial in this context actually gives me cancer.

That's deeply insulting to people suffering from cancer.



You should have said it gives you AIDS!

KungFooBob wrote: Fri Sep 02, 2022 9:48 pm

Mr. Dazzle wrote: Fri Sep 02, 2022 9:45 pm Can I just say, the mix of metric and imperial in this context actually gives me cancer.

That's deeply insulting to people suffering from cancer.



You should have said it gives you AIDS!

Nah, should have gone for hiccups. (Hiccups? Hiccoughs?). The hiccup activist groups are pretty weedy.

Mr. Dazzle wrote: Fri Sep 02, 2022 9:45 pm Can I just say, the mix of metric and imperial in this context actually gives me cancer.

You must shit yersen when you buy a tyre then!
The thing is, as you probably well know, is that some manufacturers use imperial and metric, or just like to be awkward (nissin I'm looking at you)

I just find it an unrelenting mental exercise

Is 5/8" bigger than 15mm? Who the fuck knows, I can work it out for sure but that's just the thing. I have to work it out.

Mr. Dazzle wrote: Sat Sep 03, 2022 7:41 pm I just find it an unrelenting mental exercise

Is 5/8" bigger than 15mm? Who the fuck knows, I can work it out for sure but that's just the thing. I have to work it out.

You think its bad now, just wait til our minister for making the elderly feel unthreatened (otherwise known as Jacob Rees-Mogg) takes us back towards imperial measurements as he thinks is a good idea.
https://www.civilserviceworld.com/profe ... tyle-guide

demographic wrote: Sat Sep 03, 2022 8:38 pm

Mr. Dazzle wrote: Sat Sep 03, 2022 7:41 pm I just find it an unrelenting mental exercise

Is 5/8" bigger than 15mm? Who the fuck knows, I can work it out for sure but that's just the thing. I have to work it out.

You think its bad now, just wait til our minister for making the elderly feel unthreatened (otherwise known as Jacob Rees-Mogg) takes us back towards imperial measurements as he thinks is a good idea.
https://www.civilserviceworld.com/profe ... tyle-guide

A small quote without any content. Poor journalism.

Rees-Mogg meanwhile advises staff to always use imperial measurements, most of which have been phased out in the UK from the mid-1960s onwards.

Yorick wrote: Sat Sep 03, 2022 8:41 pm

demographic wrote: Sat Sep 03, 2022 8:38 pm

Mr. Dazzle wrote: Sat Sep 03, 2022 7:41 pm I just find it an unrelenting mental exercise

Is 5/8" bigger than 15mm? Who the fuck knows, I can work it out for sure but that's just the thing. I have to work it out.

You think its bad now, just wait til our minister for making the elderly feel unthreatened (otherwise known as Jacob Rees-Mogg) takes us back towards imperial measurements as he thinks is a good idea.
https://www.civilserviceworld.com/profe ... tyle-guide

A small quote without any content. Poor journalism.

Rees-Mogg meanwhile advises staff to always use imperial measurements, most of which have been phased out in the UK from the mid-1960s onwards.

Ta for adding some context But its not even close to being his only nention of metric being a problem. He's got a real hard on over it. Like he has to measure things daily.

I much prefer the metric system of measurement, but can manage in imperial. I use inches, feet, yards and miles in conversation as much as I use mm, cm, metre and km (never really 'got' dm, though.) But when it comes to measuring stuff it's metric all the way.

And in answer to Mr. D's original question - yes 5/8" is bigger than 15mm. It's very nearly 16mm (15.9mm to be precise).

But JRM needs his arse reaming with a metric tap. M50 should be about right.

I happily mix and match Imperial, US and Metric measurements, but I can't get my head round a Whitworth King Dick

Le_Fromage_Grande wrote: Fri Sep 09, 2022 2:18 pm I happily mix and match Imperial, US and Metric measurements, but I can't get my head round a Whitworth King Dick

Yes, Whitworth is a closed book to me. I can remember my confusion as a yoof trying to make sense of a spanner size that bore absolutely no relation to the bolt head it was to be used on. King Dick, however, do make exceedingly good sockets and spanners.

Just to add to the confusion, BMC used bolts with metric threads and Whitworth heads, because they bought an engine plant from the French and Britain had Whitworth spanners.

mangocrazy wrote: Fri Sep 09, 2022 2:06 pm And in answer to Mr. D's original question - yes 5/8" is bigger than 15mm. It's very nearly 16mm (15.9mm to be precise).

Erm......15.875, to be precise

Demannu wrote: Fri Sep 09, 2022 3:50 pm

mangocrazy wrote: Fri Sep 09, 2022 2:06 pm And in answer to Mr. D's original question - yes 5/8" is bigger than 15mm. It's very nearly 16mm (15.9mm to be precise).

Erm......15.875, to be precise

The difference between 1 and 3 decimal points of precision...

Le_Fromage_Grande wrote: Fri Sep 09, 2022 3:19 pm Just to add to the confusion, BMC used bolts with metric threads and Whitworth heads, because they bought an engine plant from the French and Britain had Whitworth spanners.

That vaguely rings a bell. Dad bought a s/h Austin Cambridge in the 1960s (or early 1970s, can't remember) and that was 'challenging' to work on. It was also a rot-box.

My phone calculator is mocking me, I just asked it to work out 5/8 x 25.4. The answer......15 7/8.



BTW as far as I know the official definition of an inch is actually 25.4mm! The entire imperial system now relies on the "calibration" of the metric system.