Any question answered...

Am I right in thinking that if I wanted to make a shim for a front derailleur, 31.8 to 28.6, my shim material needs to be 1.6mm thick?

you are correct (31.8-28.6)/2

Yes, the radius of a circle is half its diameter

Cheers both, was pretty sure I was correct, but just wanted confirmation before I ordered something.

This bugs me. Any whole number can be written as the product of primes, but can any given whole number be written as the product of only one set of primes? If so, why? I can't intuit why that must be true.

https://en.wikipedia.org/wiki/Fundamental_theorem_of_arithmetic

Which London hospital has the ‘best’ orthopaedic department?

My 8yo daughter’s just broken both fibula and tibia in her left leg whilst trampolining, staying overnight in Homerton till being seen by specialist in the morning, but her mum’s paranoid as they made a meal of her broken arm last year (had to be re-set twice)...

I’m inclined to let Homerton get on with it but her mum’s insisting ‘there must be somewhere better’...

In reply to this... Can anyone recommend any available 11sp 46-30 or 48-32 94bcd chainrings?
-TA rings
-middleburn stuff (out of stock and expensive)
-FSA

Ooof, no idea I'm afraid but heal well and rest up to your daughter, that sounds painful!

There is a Royal National Orthopaedic Hospital (or some variation on the name) I seem to recall, but not sure you can just turn up with b0rked limbs.

North west, Edgeware / Watford sort of way

Edit: not LONDON London, but it is London.
Also HealTFU MiniEcto

I generally go for TA rings. I think @.gaz. is running a sub-compact 11s configuration on their Varonha if dig through the build thread.

cheers, will see what I can get in 94BCD. p17 of @.gaz. thread - Specialites TA Syrius chainring 10/11-speed 110 BCD.
I think I'd be fine with either BCD looking at the above rings and their sizes... have asked the bike shop who are selling it to me and middleburn themselves though.

think I'd be fine with either BCD

Going below 34T on 110pcd requires dubious hacks. Stick to 94pcd if you want to use standard 30T or 32T rings

Lowest you can go on 110bcd is 33t, I currently run Spa Cycles own chainrings, 46/33, they seem decent for the money. If you want to go lower, as previously suggested, stick with 94bcd and buy TA rings, bit more spendy, but from my experience a good investment.

Evelina London Child Hospital?

Thanks, she’s in the process of getting referred to UCL/Royal London/RNOH but it’s taking ages.

Second night in hospital, on loads of morphine high as shit...

Thinking of doing a CBT on my dads old 50cc Piaggio Liberty.
Im 31, I know Im not looking at grands but do you think I can insure it for less than £300?
I havent done the CBT. I dont hold a pink licence. I know theres plenty of factors that change insurance, Im looking for ballpark estimates.
Im not in London.

TLDR; how much dyu reckon a 31 year old on a 50cc ped will be to insure. First time "driver".

Cheers

You can just get a quote on compare the markets (lie and say you have your licence, make up a recent date) it isn't legally binding (just be honest when you do it properly)

Top Tip, head off to the cheapest quotes website, and generally get a cheaper quote than the comparison site

Should be able to insure it TPO for less than that. It's only when you add theft cover to peds that the insurance flies up, especially if it's not garaged overnight. In the first year, you're best off spending the other £150 on an enormous Almax or Pragmasis chain and padlock for at home, a D lock and a disc lock. That's your best theft cover, in my experience.

Edit: It's a ****ing pain in the arse when your bike gets nicked, there's a lot of waiting around while the insurance company waits a statutory amount of time to see if it gets recovered and they'll do what they can to catch you out on a technicality so they don't have to pay out (e.g. it wasn't at home, it wasn't locked up to certain thing or in a certain way, not covered if you're staying overnight somewhere else etc etc. It's not as clear cut as car insurance). All that time you'll have no transport.

Mobile pressure washers for MTBing... Kaercher or Aqua2go/Mobi whatever model vs Worx Hydroshot? What's the forum consensus?

Clearly the answer is get a roof rack, so the crud doesn't get in back of the the car and then clean at home at my leisure. But this will also help with my garage being miles from a tap (car is right next to it though, so I can run a 12V connection to the thing).

@DethBeard
@Jonny69

Cheers , deffo some good tips there.

I need to buy a number of different bearings for different bikes right now.

Is there a forum-approved bearing shop? And is it worth going stainless over standard? NTN vs Enduro?

What’s the best bang for buck?

Is there a forum-approved bearing shop? And is it worth going stainless over standard? NTN vs Enduro?

There are a couple, I tend to start at https://simplybearings.co.uk/shop/

Don't get stainless, they're weak. The design would have to have been based on stainless from the start, you can't just drop stainless into a design which was built around normal bearings and assume they'll hold up.

For regular sizes (i.e. not proprietary bike specials) any of the major brands will be fine

I'd like some carbon single speed SRAM levers for my 'mojo back' road fixed. Should I gut my perfectly functioning 10 speed Red levers or sell them and buy some new s900s? Wwjd?

10-speed is sought after at the moment and gets good money. Unless you can put the Red levers back together afterwards I wouldn’t gut them.

Sensible advice. I was hoping to make it a parts bin build but it looks like I might have to splash a bit of cash.