Shimano caliper bolts for 20mm frame

*sighs* The bike build is going slowly, I’ve already had Phoenix Cycleworks fix two of my four issues. I’m sure it’s been mentioned on here before, but I can’t find it, but the NS RAG+ has 20mm direct mount spacing for the rear brake caliper. The GRX BL-RX810-L lever and caliper come with Brake caliper mounting bolt C length of 38 mm, so I need the 33 mm length bolts. Found some online for £6.99 each, or via Taiwan so no good for a test ride tomorrow.

Can I just shovel any old M4 (I think they’re M4) bolt of the correct length in there, or does it need to be made of a particular metal…?

Oh FFS! Just bodged it temporarily with a couple of nuts to take up the slack, but it turns out that the 160mm rotors don’t fit, so I need yet another adapter. 🤬 Anyone know where I can get a Shimano Rear Mount Adaptor Flat to Flat Road SM-MA-R160 D/D from?

https://www.sjscycles.co.uk/brakes/shimano-adapter-for-flat-mount-caliper-to-road-flat-frame-mount-rear-160mm/

This comes with the M5 security bolts to attach the caliper to the adaptor. Just use the bolts you have to attach the adaptor to the flat mount on the chainstay (cutting them down if need be).

I had a similar issue building up my Forme Calver. Madison were out of stock for months but found some on Bike de I think.

Plenty UK stock right now. Madison also do a cheaper option from Aztec.

https://www.hargrovescycles.co.uk/5591/products/adapter-aztec-flat-flat-160-rear-black-160-mm.aspx

Phoned a few of the LBS’s until I found one that had an adapter in stock (the Aztec one). Will pop in tomorrow and pick it up, along with a load of outer gear cable housing.

So LBS had the flat-flat front adapter, not the flat-flat rear adapter… 🤬

I’d quite like to do a shake down ride before the weekend, so does anyone know of any online shops with the adapter, who do next day delivery? Everyone seems to be able to get me one by the weekend, which is carp.

dealer can order the Shimano one postage free on its own from Madison and it should arrive tomorrow.