GT85 Bike Disc Brake Cleaner

your in a rush and you pick up the black can with the red top and spray your disc brakes.......... and then a few seconds later you start thinking what a complete and utter bunch of lemons must work at the WD-40 Company because they stuck all of their bike maintenance range in black cans with red tops........ just like GT85...... except GT85 doesn't clean brakes and you just sprayed teflon on yours.

I don't doubt the benefit of sanding discs and pads, but how does the performance of GT85 compare with non-spray IPA on a paper towel (my preferred method), or sanding alone?

Maplins stock aerosol IPA, and it's cheaper than the GT85 can.

Wow - didn't see that coming. Thought I was reviewing bike-friendly disc brake cleaner, not a second referendum proposal.

A few facts:

The only way to get baked-on brake pad residue off of steel rotors is fine-grit sandpaper, or some sort of acid etching. It's damn hardy stuff.

What brake pad material reacts against is NOT bare steel, rather the brake pad material that has bonded to the rotor. a new, pristine rotor is next to useless until bedded/burnt in. 

This process of cleaning up everything then braking hard down a hill multiple times is non-negotiable if you want the best performance. Read up on two decades of bike-disc wisdom.

If you have spilt anything on your rotors or pads apart from pure water, and it's then been baked in at hundreds of degrees you need to get it off, or performance will suffer. This is simple physics.

I accept that some will be happy with this, and will therefore think the level of braking they have enjoyed over the last 10,000km+ is both optimal and acceptable.

The idea you would go to the trouble of skimming a £15 rotor is ludicrous. Spending 10 minutes removing, sanding and re-torquing a rotor is not. Have a cuppa and pop on a decent bikey podcast like Velocast or Cycle Systems Academy. You're welcome.

Yes the car stuff is cheaper. It's also full of more aggressive chemicals that a car/motorbike's undercarriage is immune to, but a paint or decal finish on a bike frame possibly won't be. Your bike, your choice.

It is very hard (I'd say impossible in the UK) to buy Isopropyl Alcohol in a chemist. Let alone in aerosol can form. I had to go to eBay to buy just 100ml of the liquid stuff, as chemists simply don't sell it anymore.

Happy braking folks!

Mike

to clean sintered or semi-sintered disk pads; remove, spray with window cleaner, wait, wipe off glaze, rinse with water.
to clean discs; remove, spray with dettol mould+mildew remover or mr muscle oven cleaner, wait, wipe off glaze, rinse with water.

of course you need to do the bedding-in thing afterwards, which is the biggest faff.

Car and motorbike discs get hot enough in use to get the diesel and other road crap off them whilst road discs rarely do. I know when mine get a bit yowly, a good clean quietens 'em back down.

Baffled that in 40 years of motorcycles I have never once felt the need to 'clean' a disc. Skim it when it's scored maybe, but this is snake-oil, almost literally.

I just use mine... not had any glazing or other issues in 20000km across 3 bikes (with mechanical and hydraulic discs)... the most they ever get is a wipe with a damp cloth when I have the wheel off for any reason.

You don't need to remove it. I spray bog standard brake cleaner onto a clean cloth and clean the discs in situ. No need to get any of it near the frame.

If you're removing the disc to clean it, why does it matter whether the ingredients are kind to the frame?

I use the car stuff from Screwfix, less than 2 quid a can...

Apparently the master swordsmiths of old (presumably the evil ones) would temper the steel by running the red hot blade through a prisoner and quenching it in their blood.

I thought that disc brakes worked the same way. They don't really seem to operate at their best until they have severed an artery or two.

Disclaimer: This is no worse than some of the other crap posted about disc brakes.

Does anyone actually do this?