Having bought some used IS Hopes to mount to some old IS Sids for my winter ss project, I thought I’d best get fork mount faced properly to ensure proper alignment.

Called first LBS – initially sales folks who put me through to workshop

“Workshop”
“Morning…looking to get disc mount on forks faced. Can you do that?”
“Mmmm…not sure…not done it before…let me have a look…..”
“Thanks”
“Mmmmm….found a Hope tool with the bits and instructions….but I don’t think we have the cutter bit….let me have another look….”
“Thanks”
“Mmmm…sorry….cannot find the cutter so would not like to tell you we could do it if we cannot find the cutter…..bye”

Second LBS:
Again, intially sales then passed to workshop.
“Good morning, how can I help you?”
“Looking to get disc mount faced. Can you assist/”
“Should be able to. What type of disc mount do you need faced? IS or Post?”
“IS”
“No problem. Is your caliper IS or Post?”
“IS to IS”
“No problem. Reason I asked is that it will be £10 to face and if you had a Post caliper with appropriate mount to the fork, then no real need to face – just trying to avoid you spending money”
“Perfect – thanks – be in past tomorrow”
“No problem. See you then”

Not a rant, just found it strange that the first place I called appeared to have mechanic with no real knowledge plus if I were the shop manager or head mech I’d be mighty p’d off that a pretty valuable tool was effectively not usable and hence a potential revenue generator. Plus I’d like to know that the folks I was employing had a bit of knowledge/training to avoid costly f-ups.

Yes, I know the guy at the first shop was honest and perhaps could do the job better than the more polished person at the second shop, however…..

Who is the second shop?

f you had a Post caliper with appropriate mount to the fork, then no real need to face – just trying to avoid you spending money

Shame that’s incorrect.

Do people get their disc mounts faced on their forks? Never even considered it. Would seem to me that its a service rarely requested at the first bike shop

Do people get their disc mounts faced on their forks?

Modern fork lowers are usually perfectly faced, although they sometimes need paint over-spray to be removed (even with PM). The only fork I’ve ever had that actually needed to be faced was the rigid fork on my partner’s P7.

@al – why’s that?

I thought that newer Hopes that are PM, with an IS adaptor would not really need facing as any misalignment issues can be easily overcome in the adjustment in the PM caliper bolts. Or am I wrong? (Genuinely interested – not trying to pick holes)

In terms of engineering principles, both IS and post mount could be out and need facing although with modern manufacturing techniques, it should only be paint over spray. However, I’m not aware of a bike tool to do post mounts. I actually own my own IS tool (the Hope one) and after use, it’s amazing how much deeper one cut is than the other. If you’re doing that though, it’s also worth measuring your shims properly. I’ve seen faced forks with .25 mm difference in shim stacks. What’s the point in facing then?

What facing does is make sure that the face of each brake spot is absolutely perpendicular to the axle and absolutely parallel to the rotor. Facing the tabs doesn’t mean that you have to leave both spots exactly the same distance from the rotor. Although it makes sense to do so, there’s still no harm in using a shim to make up the difference on one spot, as long as the face of the shim is still perpendicular/parallel.

Folks, some interesting replies for sure – what a diverse bunch.

Of course, who is to say that the Hope caliper is perfectly true/flat either.

I can now see (to a point) benefits of facing, but also now aware that the variance in manufacturing might mean that shim(s) of differing thicknesses will still be required anyways.

Answer – stop being picky, try it with shims first then if outcome not satisfactory then try facing. To be fair, I omitted to say that the guy in the second shop said just this….

use avids, no real need to face with the adjustment they have

use avids, no real need to face with the adjustment they have

I’d rather pay to have my spots faced.

GavinB – Member

@al – why’s that?

Mounting a post brake to an IS fork – the IS mounts can be out.

Avis CPS, the only system guaranteed to never be parallel to the rotor*!

(*although normally close enough in real terms)

three fish, the tool takes off material from one of the mounts,then you set it up after finishing the first face so that it takes off enough material so that it will keep the calliper square to the rotor etc.
If the mounting points were perfect to begin with,the tool wont be removing the same amount of material top and bottom.i cant explain it very well.. not sure if you see what i mean!

yeah,cynic.. and that does my freekin head in. post to post with nowt inbetween. nightmare.

benz, like i posted above.. you shouldnt have to use shims if you use the tool correctly.

but..

if you faced everything up and could say it was perfect.. then fitted a calliper over the disc and applied the brake, then you might find a diffrence between one of the tabs and the other when measuring each distance between calliper and tab. I dont know and have never heard of tabs on callipers being out of shape or anything.. but some lightweight callipers with long arms on them could possibly be a bit iffy.I doubt it though.If this was the case then facing as well as possible would be pointless.An out of shape calliper would be a bit random though.
magura marta sl callipers are a bit skimpy on their arms come to think of it.

one other thing. If you find that you spend ages setting up a calliper and it keeps rubbing and looking out of shape.. then no matter what sequence of shims you put in there, it will never be right. the moment you face up a disc mount and try refitting the calliper you will often find that set up is a doddle.well worth facing. it saves so much time and it keeps pad wear spot on.better for the workshop (time wise) and even better for the customer (power from a brake that doesnt have pistons squirming in their bores once the brake is applied due to a badly faced mount is obviously going to be more powerful and less likely to have problems later in life)

I’ve never (read EVER) had my mounts faced. Will I die?